This document provides an overview of environmental engineering and environmental impact assessment. It begins with definitions of environment, environmental science, and environmental engineering. It then discusses the benefits of environmental impact assessment, including improved decision making and project design. It outlines some common problems with environmental impact assessment, such as difficulties ensuring public involvement and integrating impact assessments into decision making. Finally, it provides definitions and objectives of environmental impact assessment.
This document outlines the environmental impact assessment (EIA) process. It defines EIA and environmental impact statement (EIS). It describes the purpose of EIA as ensuring comprehensive environmental assessments of projects likely to significantly impact the environment. It discusses the stages of EIA including screening projects, assessing existing environment, identifying impacts, and mitigating measures. It provides examples of projects requiring mandatory or discretionary EIA. Finally, it summarizes the roles and procedures of environmental health officers when reviewing submitted EIAs.
The document is an Initial Environmental Examination report for a power distribution enhancement project in Pakistan involving upgrades to 8 existing substations. It summarizes the project description and existing environmental conditions. Potential impacts from construction such as noise, dust and waste are identified. Mitigation measures are recommended, including restricting work hours, dust suppression, waste management and compliance with noise standards. Public consultation was conducted and stakeholder views were incorporated into project planning. The report concludes the project is feasible from engineering and environmental perspectives.
The document discusses an Initial Environmental Examination (IEE) for a proposed shopping plaza project in Islamabad, Pakistan. The project will include a 35-story building covering 2 hectares with estimated costs of $350 million USD. The IEE process identifies potential environmental issues to determine appropriate mitigation measures and requirements for additional studies. Key issues addressed include noise, waste, drainage, and traffic impacts. Public consultation is also recommended to address concerns from stakeholders. Baseline monitoring is suggested to set performance standards for contractors during construction.
This document provides an overview of environmental impact assessments for railway projects in India. It discusses how EIAs evaluate the environmental, social, and economic impacts of proposed projects. For railway projects specifically, it identifies potential impacts such as noise and vibration pollution, air pollution from train emissions, soil pollution from heavy metals, and water pollution. It also discusses how railway construction can cause soil erosion and changes to hydrology. The document outlines the key components of an EIA report and the methodology for conducting EIAs in India. It emphasizes the importance of EIAs for ensuring environmentally sound development.
Impact prediction, evaluation and mitigation in eiaMizanur R. Shohel
The document defines environmental impact assessment (EIA) and outlines its key aspects:
1. EIA is defined as a formal process for identifying the likely effects of projects on the environment, human health, and welfare, as well as means to mitigate and monitor impacts.
2. The objectives of impact prediction in EIA are to identify the magnitude, probability, spatial and temporal scale of impacts from a project in comparison to the situation without the project.
3. Impact evaluation aims to assign significance to predicted impacts through scientific and professional judgment, measures of ecological disturbance, and consideration of standards and mitigation options. Analytical methods like cost-benefit analysis and multi-criteria scoring are used.
This document outlines the key steps in the environmental impact assessment (EIA) process, including screening, initial environmental examination (IEE), scoping, full assessment, review and decision making, and monitoring. It provides details on the screening and IEE steps. Screening determines if a proposed project requires an EIA and at what level of review. An IEE is a preliminary environmental analysis used to identify potential issues and determine if a full EIA is needed. The document describes the objectives, possible outcomes, and components of conducting an IEE.
Environmental Impact Assessment and Environmental Audit- Unit IIIGAURAV. H .TANDON
This document provides an overview of environmental impact assessments and environmental audits. It defines environmental impact assessment as the systematic identification and evaluation of potential impacts of proposed projects on the natural environment. The key steps of an EIA include organizing an interdisciplinary team, performing an assessment of the site and potential impacts, writing an environmental impact statement, and reviewing the EIS. Environmental audits evaluate an organization's environmental performance and position and identify ways to improve environmental management systems. The document outlines the basic components and steps in conducting environmental audits.
Environment Impact Assessment (EIA), Environment Management Plan (EMP), Social Impact Assessment (SIA), Consent to Establish (CTE), Consent to operate (CTO), No Objection Certificate (NOC), Green Building, IGBC- LEED, TERI-GRIHA, Environment Audit, Environment Monitoring, Compliance Reporting, Hydro-geology test, Sustainability Reporting, Central Ground Water Authority (CGWA) Permission, Import and Export of Hazardous Waste Permission from Ministry of Environment Forest and Climate Change (MOEFCC), Height Clearances from Airport Authority of India (AAI), Forest Clearance, Forest NOC, Forest Diversion, Aravali NOC
This document outlines the environmental impact assessment (EIA) process. It defines EIA and environmental impact statement (EIS). It describes the purpose of EIA as ensuring comprehensive environmental assessments of projects likely to significantly impact the environment. It discusses the stages of EIA including screening projects, assessing existing environment, identifying impacts, and mitigating measures. It provides examples of projects requiring mandatory or discretionary EIA. Finally, it summarizes the roles and procedures of environmental health officers when reviewing submitted EIAs.
The document is an Initial Environmental Examination report for a power distribution enhancement project in Pakistan involving upgrades to 8 existing substations. It summarizes the project description and existing environmental conditions. Potential impacts from construction such as noise, dust and waste are identified. Mitigation measures are recommended, including restricting work hours, dust suppression, waste management and compliance with noise standards. Public consultation was conducted and stakeholder views were incorporated into project planning. The report concludes the project is feasible from engineering and environmental perspectives.
The document discusses an Initial Environmental Examination (IEE) for a proposed shopping plaza project in Islamabad, Pakistan. The project will include a 35-story building covering 2 hectares with estimated costs of $350 million USD. The IEE process identifies potential environmental issues to determine appropriate mitigation measures and requirements for additional studies. Key issues addressed include noise, waste, drainage, and traffic impacts. Public consultation is also recommended to address concerns from stakeholders. Baseline monitoring is suggested to set performance standards for contractors during construction.
This document provides an overview of environmental impact assessments for railway projects in India. It discusses how EIAs evaluate the environmental, social, and economic impacts of proposed projects. For railway projects specifically, it identifies potential impacts such as noise and vibration pollution, air pollution from train emissions, soil pollution from heavy metals, and water pollution. It also discusses how railway construction can cause soil erosion and changes to hydrology. The document outlines the key components of an EIA report and the methodology for conducting EIAs in India. It emphasizes the importance of EIAs for ensuring environmentally sound development.
Impact prediction, evaluation and mitigation in eiaMizanur R. Shohel
The document defines environmental impact assessment (EIA) and outlines its key aspects:
1. EIA is defined as a formal process for identifying the likely effects of projects on the environment, human health, and welfare, as well as means to mitigate and monitor impacts.
2. The objectives of impact prediction in EIA are to identify the magnitude, probability, spatial and temporal scale of impacts from a project in comparison to the situation without the project.
3. Impact evaluation aims to assign significance to predicted impacts through scientific and professional judgment, measures of ecological disturbance, and consideration of standards and mitigation options. Analytical methods like cost-benefit analysis and multi-criteria scoring are used.
This document outlines the key steps in the environmental impact assessment (EIA) process, including screening, initial environmental examination (IEE), scoping, full assessment, review and decision making, and monitoring. It provides details on the screening and IEE steps. Screening determines if a proposed project requires an EIA and at what level of review. An IEE is a preliminary environmental analysis used to identify potential issues and determine if a full EIA is needed. The document describes the objectives, possible outcomes, and components of conducting an IEE.
Environmental Impact Assessment and Environmental Audit- Unit IIIGAURAV. H .TANDON
This document provides an overview of environmental impact assessments and environmental audits. It defines environmental impact assessment as the systematic identification and evaluation of potential impacts of proposed projects on the natural environment. The key steps of an EIA include organizing an interdisciplinary team, performing an assessment of the site and potential impacts, writing an environmental impact statement, and reviewing the EIS. Environmental audits evaluate an organization's environmental performance and position and identify ways to improve environmental management systems. The document outlines the basic components and steps in conducting environmental audits.
Environment Impact Assessment (EIA), Environment Management Plan (EMP), Social Impact Assessment (SIA), Consent to Establish (CTE), Consent to operate (CTO), No Objection Certificate (NOC), Green Building, IGBC- LEED, TERI-GRIHA, Environment Audit, Environment Monitoring, Compliance Reporting, Hydro-geology test, Sustainability Reporting, Central Ground Water Authority (CGWA) Permission, Import and Export of Hazardous Waste Permission from Ministry of Environment Forest and Climate Change (MOEFCC), Height Clearances from Airport Authority of India (AAI), Forest Clearance, Forest NOC, Forest Diversion, Aravali NOC
"IMPACT OF COAL BED METHANE MINING IN KORBA AND RAIGARH DISTRICT OF CHHATTISG...Neeraj Parashar
Neeraj Parashar, has presented a case study on Coal Bed Methane Mining in Korba and Raigarh District of Chhattisgarh State, India to draw attention how EIA (Environmental Impact Assessment) Reports are rigged to seek approval for greenfield projects in Ministry of Environment and Forest.
JBA Consulting Guide to Environmental Assessment for Renewable ProjectsJBAConsulting
This document provides guidance on environmental assessment and regulation for renewable energy projects. It discusses the following key points:
- Environmental assessment is a process to understand potential environmental impacts of development proposals and identify mitigation measures. It may involve an Environmental Impact Assessment (EIA) required by law for certain projects.
- Legislation exists to protect the environment and promote sustainable development, and various assessments like EIAs may be required at different stages of a project's development.
- Guidance is provided on environmental assessments for different renewable energy technologies like wind, solar, and hydropower projects as well as landscape and visual impact assessments. Compliance with regulations aims to help projects meet requirements and minimize environmental risks.
The document outlines the principles of environmental impact assessment (EIA) best practices according to the International Association for Impact Assessment (IAIA). It is divided into two parts. Part 1 describes the purpose and aims of developing EIA principles, which is to provide guidance to IAIA members and others applying EIA processes. It utilized results from previous EIA studies and expertise from IAIA members. Part 2 presents the definition of EIA, its objectives, and basic and operating principles for EIA. The basic principles include transparency, certainty, participation, practicality, flexibility, cost-effectiveness, credibility and accountability. The operating principles provide guidance on applying EIA at various stages such as screening, scoping and reporting.
EVALUATION OF ENVIRONMENTAL IMPACT ASSESSMENT ON INDUSTRIAL PROJECTS: A MODEL...IAEME Publication
Objective: The objective of this study is baseline status of air, water, noise, land, biological and socio-economic environments. Environmental Impact Assessment study is key for any Project with out this study its not possible to get the approval keeping this in view this study has exist.
Methods: Methodology has been followed for Environmental Impact Assessment study has been conducted within an area of around 10 km radius around the project site as per ISO Standard Air Quality, Water Quality, Soil Quality, and Noise Quality.
Findings: Socio economic and Biological conditions under this flora and fauna available in the study area and solid waste management, Occupational safety and health management strategies has been recommended.
Applications: This type of studies very much useful for preparation of EIA Reports.
This document provides an overview of Unit 3 of a syllabus which includes embodied energy, life cycle assessment, environmental impact assessment, energy audit, and energy management. It defines key concepts such as embodied energy, life cycle assessment, environmental impact assessment, and outlines the process of conducting an EIA. It also discusses the importance of EIA as a strategic tool for sustainable development and defines energy management as tracking and monitoring energy use to reduce consumption and costs in buildings.
This document contains a presentation on the Environmental and Social Impact Assessment of the Nirvana Hills Slum Rehabilitation Project in Pune, India. The presentation covers the project background, applicable regulatory framework, and impact assessments of land use, air quality, soil and water, and socioeconomic factors. The project involves rehabilitating 4,324 slum households through new housing construction and development of commercial and community spaces. Impact assessments were conducted for planning, construction, and operational phases, and monitoring data on air quality, meteorology and land use are presented.
The document discusses various methods used for predicting and evaluating environmental impacts in environmental impact assessments (EIAs). It describes two main categories of impact prediction methods: extrapolative methods based on past data and trends, and normative methods based on desired targets or standards. Specific methods mentioned include mathematical models, statistical models, GIS, experiments, and expert judgment. Key considerations for impact prediction are also outlined. Impact evaluation methods discussed are significance determination based on factors like public concern, effects on ecosystems, and standards, as well as analytical methods like cost-benefit analysis and multi-criteria scoring. The document concludes by linking impact prediction, evaluation, and the role of mitigation measures in EIAs.
The document summarizes an environmental impact assessment report prepared for the Gujarat Maritime Board that proposes installing a hazardous waste incinerator and expanding existing landfill cells at the Alang shipyard in Gujarat, India. The report assesses the existing environmental conditions, potential social and economic impacts, and provides an environmental management plan. It describes the proposed incinerator and landfill facilities, evaluates environmental and health risks, and outlines measures to control pollution and manage disasters.
This report summarizes the environmental impact assessment of Tanjin Printing and Packing Ltd in Bangladesh. The company manufactures printing and packaging products from raw materials like paper, plastics, and chemicals. While the company provides jobs and recycles waste, it also impacts the environment through air and water pollution. The report identifies pollution sources and provides recommendations to strengthen management and monitoring to reduce negative impacts on the environment.
The document discusses conducting an Environmental Impact Assessment (EIA) for a proposed express highway project between Kasargod and Trivandrum in Kerala, India. It addresses:
A) Identifying potential impacts during construction and operation, including impacts to air quality, noise levels, water quality, and land.
B) Predicting the impacts, such as increased dust and emissions during construction, and increased vehicular emissions during operation.
C) Evaluating impacts using the BEES (Building for Environmental and Economic Sustainability) method.
D) Developing an Environmental Management Program to mitigate impacts and enhance environmental performance.
Enviromental impact assesment for highway projectsKushal Patel
Environmental Impact Assessment (EIA) is a tool to study various impact to be occurred due to new development actions.
Transportation Project are the projects which provides ease to the movement of vehicles.
This Paper presents a case study for analysis of EIA for a transportation project. This Paper would provide a methodology which will allow transportation planers to make a cost effective coordination of environmental information and data management.
The results assess the environmental vulnerability around the road and its impact on environment by integration the merits of GIS.
Environment Impact Assessment Using Remote Sensingshubham shama
This document provides an overview of using remote sensing and GIS for environmental impact assessments. It discusses how satellite imagery allows for large area coverage in short time periods and how GIS enables spatial analysis and modeling. Examples are given of assessing impacts of projects like dams by computing command areas and changes over time. Both active sensors like radar and lidar, and passive sensors like radiometers are outlined. The advantages of remote sensing for environmental monitoring and assessing rapidly changing phenomena are highlighted.
This document provides a summary of the quarter 1 impact mitigation monitoring report for Nestle Waters Greenfield Factory project in Abaji, FCT Abuja, Nigeria. Key points include:
- Air, water, soil and vegetation were sampled from 9 stations to monitor impacts from construction activities and compliance with standards.
- Air quality, noise levels, water quality and soil quality were found to be within standards except for slightly elevated levels of some parameters near construction areas.
- Vegetation and wildlife have been impacted by land clearing for construction but mitigation measures like replanting and fencing are being implemented.
