This document is an operations manual for the Duc Ninh Wastewater Treatment Plant in Quang Binh, Vietnam. It contains 9 sections that describe: 1) the characteristics and sources of wastewater that enters the plant, 2) how oxidation ponds work for wastewater treatment, 3) the characteristics and impacts of effluent water leaving the ponds, 4) processes for controlling ponds, 5) maintenance activities, 6) monitoring and record keeping, 7) discharge consents and conditions, 8) some case histories of issues at the plant, and 9) terminology used in wastewater treatment. The manual aims to help operators understand pond treatment processes, conduct normal and abnormal operations and maintenance,
internship report on performance of sewage treatment plantAshok Devasani
the report presents a clear description about the performance of 30 MLD sewage treatment plant located in the vicinity of Hyderabad. it also provides a general information of the different sewage treatment process
The document provides information on designing and operating a water treatment plant, including:
1) Key components and processes include rapid mixing, flocculation, sedimentation, and filters. Chemicals like alum are used to treat water.
2) Safety guidelines, project expectations, teamwork strategies, and plant goals are outlined. Turbidity standards and potential penalties are defined.
3) Capital and operation costs are estimated. Calculations are described to determine the cost of water production based on a plant's design.
4) Troubleshooting methods like identifying problems, developing hypotheses, and testing components are discussed. A modular design approach is recommended.
Water Treatment Plant Design by Damora, Waite, Yu, MaroofianJonathan Damora
Water treatment plant design group project with Alex Waite, Jenny Yu, Cyrus Maroofian, and Jonathan Damora. We chose the reliability of a turnkey solution by General Electric for our Reverse Osmosis and nanofiltration, while designing our own granular media filter. The focus of this project was to design a reliable system, which will perform at required standards no matter the influent composition.
This document provides information about sewage treatment plants on ships. It explains that sewage generated on ships must be treated before discharge as per regulations. The most common treatment method is a biological plant, which uses aerobic bacteria and fresh air to decompose sewage into safer byproducts. The biological plant has three chambers - an aeration chamber for decomposition, a settling tank to separate liquids and sludge, and a chlorination chamber to disinfect liquids before discharge. Key terms like BOD, coliform count and pumping levels are also defined. Proper operation and maintenance of the plant, like chemical dosing and back-flushing lines, is important for effective sewage treatment on ships.
This document provides information about the design of a sewage treatment plant for Bhagalpur municipality in India. It discusses the various components and processes involved in sewage treatment, including preliminary treatment like screening and grit removal, primary treatment using sedimentation, secondary treatment using activated sludge or rotating biological contactors, and tertiary treatment options like filtration, lagooning, and disinfection. It also provides design criteria for the sewage treatment plant including a 30-year design period and effluent quality standards.
The document presents a major project presentation for a sewage treatment plant. It includes sections on the introduction, literature review, scope of the project, methodology, design, materials, equipment, chemicals, expenditures, working procedure, conclusion, and references. The methodology section includes plans, schematic diagrams, and detailed drawings. The design considers an effluent quantity of 15 cum/day and treats the sewage to meet quality standards for parameters like pH, BOD, COD, TSS, and O&G. The project involves civil works like tanks and equipment like bar screens, pumps, filters using technologies like anaerobic digestion to treat the sewage to permissible limits for safe disposal.
DESIGN OF A 30 MLD SEWAGE TREATMENT PLANT(PROJECT REPORT) Ratnesh Kushwaha
This is a project report on design of a 30 MLD sewage treatment plant. It includes the different characteristics of waste water, various treatment units, design calculations and a layout of sewage treatment plant. This report also includes the future scope of this project.
Visit my slide share channel for downloading power point presentation of this project
This document provides an overview of wastewater treatment processes at a facility in Doha, Qatar. It describes the three main stages of treatment - primary, secondary, and tertiary. Primary treatment involves screening and grit removal. Secondary treatment uses an activated sludge process with aeration and settling tanks. Sludge is thickened and sent to aerobic digesters. Tertiary treatment includes sand filtration and ultrafiltration to further polish the effluent water before reuse or discharge.
internship report on performance of sewage treatment plantAshok Devasani
the report presents a clear description about the performance of 30 MLD sewage treatment plant located in the vicinity of Hyderabad. it also provides a general information of the different sewage treatment process
The document provides information on designing and operating a water treatment plant, including:
1) Key components and processes include rapid mixing, flocculation, sedimentation, and filters. Chemicals like alum are used to treat water.
2) Safety guidelines, project expectations, teamwork strategies, and plant goals are outlined. Turbidity standards and potential penalties are defined.
3) Capital and operation costs are estimated. Calculations are described to determine the cost of water production based on a plant's design.
4) Troubleshooting methods like identifying problems, developing hypotheses, and testing components are discussed. A modular design approach is recommended.
Water Treatment Plant Design by Damora, Waite, Yu, MaroofianJonathan Damora
Water treatment plant design group project with Alex Waite, Jenny Yu, Cyrus Maroofian, and Jonathan Damora. We chose the reliability of a turnkey solution by General Electric for our Reverse Osmosis and nanofiltration, while designing our own granular media filter. The focus of this project was to design a reliable system, which will perform at required standards no matter the influent composition.
This document provides information about sewage treatment plants on ships. It explains that sewage generated on ships must be treated before discharge as per regulations. The most common treatment method is a biological plant, which uses aerobic bacteria and fresh air to decompose sewage into safer byproducts. The biological plant has three chambers - an aeration chamber for decomposition, a settling tank to separate liquids and sludge, and a chlorination chamber to disinfect liquids before discharge. Key terms like BOD, coliform count and pumping levels are also defined. Proper operation and maintenance of the plant, like chemical dosing and back-flushing lines, is important for effective sewage treatment on ships.
This document provides information about the design of a sewage treatment plant for Bhagalpur municipality in India. It discusses the various components and processes involved in sewage treatment, including preliminary treatment like screening and grit removal, primary treatment using sedimentation, secondary treatment using activated sludge or rotating biological contactors, and tertiary treatment options like filtration, lagooning, and disinfection. It also provides design criteria for the sewage treatment plant including a 30-year design period and effluent quality standards.
The document presents a major project presentation for a sewage treatment plant. It includes sections on the introduction, literature review, scope of the project, methodology, design, materials, equipment, chemicals, expenditures, working procedure, conclusion, and references. The methodology section includes plans, schematic diagrams, and detailed drawings. The design considers an effluent quantity of 15 cum/day and treats the sewage to meet quality standards for parameters like pH, BOD, COD, TSS, and O&G. The project involves civil works like tanks and equipment like bar screens, pumps, filters using technologies like anaerobic digestion to treat the sewage to permissible limits for safe disposal.
DESIGN OF A 30 MLD SEWAGE TREATMENT PLANT(PROJECT REPORT) Ratnesh Kushwaha
This is a project report on design of a 30 MLD sewage treatment plant. It includes the different characteristics of waste water, various treatment units, design calculations and a layout of sewage treatment plant. This report also includes the future scope of this project.
Visit my slide share channel for downloading power point presentation of this project
This document provides an overview of wastewater treatment processes at a facility in Doha, Qatar. It describes the three main stages of treatment - primary, secondary, and tertiary. Primary treatment involves screening and grit removal. Secondary treatment uses an activated sludge process with aeration and settling tanks. Sludge is thickened and sent to aerobic digesters. Tertiary treatment includes sand filtration and ultrafiltration to further polish the effluent water before reuse or discharge.
It is a minor project perform by CEC, durg student... ANUPAM , RAJU, SWARAJ, BHUPENDRA, BASANT, WE take durg nala water to testing in lab which is directly dump to shivnath river .....
This document provides details on the design and process of an effluent treatment plant (ETP) at Rourkela Steel Plant. The ETP uses coagulants, flocculants and pH adjusters to treat wastewater from the gas cleaning plant. Key components of the ETP include flash mixers for chemical treatment, thickeners to separate solids from water, sludge tanks for sludge storage, and a filter press to dewater the sludge. The ETP is designed to meet performance standards for treated water quality and sludge moisture content.
This is a power point presentation on design of a 30 MLD sewage treatment plant. It includes the different characteristics of waste water,various treatment units, design results and a layout of sewage treatment plant.
Visit my slide share channel for downloading report of this project.