- Socioeconomic impacts are being mitigated through compensation, local employment, and consultations
The document discusses environmental impact assessment and monitoring services provided by CPTL Envirotech Designers & Pollution Control. It summarizes the organizational profile, services including air, water, noise monitoring and environmental impact assessment. It then discusses a project undertaken for Vardhaman Adarsh Ispat Pvt Ltd, including components of Form 1 and prefeasibility report required as per GOI notification to apply for environmental clearance for the proposed expansion project.
EIA is a systematic approach aimed at predicting, analyzing and proposing appropriate mitigation measures for the development of a project. This slide discusses the implementation of the EIA, issues and challenges in implementing the EIA effectively in Malaysia and around the world.
This document outlines the process and requirements for conducting an environmental assessment. It discusses how environmental assessments evaluate the impacts of proposed actions and alternatives on the environment, economy, and society. The process involves scoping the assessment, taking inventories, assessing impacts, evaluating findings, and producing documentation like environmental impact statements. The goal is to identify impacts, consider alternatives, and make informed decisions that justify projects while protecting environmental quality.
This document provides a summary of a post impact assessment report for Nestle's tri-generation power plant. The report includes chapters on plant description, environmental impacts, mitigation measures, and environmental management plan. Key findings are that the power plant is expected to reduce greenhouse gas emissions and improve electricity supply stability. Impacts on air and water quality are assessed, along with waste generation and management. The study was conducted over two months to evaluate the plant's environmental performance and compliance with regulations.
Regulatory Approach in Soil Erosion and Sedimentation Control for EIA ProjectDrAbdulRahmanMahmud
This document discusses regulatory approaches for soil erosion and sedimentation control in environmental impact assessments (EIAs) for projects in Malaysia. It outlines the core elements of EIAs, including existing environment studies, impact assessment, mitigation measures, and monitoring. It also discusses indicators of EIA effectiveness, such as the quality of EIA reports, implementation of effective mitigation measures, and capacity building. Finally, it proposes a successful regulatory approach involving strategic planning, improving EIA report guidelines, strengthening EIA approval conditions, promoting self-regulation and training to enhance soil erosion and sedimentation control in the EIA process.
The document discusses environmental impact assessment (EIA), which is defined as systematically identifying and evaluating potential environmental impacts of proposed projects. An ideal EIA system applies to all projects with significant environmental effects, compares alternatives, and includes public participation and enforcement. The goals of EIA are to conserve resources, minimize waste, recover byproducts, efficiently use equipment, and enable sustainable development.
"IMPACT OF COAL BED METHANE MINING IN KORBA AND RAIGARH DISTRICT OF CHHATTISG...Neeraj Parashar
Neeraj Parashar, has presented a case study on Coal Bed Methane Mining in Korba and Raigarh District of Chhattisgarh State, India to draw attention how EIA (Environmental Impact Assessment) Reports are rigged to seek approval for greenfield projects in Ministry of Environment and Forest.
JBA Consulting Guide to Environmental Assessment for Renewable ProjectsJBAConsulting
This document provides guidance on environmental assessment and regulation for renewable energy projects. It discusses the following key points:
- Environmental assessment is a process to understand potential environmental impacts of development proposals and identify mitigation measures. It may involve an Environmental Impact Assessment (EIA) required by law for certain projects.
- Legislation exists to protect the environment and promote sustainable development, and various assessments like EIAs may be required at different stages of a project's development.
- Guidance is provided on environmental assessments for different renewable energy technologies like wind, solar, and hydropower projects as well as landscape and visual impact assessments. Compliance with regulations aims to help projects meet requirements and minimize environmental risks.
The document outlines the principles of environmental impact assessment (EIA) best practices according to the International Association for Impact Assessment (IAIA). It is divided into two parts. Part 1 describes the purpose and aims of developing EIA principles, which is to provide guidance to IAIA members and others applying EIA processes. It utilized results from previous EIA studies and expertise from IAIA members. Part 2 presents the definition of EIA, its objectives, and basic and operating principles for EIA. The basic principles include transparency, certainty, participation, practicality, flexibility, cost-effectiveness, credibility and accountability. The operating principles provide guidance on applying EIA at various stages such as screening, scoping and reporting.
EVALUATION OF ENVIRONMENTAL IMPACT ASSESSMENT ON INDUSTRIAL PROJECTS: A MODEL...IAEME Publication
Objective: The objective of this study is baseline status of air, water, noise, land, biological and socio-economic environments. Environmental Impact Assessment study is key for any Project with out this study its not possible to get the approval keeping this in view this study has exist.
Methods: Methodology has been followed for Environmental Impact Assessment study has been conducted within an area of around 10 km radius around the project site as per ISO Standard Air Quality, Water Quality, Soil Quality, and Noise Quality.
Findings: Socio economic and Biological conditions under this flora and fauna available in the study area and solid waste management, Occupational safety and health management strategies has been recommended.
Applications: This type of studies very much useful for preparation of EIA Reports.
This document provides an overview of Unit 3 of a syllabus which includes embodied energy, life cycle assessment, environmental impact assessment, energy audit, and energy management. It defines key concepts such as embodied energy, life cycle assessment, environmental impact assessment, and outlines the process of conducting an EIA. It also discusses the importance of EIA as a strategic tool for sustainable development and defines energy management as tracking and monitoring energy use to reduce consumption and costs in buildings.
This document contains a presentation on the Environmental and Social Impact Assessment of the Nirvana Hills Slum Rehabilitation Project in Pune, India. The presentation covers the project background, applicable regulatory framework, and impact assessments of land use, air quality, soil and water, and socioeconomic factors. The project involves rehabilitating 4,324 slum households through new housing construction and development of commercial and community spaces. Impact assessments were conducted for planning, construction, and operational phases, and monitoring data on air quality, meteorology and land use are presented.
The document discusses various methods used for predicting and evaluating environmental impacts in environmental impact assessments (EIAs). It describes two main categories of impact prediction methods: extrapolative methods based on past data and trends, and normative methods based on desired targets or standards. Specific methods mentioned include mathematical models, statistical models, GIS, experiments, and expert judgment. Key considerations for impact prediction are also outlined. Impact evaluation methods discussed are significance determination based on factors like public concern, effects on ecosystems, and standards, as well as analytical methods like cost-benefit analysis and multi-criteria scoring. The document concludes by linking impact prediction, evaluation, and the role of mitigation measures in EIAs.
The document summarizes an environmental impact assessment report prepared for the Gujarat Maritime Board that proposes installing a hazardous waste incinerator and expanding existing landfill cells at the Alang shipyard in Gujarat, India. The report assesses the existing environmental conditions, potential social and economic impacts, and provides an environmental management plan. It describes the proposed incinerator and landfill facilities, evaluates environmental and health risks, and outlines measures to control pollution and manage disasters.
This report summarizes the environmental impact assessment of Tanjin Printing and Packing Ltd in Bangladesh. The company manufactures printing and packaging products from raw materials like paper, plastics, and chemicals. While the company provides jobs and recycles waste, it also impacts the environment through air and water pollution. The report identifies pollution sources and provides recommendations to strengthen management and monitoring to reduce negative impacts on the environment.
The document discusses conducting an Environmental Impact Assessment (EIA) for a proposed express highway project between Kasargod and Trivandrum in Kerala, India. It addresses:
A) Identifying potential impacts during construction and operation, including impacts to air quality, noise levels, water quality, and land.
B) Predicting the impacts, such as increased dust and emissions during construction, and increased vehicular emissions during operation.
C) Evaluating impacts using the BEES (Building for Environmental and Economic Sustainability) method.
D) Developing an Environmental Management Program to mitigate impacts and enhance environmental performance.
Enviromental impact assesment for highway projectsKushal Patel
Environmental Impact Assessment (EIA) is a tool to study various impact to be occurred due to new development actions.
Transportation Project are the projects which provides ease to the movement of vehicles.
This Paper presents a case study for analysis of EIA for a transportation project. This Paper would provide a methodology which will allow transportation planers to make a cost effective coordination of environmental information and data management.
The results assess the environmental vulnerability around the road and its impact on environment by integration the merits of GIS.
Environment Impact Assessment Using Remote Sensingshubham shama
This document provides an overview of using remote sensing and GIS for environmental impact assessments. It discusses how satellite imagery allows for large area coverage in short time periods and how GIS enables spatial analysis and modeling. Examples are given of assessing impacts of projects like dams by computing command areas and changes over time. Both active sensors like radar and lidar, and passive sensors like radiometers are outlined. The advantages of remote sensing for environmental monitoring and assessing rapidly changing phenomena are highlighted.
This document provides a summary of the quarter 1 impact mitigation monitoring report for Nestle Waters Greenfield Factory project in Abaji, FCT Abuja, Nigeria. Key points include:
- Air, water, soil and vegetation were sampled from 9 stations to monitor impacts from construction activities and compliance with standards.
- Air quality, noise levels, water quality and soil quality were found to be within standards except for slightly elevated levels of some parameters near construction areas.
- Vegetation and wildlife have been impacted by land clearing for construction but mitigation measures like replanting and fencing are being implemented.
- Socioeconomic impacts are being mitigated through compensation, local employment, and consultations
The document discusses environmental impact assessment and monitoring services provided by CPTL Envirotech Designers & Pollution Control. It summarizes the organizational profile, services including air, water, noise monitoring and environmental impact assessment. It then discusses a project undertaken for Vardhaman Adarsh Ispat Pvt Ltd, including components of Form 1 and prefeasibility report required as per GOI notification to apply for environmental clearance for the proposed expansion project.
EIA is a systematic approach aimed at predicting, analyzing and proposing appropriate mitigation measures for the development of a project. This slide discusses the implementation of the EIA, issues and challenges in implementing the EIA effectively in Malaysia and around the world.
This document outlines the process and requirements for conducting an environmental assessment. It discusses how environmental assessments evaluate the impacts of proposed actions and alternatives on the environment, economy, and society. The process involves scoping the assessment, taking inventories, assessing impacts, evaluating findings, and producing documentation like environmental impact statements. The goal is to identify impacts, consider alternatives, and make informed decisions that justify projects while protecting environmental quality.
This document provides a summary of a post impact assessment report for Nestle's tri-generation power plant. The report includes chapters on plant description, environmental impacts, mitigation measures, and environmental management plan. Key findings are that the power plant is expected to reduce greenhouse gas emissions and improve electricity supply stability. Impacts on air and water quality are assessed, along with waste generation and management. The study was conducted over two months to evaluate the plant's environmental performance and compliance with regulations.
Regulatory Approach in Soil Erosion and Sedimentation Control for EIA ProjectDrAbdulRahmanMahmud
This document discusses regulatory approaches for soil erosion and sedimentation control in environmental impact assessments (EIAs) for projects in Malaysia. It outlines the core elements of EIAs, including existing environment studies, impact assessment, mitigation measures, and monitoring. It also discusses indicators of EIA effectiveness, such as the quality of EIA reports, implementation of effective mitigation measures, and capacity building. Finally, it proposes a successful regulatory approach involving strategic planning, improving EIA report guidelines, strengthening EIA approval conditions, promoting self-regulation and training to enhance soil erosion and sedimentation control in the EIA process.
The document discusses environmental impact assessment (EIA), which is defined as systematically identifying and evaluating potential environmental impacts of proposed projects. An ideal EIA system applies to all projects with significant environmental effects, compares alternatives, and includes public participation and enforcement. The goals of EIA are to conserve resources, minimize waste, recover byproducts, efficiently use equipment, and enable sustainable development.
The document provides information on environmental impact assessments (EIAs) and environmental management plans (EMPs). It defines EIAs as processes that identify, predict, evaluate, and mitigate biophysical, social, and other effects of development proposals prior to major decisions. The objectives of EIAs are to consider environmental factors in decision-making, identify potential impacts, and promote sustainable development through impact minimization. Methods used in EIAs include life cycle analyses for products, specific assessment protocols for GMOs, and fuzzy logic for hard-to-quantify impacts. EMPs are action plans that indicate which mitigation measures from EIA reports will be implemented to manage environmental impacts from projects. They ensure impacts are monitored and responsibility
This document discusses environmental impact assessments (EIAs) and management plans. It defines EIAs as processes that identify, predict, evaluate and mitigate biophysical, social and other effects of development proposals before major decisions. The objectives of EIAs are to consider environmental factors in decision-making, identify potential impacts, minimize adverse impacts, and promote sustainable development through public participation and environmental management plans. Common EIA methods discussed include product life cycle analysis, assessments of genetically modified organisms, and fuzzy logic to measure hard to quantify impacts. The document also outlines types of EIAs like strategic, regional and sectoral EIAs, and describes the typical steps involved in conducting an EIA.
Environment impact assessment in environment impact assessmentArunAngadi5
This document provides an overview of environmental impact assessments (EIAs). It defines EIA as a formal process used to identify and address the likely environmental effects of proposed activities or projects. The key points are:
- EIAs ensure potential environmental problems are identified early in project planning to allow for mitigation strategies.
- They examine impacts on physical, biological, and social aspects of the environment, as well as human health and welfare.
- The baseline or existing environmental conditions without the project are established to measure project impacts.
- EIAs have evolved over time to better integrate cumulative effects and sustainability considerations.
The document provides an introduction to environmental impact assessment (EIA). It discusses the basic concepts of EIA, including that EIAs are conducted before projects to identify potential environmental impacts. The purpose of EIAs is to inform decision making and promote sustainable development. Key principles of EIAs are that they integrate environmental considerations into decision making, identify appropriate mitigation measures, and facilitate informed decisions. While EIAs have limitations, they aim to improve environmental design, ensure appropriate resource use, and enhance social aspects of projects.
This document provides an introduction to environmental impact assessment (EIA). It defines EIA as an activity to identify and predict impacts of projects on the environment and human health to recommend measures to minimize impacts. EIA is done before projects to ensure no short-term or long-term environmental harm. The purposes of EIA are to provide information for decision-making on environmental consequences and promote sustainable development by identifying mitigation measures. While EIA cannot veto projects, it aims to improve environmental design, ensure efficient resource use, and facilitate informed decisions.
This document outlines a study that aims to investigate and compare different wastewater treatment methods to assess their effectiveness in removing pollutants. The study will explore conventional treatment methods like activated sludge and membrane filtration, as well as chemical precipitation. Experiments will be conducted to evaluate the treatment performance of each method based on parameters like COD and BOD. The results will then be analyzed to compare costs, energy usage, and environmental impacts in order to recommend the most sustainable wastewater treatment approaches.
What is an Environmental Clearance Certificate and How to Obtain It.pdfPranshuSharma18498
The document discusses environmental clearance certificates (ECC), which authorize projects that may impact the environment. It provides the following key points:
1. ECCs are granted after an environmental impact assessment (EIA) evaluates factors like air/water quality, biodiversity, land use, and social impacts. The EIA identifies impacts and mitigation measures.
2. ECCs ensure projects adhere to ecological, social, and ethical standards, and protect ecosystems and biodiversity.
3. Obtaining an ECC requires preparing an EIA report, applying for clearance, public consultation, and regulatory review and evaluation. Clearance considers potential impacts and proposed mitigation measures.
Environment impact Assessment (EIA) in Ugandakayondo alex
The document provides information about environmental impact assessments (EIAs) in Uganda. It defines key terms related to EIAs and describes the EIA process and requirements in Uganda. The EIA process involves 8 main steps: 1) screening, 2) scoping, 3) impact analysis, 4) impact mitigation, 5) reporting, 6) review, 7) decision making, and 8) monitoring. The document lists various projects that typically require an EIA in Uganda, such as urban development, transportation, mining, forestry, and waste disposal projects. It also outlines some projects that may be exempted from an EIA.
This document presents an environmental impact assessment report prepared by six students for a project referred to as MEL422. It summarizes the key aspects and steps of an environmental impact assessment process, including identifying and predicting environmental effects, considering social and health impacts, and preventing, mitigating and offsetting significant adverse effects. The report then outlines the various stages of an environmental impact assessment, from screening and scoping to impact analysis, mitigation, reporting and environmental management planning. It provides examples and checklists to guide the environmental impact assessment process.
The document discusses environmental impact assessment (EIA) and its key aspects. EIA is a tool used to identify environmental, social and economic impacts of projects prior to decision-making. It aims to predict impacts early and find ways to reduce adverse impacts. The key stages of an EIA typically involve screening, scoping, assessment, reporting, review and decision-making, and monitoring. Public participation is also an important part of EIA to help integrate objectives and minimize controversy. Principles of best practice in EIA outlined by the International Association for Impact Assessment emphasize that EIA should be rigorous, practical, and participatory.
The document discusses environmental impact assessments (EIAs). It notes that EIAs identify, predict, and mitigate potential environmental effects of development projects. The main steps in an EIA are screening, scoping, prediction and mitigation, management and monitoring, and auditing. EIAs began in the 1960s and were codified in legislation like the US's NEPA in 1969. The document outlines the EIA process and data requirements, discusses positive and negative externalities of EIAs, and notes their benefits like informed decision making and mitigation of environmental impacts.
The document discusses environmental impact assessments (EIAs). It defines EIAs as processes that identify, predict, and evaluate the physical, chemical, biological, social, and other impacts of proposed projects prior to major decisions. The document outlines the key stages of EIAs, including screening, scoping, preliminary assessments, mitigation, environmental management plans, public participation, and impact assessment methods. It emphasizes that EIAs are tools used to reduce negative environmental impacts and promote sustainable development.
The document provides an overview of environmental impact assessment (EIA). It defines EIA as assessing the effects of proposed projects on the environment. EIA identifies alternatives and aims to balance economic and environmental costs and benefits. It integrates environmental concerns early in project planning. EIA started as a mandatory regulatory process in the US in 1969 and is now required in over 100 countries. The key stages of EIA are screening, scoping, baseline data collection, impact analysis, mitigation planning, public hearings, decision making, and monitoring. EIA aims to be fair, provide credible information for decisions, and ensure sustainability.
1) EIA – Definition, History and Objective.
2) Reasons for using EIA
3) Key elements of EIA
4) Benefits of an EIA
5) Major Environmental Issues
6) PROCEDURE FOR EIA
7) IMPACT OF A PROPOSED PAPER INDUSTRY
8) Impact Mitigation
9) Key components of Monitoring
10) Public Involvement in the EIA Steps
11) Hierarchy in EIA
12)Impact indicators
BasConcept of Eic nvironmental Impact Assessment-pages-2-13,18-65.pdfTausifAhmad53
The document defines the environment and environmental impact assessment (EIA). It states that the environment includes physical, biological, social, cultural, and economic factors that surround organisms. An EIA is the process of identifying and assessing the potential impacts of a proposed project or action on the environment. The goals of an EIA include informing decisions, improving project design, promoting sustainability, and providing information to the public. The document also outlines the different components of the environment and reasons for conducting EIAs, such as preventing negative environmental and social consequences of past projects.
This document outlines the principles of environmental impact assessment (EIA) best practices. It is organized into two main parts. Part 1 describes the purpose, aims, and approach used to develop the principles. The principles are intended to provide guidance to those involved in applying EIA processes. Part 2 presents the definition of EIA as identifying, predicting, evaluating, and mitigating environmental effects prior to major decisions. It lists the objectives of EIA and introduces the basic and operating principles, which include transparency, participation, practicality, and applying EIA early in decision making.
This document discusses life cycle assessment (LCA), a tool used to evaluate the environmental impacts of products and processes across their entire life cycles. It describes how LCA involves compiling an inventory of relevant energy and material inputs and environmental releases, then evaluating the potential human and ecological effects. The document provides background on the origins and development of LCA, outlines the typical phases of an LCA process, and discusses some limitations and challenges and how LCA can inform decision making.
This document provides information about construction materials and techniques. It discusses bricks, including their standard sizes, qualities of good bricks, terms used in brick masonry, colors, cuts, orientations, and different brick bonding techniques. Specifically, it defines terms like headers, stretchers, bats, and explains common brick bonds like header bond, stretcher bond, English bond, and Flemish bond. It also lists factors that affect brick quality.
Misaali Mard مثالی مرد by peer Zulfiqaar Ahmad Naqshbandi
https://www.scribd.com/document/487090333/Misaali-Mard-%D9%85%D8%AB%D8%A7%D9%84%DB%8C-%D9%85%D8%B1%D8%AF
The document provides a summary of events in 3 sentences:
The document discusses events related to an organization and mentions dates, locations, and details of meetings. Names and dates are provided but many parts are illegible. Overall it appears to be notes or minutes from several meetings discussing various topics and attendees.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
This document provides information about construction materials and techniques. It discusses bricks, including their standard sizes, qualities of good bricks, terms used in brick masonry, colors, cuts, orientations, and different brick bonding techniques. Specifically, it defines terms like headers, stretchers, bats, and explains common brick bonds like header bond, stretcher bond, English bond, and Flemish bond. It also lists factors that affect brick quality.
Pre stressed & pre-cast concrete technology - ce462Saqib Imran
1) Precast concrete consists of concrete elements that are cast and cured off-site and then transported for assembly. Prestressed concrete uses high-strength steel strands or bars that are tensioned to put the concrete in compression and improve its strength.
2) Common precasting techniques include pre-tensioning, where steel is tensioned before the concrete is poured, and post-tensioning, where steel is tensioned after the concrete cures.
3) Advantages of prestressed concrete include reduced cracking, lighter weight, and improved durability; disadvantages include higher material costs and need for specialized equipment.
1. The document discusses foundations and foundation engineering. It defines a foundation as the lowest part of a building structure. Foundation engineering applies knowledge of soil mechanics, rock mechanics, geology, and structural engineering to design foundations for buildings and other structures.
2. Foundations are classified as either shallow foundations, which are placed near the ground surface, or deep foundations, which extend deeper into the ground. Common types of shallow foundations include spread footings, mat foundations, and combined footings. Common types of deep foundations include pile foundations, well foundations, and caisson foundations.
3. The document outlines general requirements for foundation design, including that foundations must safely support building loads without risk of structural failure or excessive settlement that could
This document provides information about hydraulic structures and diversion head works. It discusses that a hydraulic structure disrupts natural water flow and examples include dams and weirs. It then describes the key components of diversion head works, including weirs, barrages, under-sluices, divide walls, river training works, fish ladders, and canal head regulators. The purpose and functions of each component are explained. Design considerations for weirs and barrages such as their cost, control of flow, and ability to incorporate transportation are compared.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
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Assala mu alykum My Name is saqib imran and I
am the student of b.tech (civil) in sarhad
univeristy of science and technology peshawer.
I have written this notes by different websites
and some by self and prepare it for the student
and also for engineer who work on field to get
some knowledge from it.
I hope you all students may like it.
Remember me in your pray, allah bless me and
all of you friends.
If u have any confusion in this notes contact me
on my gmail id: Saqibimran43@gmail.com
or text me on 0341-7549889.
Saqib imran.
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Environmental Engineering
Environment:
The physical and biotic habitat which surrounds us; that which can be seen,
heard, touched, smelled and tasted.
Environmental Science:
An integrative applied science that draws upon nearly all of the natural
sciences to address environmental quality and health issues.
Environmental Engineering:
Uses environmental science principles, along with engineering concepts and
techniques, to assess the impacts of social activities on the environment,
people, and to protect both human and environmental health. Environmental
engineering requires a sound foundation in the environmental sciences and
consists of;
Provision of safe, palatable and ample water supplies
Proper disposal of or recycling of wastewater and solid wastes
Control of water, soil and atmospheric pollution.
Scope, Benefits and Problems in Environmental
Impact Assessment
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Benefits of Environmental Impact Assessment
The main benefits of EIA process are:
Improved project design / siting
More informed decision making with improved opportunities for public involvement in
decision making.
More environmentally sensitive decisions;
Increased accountability and transparency during the development process;
Improved integration of projects into their environmental and social setting;
Reduced environmental damage;
More effective projects in terms of meeting their financial and/or socio-economic
objectives; and
A positive contribution towards achieving sustainability.
The study of EIA effectiveness shows a number of difficulties and constraints, generally,
although not universally applicable, that continue to prevent and hinder EIA from
consistently delivering these advantages and benefits:
Scope of EIA
Small scale projects not included in most environmental impact assessment systems
although their cumulative impacts may be significant over time.
Problems in Environmental Impact Assessment
Difficulties in ensuring adequate and useful public involvement (or participation);
Insufficient integration of EIA work at key decision points in relation to feasibility and
similar studies in the project life-cycle; with some major decisions being made even before
EIAs are completed;
Lack of consistency in selection of developments requiring specific environmental impact
assessment studies;
Inadequate understanding of the relative roles of baseline description and impact
prediction;
Poor integration of biophysical environmental impacts with social, economic and health
effects also adds to the Problems in Environmental Impact Assessment;
Production of EIA reports which are not easily understood by decision makers and the
public because of their length and technical complexity;
Lack of mechanisms to ensure that EIA reports are considered in decision-making;
Weak linkages between environmental impact assessment report recommendations on
mitigation and monitoring and project implementation and operation; and
Limited technical and managerial capacities in many countries to implement EIAs result
in Problems in carrying out Environmental Impact Assessment.
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What is Environmental Impact Assessment and
its Objectives
Definition of EIA
A systematic identification and evaluation of the potential impacts of proposed projects,
plans, programs, or legislative action relative to physical-chemical, biological, cultural and
socioeconomic components of environment is called Environmental Impact Assessment.
OR
The process of predicting, identifying, evaluating and mitigating the biological, social and
other relevant effects of developmental proposals prior to major decision being taken and
commitment made. It is an important procedure for ensuring that the likely effects of new
developmental activities on the environment are fully understood and taken into account
before the development is allowed to go ahead.
Environmental impact Assessment is an event or effect, which results from a prior event.
It can be described as the change in an environmental parameter, over a specific period and
within a defined area, resulting from a particular activity compared with the situation which
would have occurred had the activity not been initiated.
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Objectives of Environmental Impact Assessment (EIA)
To ensure that Environmental considerations are addressed properly and incorporated into
decision making process.
To avoid, minimize or balance the adverse significant bio-physical, social and other
relevant effects of developmental projects.
To protect the productivity and capacity of natural system and ecological processes with
maintain their function.
To promote development that is sustainable and optimize resources use and management
opportunities.
Characteristics of Environmental Impact Assessment
An ideal EIA should have the following characteristics:
Apply to all activities that have significant environmental impact and address all the
impacts that are expected to be significant.
Compare alternatives to a proposed project (including the possibility of not developing the
site), management, techniques and mitigation measures.
Clear EIS mentioning importance of impacts and their specific characteristics to experts as
well as to non expert in the field.
Public participation and stringent administrative review procedure
Be on time so as to provide information for decision making and be enforceable.
Including monitoring and feed back procedures.
Types of Activated Sludge Process - Plug Flow,
Complete Mix, SBR
Following are the types of Activated Sludge Process
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1. Plug Flow
2. Complete Mix
3. Sequencing Batch Reactor
Plug Flow (PF) Process
Involves relatively long and narrow aeration basins so that concentration of soluble
substances and colloidal and suspended solids varies along reactor length.
Complete-Mix Activated Sludge (CMAS) Process
In CMAS, mixing of tank contents is sufficient so that ideally concentrations of mixed-
liquor constituents, soluble substances (COD, BOD, NH4-N), and colloidal and suspended
solids do not vary with location in aeration basin.
Sequencing Batch Reactor (SBR) Process
With development of program logic controllers (PLCs) and availability of level sensors
and automatically operated valves, SBR process became widely used by late 1970s.
Sequencing Batch Reactor process is fill-and-draw type of reactor system involving single
complete-mix reactor in which all steps of ASP occur.
Mixed liquor remains in reactor during all cycles, eliminating need for separate
sedimentation tanks.
Membrane technology has found increasing application for enhanced solids separation for
water reuse and use in suspended growth reactors for wastewater treatment. Membrane
biological reactors (MBRs) may change look of wastewater treatment in the future.
Microbial Metabolism in Biological Waste Water
Treatment
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Carbon and Energy Sources for Microbial Growth:
Organism must have sources of energy, carbon for synthesis of new cellular
material, and inorganic elements (nutrients) such as nitrogen, phosphorus, sulfur,
potassium, calcium and magnesium;
Carbon Sources:
Organisms that use organic carbon for formation of new biomass are called
heterotrophs; Organisms that derive cell carbon from carbon dioxide are called
autotrophs
Energy Sources:
Energy needed for cell synthesis supplied by light or by chemical oxidation reaction;
Those organisms that are able to use light as energy source are called phototrophs;
Phototrophic organisms either heterotrophic or autotrophic;
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Organisms that derive energy from chemical reactions are known as chemotrophs;
Chemoautotrophs obtain energy from oxidation of reduced inorganic compounds
(ammonia, nitrite, ferrous iron and sulfide); Chemoheterotrophs derive their energy
from oxidation of organic compounds
Oxidation‐reduction reactions involve transfer of electrons from electron donor to
electron acceptor; Electron donor is oxidized and electron acceptor is reduced;
Electron acceptor available within cell during metabolism (endogenous) or it
obtained from outside cell (i.e., dissolved oxygen) (exogenous);
Respiratory Metabolism:
Organisms that generate energy by enzyme‐mediated electron transport to external
electron acceptor
Fermentative Metabolism:
Use of internal electron acceptor and is less efficient energy yielding process than
respiration
Aerobic:
When oxygen is used as electron acceptor the reaction is termed aerobic;
Anaerobic:
When electron acceptors other than oxygen are involved, reaction is considered
anaerobic;
Anoxic:
When nitrite or nitrate is used as electron acceptor, reaction is termed anoxic; Under
anoxic conditions nitrite or nitrate reduction to gaseous nitrogen occurs, also
referred to as biological denitrification.
Organisms that can only meet their energy needs with oxygen are called obligate
aerobes
Bacteria that can use oxygen or nitrite/nitrate as electron acceptor in absence of
oxygen are called facultative aerobes
Organisms that generate energy by fermentation and that can exist only in
environment devoid of oxygen are obligate anaerobes
Organisms having ability to grow in either presence or absence of oxygen are
facultative anaerobes.