SEWAGE TREATMENT PLANT mini project reportNitesh Dubey
This document provides information about a research project analyzing the quality of treated sewage water from shipboard sewage treatment plants. Water samples were taken from 32 ships and analyzed for parameters like coliform bacteria, suspended solids, and biological oxygen demand. The results showed that none of the treated sewage water samples met standards in the MARPOL Annex IV regulations. The document also describes regulations for sewage discharge, potential health and environmental risks of untreated sewage, and common types of sewage treatment systems used on ships.
Performance Evaluation of Dairy Wastewater Treatment PlantIRJET Journal
1) The document analyzes the performance of a dairy wastewater treatment plant in Jaipur, India.
2) It evaluates various water quality parameters (BOD, COD, TSS, oil/grease) at the plant's inlet and outlet to assess the plant's ability to treat wastewater to regulatory standards.
3) The results show that the plant significantly reduces all parameters measured (BOD reduced from 1477 mg/L to 12 mg/L) and meets regulatory limits for treated water discharge.
This document provides an overview of common effluent treatment plants (CETPs) in India. It discusses how CETPs were originally promoted to reduce wastewater treatment costs for small and medium industries. It then describes the typical wastewater treatment processes used at CETPs, including preliminary treatment, primary treatment, secondary treatment and tertiary treatment. The document also discusses advantages and disadvantages of CETPs, different disposal methods for treated wastewater, and provides case studies of three CETPs in India.
Electro Chem Enviro Solutions manufactures advanced, compact, and economical water treatment plants, effluent treatment plants, and sewage treatment plants using electro-chemical processes. The document provides details on the types of treatment plants and applications. It also lists the company's contact information.
Design of 210 Mld Sewage Treatment PlantARUN KUMAR
This document provides details on the design of a 210 million liter per day sewage treatment plant. It discusses the need for the plant to treat sewage and prevent pollution. It then describes the three main stages of sewage treatment - primary, secondary, and tertiary treatment. Primary treatment involves removing solids and debris. Secondary treatment uses microorganisms to break down dissolved organic matter. Tertiary treatment further polishes the water with methods like filtration and chlorination before discharge.
This document describes upgrades to Attock Refinery Ltd.'s effluent treatment plant (ETP) to enhance its capacity and comply with environmental regulations. The upgrades include:
1) Adding secondary treatment with an activated sludge system and clarifier after primary treatment via dissolved air flotation.
2) Upgrading API separators with scrapers to remove solids, oil skimmers to remove oil, and oil coalescers.
3) Expanding effluent treatment capacity from 100 to 200 gallons per minute and adding biological secondary treatment to remove more contaminants like BOD, COD, and oil/grease.
Effluent treatment plant - design, operation and analysis of waste water trea...Shubham Hydrosys Pvt. Ltd
The Effluent Treatment Plants [ETP] plant is designed to treat the effluent coming from various areas of the plant. The treatment of different effluents varies with the type of effluent. Industrial wastewater contains a diversity of impurities and therefore for this reason alone, its treatment establishes a special task. Shubham Inc. offers comprehensive range of Effluent Treatment Plants that is highly effective.
The complete treatment solution works at many levels and comprises of different physical, chemical, biological and membrane processes. For reducing the BOD, COD, color, nitrogen and toxic level of the effluent, SHUBHAM is offeringa various solutions from ASP (activated sludge process) to advance Membrane technologies as per treated water uses.Shubham OffersCustomized systems to suit the extensive variety of effluents and to maintain efficiency are provided to industries.
We provide innovative and economical systems for waste withexpertise is advantageously employed for the technical and economic optimization of every subsequent facility.
SHUBHAM INC use the best-in-class technology and cutting-edge tools to foster high-quality, sustainable, community-level water supply sewage treatment plant and Effluent Treatment Plants projects in Gujarat, India across the ahmedabad, Surat, Rajkot and Baroda.
Some processes followed by us are:
• Aerobic Biological Process
• Anaerobic Biological Process
• Chemical-physical process
TREATMENT REQUIREMENTS:
1. Oil & grease Separation
2. Neutralization of Acids and Alkali
3. Removal of Suspended Solids
4. Reduction & Removal of metallic impurities
5. Reduction of high organic content: BOD, COD, P, TKN, etc.
6. Dissolve impurities for ZLD system.
TREATMENT METHODS
• Primary clarifications
• Biological process
• Secondary clarifications.
• Tertiary treatment
• Polishing units i.e. UF, RO and DM (Optional for recycling or ZLD)
Applications:
• Textile Industries
• Distilleries
• Pharmacy Industries.
• Chemical Industries
• Paper Industries
• Tannery Industries
• Dye & Dye Intermediaries
• Edible Oil Refineries
• Electroplating Industries
Features:
• Sturdy construction
• Resistant to corrosion
• Superior performance
• Rapid installation
• Less civil work involved
• Flexible in reworking
These regulations establish standards and requirements for industrial effluent discharge in Malaysia. They require industries that discharge effluent to:
1. Notify authorities of new or changed discharge sources and treat effluent according to approved standards.
2. Monitor effluent quality and quantity, maintain records, and submit monitoring reports.
3. Operate and maintain effluent treatment systems properly using competent supervisors, and conduct performance monitoring according to guidelines.
The regulations specify effluent quality standards, record keeping and personnel training requirements to control pollution from industrial sources.
This SlideShare was authored by Dr. Ananth Seshadri Kodavasal who has more than 30 years of experience as an environmental Engineer and is a looked upon as a foremost authority on Sewage Treatment Plants.
It was presented during Water Workshop conducted by ApartmentADDA on 25-Feb-2012. It explains the below topics
• Wastewater Pollutants/Impact
• Physical, Chemical, Biological Unit Operations
• Types & Effects of Pollution
• Biological Treatment Variants
• Pros and Cons
At last the SlideShare details on the Important Acts and rules related to Environmental Protection.
Check the link below for details
http://apartmentadda.com/blog/water-workshop-for-apartments-report/
IRJET- Design of Sewage Treatment Plant of 7.5 MLD Capacity based on Sequenti...IRJET Journal
This document describes the design of a 7.5 MLD sewage treatment plant using sequential batch reactor technology in Dhanas, India. Key aspects of the design include:
- Testing of sewage samples to determine treatment requirements.
- Design of treatment units including screens, grit removal, SBR basins, sludge handling, and chlorination.
- The plant is designed to treat sewage from the existing population of 7,094 people and future estimated population of 50,000 to meet effluent standards for irrigation and drainage.
Report on Effluent Treatment Plant (ETP) Operation and Maintenance of Interst...Kowshick Sen
Interstoff Apparels Ltd (IAL) comprises of the latest, most technologically advanced 100% export oriented private limited company with composite knitting, dyeing, finishing and apparel manufacturing plants situated in Chandra, Kaliyakoir, Gazipur, Bangladesh. IAL installed an Effluent Treatment Plant of 75 m3/Hr capacity which is running 24 Hr in a day. By nature, our ETP is Bio-logical with Chemical namely Bio-Chemical plant. This treatment is done by four stages such as preliminary, primary, secondary and tertiary treatment. Waste water comes from mainly dyeing and washing through a trench to equalization tank so for preliminary treatment is done by screening by using net or sieve for removal of large solids such as rags, sticks, grit and grease that may result in damage to equipment or operational problems at different stages of trench.
This document provides an overview of a turnkey solution for water and wastewater treatment. It discusses various treatment processes including bioaugmentation, screens, primary clarification, biological processes, and sedimentation tanks. It then focuses on the activated sludge process for secondary treatment, describing the basic process, design considerations like organic loading and aeration requirements, and different aeration methods like diffused, spray, turbine, and surface aeration.
The document discusses hazard and risk management in effluent treatment. It defines hazards, risk, and management. It then describes the effluent treatment process, which uses physical, chemical, and biological processes to remove contaminants from wastewater. This includes preliminary treatment to remove solids, primary treatment using sedimentation to remove suspended solids, and secondary biological treatment using methods like activated sludge processes to break down organic matter. The document provides details on various treatment units and procedures to produce safely treated effluent. It also briefly mentions the roles of emergency services in public safety.
This document describes a common effluent treatment plant (CETP) designed to treat wastewater from tanneries. It first provides background on tanneries and the wastewater generation process. It then outlines the key components of the CETP, including primary treatment using screens and settling tanks, secondary treatment using aeration and clarification, and tertiary treatment using filters. It also discusses chemical dosing requirements and design parameters like retention time. The CETP is presented as an effective way to treat combined wastewater from multiple tanneries to reduce costs and help meet discharge standards.
Primary and secondary wastewater treatment..snehalmenon92
This document provides an overview of primary and secondary wastewater treatment processes. It begins by defining wastewater treatment as applying technology to improve water quality. Primary treatment involves removing coarse solids and grit, while secondary treatment uses biological processes like activated sludge to further break down organic matter. The document then describes various primary and secondary treatment units and processes in detail, such as grit chambers, primary clarifiers, trickling filters, and biological nutrient removal. It concludes by discussing tertiary/advanced treatment options for removing additional contaminants.
The Hydro MicroScreen is an alternative to primary settling tanks for wastewater treatment that uses a rotating belt to physically separate solids and liquids. It can achieve equivalent or better removal of TSS, BOD, and FOG compared to primary tanks, while using half the cost, 90% less space, and 50% less power. The Hydro MicroScreen also produces sludge that is up to 50% drier than primary settling tanks. It has been successfully used to reduce treatment costs and space needs at wastewater plants.
This document provides guidance on sequencing batch reactor (SBR) design and operation. It was developed by the New England Interstate Water Pollution Control Commission based on a literature review and visits to five SBR facilities. The document aims to highlight design and operational enhancements that can improve wastewater treatment performance. It is intended to assist municipalities, engineers, regulators and operators working with SBR systems.
This document provides guidance on hygrometry principles for measuring moisture content. It discusses factors that can affect moisture monitor performance such as pressure, temperature, flow rate and contaminants. It also covers maintaining aluminum oxide probes, dealing with corrosive gases/liquids, and formulas for calculating moisture measurements in gases and liquids.
It is a minor project perform by CEC, durg student... ANUPAM , RAJU, SWARAJ, BHUPENDRA, BASANT, WE take durg nala water to testing in lab which is directly dump to shivnath river .....
This document provides details on the design and process of an effluent treatment plant (ETP) at Rourkela Steel Plant. The ETP uses coagulants, flocculants and pH adjusters to treat wastewater from the gas cleaning plant. Key components of the ETP include flash mixers for chemical treatment, thickeners to separate solids from water, sludge tanks for sludge storage, and a filter press to dewater the sludge. The ETP is designed to meet performance standards for treated water quality and sludge moisture content.
This is a power point presentation on design of a 30 MLD sewage treatment plant. It includes the different characteristics of waste water,various treatment units, design results and a layout of sewage treatment plant.
Visit my slide share channel for downloading report of this project.
SEWAGE TREATMENT PLANT mini project reportNitesh Dubey
This document provides information about a research project analyzing the quality of treated sewage water from shipboard sewage treatment plants. Water samples were taken from 32 ships and analyzed for parameters like coliform bacteria, suspended solids, and biological oxygen demand. The results showed that none of the treated sewage water samples met standards in the MARPOL Annex IV regulations. The document also describes regulations for sewage discharge, potential health and environmental risks of untreated sewage, and common types of sewage treatment systems used on ships.
Performance Evaluation of Dairy Wastewater Treatment PlantIRJET Journal
1) The document analyzes the performance of a dairy wastewater treatment plant in Jaipur, India.
2) It evaluates various water quality parameters (BOD, COD, TSS, oil/grease) at the plant's inlet and outlet to assess the plant's ability to treat wastewater to regulatory standards.
3) The results show that the plant significantly reduces all parameters measured (BOD reduced from 1477 mg/L to 12 mg/L) and meets regulatory limits for treated water discharge.
This document provides an overview of common effluent treatment plants (CETPs) in India. It discusses how CETPs were originally promoted to reduce wastewater treatment costs for small and medium industries. It then describes the typical wastewater treatment processes used at CETPs, including preliminary treatment, primary treatment, secondary treatment and tertiary treatment. The document also discusses advantages and disadvantages of CETPs, different disposal methods for treated wastewater, and provides case studies of three CETPs in India.
Electro Chem Enviro Solutions manufactures advanced, compact, and economical water treatment plants, effluent treatment plants, and sewage treatment plants using electro-chemical processes. The document provides details on the types of treatment plants and applications. It also lists the company's contact information.
Design of 210 Mld Sewage Treatment PlantARUN KUMAR
This document provides details on the design of a 210 million liter per day sewage treatment plant. It discusses the need for the plant to treat sewage and prevent pollution. It then describes the three main stages of sewage treatment - primary, secondary, and tertiary treatment. Primary treatment involves removing solids and debris. Secondary treatment uses microorganisms to break down dissolved organic matter. Tertiary treatment further polishes the water with methods like filtration and chlorination before discharge.
This document describes upgrades to Attock Refinery Ltd.'s effluent treatment plant (ETP) to enhance its capacity and comply with environmental regulations. The upgrades include:
1) Adding secondary treatment with an activated sludge system and clarifier after primary treatment via dissolved air flotation.
2) Upgrading API separators with scrapers to remove solids, oil skimmers to remove oil, and oil coalescers.
3) Expanding effluent treatment capacity from 100 to 200 gallons per minute and adding biological secondary treatment to remove more contaminants like BOD, COD, and oil/grease.
Effluent treatment plant - design, operation and analysis of waste water trea...Shubham Hydrosys Pvt. Ltd
The Effluent Treatment Plants [ETP] plant is designed to treat the effluent coming from various areas of the plant. The treatment of different effluents varies with the type of effluent. Industrial wastewater contains a diversity of impurities and therefore for this reason alone, its treatment establishes a special task. Shubham Inc. offers comprehensive range of Effluent Treatment Plants that is highly effective.
The complete treatment solution works at many levels and comprises of different physical, chemical, biological and membrane processes. For reducing the BOD, COD, color, nitrogen and toxic level of the effluent, SHUBHAM is offeringa various solutions from ASP (activated sludge process) to advance Membrane technologies as per treated water uses.Shubham OffersCustomized systems to suit the extensive variety of effluents and to maintain efficiency are provided to industries.
We provide innovative and economical systems for waste withexpertise is advantageously employed for the technical and economic optimization of every subsequent facility.
SHUBHAM INC use the best-in-class technology and cutting-edge tools to foster high-quality, sustainable, community-level water supply sewage treatment plant and Effluent Treatment Plants projects in Gujarat, India across the ahmedabad, Surat, Rajkot and Baroda.
Some processes followed by us are:
• Aerobic Biological Process
• Anaerobic Biological Process
• Chemical-physical process
TREATMENT REQUIREMENTS:
1. Oil & grease Separation
2. Neutralization of Acids and Alkali
3. Removal of Suspended Solids
4. Reduction & Removal of metallic impurities
5. Reduction of high organic content: BOD, COD, P, TKN, etc.
6. Dissolve impurities for ZLD system.
TREATMENT METHODS
• Primary clarifications
• Biological process
• Secondary clarifications.
• Tertiary treatment
• Polishing units i.e. UF, RO and DM (Optional for recycling or ZLD)
Applications:
• Textile Industries
• Distilleries
• Pharmacy Industries.
• Chemical Industries
• Paper Industries
• Tannery Industries
• Dye & Dye Intermediaries
• Edible Oil Refineries
• Electroplating Industries
Features:
• Sturdy construction
• Resistant to corrosion
• Superior performance
• Rapid installation
• Less civil work involved
• Flexible in reworking
These regulations establish standards and requirements for industrial effluent discharge in Malaysia. They require industries that discharge effluent to:
1. Notify authorities of new or changed discharge sources and treat effluent according to approved standards.
2. Monitor effluent quality and quantity, maintain records, and submit monitoring reports.
3. Operate and maintain effluent treatment systems properly using competent supervisors, and conduct performance monitoring according to guidelines.
The regulations specify effluent quality standards, record keeping and personnel training requirements to control pollution from industrial sources.
This SlideShare was authored by Dr. Ananth Seshadri Kodavasal who has more than 30 years of experience as an environmental Engineer and is a looked upon as a foremost authority on Sewage Treatment Plants.
It was presented during Water Workshop conducted by ApartmentADDA on 25-Feb-2012. It explains the below topics
• Wastewater Pollutants/Impact
• Physical, Chemical, Biological Unit Operations
• Types & Effects of Pollution
• Biological Treatment Variants
• Pros and Cons
At last the SlideShare details on the Important Acts and rules related to Environmental Protection.
Check the link below for details
http://apartmentadda.com/blog/water-workshop-for-apartments-report/
IRJET- Design of Sewage Treatment Plant of 7.5 MLD Capacity based on Sequenti...IRJET Journal
This document describes the design of a 7.5 MLD sewage treatment plant using sequential batch reactor technology in Dhanas, India. Key aspects of the design include:
- Testing of sewage samples to determine treatment requirements.