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Biological De-Nitrification Process in Waste
Water Treatment System
Denitrification
Biological reduction of nitrate to nitric oxide, nitrousoxide, and nitrogen gas
Involves both nitrification and denitrification
Biological nitrogen removal (BNR) is more cost effective and used more often as
compared to ammonia stripping, breakpoint chlorination and ion exchange;
BNR is used in wastewater treatment where
o there are concerns for eutrophication;
o where groundwater must be protected against elevated NO3‐N concentration;
o where WWTP effluent is used for groundwater recharge and other reclaimed
water applications
Process Description
Two modes of nitrate removal can occur in biological processes:
1. Assimilating and
2. Dissimilating nitrate reduction
Assimilating nitrate reduction
Involves reduction of nitrate to ammonia for use in cell synthesis;
Occurs when NH4‐N is not available and is independent of DO concentration
Dissimilating nitrate reduction
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Nitrate or nitrite is used as electron acceptor for oxidation of variety of organic or
inorganic electron donors
Substrate driven (preanoxic denitrification)
Figure 7‐21 (a) most common process used for biological nitrogen removal (BNR) in
municipal WWT;
Process consists of anoxic tank followed by aeration tank;
Nitrate produced in aeration tank is recycled back to anoxic tank;
Organic substrate in influent WW provides electron donor for oxidation reduction
reactions using nitrate; Process is termed substrate denitrification;
Furthermore, process is known as preanoxic denitrification because anoxic process
precedes aeration tank
Endogenous driven (postanoxic denitrification)
Figure 7‐21 (b), denitrification occurs after nitrification
and electron donor source is from endogenous decay;
Process is termed as postanoxic denitrification as BOD removal has occurred first and is
not available to drive nitrate reduction reaction
Depends on endogenous respiration for energy
Much slower rate of reaction than preanoxic processes
Exogenous carbon source such as methanol or acetate is added to provide sufficient BOD
for nitrate reduction and to increase rate of denitrification
Include suspended and attached growth systems
Biological Nitrification Process in Waste Water
Treatment System
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Definition
The removal of nitrogen by biological nitrification and denitrification is a two-step process.
In the first step (nitrification), ammonia is converted aerobically to nitrate (NO3−). In the
second step (denitrification), nitrates are converted to N2O or nitrogen gas (N2) under
anoxic conditions. Two‐step biological process in which ammonia (NH4‐N) is oxidized to
nitrite (NO2) and nitrite is oxidized to nitrate (NO3‐N).
Purpose of Nitrification
1. Effect of ammonia on receiving water with respect to DO concentrations and fish toxicity
2. Need to provide nitrogen removal to control eutrophication
3. Need to provide nitrogen control for water‐reuse applications including groundwater
recharge
4. Drinking water maximum MCL for nitrate nitrogen is 45 mg/L as nitrate or 10 mg/L as
nitrogen
5. Total concentration of organic and ammonia nitrogen in municipal wastewater in the
range 25‐ 45 mg/L as nitrogen based on flowrate of 450 L/capita.d (120 gal/capita.d)
6. With limited water supplies, total nitrogen in excess of 200 mg/L as N measured in
domestic wastewater
Nitrification Process
Nitrification process in waste water treatment is accomplished in both suspended growth
and attached growth biological processes
Suspended Growth Processes
Nitrification along with BOD removal in single‐sludge process can be achieved, consisting
of aeration tank, clarifier, and sludge recycle system
In case of toxic and inhibitory substances in wastewater, two‐sludge suspended growth
system may be considered, consisting of two aeration tanks and two clarifiers in series. The
first aeration tank/clarifier unit operated at short SRT for BOD and toxic substances
removal, followed by nitrification in second aeration tank/clarifier unit operated at long
SRT; Nitrifying bacteria grow much more slowly than heterotrophic bacteria.
Attached Growth Processes
For nitrification, most of BOD must be removed before nitrifying organisms can be
established
Heterotrophic bacteria higher biomass yield and dominate surface area of fixed‐film
systems over nitrifying bacteria;
Nitrification accomplished in attached growth reactor after BOD removal or in separate
attached growth system designed for nitrification.
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The nitrification rate for the attached-growth processes is higher than for the suspended-
growth processes. Attached-growth processes normally carry more suspended solids in the
effluent than the suspended-growth processes.
Microbiology of Nitrification
Aerobic autotrophic bacteria are responsible for nitrification in activated sludge and
biofilm processes;
Two‐step process in nitrication involve two groups of bacteria; First stage, ammonia is
oxidized to nitrite by one group (Nitrosomonas) and second stage, nitrite is oxidized to
nitrate by another group of autotrophic bacteria (Nitrobacter)
Other autotrophic bacteria for oxidation of ammonia to nitrite (prefix with Nitroso‐):
Nitrosococcus, Nitrosospira, Nitrosolobus, and Nitrosorobrio
Other autotrophic bacteria for oxidation of nitrite to nitrate (prefix with Nitro‐):
Nitrococcus, Nitrospira, Nitrospina, and Nitroeystis
Factors affecting Process of Nitrification
Environmental Factors: pH
Nitrification process in waste water treatment is pH sensitive and rates decline significantly
at pH values below 6.8; Optimal nitrification rates occur at pH values in 7.5‐8.0 range; pH
of 7.0 to 7.2 is normally used;
Low alkaline waters require alkalinity to be added to maintain acceptable pH values;
Amount of alkalinity added depends on initial alkalinity concentration and amount of NH4‐
N to be oxidized;
Alkalinity added in form of lime, soda ash, sodium bicarbonate, or magnesium hydroxide.
Environmental Factors: Toxicity
Nitrifiers are good indicators of presence of organic toxic compounds at low
concentrations;
Toxic compounds include: Solvent organic chemicals, amines, proteins, tannins, phenolic
compounds, alcohols, cyanates, ethers, carbamates, and benzene
Environmental Factors: Metals
Complete inhibition of ammonia oxidation at 0.25 mg/L nickel, 0.25 mg/L chromium, and
0.10 mg/L copper
Environmental Factors: Un‐ionized Ammonia
Nitrification is also inhibited by un‐ionized ammonia (NH3) or free ammonia, and un‐
ionized nitrous acid (HNO2);
Inhibition effects are dependent on total nitrogen species concentration, temperature, and
pH.
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Sources of Drinking Water
Water for drinking and domestic use may be obtained from natural sources like surface
water, groundwater and rainwater.
Surface water
Streams, rivers and lakes are the major sources of surface waters. Usually these sources
fulfill the requirements of municipal supplies. Water in these sources originates partly
from groundwater outflows and partly from rainwater which flows over the terrestrial
areas into the surface water bodies. Outflows from groundwater brings in, the dissolved
solids.
The surface run off contributes turbidity, organic matter and pathogenic organisms.
Usually in surface water bodies, the dissolved mineral particles will remain unchanged
while the organic impurities are degraded by chemical and microbial action. In slow-
flowing or impounded surface waters sedimentation of suspended solids occurs naturally.
Due to the lack of nutrients micro-organisms wil1 die off.
Although clear water from rivers and lakes requires no treatment, on taking into account
the risk of incidental contamination, it is better to practice chlorination. Unpolluted surface
water of low turbidity may be purified by slow sand filtration alone. Alternatively, rapid
sand filtration followed by chlorination can be practiced.
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Groundwater
Wells and springs constitute groundwater supplies. Groundwater mostly originates from
infiltrated rainwater which after reaching the aquifer flows through the underground.
Groundwater provides water to meet the requirements of individual household supplies as
well as municipal supplies.
The treatment processes also differ in these two cases with simply boiling the water before
use for household supplies. However, municipal supplies require one or more treatment
processes depending upon the impurities found in the water. A little contamination of
groundwater occurs from organic and inorganic soil particles, animal and plant debris,
fertilizers, pesticides, microorganisms, etc. as it flows through the soil layers. In spite of
this contamination, infiltration causes partial removal of suspended particles including
microorganisms. Organic substances are also degraded by oxidation. Partial removal of
microorganisms occurs by the death of cells due to lack of nutrients.
Thus, properly withdrawn groundwater will be free from turbidity and pathogenic
microorganisms. It is important to select the location of groundwater supply at a safe
distance from other sources of contamination.. If done so, groundwater will be of high
quality and can be used directly without any treatment.
Rainwater
Rainwater runoff from roofs can be collected and stored for domestic use. Rainwater will
be of high quality and the only possible source of contamination is airborne
microorganisms that too will be present in very low numbers.
Upland Lakes and Reservoirs
Typically located in the headwaters of river systems, upland reservoirs are usually sited
above any human habitation and may be surrounded by a protective zone to restrict the
opportunities for contamination. Bacteria and pathogen levels are usually low, but some
bacteria, protozoa or algae will be present. Where uplands are forested or peaty, humic acid
can color the water.
Many upland sources have low PH which requires adjustment.
Rivers, Canals and Low Land Reservoirs
Low land surface waters will have a significant bacterial load and may also contain algae,
suspended solids and a variety of dissolved constituents.
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Atmospheric Water Generation
It is a new technology that can provide high quality drinking water by extracting water
from the air by cooling the air and thus condensing water vapor
What is Disinfection and Methods of Disinfection
of Water
Definition of Disinfection
Disinfection is a process to destroy the disease causing organisms or
pathogens.
Methods of Disinfection of water
Disinfection of water can be done by
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1. Boiling the water
2. Physical method (Ultraviolet radiation)
3. A chemical inactivation of pathogen
In the water treatment processes, pathogens & other organisms can be partly physically
eliminated through coagulation, flocculation, sedimentation, & filtration, in addition to the
natural die-off. After filtration, to ensure pathogen free water, the chemical addition of
chlorine (so called chlorination), rightly or wrongly, is most widely used for disinfection of
drinking water. This less expensive & powerful disinfection of drinking water provides
more benefits than its short coming due to disinfection by-product (DBPs). DBPs have
to be controlled. The use of ozone & ultraviolet for disinfection of water & waste water is
increasing in the United States.
Chemical Characteristics of Sewage - BOD, COD,
Nutrients, DO
Sewerage characteristics can be divided into three broad categories:
Physical (Temperature, colour, smell, solids)
Chemical (BOD, COD, Nutrients and dissolved solids; and
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Biological
Chemical Characteristics of Sewage (Waste Water)
In sanitary sewage about 75 % of suspended solids and 40% of filterable solids are organic.
These solids are derived from both animals, plant and humans. Organic compounds usually
consist of C; H; O; N along with S; P and Iron.
The organic substances found in sewage are Protein (40-60%); Carbohydrates (25-50%),
fats and oils (10%).
Along with these organic compounds small amount of synthetic organic compounds like
VOCs, pesticides, insecticides, Organic Priority Pollutants are also presents in sewage.
Sewage also contain inorganic substances.
Tests like BOD, COD, Nitrogen, phosphorus, alkalinity etc. give the chemical
characteristics of sewage.
BOD (Biochemical Oxygen Demand):
When biodegradable organic matter is released into a water body, microorganisms feed on
the wastes, breaking them into simpler organic and inorganic substances. When this
decomposition occurs in aerobic environment the process produces non-objectionable,
stable end products like CO2, SO4, PO4 and NO3. A simplified form of Aerobic
decomposition is
O.M + O2 + Microorganisms
CO2 + H2O + C5 H7 NO2 (New Cells) = stable Products like NO3; PO4; NO3)
When sufficient O2 is not available Anaerobic decomposition occurs by different
microorganisms. They produce end products that can be highly objectionable, including
H2S; NH3 and CH4.
The reaction is O.M + Microorganisms
CO2 + H2O + C5 H7 NO2 (New Cells) = Unstable Products (NH3; H2S; CH4
Such products are usually unstable.
Bacteria placed in contact with organic matter will utilize it as food source.
In the utilization of the organic material it will eventually be oxidized to stable end products
such as CO2 and H2O etc.
The amount of oxygen required by the bacteria to oxidize the organic matter present in
sewage to stable end products is known as biochemical oxygen demand.
BODu is the maximum amount of oxygen usage by microorganisms over a long period of
time. A good measure of maximum bioavailability.
BOD5 is the amount of oxygen consumed (in mg/L) over a 5-day period at 20 o
C (in the
dark). BOD5 is a measure of the bioavailability over a 5-day period under controlled
conditions.
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CBOD
Carbonaceous biochemical oxygen demand or CBOD is a method defined test measured
by the depletion of dissolved oxygen by biological organisms in a body of water in which
the contribution from nitrogenous bacteria has been suppressed. CBOD is a method defined
parameter is widely used as an indication of the pollutant removal from wastewater. It is
listed as a conventional pollutant in the U.S. Clean Water Act.
Chemical Oxygen Demand
In addition to CBOD and NBOD measured, there are two other indicators to describe the
oxygen demands of wastewater. They are Chemical oxygen demand and theoretical oxygen
demand.
The biodegradable organic matters are degraded completely by microorganisms either by
CBOD or NBOD.
There are some organic matters like cellulose, phenols, benzene and tannic acid which are
resistant to biodegradation. Similarly, other organic matters like pesticides, insecticides
and various industrial chemicals are non biodegradable and they are toxic to
microorganisms.
The COD is a measured quantity that does not depend on microorganisms. To calculate the
concentration of oxygen for non biodegradable materials a strong oxidizing agent known
as potassium dichromate will be used.
The reaction is Organic matter (CaHbOc) + Cr2O7
-2
+ H2O – Cr +3
+ CO2 + H2O
The COD test is much quicker than BOD test, but it does not distinguish between the
biodegradable and non biodegradable organic matter. The measured COD is usually more
than BOD if there is non biodegradable impurity present. If all are the biodegradable
organic matter, then COD remains the same as that of BOD. Roughly the BOD/COD is 0.4
to 0.8.
Theoretical Oxygen Demand (TheoD):
Organic matter of animal or vegetable origin in wastewater is generally a combination of
carbon, hydrogen, oxygen, nitrogen and other elements. If the chemical composition of an
organic matter is known then the amount of oxygen required to oxidize it to carbon dioxide
and water can be calculated using stoichiometry. This amount of oxygen is known as
Theoretical Oxygen Demand. If that oxidation is carried out by bacteria then it is BOD, if
by chemical process then it is COD. If a combination of both then it is TheoD.
Physical Characteristics of Sewage
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Sewage Characteristics
Sewerage characteristics can be divided into three broad categories:
1. Physical (Temperature, colour, smell, solids)
2. Chemical (BOD, COD, Nutrients and dissolved solids; and
3. Biological
Physical Characteristics of Sewage
Following are the detailed physical characteristics of Sewage:
Temperature:
The normal temperature of sewage is commonly higher than water supply due to domestic
and industrial activities. Depending on geographical location, the mean annual temperature
of sewage is in the range of 10 to 21°C. Temperature of sewage is an important parameter
because of its effect on chemical reaction rates and aquatic life.
Increase temperature can cause a change in fish species that are present in water bodies.
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Similarly, oxygen is less soluble in warm water, while some species of aquatic life
population increases with temperature causing more demand of oxygen and result in
depletion of dissolved oxygen in summer.
Similarly, sudden change of temperature cause mortality of species.
Colour:
Fresh sewage is light brownish grey colour.
At a temperature of above 20 °C, sewage will change from fresh to old in 2 - 6 hours.
The old sewage is converted to dark grey and black color due to anaerobic activities, known
as stale or septic color.
Some industrial sewage also add color to domestic wastewater.
The grey, dark grey and black color is due to formation of sulfide produced under anaerobic
conditions reacts with the metals present in wastewater.
Odor:
Fresh domestic sewage has a slightly soapy or oil odour.
Stale sewage has a pronounced odour of Hydrogen Sulphide (H2S).
The odor at low concentration has no effect, but high concentration causes poor appetite
for food, lower water consumption, impaired respiration, vomiting etc.
Solids:
Solids comprise matter suspended or dissolved in water and wastewater.
Solids are divided into several different fractions and their concentration provide useful
information for characterization of wastewater and control of treatment processes.
Total solids:
Total solids (TS) are the sum of total suspended solids and total dissolved solids (TDS).
Each of these groups can further be divided into volatile and fixed fractions.
Total solids (TS) is the material left in the evaporation dish after it has dried at 103-105
°C.
Total solids can be expressed in mg/L.
Total suspended solids:
Total suspended solids (TSS) are referred to as non-filterable residue.
It is determined by filtering a well mixed sample through 0.45μm to 2 μm pore sized
membrane. The residue retained on the filter is dried in an oven at a temperature of 103-
105 °C for at least 1 hour.
TSS is expressed in the unit mg/L.
Fixed and Volatile Solids:
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The residue for total solids, total suspended solids or total dissolved solids tests is ignited
to constant weight at 500 o
C ± 50.
The weight lost on ignition is called volatile solids, whereas the remaining solids represent
the fixed total suspended or dissolved solids.
The determination of volatile portion of solids is useful in controlling waster water
treatment plant operations because it gives a rough estimation of the amount of organic
matter present in the solid fraction of waster water, activated sludge and industrial waste.
Absorption
Measure of amount of light, of specified wavelength, absorbed by constituents in
solution;
Absorbance measured with spectrophotometer using specified wavelength (254 nm)
Absorbance, measured using spectrophotometer and fixed path length (usually 1 cm) is
given by:
Absorbance
where A = absorbance, absorbance units (au)/cm
Io = initial detector reading for blank (distilled water) after passing through solution of
known depth I = final detector reading after passing through solution containing
constituents of interest
Turbidity
Measure of light‐transmitting properties of water, used to indicate quality of waste
discharges and natural waters with respect to colloidal and residential suspended matter
Measurement based on comparison of intensity of light scattered by a sample to the light
scattered by reference suspension under same conditions. Formazin suspensions are used
as primary reference standard
Results of turbidity reported as nephelometric turbidity units (NTU)
Relationship between turbidity and TSS for settled and filtered secondary effluent from
activated sludge process:
Relationship between turbidity and TSS for settled and filtered secondary effluent from
activated sludge process
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TSSf vary for each treatment plant; TSSf for settled secondary effluent and for secondary
effluent filtered with granular medium depth filter vary from 2.3 to 2.4 and 1.3 to 1.6,
respectively
Conductivity
Electrical conductivity (EC) is measure of ability of solution to conduct electrical current
Electrical current is transported by ions in solution, conductivity increases as concentration
of ions increases;
EC value is used to substitute measure of TDS concentration; EC of water important
parameter to determine its suitability for irrigation;
Salinity of treated wastewater to be used for irrigation is estimated by its EC;
SI units: millisiemens per meter (mS/m);
Estimation of TDS of water sample based on measured EC value:
TDS (mg / L) ≅ EC (dS / m)×(0.55 − 0.70)
Density and Specific Gravity
Physical Characteristics of Sewage also include aspects like density and specific gravity
of the sewage.
Density: Mass per unit volume expressed as g/L or kg/m3; density of domestic
wastewater is the same as that of water at same temperature;
Specific Gravity: sw =ρw/ρo
where ρw = density of wastewater
ρo = density of water
Both density and specific gravity are temperature dependent and will vary with
concentration of TSS in wastewater.
Types of Grit Chambers in Waste Water
Treatment
The objectives of Grit Chambers are:
1. Protect moving mechanical equipment from abrasion and abnormal wear
2. Reduce formation of heavy deposits in pipelines, channels and conduits
3. Reduce the frequency of digester cleaning caused by excessive accumulation of grit
Types of Grit Chamber
1. Horizontal flow (Rectangular or square) (configuration type)
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Designing a Rectangular horizontal flow type grit chamber:
Cross-sectional area, Ax = (Qdesign / Vh) for each unit (Vh ≈ 1 ft/sec), depth ≈ 3-5 ft
Assuming (tD = 1-2 minutes), determine the length L = Vh * tD (Add 10% additional)
Check the SLR (1200-1700 m3
/m2
-day) and Vs (≥ 0.01 m/sec). Grit produced is about 1.5
ft3
/ML of wastewater flow. Add to depth {1ft FB + grit}
2. Aerated Grit Chamber
Basic Info
Air is introduced along one side of a rectangular tank to create a spiral flow pattern
perpendicular to the flow through the tank.
If the velocity is too great, grit will be carried out of the chamber; if it is too small,
organic material will be removed with the grit.
Normally designed to remove 0.21-mm-diameter or larger, with 2-5-minute
detention periods at the peak hourly rate of flow
Air diffusers are located about 0.45 to 0.6m above the normal plane of the bottom.
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Aerated Grit Chamber
Designing an Aerated grit chamber:
Assume a “tD” (3-4 min), determine the volume of the basin.
Assume a depth (D = 08-15 ft), determine the surface area of the basin. And check the
SLR (1200-1700 m3
/m2
-day)
The amount of grit produced is about 1.5 ft3
/ML of wastewater flow. Add suitable depth
from grit and free board.
Calculate the amount of air required (0.2-0.5 m3
/min/m length of the tank)
Advantages & Disadvantages of Comminutors
Advantages
Elimination of extra steps and problems involved in the excavation of the disposals of
screening (screened material)
Often difficult to dispose highly polluted screenings - In USA if buried, 6 inches of cover
material should be used
Highly suitable for small treatment plants. e.g. : mountain or beach resorts.
Disadvantages
Frequent maintenance of cutting tools ( delicate equipment)
Risk accumulation of comminuted materials (textiles, vegetable fibers) eventual clogging
of pumps and piping.
These materials to form floating scum in anaerobic digestion
Problems in trickling filter (clogging of distribution pipe holes) mainly used in activated
sludge process.
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Definitions in Waste Water Treatment
Sludge Volume Index (SVI-TEST)
It is the measure of the settleability and compatibility of sludge and is made from a
laboratory column setting test.
Definition
The sludge volume index is defined as ‘the volume in mm occupied by 1 gm of sludge
after it has settled for a specified period of time’ generally ranging from 20 min to 1 or 2
hr in a 1 – or 2-l cylinder. One-half hour is most common setting time allowed to the
mixed liquor to settle for 30 min. ( larger cylinder is desirable to minimize bridging of
sludge floe and war effects). Take the reading let Vs is the settled volume of sludge (ml/l)
in 30 min.
* If SVI is 50 - 150 ml/mg, the sludge settle ability is Good.
Return Activated Sludge System:
1. The activated sludge form the underflow of the final setting tanks should be returned to the
inlet of the aeration tanks at a rote sufficient to maintain the MLSS concentration at the
design value.
2. The flow are needed for return-sludge is determined form the incoming sewage flow rate
and the concentration at which the sludge is with drawn form the final setting tanks.
Hence a simple measure of the underflow concentration form the setting tanks is required.
The parameter conventionally employed for this purpose the sludge volume index, SVI
which is defined as 4 the volume occupied by sludge containing 1.0g of sludge soiled (dry
weight) after 30 min setting and thus it has ht units ml/g. Some time represented as SDI
i.e sludge density index. Once the SVI and operating MLSS concentration (x) is known,
the required rate of activated sludge return can be determined
R = 100 / [ 106/ (x) (SVI) -1] where r = return sludge flow rate as a % age of incoming
sewage flow.
SEDIMENTATION:
It is the removal of solid particles form a suspension by settling under gravity.
CLARIFICATION:
It is a similar term which refers specifically to the function of a sedimentation removal.
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THICKENING:
It means the separation of water from Suspended Solids where R = return sludge flow
rate (ML/D) for Q in ML/D)
SURFACE GEOMETRY OF FINAL SEDIMENTATION TANKS:
VARIATION OF THE ACTIVATED SLUDGE PROCESS:
1. Activated sludge was introduced in 1941 and has undergone many variations and
adaptations.
2. The main objective of many modifications has been to increase the loading capacity of the
basic plug flow activated sludge plant by provision of optimum condition design
parameters for different variations are summarized in table. It is worthy of note that 5
modifications tapered aeration step aeration the CMAS process, the pure oxygen system
and the deep shaft process all aim at either the improvement of oxygen transfer efficiency
t the efficient distribution of available oxygen to match demand. A flow sheet of most of
the commonly used variations is similar to that of CAS (Conventional Activated Sludge).
CONVENTIONAL ACTIVATED SLUDGE:
Volumetric loading = kg of BOD
m3
-d
Aerial loading rate = gm of BOD
m3
-d
Td = V/Q in days and grater than 5 days.
ALGAL-BACTERIAL SYMBOPSTS:
The combined and mutually- been facial action of algae and bacteria in this process is
called algal-bacterial symbioses.
Shock loading (CSTR)
BODu
Aerated Lagoons:
Aerate lagoons are activated sludge units operated without sludge return. Historically they
were developed from waste stabilization ponds in temperate climate where mechanical
aeration was used to supplement the algal oxygen supply in winter. It was found, however
that soon after the aerations were put into operation the algal disappeared and the microbial
flora resembled that of activated sludge. Aerated lagoons were now usually design as
completely mixed not-return activated sludge units. Floating aerates are most commonly
used to supply the necessary oxygen and mixing power.
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Sludge Treatment:
Anaerobic sludge treatment cell Primary Sedimentation Tank and Secondary
Sedimentation Tank are basically organic these can treated to aerobic.
Anaerobic ponds and septic tank are for waste water treatment .
Sludge treatment = Anaerobic sludge treatment.
COLD DIGESTION:
Two stage digestion up
High rate digestion up
Fixed film processes. A swm zone
SLUDGE DIGESTION:
SLUDGE: the concentrated impurities settled at the bottom of the flower bed of
sedimentation tanks.
Digestion:
To decompose or breakdown by heat and moisture or chemical action. (to invent food
equable forms)
Sludge treatment:
Aerobic digestion it is defined as ‘it is the use of microbial organisms in the absence of
oxygen I for the stabilization of oxygen materials by conversion to mean and inure produce
including CO2.
Organic matter + H2O (amoebas) CH4+ CO2 + NH3+ H2S + heat
Benefices of anaerobic digestion. Types of anabolic detectors. It’s of two types:
Conventional (stranded) or low-rate digester or cold digester.
High rate digesters / two stage digester are characterized by continuous miring except at
time of sludge with draw.
What is the Composition of Wastewater?
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Constituents of Waste Water
Constituents of Waste Water are characterized in terms of its physical, chemical and
biological composition
Physical Characteristics
Solids content
Floating matter
Settleable matter
Colloidal matter
Matter in solution
Particle size distribution; Turbidity; Color; Transmittance; Temperature; Conductivity;
Density; Specific gravity; Specific Weight
Solids classification
Solids interrelationships
Settleable solids: Placing 1‐L sample in Imhoff cone and noting volume of solids in mm
that settle after 1 h; Typically 60% of suspended solids (SS) in municipal wastewater are
settleable
Total solids (TS): Obtained by evaporating wastewater sample to dryness (at 103‐ 105°C)
and measuring mass of residue
Total suspended solids (TSS): Filtration step is used to separate TSS from total dissolved
solids (TDS); Portion of TS retained on filter (e.g., Whatman fiber glass filter‐GF/C)
measured after being dried at 105°C
Total Suspended Solids (TSS)
More TSS measured as pore size of filter used is reduced;
Important to note filter paper pore size, when comparing TSS values;
TSS and BOD universal effluent standards by which performance of treatment plants is
judged for regulatory control purposes
Total Dissolved Solids (TDS)
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Solids contained in filtrate that passes through a filter with nominal pore size of 2 μm or
less are classified as dissolved; Size of colloidal particles in wastewater typically in range
from 0.01‐1 μm
Volatile and Fixed Solids (VS and FS) Material volatilized and burned off when ignited
at 500 ± 50oC classified as volatile solids (VS);
In general, VS are organic matter
Residue that remains after sample is ignited at 500 ± 50oC classified as fixed solids (FS);
TS, TSS, and TDS comprised of both VS and FS Ratio of VS to FS used to characterize
wastewater with respect to amount of organic matter present
Particle Size Distribution (PSD)
To understand nature of particles that comprise TSS in wastewater, measurement of
particle size is undertaken
PSD important in assessing effectiveness of treatment processes (secondary sedimentation,
effluent filtration, and effluent disinfection)
PSD methods can be divided into two general categories:
1. Methods based on observation and measurement
2. Methods based on separation and analysis techniques
Commonly used methods for particle size analysis:
1. Serial filtration: Wastewater sample is passed sequentially through series of membrane
filters with circular openings of known diameter, and amount of suspended solids retained
in each filter is measured.
Electronic Particle Counting
Particles in wastewater are counted by diluting a sample and then passing diluted sample
through calibrated orifice or past laser beams;
As particles pass through orifice, conductivity of fluid changes, owing to presence of
particle. Change in conductivity is correlated to size of equivalent sphere;
Similarly, as particle passes by laser beam, it reduces intensity of laser because of light
scattering. Reduced intensity is correlated to diameter of particle. Particles counted are
grouped into particle size ranges. In turn, volume fraction corresponding to each particle
size range is computed.
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Microscopic Observation:
Placing small wastewater sample in particle counting chamber and counting individual
particles;
To aid in differentiating different types of particles, various types of stains are used;
In general, microscopic particle counting is impractical on routine basis;
However, it can be used to qualitatively assess nature and size of particles in wastewater
The typical composition of wastewater based on strength. The important characteristics
measured in wastewater included...
Biochemical Oxygen Demand (BOD) [100-300 mg/L as O2]
Suspended solids (SS) [100 – 350 mg/L]
Settleable solids [5-20 mL/L]
Total Kjeldahl nitrogen (TKN) [20-80 mg/L]
Total Phosphorus [5-20 mg/L as P]
A typical solids analysis of wastewater, of the total solids, 50% is dissolved, 50%
suspended. Of the suspended solids, 50% will settle. Industrial activity changes the
composition of wastewater, often introducing toxic substances such as chromium and
cadmium from plating operations.