- Design of treatment units including screens, grit removal, SBR basins, sludge handling, and chlorination.
- The plant is designed to treat sewage from the existing population of 7,094 people and future estimated population of 50,000 to meet effluent standards for irrigation and drainage.
Report on Effluent Treatment Plant (ETP) Operation and Maintenance of Interst...Kowshick Sen
Interstoff Apparels Ltd (IAL) comprises of the latest, most technologically advanced 100% export oriented private limited company with composite knitting, dyeing, finishing and apparel manufacturing plants situated in Chandra, Kaliyakoir, Gazipur, Bangladesh. IAL installed an Effluent Treatment Plant of 75 m3/Hr capacity which is running 24 Hr in a day. By nature, our ETP is Bio-logical with Chemical namely Bio-Chemical plant. This treatment is done by four stages such as preliminary, primary, secondary and tertiary treatment. Waste water comes from mainly dyeing and washing through a trench to equalization tank so for preliminary treatment is done by screening by using net or sieve for removal of large solids such as rags, sticks, grit and grease that may result in damage to equipment or operational problems at different stages of trench.
This document provides an overview of a turnkey solution for water and wastewater treatment. It discusses various treatment processes including bioaugmentation, screens, primary clarification, biological processes, and sedimentation tanks. It then focuses on the activated sludge process for secondary treatment, describing the basic process, design considerations like organic loading and aeration requirements, and different aeration methods like diffused, spray, turbine, and surface aeration.
The document discusses hazard and risk management in effluent treatment. It defines hazards, risk, and management. It then describes the effluent treatment process, which uses physical, chemical, and biological processes to remove contaminants from wastewater. This includes preliminary treatment to remove solids, primary treatment using sedimentation to remove suspended solids, and secondary biological treatment using methods like activated sludge processes to break down organic matter. The document provides details on various treatment units and procedures to produce safely treated effluent. It also briefly mentions the roles of emergency services in public safety.
This document describes a common effluent treatment plant (CETP) designed to treat wastewater from tanneries. It first provides background on tanneries and the wastewater generation process. It then outlines the key components of the CETP, including primary treatment using screens and settling tanks, secondary treatment using aeration and clarification, and tertiary treatment using filters. It also discusses chemical dosing requirements and design parameters like retention time. The CETP is presented as an effective way to treat combined wastewater from multiple tanneries to reduce costs and help meet discharge standards.
Primary and secondary wastewater treatment..snehalmenon92
This document provides an overview of primary and secondary wastewater treatment processes. It begins by defining wastewater treatment as applying technology to improve water quality. Primary treatment involves removing coarse solids and grit, while secondary treatment uses biological processes like activated sludge to further break down organic matter. The document then describes various primary and secondary treatment units and processes in detail, such as grit chambers, primary clarifiers, trickling filters, and biological nutrient removal. It concludes by discussing tertiary/advanced treatment options for removing additional contaminants.
The Hydro MicroScreen is an alternative to primary settling tanks for wastewater treatment that uses a rotating belt to physically separate solids and liquids. It can achieve equivalent or better removal of TSS, BOD, and FOG compared to primary tanks, while using half the cost, 90% less space, and 50% less power. The Hydro MicroScreen also produces sludge that is up to 50% drier than primary settling tanks. It has been successfully used to reduce treatment costs and space needs at wastewater plants.
This document provides guidance on sequencing batch reactor (SBR) design and operation. It was developed by the New England Interstate Water Pollution Control Commission based on a literature review and visits to five SBR facilities. The document aims to highlight design and operational enhancements that can improve wastewater treatment performance. It is intended to assist municipalities, engineers, regulators and operators working with SBR systems.
This document provides guidance on hygrometry principles for measuring moisture content. It discusses factors that can affect moisture monitor performance such as pressure, temperature, flow rate and contaminants. It also covers maintaining aluminum oxide probes, dealing with corrosive gases/liquids, and formulas for calculating moisture measurements in gases and liquids.
Dialysis water treatment equipment cleaning and disinfectionSomaia Alakhras
This document provides guidelines for cleaning and disinfecting equipment used to treat dialysis water in hemodialysis units. It recommends cleaning and disinfecting reverse osmosis systems, portable reverse osmosis systems, and reverse osmosis distribution loops on specific schedules depending on the component. Procedures should be documented on log sheets and follow manufacturer guidelines for chemicals, dosages, temperatures, and contact times. The guidelines aim to standardize practices across dialysis units in BC to support best practices and quality patient outcomes.
Use of reed_beds_for_the_treatment_opf_sewage_and_wastewater_from_domestic_ho...Durga Madhab Mahapatra
This document provides information on using reed beds for treating sewage and wastewater from households. It discusses regulatory requirements for on-site wastewater treatment and the multi-stage treatment train process involving collection, secondary treatment (such as with reed beds), and disposal or reuse through land application. Reed beds provide secondary treatment by removing pollutants and suspending solids as wastewater passes through the gravel substrate and is treated by aquatic plants. Sizing, construction, maintenance, and land application methods are also outlined.
The report provides a preliminary design for a wastewater collection and treatment system for the town of Bahía Ballena, Costa Rica. The town currently has a population of 1,000 people that is projected to grow to 3,000-4,000 people within 10 years. Three potential sites for the wastewater treatment facility were evaluated. Site 3 was selected as it allows for gravity flow of wastewater through most of the system, has room for expansion, and is easily acquired. The designed collection system relies on gravity and costs $750,000. The treatment facility is capable of reducing wastewater to below effluent standards and costs $250,000 initially with $50,000 annual operating costs.
This document proposes a decentralized wastewater treatment system for Township of Wainfleet to effectively treat household wastewater. A biogas system is chosen that can treat 40 cubic meters of sewage per day to produce biogas and fertilizer. The capital cost is estimated to be $89,712 CDN and would be paid back within 4.3 years through profits from biogas, fertilizer and land taxes. The system is designed to be economically feasible and provide environmental and social benefits to the rural community.
This document describes a prototype for a mobile biological wastewater treatment system created by engineering students. The system uses a sequencing batch reactor (SBR) with a 300 gallon tank that can switch between aerobic and anaerobic treatment. It includes a tank mixer, centrifugal pump, air pump, air diffuser, programmable logic controller, and sensors for monitoring water conditions. The total cost is $8,197, below the $10,000 budget. The system has been designed but not yet tested for biological wastewater treatment.
This document provides environmental guidelines for the textile dyeing and finishing industry in Victoria, Australia. It was developed by the Environment Protection Authority in consultation with the industry and endorsed by it. The guidelines cover statutory requirements, waste minimization, and environmental elements to consider like siting facilities, air and water quality, chemical storage, solid waste handling, and noise reduction. The goal is to define best practice environmental management for the industry to improve its environmental performance.
This document provides an overview of oil and gas production. It begins with a brief history of oil exploration and use. It then provides a simplified process overview showing the main steps and equipment. These include wellheads, manifolds, separation, compression, storage and export. It also discusses various onshore and offshore facilities used in production. The document aims to give readers an appreciation of the key characteristics and design issues of the upstream oil and gas industry.
This document provides an overview of oil and gas production processes. It begins with a brief history of oil drilling and uses. Section 2 provides a high-level process overview showing the key stages from wellheads through separation, compression, storage and export. The main stages include manifolds and gathering, separation, gas treatment and compression, and metering and export. Supporting utility systems are also outlined.
The document provides an introduction to industrial wastewater treatment. It discusses how industries use water for manufacturing and processing, which becomes wastewater after use. The wastewater must be treated before discharge to prevent environmental pollution and protect domestic sewage systems. Common contaminants in wastewater are discussed, along with characteristics of industrial wastewater. Finally, the main treatment technologies are described at a high level, including mechanical, physical, chemical, biological, and advanced processes.
This document provides an introduction and overview of industrial wastewater treatment. It discusses how industries use water for manufacturing and processing purposes, which becomes wastewater that must be treated before discharge to prevent environmental pollution. The document then outlines some key contaminants found in wastewater and characteristics of industrial wastewater. It describes common wastewater treatment methods including physical, mechanical, chemical and biological processes and provides details on specific unit operations like screening, sedimentation, flotation and biological treatment methods.
This document outlines Colgate Palmolive's EOHS Standard 14-01 on water stewardship. It provides definitions and establishes requirements for facilities regarding management commitment to water conservation, conducting water balances and risk assessments, developing water stewardship plans, assessing water conservation opportunities, and optimizing water systems and equipment. Facilities must demonstrate leadership on water issues, understand their water usage and risks, set goals to reduce usage, and continuously identify projects to improve water efficiency and management.
Chapter 6 Running Case Assignment Improving Decision MakingWilheminaRossi174
Chapter 6 Running Case Assignment: Improving Decision Making:
Redesigning the Customer Database
Software skills: Database design; querying and reporting
Business skills: Customer profiling
Dirt Bikes U.S.A. sells primarily through its distributors. It maintains a
small customer database with the following data: customer name, address
(street, city, state, zip code), telephone number, model purchased, date of
purchase, and distributor. These data are collected by its distributors when
they make a sale and are then forwarded to Dirt Bikes. Dirt Bikes would like
to be able to market more aggressively to its customers.
The Marketing Department would like to be able to send customers e-
mail notices of special racing events and of sales on parts. It would also like
to learn more about customers’ interests and tastes: their ages, years of
schooling, another sport in which they are interested, and whether they
attend dirt bike racing events. Additionally, Dirt Bikes would like to know
whether customers own more than one motorcycle. (Some Dirt Bikes
customers own two or three motorcycles purchased from Dirt Bikes U.S.A.
or other manufacturer.) If a motorcycle was purchased from Dirt Bikes, the
company would like to know the date of purchase, model purchased, and
distributor. If the customer owns a non–Dirt Bikes motorcycle, the company
would like to know the manufacturer and model of the other motorcycle (or
motorcycles) and the distributor from whom the customer purchased that
motorcycle. Dirt Bikes’s customer database was redesigned so that it can
store and provide the information needed for marketing.
Case Questions:
Develop the following queries and reports that would be of great interest to
Dirt Bikes’s marketing and sales department.
1- Create a report of customers and motorcycles model grouped by
manufacturer.
2- Create a query about Dirt Bikes customers who attend racing events.
3- Create a query of the customers who have more than 12 years of
education.
Part 1
This is an individual assignment. Read the recent research article "Biochar Wastewater Treatment 2020." Prepare a 2-3 paragraph response for the following:
What are the main points of the article? How can it connect to scouring wool washing discussions for the wool industry? How can this technique be used more broadly in the apparel industry? Refer to the book Raw Material and Sustainability & Social Change in Fashion to develop your response. Provide key citations in APA format.
Part 2
After reading Raw Material Ch. 11- 15 (p. 138- 213), what are the main points that resonated with you? How does this connect with broader discussions about sustainable fashion in the book Sustainability & Social Change in Fashion?
lable at ScienceDirect
Chemosphere 252 (2020) 126539
Contents lists avai
Chemosphere
journal homepage: www.elsevier.com/locate/chemosphere
Review
Biochar technology in wastewater treatme ...
This document provides an overview of oil and gas production processes and facilities. It was compiled by Håvard Devold from various sources to serve as an introduction for new engineers. The document describes the main sections of the production process including wellheads, manifolds, separation, compression, and storage. It also covers reservoir characteristics, exploration and drilling, artificial lift methods, and utility systems like control and safety systems. While not a complete technical reference, it aims to give readers an appreciation of the key aspects and design issues involved in upstream oil and gas production.
This document provides design information for an activated sludge wastewater treatment plant. It discusses that each plant must be custom designed to fit the specific site conditions. It emphasizes flexibility in design to accommodate variations in wastewater flow and composition over the plant's lifetime. The key steps in design include determining effluent requirements, selecting the appropriate activated sludge process, and sizing major treatment components like aeration basins and clarifiers based on wastewater loading. Design guidelines and equations are provided for sizing major treatment processes and tanks.
Designing of Sewage Treatment Plant for Society Level By using Sequential Bat...IRJET Journal
The document describes the design of a sewage treatment plant (STP) for a residential society using Sequential Batch Reactor (SBR) technology. Key aspects of the design include:
1) The STP will treat 80,000 liters per day (80 KLD) of sewage generated by 500-600 people in the society.
2) The STP design includes tanks for screening, grit removal, equalization, aeration, clarification, and sludge/effluent storage.
3) The aeration tank volume is designed to be 40 cubic meters to treat the sewage using a 4 hour SBR cycle with 3 batches per day. Oxygen requirements and blower sizing
Designing of Sewage Treatment Plant for Society Level By using Sequential Bat...IRJET Journal
The document describes the design of a sewage treatment plant (STP) at the society level using Sequential Batch Reactor (SBR) technology. Key points:
- The STP will treat 80,000 liters per day (KLD) of sewage generated from a society of 500-600 people and return treated water that can be used for purposes like washing, gardening, etc. except for drinking and cooking.
- The STP design using SBR technology involves processes like primary treatment to remove large solids, secondary biological treatment using aeration, and tertiary treatment to produce treated water and residue.
- Design considerations include the daily sewage quantity, water quality standards for influent and
This Phase 1 environmental site assessment evaluated the 12 acre property at 321 W. California Avenue in Ruston, LA for potential environmental concerns. The assessment identified 11 potential problems at the site including transformers lacking PCB labels, vehicle spillage in parking areas, an upstream fertilizer plant, and a past underground storage tank removal. Soil and groundwater sampling were recommended to test for contaminants around the transformers, in parking areas, along the on-site waterway, and at the former underground storage tank location. The report provided details on the assessment process, site features and history, and recommendations for addressing identified environmental issues.
EC - Env and Climate Guidelines - 2011 v2Torsten Kowal
This document provides guidelines for integrating environment and climate change considerations into development cooperation programs. It aims to help development practitioners mainstream these issues.
The guidelines cover how to integrate environmental and climate aspects into multi-annual programming, sector policy support programs, general budget support, and projects. They provide advice on identification, formulation, implementation and evaluation phases. Key tools discussed include country environmental profiles, strategic environmental assessments, environmental impact assessments, and climate risk assessments.
The guidelines emphasize that environmental sustainability is crucial for poverty reduction, sustainable development, human rights and security. All development sectors are concerned by environmental opportunities and impacts. Mainstreaming environment and climate change helps ensure programs support partner countries' development in an environmentally sound manner.
Evolving Lifecycles with High Resolution Site Characterization (HRSC) and 3-D...Joshua Orris
The incorporation of a 3DCSM and completion of HRSC provided a tool for enhanced, data-driven, decisions to support a change in remediation closure strategies. Currently, an approved pilot study has been obtained to shut-down the remediation systems (ISCO, P&T) and conduct a hydraulic study under non-pumping conditions. A separate micro-biological bench scale treatability study was competed that yielded positive results for an emerging innovative technology. As a result, a field pilot study has commenced with results expected in nine-twelve months. With the results of the hydraulic study, field pilot studies and an updated risk assessment leading site monitoring optimization cost lifecycle savings upwards of $15MM towards an alternatively evolved best available technology remediation closure strategy.
Optimizing Post Remediation Groundwater Performance with Enhanced Microbiolog...Joshua Orris
Results of geophysics and pneumatic injection pilot tests during 2003 – 2007 yielded significant positive results for injection delivery design and contaminant mass treatment, resulting in permanent shut-down of an existing groundwater Pump & Treat system.
Accessible source areas were subsequently removed (2011) by soil excavation and treated with the placement of Emulsified Vegetable Oil EVO and zero-valent iron ZVI to accelerate treatment of impacted groundwater in overburden and weathered fractured bedrock. Post pilot test and post remediation groundwater monitoring has included analyses of CVOCs, organic fatty acids, dissolved gases and QuantArray® -Chlor to quantify key microorganisms (e.g., Dehalococcoides, Dehalobacter, etc.) and functional genes (e.g., vinyl chloride reductase, methane monooxygenase, etc.) to assess potential for reductive dechlorination and aerobic cometabolism of CVOCs.
In 2022, the first commercial application of MetaArray™ was performed at the site. MetaArray™ utilizes statistical analysis, such as principal component analysis and multivariate analysis to provide evidence that reductive dechlorination is active or even that it is slowing. This creates actionable data allowing users to save money by making important site management decisions earlier.
The results of the MetaArray™ analysis’ support vector machine (SVM) identified groundwater monitoring wells with a 80% confidence that were characterized as either Limited for Reductive Decholorination or had a High Reductive Reduction Dechlorination potential. The results of MetaArray™ will be used to further optimize the site’s post remediation monitoring program for monitored natural attenuation.
Earth Day How has technology changed our life?
Thinkers/Inquiry • How has our ability to think and inquire helped to advance technology?