Food to Microorganisms Ratio (F/M)
Definition
A parameter of organic loading rate in the design aerated sludge parameter in the design of
Trickling Filter in organic loading rate = kg of BOD / m3-d
F/M ratio =
F/M ratio = BOD / MLSS x t kg of BOD / Kg of MLSS/day
FM ratio varies between 0.2 -0.5 day-1
F/M ratio -0.5 day-1 has a good settleabilty of a sludge. ( even in some cases it can go to
1)
F/M ratio -<0.2 Food is very limited so the bacteria will die.
F/M ratio 70.5 day-1
Food is more so the bacteria will move the effluent (failure of the
system)
If high F/M ratio, filamentous bacteria will also grow. They not settle easily because of
long tails, get entangled with each other. Food to micro organism ratio(F/M) is a common
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used parameter in the activated-sludge process which is defined as the kg of BOD5applied
per kg MLSS per day.
Derivation of F/M Ratio:
Q = Flow of Sewage (m3/day)
BOD = organic matter (mg/l)
FOOD = Q (m3/day) x BOD (mg/l)
FOOD = Q x BOD / 1000 (Kg of BOD/ day)
V = Volume of Aeration (m3)
MLSS = Mixed liquor suspended solids (mg/l)
Micro-organisms = V (m3) x MLSS (log/l) / 1000 = V x MLSS / 1000 (kg of MLSS in
aeration tank)
Uses & Design of Flow Equalization Tank
Definition:
Flow equalization is method used to overcome the operational problems and flow rate
variations to improve the performance of downstream processes and to reduce the size &
cost of downstream treatment facilities. To prevent flow rate, temperature, and
contaminant concentrations from varying widely, flow equalization is often used.
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Objective
Give a relatively constant flowrate to the downstream operations and processes
Functions of FET
Dampen the daily variation in flowrate and loadings
Reduce the required size of the downstream treatment facilities
Feasible dry weather flows in separate sewer system and sometimes for storm
Effects of flow equalization
10-20% of BOD entering is stabilized in the equalization basin
23-47% of SS is further removed in the primary clarifier
reduce shock load on biological process
Why to Use flow Equalization Tanks
Variations occur characteristically in domestic wastewater flow rate and composition as a
result of cyclic activities of the human population. Additional variations are commonly
imposed by a combination of:
1. Random and cyclic activities in the collective industrial-wastewater-generating segment of
the community and
2. By storm-related effects of infiltration and inflow
3. In addition, the average waste water flow rate at typical municipal treatment plants may be
expected to increase by 25 to 100 percent or more over the design life of the facilities.
4. Operation of waste water treatment plant at uniform conditions is assumed to be
advantageous. It results in improved efficiency, reliability, and control of various physical,
chemical and biological treatment processes. Costs can also be reduced by elimination of
excessive peak treatment capacity and from reduced periods of operation under peaking
conditions.
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Design of Flow Equalization Tanks
The design of equalization facilities requires evaluation and selection of a number of
features:
1. Type and magnitude of input variations
2. Required volume
3. Facility configuration
4. Pumping/control mode
5. Type of construction
6. Appurtenances; aeration, mixing, odor control, cover, flushing
7. Cost and benefits
Benefits - Advantages of Flow Equalization Tank
1. Reduction of peaking requirements
2. Reduction of process overloads at existing plants under some conditions
3. Protection against toxic upsets
4. Potential reduction of operational problems
5. Provides increasing benefits with increasing plant complexity
6. Placement of equalization following primary treatment minimizes operation and
maintenance, and minimizes requirements for solids removal, aeration, and odor control
equipment.
To Measure COD of WasteWater using Open
Reflux Method
History of COD :
KMnO4 was used as oxidizing agent for many time pb with KMnO4 was that different value
of COD obtained due to strength change of KMnO4. BOD value obtained greater than COD
with KMnO4 means KMnO4 was not oxidizing all the substances. Tthen ceric sulphate
potassium loadate and potassium dichromate all tested separately and at the end potassium
sichromate was found practical.
Pottassium dichromate is used in excess a mount to oxidize all the organic matter, this
excess aomunt can be found at the end by using ferrousiion.
Method for cod test :
1. open reflux (drawback: end product is dangerous and cannot be discharged in open
draws)
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2. close reflux (same chemicals as for open reflux but sample and chemicals used in less
quantity) spectro photometric (septrophotometer) titremetric ( titration)
Chemicals/ regents in open reflux method:
1. Potassium di-chromate (oxidation agents)
2. Sulphuric acid.
3. Mercuri sulphate (Hgs04)
4. Ferrous ammonium sulphate (Fe NH4)2 (So4)2 0.25 N used as tritrante,
5. Fezroin indicator.
Limitations of COD:
cannot differentiate between biodegradable and non-biodegradable material
N-value cannot be accurately found.
Advantages of COD:
1. can be performed in short time i.e 30 min can be correlated with BOD with a factor.
2. More biological resistant matter, more will be the difference in Bod and Cod results,
Apparatus
1. Digestion vessels (vial)
2. COD Reactor
3. Spectro-photometer
4. Premixed Reagents in Digestion Vessel (vials)
5. K2G2O7
6. Concentrated H2SO4
7. HgSO4
8. Ag2SO4
Procedure:
1. Place Approximately 500ml Of Sample In a clean blender bowl and homogenize
at high speed for two minutes. blending the sample ensures a uniform distribution
of suspended solids and thus improves the accuracy of test results.
2. Pre heat the COD reaction to Iso c
3. Carefully remove the cap of COD digestion Reagent vial.
4. While holding The vial at a 45 degree angle carefully pipette 2 ml sample into the
vial.
5. Replace and tighten the cap.
6. Holding the vial by the cap in an empty sink, gently invert several times to mix the
contents they will become very hot during mixing.
7. Place the vial in preheated COD reaction.
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8. Prepare a reagent blank by repeating step 3 through 6, substituting2 ml of distilled
water in place of sample.
9. Incubate the vial for two hours at size.
10.Turn off the reaction off and allow the vials to cool to 120 degree and less. invert
each vial several times while still warm place vial in a cooling reach and allow
them to room temp.
11.Measure the COD using spetrcophotometer method.
Public Health Engineering
The public health engineering sector is responsible for the Collection of water, purification,
transmission and distribution of water. A Public Health Engineer has to perform his job by
calculating design flow, design population, design area and population density
1. Collection of water
2. Purification works
3. Transmission works
4. Distribution works
Water Works Explained
1. Collection of water:
This includes the collection of water from all available sources to ensure continuous
supply of water to the community.
2. Purification works:
Quality of the collected water is checked by physical and chemical tests on water and if
the quantity is not satisfactory and according to WHO standards then, purification or
treatment of water is done to make it suitable for its intended use e.g. cooking, drinking,
bathing, washing etc.
3. Transmission works:
Transmission works includes measure taken to ensure the purified supply of water by
laying out conduits, which do not affect the quality of water
4. Distribution works:
Water is then distributed to the consumers in desired quantity at adequate pressure. The
quantity of water may be different for residential, commercial and industrial zones. So
accordingly, there should be a difference between the quantities of water that they will
receive and hence the transmission works.Similarly, the pressure of water is also
important in industries, storied buildings, and hilly areas.
Design population:
It is the no. of people for whom the project is designed. The population should be
considered as it would be at the end of design period.
Design Flows:
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The maximum discharge required at the end of transmission system is called design flow.
Per capita consumption is the average intake of water per person. It may be for a single
day, a week, a month or annually. It can be found out by dividing the total consumption of
water by the number of individuals in population using that water. The flow of water for
design is calculated by multiplying the average per capita consumption annually with the
design period (in years) and the design population.
Design period:
It is the number of years in future for which the excess capacity is provided. For this amount
of time the proposed system, its component structures and equipment should be appropriate
and adequate. The design period depends upon:
Life of components system structures used.
Ease of expansion of the project
The type of technology used
The rate of increase of population
The rate of increase in water demand.
The flow required for design period must be estimated and not over-estimated, to prevent
the project from becoming un-economical and over-burdening the community with extra
cost.
Population density
The number of persons per unit area – e.g. persons/Km2
Population Forecasting Methods & Techniques
Population is one of the most important factors for design of the water systems, so it should
be estimated, so as to know the increasing demand and ensure continuous supply to them.
Population data is obtained by previous records and the rate of increase is found out and
this used for further analysis, which may be by using the methods described below
1. Arithmetic growth method
2. Geometric growth method
3. Curvilinear method
4. Logistic method
5. Decline growth method
6. Ratio growth
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Arithmetic growth method:
It is based on the assumption that the rate of growth of population is constant. It means that
the each year population increase by the same increment.
Mathematically;
dp / dt = Ka
Where,
dp / dt is the rate of change of population
Ka = the constant arithmetic increment
Ka can be determined by finding the slop of the graph of population against time. The
population in the future is thus estimated.
Geometric method:
It is based on the hypothesis that rate of change of population is proportional to the
population. According to this, method it is assumed that the rate of increase of population
growth in a community is proportional to the present population.
Mathematically:
dP /dt ∝ P => dp / dt = Kg where Kg = Geometric Growth constant.
If P0 is the population at any time t0 and Pf is the population at time tf then
∫Pf P0 dp/p = Kg ∫ tf t0 dt = Ln (Pf/P0 = Kg (tf/t0)
=> Ln (Pf/P0 = Kg Δt
=> (Pf/P0 = (e) Kg Δt and Pf = P0 (e) Kg Δt
This method gives somewhat larger value as compared to arithmetic method and can be
used for new cities with rapid growth. In normal practice, arithmetic and geometric growth
average is taken.
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Curvilinear method:
In this it is assumed that the population of a city will grow, in the same manner as in other
cities in the past. This similarity between the cities includes geographical proximity,
similarity of economic base, access to similar transportation system etc. In practice it is
difficult to find similar cities.
Logistic method:
When the growth rate of population due to birth, death and migration are under normal
situation and not subjected to extraordinary changes due to unusual situation like war,
epidemics earth quakes and refugees etc. Then this method is used:
According to this method
P = P sat / (1+ ea
+ bΔt), where P sat is the saturation population, of the community and a, b are
constants. P sat, a and b can be determined from three successive census populations and
the equations are
Psat = 2 P0 P1P2 - P1
2
(P0 + P2) / (P0 P2 - P1
2
)
Decline growth method:
This method like, logistic, assumes that the city has some limiting saturation population
and that its rate of growth is a function of population deficit;
Ratio method:
Ratio method of fore casting is based on the assumption that the population of a certain
area or a city will increase in the same manner to a larger entity like a province, or a country.
It requires calculation of ratio of locals to required population in a series of census years.
Projection of the trend line using any of the technique and application of projected ratio to
the estimated required population of projected ratio to the estimated required population in
the year of interest. This method of forecasting does not take into account some special
calculations in certain area but have the following advantages.
Estimation of Water Demand
While estimating the water demand, the above factors should be considered e.g. the size of
the city; its population does matter when estimating the water demand. The more the size
of population, more will be the demand. Estimation of water demand is necessary to:
Calculate design flow
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Determine the pumping power of machines to be used
Reservoir capacity
Pipe capacity
To estimate water demand, following parameters must be determined or calculated.
To determine the maximum water demand during a fire, the required fir flow must be added
to the maximum daily consumption rate. The shortage is fulfilled by elevated storage tanks
which have been filled during lower demand in usual days
Keywords: county population forecasts, population forecasting, forecasting population
growth, population forecasting methods, growth forecasting, demographic forecasting, fire
water demand, fire flow demand, firefighter demand,
1. Average daily water consumption: It is based on complete one year supply of water. It
is the total consumption during one year, divided by the population.
q = (Q / P x 365) lpcd (liters per capita per day)
2. Maximum daily consumption: It is the maximum amount of water used during one day
in the year. This amount is 180% of the average daily consumption
MDC = 1.8 x Avg. daily consumption. It is usually a working day (Monday) of summer
season.
3. Maximum weekly demand: The amount of water used by a population during a whole
single week in a study span of 1 year.
Maximum weekly demand = 1.48 x Avg. D. C
Maximum monthly demand = 1.28 x Avg. D. C
Maximum hourly demand = 1.5 x Avg. D. C
Maximum daily demand = 1.8 x Avg. D. C
4. Fire water demand | Fire Demand: The amount of water used for fire fighting is termed
as fire demand. Although, the amount of water used in fire fighting is a negligible part of
the combine uses of water but the rate of flow and the volume required may be so high
during fire that it is a deciding factor for pumps, reservoirs and distribution mains.
Minimum fire flow should be 500 gpm (1890 L/m)
Minimum fire flow should be 8000 gpm (32, 400 L/m)
Additional flow may be required to protect adjacent buildings.
Sectoral Consumption of Water
1. Domestic use
2. Commercial use
3. Public use
4. Loss and waste
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Domestic use of water:
Domestic uses of water include the consumption of water for drinking, washing, cooking,
toilets, livestock etc. the domestic average use per capita per day is 50 – 90 gallons (70 –
380 liters per capita per day). This use is increasing by 0.5% - 1.0% per year and at this
time comprises 50% of all the uses of water. Water uses are for drinking, cooking, meeting
of sanitary needs in houses and hotels, irrigating lawns etc. Residential water use rates
fluctuate regularly. Average daily winter consumption is less than annual daily average,
whereas summer consumption averages are greater. Similarly, peak hourly demand, is
higher than maximum. No universally applied rule for prediction
Commercial and industrial:
This is the amount of water used by the shops, markets, industries, factories etc. It
contributes 15 – 24% of total use of water. It includes factories, offices and commercial
places demand. It is based on either having a separate or combined water supply
system. Demand of water based on unit production: No. of persons working and floor area
Public use:
The public use of water is that one which is used by city halls, jails, hospitals, offices,
schools etc. This consumes 9% of total use of water. Its water demand is 50 – 75 liters per
capita per day. Fire protection's need of water is also fulfilled by this sector. The fire
demand does not greatly affect the average consumption but has a considerable effect on
peak rates. Schools, hospitals, fire fighting etc
Loss and wastes:
: Unauthorized, connections; leakage in distribution system, Hydrant flushing, major line
breakage and cleaning of streets, irrigating parks. Total consumption is sum of the above
demands. The water which is not intended for specific purpose or use is also called "Un-
accounted for". Loss and wastage of water is due to:
1. Errors in measurements
2. Leakages, evaporation or overflow
3. Un-metered uses e.g. fire fighting, main flushing
4. Un-authorized connections
Factors affecting the use of water
Size of the city
Industry and commerce
Climate
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Time of the day
Day of the week or month
Factors Affecting Selection of Water Source
Quantity of water:
The quantity of water available at the source must be sufficient to meet various demands
and requirements of the design population during the entire design period. Plans should be
made to bring water from other sources if the available water is insufficient.
Quality of water:
The water available at the source must not be toxic, poisonous or in anyway injurious to
health. The impurities should be as minimum as possible and such that, can be removed
easily and economically.
Distance of water supply source:
The source of supply must be situated as near to the city as possible. Hence, less length of
pipes needs to be installed and thus economical transfer and supply of water. The source
nearest to the city is usually selected.