Vocabulary • Nature Deficit Disorder~ A condition that some people maintain is a spreading affliction especially affecting youth but also their adult counterparts, characterized by an excessive lack of familiarity with the outdoors and the natural world. • Precautionary Principle~ The approach whereby any possible risk associated with the introduction of a new technology is largely avoided, until a full understanding of its impact on health, environment and other areas is available.
What is technology? • Brainstorm a list of technology that you use everyday that your parents or grandparents did not have. • Compare your list with a partner.
The modification of an existing product or the formulation of a new product to fill a newly identified market niche or customer need are both examples of product development. This study generally developed and conducted the formulation of aramang baked products enriched with malunggay conducted by the researchers. Specifically, it answered the acceptability level in terms of taste, texture, flavor, odor, and color also the overall acceptability of enriched aramang baked products. The study used the frequency distribution for evaluators to determine the acceptability of enriched aramang baked products enriched with malunggay. As per sensory evaluation conducted by the researchers, it was proven that aramang baked products enriched with malunggay was acceptable in terms of Odor, Taste, Flavor, Color, and Texture. Based on the results of sensory evaluation of enriched aramang baked products proven that three (3) treatments were all highly acceptable in terms of variable Odor, Taste, Flavor, Color and Textures conducted by the researchers.
Monitor indicators of genetic diversity from space using Earth Observation dataSpatial Genetics
Genetic diversity within and among populations is essential for species persistence. While targets and indicators for genetic diversity are captured in the Kunming-Montreal Global Biodiversity Framework, assessing genetic diversity across many species at national and regional scales remains challenging. Parties to the Convention on Biological Diversity (CBD) need accessible tools for reliable and efficient monitoring at relevant scales. Here, we describe how Earth Observation satellites (EO) make essential contributions to enable, accelerate, and improve genetic diversity monitoring and preservation. Specifically, we introduce a workflow integrating EO into existing genetic diversity monitoring strategies and present a set of examples where EO data is or can be integrated to improve assessment, monitoring, and conservation. We describe how available EO data can be integrated in innovative ways to support calculation of the genetic diversity indicators of the GBF monitoring framework and to inform management and monitoring decisions, especially in areas with limited research infrastructure or access. We also describe novel, integrative approaches to improve the indicators that can be implemented with the coming generation of EO data, and new capabilities that will provide unprecedented detail to characterize the changes to Earth’s surface and their implications for biodiversity, on a global scale.
Kinetic studies on malachite green dye adsorption from aqueous solutions by A...Open Access Research Paper
Water polluted by dyestuffs compounds is a global threat to health and the environment; accordingly, we prepared a green novel sorbent chemical and Physical system from an algae, chitosan and chitosan nanoparticle and impregnated with algae with chitosan nanocomposite for the sorption of Malachite green dye from water. The algae with chitosan nanocomposite by a simple method and used as a recyclable and effective adsorbent for the removal of malachite green dye from aqueous solutions. Algae, chitosan, chitosan nanoparticle and algae with chitosan nanocomposite were characterized using different physicochemical methods. The functional groups and chemical compounds found in algae, chitosan, chitosan algae, chitosan nanoparticle, and chitosan nanoparticle with algae were identified using FTIR, SEM, and TGADTA/DTG techniques. The optimal adsorption conditions, different dosages, pH and Temperature the amount of algae with chitosan nanocomposite were determined. At optimized conditions and the batch equilibrium studies more than 99% of the dye was removed. The adsorption process data matched well kinetics showed that the reaction order for dye varied with pseudo-first order and pseudo-second order. Furthermore, the maximum adsorption capacity of the algae with chitosan nanocomposite toward malachite green dye reached as high as 15.5mg/g, respectively. Finally, multiple times reusing of algae with chitosan nanocomposite and removing dye from a real wastewater has made it a promising and attractive option for further practical applications.
2. Table of Contents
GENERAL OBJECTIVES............................................................................................................5
Objectives.............................................................................................................................5
Structure of the manual......................................................................................................5
1. What goes in ........................................................................................................................6
1.1 Introduction ............................................................................................................6
2. What is an oxidation pond ? ............................................................................................10
2.1 What is an oxidation pond ?..............................................................................10
2.2 Why and where oxidation ponds should be used ?.......................................11
2.3 Who is responsible for what ?...........................................................................11
3. How do ponds work? .......................................................................................................12
3.1 Oxidation pond process description.................................................................12
3.2 Classification of wastewater treatment ponds................................................15
3.3 Use of ponds........................................................................................................16
3.4 The main advantages and disadvantages of stabilization ponds................17
4. What come out ? ...............................................................................................................18
4.1 Effluent characteristics .......................................................................................18
4.2 What affects pond effluent quality ....................................................................18
4.3 Upgrading the quality of oxidation pond effluents..........................................19
4.4 Some impacts of pond effluent on the environment......................................19
5. Practice and problems in process control .....................................................................20
5.1 Staging of ponds .................................................................................................20
5.2 Pond recirculation ...............................................................................................20
5.3 Pond mixing and aeration..................................................................................21
5.4 Odor problem.......................................................................................................22
5.5 Algae problem......................................................................................................23
5.6 Insect problem .....................................................................................................24
6. Maintenance.......................................................................................................................24
6.1 Litter control .........................................................................................................25
6.2 Accumulated material on the wave bands ......................................................25
6.3 Floating material control.....................................................................................26
6.4 Odour control.......................................................................................................26
6.5 Weed control........................................................................................................27
3. 6.6 Vegetable control on the banks ........................................................................28
6.7 Bank maintenance ..............................................................................................29
6.8 Control structure maintenance..........................................................................30
6.9 Seepage control ..................................................................................................30
6.10 Toxic material control .........................................................................................30
7. Monitoring and record keeping........................................................................................31
7.1 Introduction ..........................................................................................................31
7.2 Problems with BOD and SS testing .................................................................31
7.3 Where the sample should be taken from ........................................................32
7.4 Frequency and location of laboratory samples ..............................................32
8. Discharge consents and conditions................................................................................34
8.1 Odour treatment ..................................................................................................34
8.2 Wastewater treatment ........................................................................................34
8.3 Sludge disposal...................................................................................................35
9. Some case histories..........................................................................................................35
9.1 Septic tank cleaner problem..............................................................................35
9.2 Industrial overloading and excess grease problems .....................................35
9.3 Butynol rubber bank collapse............................................................................36
9.4 Concrete wave band cracking and breaking up by wave action erosion ...36
9.5 Fat/oil slick over the first or primary pond surface.........................................36
4. LIST OF ACRONYMS:
ASOP Administrative Standard Operating Procedure
CCESP Coastal Cities Environmental Sanitation Project
CDP Corporate Development Plan
D/S&WW Drainage, Sewerage and Wastewater
GIS Geographic Information System
GOV Government of Vietnam
HRD Human Resources Development
ICT Information and Communication Technology
IT Information Technology
LS Lift Station
O&M Operations and Maintenance
PD Project Director
PMU Project Management Unit
QB Quang Binh
QB URENCO Quang Binh Urban Environment Company
SOP Standard Operating Procedure
SW Solid Waste
TL Team Leader
TOR Terms of Reference
WB World Bank
WWTP Wastewater Treatment Plant
5. GENERAL OBJECTIVES
Objectives
The aim of this manual is to help staffs and operators of the Duc Ninh WWTP to:
Understand how wastewater treatment ponds work and what factors affect
and control pond treatment processes
Schedule and conduct normal and abnormal operational and maintenance
duties
Collect samples, interpret lab results, and make proper adjustments in pond
operation
Recognize factors that indicate a pond is not performing properly, identify the
source of the problem, and make corrective action
Determine pond loadings
Keep records for the wastewater treatment pond facility
Structure of the manual
The Operations Manual for Wastewater treatment has four parts:
Part A : Wastewater Treatment Theory
Part B: Operation and Maintenance of Duc Ninh Wastewater System
Part C: Laboratory Procedures
Part D: Equipment Suppliers’ Manuals and Instruction Books
This is Part A and it is a stand alone manual
6. PART A: WASTEWATER TREATMENT THEORY
1. What goes in
1.1 Introduction
This section introduces terms which are used in this manual for discussions of
wastewater characteristics and treatment technology.
Sewerage: This is the system that removes, treat and disposes of sewage
Sewage: This is domestic and industrial liquid waste matter.
Wastewater: This term is an alternative for sewage, but is often used
nowadays to refer to a mixture of both domestic or foul sewage and trade
waste.
A combined sewerage scheme: A sewerage scheme where both the foul
sewage and stormwater use the same piping system as occurs in many older
towns and cities.
A separate sewerage scheme: The type of sewerage scheme nowadays
conventionally used where the foul sewage only is piped in the sewerage
system with a separate system to handle stormwater.
It should be noted that in Dong Hoi, the wastewater from households, service,
offices, public areas… is collected into the wastewater drainage system
through gas holes connected and then lead to main wastewater collecting
system to wastewater pumping station and then to treating station.
Therefore, wastewater is collected separately without being mixed with rain
water, which lessens the risk of polluting the water and environmental
pollution.
Sewage and effluent terminology: The most important sewage parameters are briefly
described below.
SS: suspended solids which are removed from sewage sample by filtration
through a very fine filter. A certain portion of sewage solids will settle out
after a certain time in calm conditions, and these are defined as settleable
solids.
7. Settleable solids: it is applied to that fraction of total solids in sewage which
will settle out in calm conditions within a defined period of time.
BOD: biochemical oxygen demand, the standard measure of biodegradable
organic matter in sewage. Normally, references are to the standard five day
test.
COD: chemical oxygen demand, a measurement of the oxygen consuming
capacity of organic matter present in wastewater.
Total oils and grease: this is a non-specific term used to mean total grease
component of sewage which is recovered via a certain specified test
procedure
Floatable oils and grease: this term describes that fraction of the total oils
and grease in a sample which will separate out by floatation in calm
conditions in a defined time period.
pH: a measure of the acidity/alkalinity of wastewater, in a logarithmic scale
from 1 (very acid) to 14 (very alkaline). pH 7 is neutral, and domestic sewage
is approximately this.
Faecal coliform (FC): a group of bacteria found in large numbers in the gut
and faeces of warm blooded animals, including man, and therefore used to
indicated the presence of sewage contamination and possible presence of
disease causing organisms. Esherichi Coli ( E,Coli ) a particular bacteria is now
uses as a more specific indicator of faecal contamination.
Nutrients: In some discharge situations (rivers, lakes) the concentration of
plant nutrients in the effluent can have resultant detrimental consequences,
such as aquatic weed infestation, algal scums and slimes. Therefore the
concentrations of nitrate, phosphate and ammonia become of concern, and
may be subject of discharge limits.
Toxic compounds: many industrial wastewater contain toxic compounds,
namely those inorganic or organic materials which would prove deleterious to
either biological sewage treatment processes, or the receiving environment
for the final effluent.
Typical composition of raw sewage:
Raw domestic sewage typically contains the following:
BOD 250 – 300 mg/L
SS 200 – 300 mg/L
Faecal coliform 107
– 5x107
/ 100 mL
Oil and grease 50 – 100 mg/L
Terminology in sewage and wastewater treatment technology:
8. Domestic sewage in a water-borne sewerage system is approximately 99.9%
water and 0.1% contaminants. Wastewater treatment is aimed at protecting
public health and the environment by removing and breaking down these
various contaminants The products of the large variety of sewage treatment
processes usually are a liquid effluent, solids or sludge, and possible gas.
Treatment and disposal of the liquid are interrelated as the nature of the
environment receiving the treated effluent will, in part, dictate the degree of
treatment required. Selection of the most appropriate methods of treatment
and disposal involves consideration of:
o Water quality including public healthe issues, levels of toxicants and
pathogens, colour and clarity.
o Economic, financial and cost aspects.
o Environmental issues
o Community attitudes and cultural values
o Engineering and operational feasibility and reliability
o Relevant legislation
Sewage and wastewater treatment is conventionally categorised under the following
headings:
Preliminary treatment: The removal of large solids, grit, and other
problematic material which might interfere with downstream processes and
damage equipment. Screening is usually considered as a preliminary
treatment process. At Dong Hoi, mechanical screening is used to to the
removal of coarse solids bigger than allowable distance between screen bars.
Primary treatment: The removal of floating and settleable solids by a variety
of means, but normally by physical processes such as sedimentation and
floatation tanks. At Dong Hoi, the aerated grit chamber is used for 3
simultaneous purposes: (i) grit removal, (ii) grease and fatty solids separation
for raw influent, and (iii) odour stripping. This treatment step helps to protect
pumping equipment and to avoid the effects of solids in aerated lagoons.
Secondary treatment: The removal of dissolved nutrients, organics matter
(BOD) and non-setteable solids by a variety of means, including biological and
chemical processes. The biological processes involve concentrated growth of
microorganisms either on fixed surfaces or in suspension. At Dong Hoi, the
organic pollutant in wastewater is treated in the aerated lagoons. The
facultative lagoons are followed for further removal of organic pollutant.
9. Tertiary treatment: Further treatment to remove specific elements which
may be of concern (nutrients, trace materials, bacteria) by array of processes,
including disinfection. At Dong Hoi, nutrients (nitrogen and phosphorus)
removal is carried out by aquatic floating system (water hyacinthes) in the
maturation pond. Water hyacinth (Eichhornia crassipes) is widely distributed
in VietNam’s rivers.
Disinfection: A process designed to reduce the number of microorganism in a
particular effluent, including use of chlorination, UV light, ozone. It is usual to
refer to a disinfected effluent. At Dong Hoi, solar disinfection is carried out a
maturation pond. This is a natural disinfection way then it can avoid expensive
use of UV-radiation and harmful by-products from chlorine disinfection.
Land treatment: The treatment of sewage effluent on the land. This usually
involves things such as overland flow of effluent over grassed fields, or
wetlands treatment systems. In case of Dong Hoi, only aquatic floating system
(water hyacinthes) in the maturation pond is used.
Land-based treatment: A common term but not really defined. Generally
means any form of treatment which includes tanks, facilities on land.
Marine treatment: The use of the marine environment to treat and dilute
sewage by natural processes to harmless meets the acceptable levels. This
treatment system also includes the final disposal of the effluent. This does not
apply to Dong Hoi wastewater treatment.
Effluent disposal: Is the discharging of the treated effluent from any
treatment process, either to a receiving water such as a river, lake or ocean,
or onto land. At Dong Hoi, the treated wastewater is discharged into the Le Ky
river, then to the East Sea eventually.
Sludge: Sludge is the by product which is drawn off the bottom when the
liquid in a treatmet stage is allowed to settle. Various processes can then be
used to stabilise and/or dewater the sludes prior to reuse or disposal. At Dong
Hoi, sludge from the wastewater treatment plant is dewatered in the reed
bed system, then can be reused as a rich fertilizer.
Sewage flows: The flow of sewage into a plant or pond is not constant.
During the night and early morning, flows are very low, and in smaller communities
are made up largely of flushing urinals, groundwater infiltration into the sewers, and
the occasional results of a late night party.Flows start increasing as people wake up,
having breakfast and commence work.
A general pattern of sewage flow over a 24 hour day is shown in the following
diagram. The average daily flow is the flow used for designing sewage treatment
processes, although pipes, tanks etcmust be able to cope with peak flow.
10. Fig. 1. A diagram of sewage flow over a 24 hour day
2. What is an oxidation pond ?
2.1 What is an oxidation pond ?
Oxidation ponds are shallow basins which utilise light and wind action in to allow
natural processes to break down and treat the polluting components of sewage.
Ponds are ideally rectangular or square in shape and are located in open, windy
areas. The inlet and outlet of a pond should be located at opposite sides of corners of
the pond, with the prevailing wind not blowing towards the outlet.
There are various layouts for pond systems:
A single pond receiving raw sewage. Such a pond provides primary and
secondary treatment, and a significant kill of decrease causing microorganism.
A single pond can also be used as the final stage in a treatment system,
following conventional in tank processes (primary settlement of solids,
secondary biological treatment). In these instances the pond provided
enhanced treatment and breakdown of organic matter, and better kill of
microorganisms. There are often called tertiary ponds.
A conventional 2-pond system, where the effluent from one pond enters a
second pond. The idea behind such systems is to provide a major reduction in
numbers of di disease causing microorganism, particularly where the effluent
is to be discharged into well used or sensitive receiving waters.
At Dong Hoi, the oxidation pond is used as the aerated lagoon. The system
includes two aerated lagoons run in parallel.
Hourly fluctuations of flowrate during a 24-h period
for a total of 10 000 m3
/d
0
100
200
300
400
500
600
700
800
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hours
m3/h
11. 2.2 Why and where oxidation ponds should be used ?