Topography of city and its surroundings:
The area or land between the source and the city should not be highly uneven i.e. it should
not have steep slopes because cost of construction or laying or pipes is very high in these
areas.
Elevation of source of water supply:
The source of water must be on a high elevation than the city so as to provide sufficient
pressure in the water for daily requirements. When the water is available at lower levels,
then pumps are used to pressurize water. This requires an excess developmental and
operational tasks and cost. It may also have breakdowns and need repairs.
Water quality
Impurities present in water and their health significance
Water quality standards set by U.S and W.H.O
Water quality tests
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Sources of Fresh Water in Environmentl Engg.
Flowchart of the sources of clean drinking water
WasteWater Treatment Disposal & Management
The quantity of water required for a community depends upon:
1. Forecasted population
2. Types and variation in demand (e.g. seasonal variation)
3. Maximum demand (Per day/Per month)
4. Fire demand
5. Rural demand and supplies
6. Appropriate / Available technology
Main sources of water are
Surface water sources: Lakes impounding reservoirs, streams, seas, irrigation canals
Ground water sources: Springs, wells, infiltration wells
Above are the common sources of clean drinking water, other different sources of drinking
water are
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Merits of surface sources
Merits of ground water sources
1. Being underground, the ground water supply has less chance of being contaminated by
atmospheric pollution.
2. The water quality is good and better than surface source.
3. Prevention of water through evaporation is ensured and thus loss of water is reduced.
4. Ground water supply is available and can even be maintained in deserted areas.
5. The land above ground water source can be used for other purposes and has less
environmental impacts.
Demerits of ground water source
1. The water obtained from ground water source is always pressure less. A mump is required
to take the water out and is then again pumped for daily use.
2. The transport / transmission of ground water is a problem and an expensive work. The
water has to be surfaced or underground conduits are required.
3. Boring and excavation for finding and using ground water is expensive work.
4. The modeling, analysis and calculation of ground water is less reliable and based on the
past experience, thus posing high risk of uncertainty.
Chemical Characteristics of Water
1. Acidity
2. Alkalinity
3. Hardness
4. Turbidity
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Acidity:
Acidity or alkalinity is measured by pH. PH measures the concentration of Hydrogen ions
in water. Ionization of water is
HOH H+ + OH-
In neutral solutions [OH] = [H] hence pH = 7
If acidity is increased, [H] increases and pH reduces from 7 (because H is log of [H]). The
value of pH of water is important in the operations of many water and waste water treatment
processes and in the control of corrosion.
Alkalinity:
The values of pH higher than 7, shows alkalinity. The alkaline species in water can
neutralize acids. The major constituents of alkalinity (or causticity) are OH-, CO32- and
bicarbonates HCO3 ions. Alkalinity in water is usually caused by bicarbonate ions.
Hardness of water:
Definition of hard water
Hardness is the property that makes water to require more soap to produce a foam or
lather. Hardness of water is not harmful for human health but can be precipitated by
heating so can produce damaging effects in boilers, hot pipes etc by depositing the material
and reducing the water storage and carriage capacity. Absolute soft water on the other
hand is not acceptable for humans because it may cause ailments, especially to heart
patients. Hardness in water is commonly classified in terms of the amount of CaCO3
(Calcium Carbonate) in it.
Concentration of CaCO3 Degree of hardness
0 – 75 mg / L Soft
75 – 150 mg / L Moderately hard
150 – 300 mg / L Hard
300 up mg / L Very Hard
Table 1 - Degree of Hardness
Low level of hardness can be removed just by boiling but high degree of hardness can be
removed by addition of lime. This method has also the benefit that iron and manganese
contents are removed and suspended particles including micro-organisms are reduced.
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Turbidity:
Keywords: study and interpretation of the chemical characteristics of natural water,
chemical characteristics of water, chemical characteristics of natural water, water chemical
properties.
Municipal Wastewater Treatment Systems
Objectives of Wastewater Treatment
To kill the pathogens
To improve the quality of waste-water
To avoid unhygienic conditions
To protect the aquatic life from the toxicity wastes
To make the waste water usable for agricultural, aquaculture etc
There are three constituents and interrelated aspects of waste water management.
1. Collection of Wastewater
o Collection of domestic wastewater is best achieved by a full sewerage water drain
age system. Unfortunately this method is most expensive and there is relatively few
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communities in hot climate which afford it. A modern hygienic method of night
soil collection is the only realistic alternative.
2. Treatment of Wastewater
o Treatment is required principally to destroy pathogenic agents in sewage or night
soil and to encore that it is suitable for whatever re-use process is secreted for it.
3. Re-use of wastewater (Recycling of wastewater)
o The responsible re-use of night soil and sewage effluent is aqua culture and crop
irrigation can make a significant contribution to a community food supply and
hence it’s general social development. The best example is china where over 90%
of waste after treatment is applied to land
Performance criteria for Wastewater Treatment Management System
The ideal system would satisfy all of the following criteria.
i. Health criteria
ii. Water Recycling criteria
iii. Ecological criteria
iv. Nuisance criteria
v. Cultural criteria
vi. Operational criteria
vii. Cost criteria
i. Health Criteria:
Pathogenic organisms should not be spread either by direct contact with right soil or
sewage or indirectly via soil, water or food. The treatment chosen should achieve a high
degree of pathogen destruction.
ii. Re-use/Recycle Criteria:
The treatment process should yield a safe product for re-use, preferably in aquaculture and
agriculture.
iii. Ecological criteria:
In those cases land the should be considered exception when the waste cannot be re-use,
the discharge of effluent into a surface water should not exceed the self-purification
capacity of the recipient water.
iv. Nuisance Criteria:
The degree of odor release must be below the nuisance threshold. No part of the system
should become aesthetically offensive.
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v. Cultural Criteria.
The methods chosen for waste collection, treatment and re-use should be compatible with
local habits and social (religious) practice.
vi. Operational Criteria:
The skills required for the routine operation and maintenance of the system components
must be available locally or are such that they can be acquired with only minimum training.
vii. Cost criteria:
Capital and running costs must not exceed the community’s ability to pay. The financial
return from re-use schemes is an important factor is an important factor in this regard.
However, no one system completely satisfies all these demands. The problem becomes one
of minimizing disadvantages.
Waste Water Treatment Processes
Municipal wastewater is primarily organic in content and a significant number of industries
including chemical pharmaceutical and food have high organic waste load. This means that
the main treatment processes are geared towards organic removal. In a typical treatment
plant, the wastewater is directed through a series of physical, chemical and biological
processes each with specific waste load reduction task. The tasks are typically.
1. Pre-treatment ==> Physical and / or chemical
2. Primary treatment ==> Physical
3. Secondary treatment ==> Biological
4. Advanced treatment ==> Physical and / or chemical and / or biological.
Conventional Wastewater Treatment Plant Processes
Municipal Wastewater Treatment
Conventional treatment or conventional mechanical wastewater treatment is the term used
to describe the standard method of treatment designed to remove organic matter and solid
from solution. It comprises four stages of treatment.
Preliminary treatment ( influent flow measurement, screening (Bar racks),
Shredders, comminutors (maceratours), pumping, grit removal)
Primary treatment (sedimentation)
Secondary treatment (biofitration or activated sludge)
Sludge treatment (anaerobic digestion of the sludge produced in primary and
biological treatment)
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Preliminary Treatment of Waste Water
Preliminary treatment of wastewater consists of the following steps:
1. Screening
2. Comminution
3. Grit Removal
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4. Flow Equalization
5. Oil and Grease Removal
6. Pre-Aeration
1. Screening
The first unit operation generally encountered in wastewater treatment plants is screening.
A screen is a device with openings, generally of uniform size, that is used to retain solids
found in the influent wastewater to the treatment pant. The principal role of screening is to
remove coarse materials (pieces of wood, plastics, rags, papers, leaves, roots etc.) from the
flow stream that could:
1. Damage subsequent process equipment e.g. pumps, valves, pipe lines, impellers.
2. Reduce overall treatment process reliability & effectiveness, or
3. Contaminate waste way
Design of screening chamber:
The objective of screens is to remove large floating material and coarse solids from
wastewater. It may consist of parallel bars, wires or grating placed across the flow inclined
at 30o-60o. According to method of cleaning; the screens are hand cleaned screens or
mechanically cleaned screens. Whereas, according to the size of clear opening, they are
coarse screens (≥ 50 mm), medium screens (25-50 mm) and fine screens (10-25 mm).
Normally, medium screens are used in domestic wastewater treatment.
Dimensions of an approach channel
Used in wastewater treatment is mostly rectangular in shape. Wastewater from the wet well
of the pumping station is pumped into the approach channel from where it flows by gravity
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to the treatment plant. Its main function is to provide a steady and uniform flow after
pumping.
Select the size of bar/clear opening, say 10mm x 10 mm (medium screens)
No. of bars; {(n + 1) + (n) = B}, and {Be = B – (width of bar)(n)}
Head loss, hL = 0.0729 (V2 – Vh2) ------ {Vh 0.75m/sec, hL ≤ 0.5 ft}
For perforated plate; amount of screening produce = (1-2) ft3/MG
Length of bar; L = D/sinθ, and Lh = L * cosθ.
Screen chamber. Lc = inlet zone (2-3 ft) + Lh + outlet zone {outlet zone = width of p
plate + (0.5-1.0 ft)}
2. Wastewater treatment through Coarse Solids Reduction:
As an alternative to coarse bar screens or fine screens, communitors and macerators be use
to intercept coarse solids and grind or shred them in the screen channel. High – speed
grinders are used in conjunction with mechanically cleaned screens to grin and shred
screenings that are cit up into a smaller, more uniform size for return to the flow stream for
subsequent removal by downstream treatment operations and processes, communitors,
macerators and grinders can theoretically eliminate the messy and offensive task of
screening handling and disposal.
Comminutors – small WWT (0.2 m3
/s or 5 MGD) 6 - 20 mm (0.25 N 0.77in)
a. Comminutors:
Comminutors are used commonly in small wastewater treatment plants having discharge
less than (0.2m3
/s or 5MGD). They are installed in a wastewater flow channel to screen and
shred material to sizes from 6 to 20 mm (0.25 to 0.77 in) without removing the shredded
solids from the flow stream. It cuts them to a relatively uniform size and prevents the solids
from freezing/clogging in the flow.
Comminutors are always placed before the grit chamber to reduce wear and tear occurring
on the surfaces.
b. Macerators:
Macerators are slow speed grinders that typically consist of two sets of counter rotating
assemblies with blades. The assemblies are mounted vertically in the flow channel. The
blades or teeth on the rotation assembles have a close tolerance that effectively chop
material as it passes through the unit.
c. Grinders:
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High speed grinders typically referred to as fiammermills, receive screened materials from
base screen. The materials are pulverized by a high speed rotation assembly that wets the
materials passing through the unit.
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3. Grit Removal system from Wastewater:
It is a Unit operation (physical). Removal of grit form waste Swater may be accomplished
in grit chambers or by centrifugal separation of solids. Grit chambers are designed to
remove grit, consisting of sand, gravel, sanders, or other heavy solid materials that have
specific gravities or setting velocities substantially greater than those of organic particles
in wastewater. Grit chambers are most commonly located after the bar screens and before
the primary sedimentation.
These are just like sedimentation tanks, design mainly to remove heavier particles or coarse
inert and relatively dry suspended solids from the wastewater. There are two main types of
grit chambers like rectangular horizontal flow types and aerated grit chambers. In the
aerated grit chamber the organic solids are kept in suspension by rising aerted system
provided at the bottom of the tank.
Purpose of Grit Chamber
Grit chambers are provided to:
1. Protect moving mechanical equipment from abrasion and accompanying abnormal wear.
2. Reduce formation of heavy deposits in pipelines, channels and conduits.
3. Reduce the frequency of digester.
Flow Equalization tank
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Flow equalization is method used to overcome the operational problems and flow rate
variations to improve the performance of downstream processes and to reduce the size &
cost of downstream treatment facilities. To prevent flow rate, temperature, and contaminant
concentrations from varying widely, flow equalization is often used. It achieves its
objective by providing storage to hold water when it is arriving too rapidly, and to supply
additional water when it is arriving less rapidly than desired. A smaller the screen opening,
greater will be the amount of material screened.
In order to improve the performance of a reactor, particularly the biological processes, it
is required to equalize the strength of wastewater and to provide uniform flow, an
equalization tank is design after screen and grit chamber. This may be in the line-off or
off-line, as shown in the figure;
5. Primary Sedimentation Tank
Sedimentation or setting tanks that receive raw wastewater prior to biological treatment are
called primary tanks. The objective of the primary sedimentation tank is to remove readily
settleable organic solids and floating material and thus reduce the suspended solid content.
Efficiently designed and operated primary sedimentation tanks should remove from 50 to
70% the suspended solids and 25 to 40% of the BOD.
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Sedimentation is carried out in variety of tank configurations including:
Circular sedimentation tank
Rectangular sedimentation tank
Square sedimentation tank
Primary sedimentation is among the oldest wastewater treatment process. Traditionally the
design criteria for sizing setting tanks are:
Average overflow rate: 30 - 50 m3
/m2
/d (Typical 40 m3
/m2
/d) [800-1200 gal/ft2
-d
(Typical 1000 gal/ft2
-d]
Peak hourly overflow rate: 50 - 120 m3
/m2
/d (Typical 100 m3
/m2
/d) [2000-3000 gal/ft2
-d
(Typical 2500 gal/ft2
-d]
Weir loading rate: 1.5 - 2.5h (Typical 2.0 h) [1.5 - 2.5 h (Typical 2.0h)]
Types of Primary Sedimentation Tanks
Primary Sedimentation takes place in the sedimentation tanks with the objective to remove
readily settleable solids and floating materials and thus reduce the suspended solids
content. The removal rate is 50-70% of suspended solids and 25-40% of BOD whereas,
generally more than two rectangular or circular tanks are used.
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Rectangular Horizontal Flow Tanks
These are most commonly used for primary sedimentation, since they
Occupy less space than circular tanks.
They can be economically built side-by-side with common walls.
Length ranges 15 to 100m an width from 3 to 24m (length/ width ratio 3:1 to 5:1)
The maximum forward velocity to avoid the risk of scouring settled sludge is 10 to 15
mm/s (06 to 09m/min or 2 to 3 ft/ min), indicating that the ratio of length to width l/w
should referrals be about.
The maximum weir loading rate, to limit the influence of draw-down currents, is preferably
about 300 m3
/d-m, this figure is sometime increased where the design flow is great then 3
ADWF.
Inlets should be baffled to dissipate the momentum of the incoming flow and to assist in
establishing uniform forward flow.
Sludge is removed by scraping it into collecting hoppers at the inlet end of the tank.
Some removal is essential in primary sedimentation tanks because of the grease and other
floating matter which is present in wastewater. The sludge serapes can return along the
length of the tank a the water surface. As they move towards the outlet end of the bank, the
flights then move the sum towards a skimmer located just upstream of the effluent weirs.
Rectangular Sedimentation Tank
Circular Radial Flow Tanks
These are also used for primary sedimentation.