Domestic or municipal and some industrial wastewater may be treated in oxidation
ponds which also can be called stabilisation ponds or lagoons.
Ponds are classified according to the type of bacteria working in them. Treatment in
wastewater in ponds is considered to be inexpensive, straightforward in design,
construction and for maintenance. If maintained properly, they provide reasonably
efficient treatment of wastewater.
One reason why ponds are readily accepted by all concerned, is the belief that the
ponds need little or no operation or maintenance and that they simply go on
forever producing a good quality effluent. Unfortunately this is not the case.
Actually, pond operation may be as difficult as any other form of wastewater
treatment to manage. A poorly operated and maintained pond can become a public
nuisance, producing effluent of low quality.
2.3 Who is responsible for what ?
The operation of the wastewater treatment system is the responsibility of the Owner
as well as the Operator. At Dong Hoi management of the wastewater treatment
system is the responsibility of Quang Binh URENCO under the The Decision no.
1136/QD - UBND dated May 28, 2009 of Quang Binh PPC. Quang Binh URENCO has
establised the Dong Hoi City Environment Sanitation Project Acceptance and
Operation and Management Unit (Decision No. 245/QD-CT, dated November 15,
2013) which has one of the duties to organize for management and operation of Duc
Ninh WWTP meet to the requirements of environment for wastewater after
treatment (TCVN 7222-2002, column B).
URENCO as the Operator is responsible for:
The effluent and proper operation of the ponds to meet the effluent qualities
stipulated by the regulatory agencies
Maintaining a safe and healthy environment
Performing tests and making observations needed for the proper operation of
the ponds
Properly interpreting and applying laboratory tests and results
Notifying the Owner far enough in advance so that tools, parts and supplies
will be available when needed
Keeping the drainage course or pipe to the receiving stream or other location
clear of observations
12. Keeping records
Meeting all other requirements of the Contract
3. How do ponds work?
3.1 Oxidation pond process description
The oxidation pond is a self-contained, complete treatment process where everything
that is needed for waste stabilisation is provided by nature. Therefore, this form of
wastewater treatment can be called as natural treatment.
Oxidation pond is one of the simplest forms of biological treatment processes. This
versatile installation serves many basic purposes, including:
storage or impoundment of wastewater
settling and removal of suspended solids
storage or impoundment of settled solids
equalization
aeration
biological treatment
evaporation
The relative simplicity and low operating costs of a stabilization pond make it the
preferred technology for handling, treatment and disposal of industrial wastewater
as well as municipalwastewater for small communities.
In oxidation ponds bacteria use the organic matter in the wastewater as their food.
There are three types of bacteria, aerobic, anaerobic and facultative, at work in this
type of pond. Aerobic bacteria can only work in the presence of dissolved oxygen,
whereas anaerobic bacteria are actually killed by dissolved oxygen. Facultative
bacteria can operate in both areas.
In the oxidation pond oxygen must be provided for the aerobic bacteria. Nature helps
to do this in two ways: photosynthesis and pond re-aeration.
Photosynthesis is the use of sunlight energy by small green plants called algae to
convert carbon dioxide gas and water into new cells. As the algae produce new cells,
they release oxygen as a by-product. This oxygen dissolves in the water, and is used
by the bacteria to decompose the waste.
13. This all means that bacteria and algae work together in a waste stabilisation pond.
The algae produce the oxygen needed by the bacteria, and the bacteria in turn
produce carbon dioxide and other things needed by the algae.
Aerobic bacteria need dissolved oxygen to decompose organic waste. As aerobic
decomposition takes place, carbon dioxide as well as new bacteria are produced. If
there is sunlight present, then algae can use this carbon dioxide to live and
reproduce.
As the algae grow, oxygen is produced. It’s a cycle. Algae produce oxygen which is
used by the bacteria to decompose waste. The bacteria produce carbon dioxide,
which is used by the algae to produce more carbon dioxide and so on.
The second way of providing oxygen to bacteria is pond re-aeration. Aeration occurs
as a result of turbulence caused by the wind. The amount of oxygen added by the
surface re-aeration depends on the amount of wind there is another condition
affecting surface re-aeration. Oxygen dissolves more quickly in colder water than in
warmer water. Temperature of wastewater determines how much oxygen is
dissolved in it.
14. Fig. 2. Transfer coefficients as functions of various powers of wind velocity
The various, complex processes which occur in a pond are shown in the next
diagrams.
Fig. 3. Processes occur in the oxidation pond
Fig. 4. Ecology and major reactions of wastewater treatment ponds
15. Fig. 5. Basic biological reaction in an oxidation pond
3.2 Classification of wastewater treatment ponds
According to the type of biological transformation and methods of oxygen supply,
ponds can be divided into four general classes.
1. Anaerobic Ponds
These are deep ponds where anoxic condition prevails throughout. Organic loadings
are very high and BOD removal is limited to 80% or below. Further treatment of the
anaerobic pond effluent by aerobic ponds is usually required.
2. Facultative Ponds
Facultative ponds receive medium to low organic loadings. The bottom layer is
usually anaerobic, but the surface layer is kept aerobic through photosynthesis and
surface reaeration. BOD removal is higher than that of anaerobic ponds.
3. Aerated Lagoons
16. Oxygen supply in aerated lagoons for aerobic stabilization relies almost completely
on mechanical aeration devices. Either air diffusion or mechanical aeration can be
used. Depending on the power level used for aeration, aerated lagoons can be
further classified as aerobic and aerobic-anaerobic lagoons. With power levels at
6W/m3
or above, ponds are usually aerobic throughout. At lower power levels, an
anoxic bottom layer can be expected. An aerobic-anaerobic lagoon is therefore
equivalent to a facultative pond, except that the former uses mechanical aeration for
oxygen supply. Aerated lagoons usually are deeper than facultative ponds and
receive medium to high organic loadings. Treatment efficiency can be very high. The
mixing characteristic that separates aerobic (near complete mix) to aerobic-anaerobic
(poorly mixed) is more dependent upon the pond geometric parameters than upon
operating parameters such as horsepower input.
So in summary for Dong Hoi, a series of pond has been used. The system includes two
aerated lagoons (the aeration provided by the air blower) for removal of high organic
loadings, two facultative lagoons for removal of low organic loadings, and a
maturation pond for solar disinfection.
3.3 Use of ponds
Shallow ponds are often used to treat wastewater instead of conventional
wastewater treatment processes. Table 1 present the purpose of each pond parts.
When discharged in to ponds, wastewater is treated by several natural processes
acting at the same time.
Table 1. Purpose of pond parts
Parts Purpose
Flowmeter Measures and records flows into pond
Bar screen Remove coarse material from pond influent
Pond inlets Distribute influent in pond
Pond depth and outlet
control
Regulates outflow from pond and depth of
water in pond. Allows pond to be drained for
cleaning and inspection.
Outlet baffle Prevent scum and other surface debris from
flowing to next pond or receiving waters.
Dike or levee Separates ponds and holds wastewater being
treating in ponds
Transfer line Conveys wastewater from one pond to
another
Recirculation line Returns pond effluent rich in algae and oxygen
from second pond to first pond for seeding,
dilution and process control
Chlorination Applied chlorine to treated wastewater for
disinfection purpose
Effluent line Conveys treated wastewater to receiving
waters, to point of reuse (irrigation), or to land
disposal site or to receiving water
17. 3.4 The main advantages and disadvantages of stabilization ponds
Advantages
Do not require expensive equipment
Do not require highly trained operating personnel
Is economical to construct
Provides treatment that is equal or superior to some conventional processes
Is a satisfactory method of treating wastewater on a temporary basis
Is adaptable to changing loads
Has few sludge handling and disposal problems
Low operational and maintenance cost
Works well in clay soils where conventional subsurface on-site absorption fields
will not work
Disadvantages
Lagoons must be constructed in clay soil or be lined to prevent leakage.
May overflow occasionally during extended periods of heavy rainfall
If there are extended periods of overcast windless days, offensive odors may
occur for a brief time but usually recover rapidly if this occurs.
Takes up a relatively large space
Lagoons are not aesthetically acceptable to some people. Some people consider
lagoons unsightly and unsafe.
As with any other open body of water, there is some potential danger. Although
ponds should be fenced, this does not always prevent access by people or pets.
18. 4. What come out ?
4.1 Effluent characteristics
The reference data showed the following pond effluent data. In general, 2-pond
systems produce better effluent quality than for single pond systems.
Table 2. Reference pond effluent data
Average 90% of samples
Temperature, o
C 