Most common-have diameters from 3 to 60m (side water depth range from 3 to 5m)
Careful design of the inlet stilling well is needed to active a stable radial flow pattern
without causing excessive turbulence in the vicinity of the central sludge hopper.
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The weir length aroid the perimeter of the tank is usually sufficient to give a sates
factory weir loading rate at maximum flow, but at low flows, very low flow depths
may result.
To overcome the sensitivity of these tanks to slight errors in weir level and wind
effects, it is common to provide v-much wares.
Sludge removal is effected by means of a rotary sludge scrapper who moves the
sludge into a central hopper, form which it is with drown.
Scum removal is carried out by surface skimming board attached to the sludge
scrapper mechanism and positioned so that scum is moved towards a collecting
hopper at the surface.
Up Flow Tanks:
Up flow tanks, usually square in plan and with deep hopper bottoms, are common
in small treatment plants.
Their main advantage is that sludge removal is cared out entirely by activity and no
mechanical parts are required for cleaning them.
The steeply sloping sides usually to to horizontal concentrate the sludge at the
bottom of the hopper.
Weir loading rate is a problem only at low flows. So that v-match weirs are
desirable.
The required up flow pattern is maintained by weir troughs.
True up flow tanks have an disadvantage on that hydraulic over loading may have
more serious effects than in horizontal flow tanks.
Any practical with a velocity lower than VP = Q/A will not removed in an up flow
tank, but will escape in the effluent.
In a horizontal flow tank assuming that such particles were uniformly distributed to
the flow, particle with Vp=Q/A still be removed in proportion.
Square sedimentation tank
They may be flat bottomed or hopper bottomed. Wastewater enters the tanks, usually at the
center, through a well or diffusion box. The tank is sized so that retention time is about 24
(range 20 minutes to 3h). In the quiescent period, the suspended part ides settle to the
bottom as sludge and are raked towards a central hopper from where the sludge is
withdrawn.
Primary sedimentation is among the oldest wastewater treatment process. Traditionally the
design criteria for sizing setting tanks are:
Average overflow rate: 30 - 50 m3
/m2
/d (Typical 40 m3
/m2
/d) [800-1200 gal/ft2
-d
(Typical 1000 gal/ft2
-d]
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Peak hourly overflow rate: 50 - 120 m3
/m2
/d (Typical 100 m3
/m2
/d) [2000-3000 gal/ft2
-d
(Typical 2500 gal/ft2
-d]
Weir loading rate: 1.5 - 2.5h (Typical 2.0 h) [1.5 - 2.5 h (Typical 2.0h)]
Rectangular Sedimentation Tanks Circular Sedimentation Tanks
Depth
10-16 ft (Typical 14) 3 - 3.9 m
(Typical 4.3)
10-6 (Typical 14)3.39m (Typical 4.3 m)
Length 50-300 ft (Typical 80-30 ft)
Diameter 10-200 (Typical 40-150ft) 3-
60 m (Typical 12-45m
Flight speed
2-4 ft/min (Typical 3 ft/min) or
(Typical 0.9 m/min)
Scraper’s speed 0.02-0.05/min (Typical
0.03 Rev/min)
Bottom
Slope
1in/ft or Typical 0.9m/m check 1.12 ft
Always provide minimum of 2 sedimentation tanks.
Sludge accumulation is same for both.
Sludgy accumulation 2.5kg of wet solids per m3
of flow.
Secondary Biological Wastewater Treatment
Process
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1. Objectives of Secondary Treatment of waste water
Main objective
The main objective of secondary treatment: To remove most of the fine suspended and
dissolved degradable organic matter that remains after primary treatment, so that the
effluent may be rendered suitable for discharge. Conventional secondary treatment can
reduce the BOD's to below 20mg/l and Suspended Solids to below 30mg/l which is
acceptable in many cases.
Second objective
The second objective of secondary treatment: The reduction of ammonia toxicity and
nitrification oxygen demand in the stream. This is achieved by oxidation of most of the
ammonia to nitrate during treatment (nitrification).
2. Nitrification:
Means the oxidation of ammonia to nitrate. Nitrification is possible with aerobic biological
processes. If they are operated at low organic load rates-hence the units must be large than
those which would be required for oxidation of carbonaceous matter alone.
1. Conventional sedimentation the major process in primary wastewater treatment, normally
removes 60 to 70 % of suspended solids matter containing 30% to 40% of the BOD present
in municipal wastewater, leaving 150 to 200 mg/ l of BOD's and about 100mg/l SS in the
primary effluent.
2. Discharge or effluent of this quality with exceeding the assimilative capacity of the
receiving the assimilative capacity of the receiving environment is only possible where
very large volumes of water are available for delectation or where the effluent may be
irrigated over a large land area.
3. For discharge to inland streams or lakes, a considerably higher quality is necessary.
Assimilative capacity of O2 in H2O = 9mg/l not less then 2mg/l.
Biological Wastewater Treatment Processes
1. Aerobic biological processed
2. Anaerobic biological processed
3. Facultative biological processed
1. Aerobic Biological Processes
Are those where sufficed amount of dissolved oxygen is required into the wastewater to
sustain aerobic action, as one of the major polluting effects of wastewater on streams results
form the depletion of dissolved oxygen by the action of aerobic organisms in degrading the
organic content of the waste. Practical aerobic biological treatment processes seek to to
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this, within the constraints of available land area and economic resources available to
construct and operate treatment works.
2. Anaerobic Biological Processes
Are those where micro-organisms oxidize organic matter in the completed absence of
dissolved oxygen. The micro-organisms take oxygen form inorganic salts which contain
bound oxygen (Nitrate NO3, Sulphate So4
2-
, Phosphate PO4
2-
). This mode of operation is
termed as anaerobic processes. Sufficiently fore dissolved oxygen is either physically
difficult or economically impracticable to transfer into the wastewater to sustain aerobic
action to biodegrade strong organic wastes.
Tip: Assimilative capacity of BOD in water is not more than or should be less then 4mg/l.
Aerobic Biological Treatment Processes
There are five types of aerobic biological treatment processes used to treat municipal
sewage
1. Tricking filters
2. Rotating biological contactors (filter)
3. Activated sludge.
4. Oxidization ponds.
5. Aerated lagoons (used for pre treat ion industrial effluent)
Trickling Filter
Introduction to trickling filter system:
It is the most common attached growth process. The trickling filter is like a circular well
having depth up to 2 meter filled with granular media like stone, plastic sheets and
redwood, slag, slate. The first tricking filter was placed in operation in England in 1893.
the concept of a tricking filter was grew form the of contact frets which were water tight
basins filled with broken stones. The limitation the contact filters included a relatively.
Wastewater is distributed over top area of vessel containing non-submerged packing
material;
Historically, rock was used with typical depths 1.25‐ 2 m
Modern trickling filters 5 to 10 m and filled with plastic packing material for biofilm
attachment;
90‐95% of volume in tower consists of void space;
Air circulation in void space provides oxygen for microorganisms growing as attached
biofilm;
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Excess biomass sloughs from attached growth periodically and clarification is required for
liquid/solids separation
High incidence of clogging,
The long retention time (a typical cycle required 12 hours, 6 hours for operation and 6
hours for resting) and relatively
Low loading rate. life cycle/ biological circle of bacteria: 20-30 mints. The tricking filter
itself consists of a bed of coarse material, such as stones, slates or plastic materials (media)
over which wastewater is applied. Because the micro-organisms that biodegrade the waste
form a film on the media this process is known as an attached growth process.
Tricking filters have been a popular biological treatment processes the must widely used
design for many years are:
Design diameter of Rock filters = 60m (2007t) and for Rock size Design diameter = 25 to
100mm
Activated Sludge Process
It involves production of activated mass of microorganisms capable of stabilizing waste
under aerobic conditions;
In aeration tank, contact time is provided for mixing and aerating influent wastewater with
microbial suspension, generally referred to mixed liquor suspended solids (MLSS) or
mixed liquor volatile suspended solids (MLVSS)
Mixed liquor than flows to clarifier where microbial suspension is settled and thickened;
Settled biomass (activated sludge) is returned to aeration tank to continue biodegradation
of influent;
Portion of thickened solids is removed daily or periodically as process produces excess
biomass;
Formation of floc particles, ranging in size from 50 to 200 μm, removed by gravity settling,
leaving relatively clear liquid as treated effluent;
Typically 99% of suspended solids removed by clarification step;
Biological Treatment systems
1. Attached growth processes
2. Suspended growth processes
3. Dual (hybrid) biological treatment processes.
Attached growth process
Microorganisms responsible for conversion of organic material or nutrients are attached
to an inert packing material;
Organic material and nutrients are removed from wastewater flowing past attached
growth also known as biofilm
Packing materials used in attached growth processes include rock, gravel, slag, sand,
redwood and wide range of plastic and other synthetic materials
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Suspended Growth (SG) Processes
Microorganisms responsible for treatment are maintained in liquid suspension by
appropriate mixing methods;
Many SG processes are operated with positive dissolved oxygen concentration;
Most common SG process is activated sludge process
Activated Sludge Wastewater Treatment Process
It is a:
Unit process
Biological treatment process
Suspended growth process
Aerobic process
Activated Sludge:
Definition
Is defined as a ‘Suspension’ of microorganisms, both living and dead’ in a wastewater.
The microorganisms are active by an input of air (oxygen) thus known as activated-sludge.
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Activate-sludge is that sludge which settle down in a secondary sedimentation tank after
the sewage has been freely aerated and agitated for a certain time in an Aeration tank.
Working Mechanism of Activated Sludge
The activated-sludge contains numerous bacteria and other microorganisms, when it is
mixed with raw sewage saturated with oxygen, the bacteria perform the following function.
1. Oxidize the organic solids.
2. Promote coagulation and flocculation and convert dissolved, colloid and suspended solids
into settle able solids. In practice the following operations are carried out in an activated -
sludge process.
3. The sewage is given treatment in the primary sedimentation tank. The detention time is
kept as short as 1-1/2 hours.
4. The settled sewage form the Primary Sedimentation Tank is the mixed with the required
quantity of activated-sludge in the aeration tank. The mixture of activated-sludge and
wastewater in the aeration tank is called ‘mixed liquor or mixed liquor suspended
solids MLSS or MLVSS mixed liquor volatile suspended solids’.
5. The Mixed Liquor Suspended Solids is aerated for 6-8 hours in the aeration tank, called
the hydraulic detention timeaccording to the degree of purification. About 8m3
of air is
provided from each m3 of waste-water treated. The volumes of sludge returned to the
aeration basin is typically 20 to 30% of waste water flow air supply 8-10 m3
of sewage
6. The aerated Mixed Liquor Suspended Solids resulting in the formation of flock particles,
ranging in size from 50 to 200pm.which is then removed in the secondary sedimentation
tank by gravity settling, leeching a relatively clear liquid as the treated effluent. Typically
greater than 99% of suspend solids can be removed in the clarification step.
7. Most of the settled sludge is returned to the aeration tank (and is called return sludge) to
maintain the high population of microbes that permits rapid breakdown of the organic
compounds. Because more activated-sludge is produced tan is desirable in the process,
some of the return sludge is diverted or wasted to the sludge handling system for treatment
and disposal.
Activated Sludge Process
Consists of three basic components:
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1. Reactor in which microorganisms responsible for treatment are kept in suspension and
aerated;
2. Liquid-solids separation usually in sedimentation tank;
3. Recycle system for returning solids removed from liquid-solids separation unit back to
reactor;
Important feature is formation of flocculent settleable solids removed by gravity settling in
sedimentation tanks. Pretreatment with primary sedimentation removes settleable solids
whereas biological processes remove soluble, colloidal, and particulate (suspended)
organic substances; for biological nitrification and denitrification; and for biological
phosphorus removal.
Activated Sludge Process Design
Design of Activated Sludge Systems:
Design of activated-sludge process involves details of sizing and operation
of the following main elements.
1. Aeration tank (reactor)-capacity and dimensions.
2. Aeration system-oxygen requirements and oxygen transfer system.
3. Final sedimentation tank – (deifier)
4. Return activated sludge system.SV1
5. Excess activated sludge withdrawal system and subsequent treatment and
disposal of waste sludge. Since the whole process takes place in a liquid medium
the hydraulic regime essentially in the aeration tank and final sedimentation tank.
6. MLSS – a mixture of settled sewage + activated sludge dissolved oxygen < 2mg/l
Design Criteria
1. F/M ratio = 0.2 – 0.5 day -1 or 0.2 – 0.5 kg BOD's / kg MLSS – d
2. Detention time (aeration time) of sewage = 6 to 6 hours
3. MLVSS or MLSS = 1500 -3000 mg/l
4. Air supply = 10m3/m3 sewage treated
5. return sludge = 0.25 -10 of Q (influent sewage flow) Qr / Q = 0.20-0.30 =
Vs/100Vs (Volume of sludge)
6. Depth = 3-5m
7. L=W ratio =5:1
8. SVI 50-150 ml/gm
Bacterial Classification in Wastewater Treatment
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Microbiology in Waste Water Treatment:
It is the branch of biology which deals with micro organisms which is unclear or cluster of
cell microscopic organisms.
MICROORGANISMS:
Microorganisms are significant in water and wastewater because of their roles in different
transmission and they are the primary agents of biological treatment. They are the most
divers group of living organisms on earth and occupy important place in the ecosystem.
Are called OMNIPRESENT.
Classification of Bacteria in Waste Water Treatment Process
1. Classification of bacteria based on Oxygen requirements (ORP)
The heterotrophic bacteria are grouped into three classification, depending on their action
toward free oxygen (O4) or more precisely oxygen-reduction potential (ORP) for survival
and optimum growth.
1. Obligate aerobe or Aerobes or bacteria are micro-organisms require free dissolved oxygen
to oxidize organic mate and to live and multiply. These conditions are referred to as aerobic
processes.
2. Anaerobes or anaerobic bacteria are micro-organisms oxidize organic matter in the
complete absence of dissolved oxygen. The micro-organisms take oxygen from inorganic
sates which contain bound oxygen (Nitrate NO3, Sulphate So4
2-
, Phosphate PO4
2-
). This
mode of operation is termed as anaerobic process.
3. Facultative bacteria are a class of batter that use free dissolved oxygen when available but
can also Respire and multiply in the absence. "Escherichia Coli" a facile coli from is a
facultative elaterium. (Facultative Bacteria = Aerobic anaerobic bacteria)
2. Classification of Microorganisms by Kingdom:
Microorganisms are organized into five broad groups based on their structural functional
differences. The groups are called “Kingdoms”. The five kingdoms are animals, plants,
protista fungi and bacteria.
Representative examples and characteristics of differentiation are shown:
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3. Classification by their preferred Temperature Regimes:
Each specie of bacteria reproduces best within a limited range of temperatures. Four
temperature ranges for bacteria:
1. That best at temperatures below 20°C are called psychrophiles.
2. Grows best in between 25°C and 40°C are called Mesophiles.
3. Between 45°C and 60°C thermopiles can grow.
4. Above 60 °C stenothermophiles grow best.
BACTERIA: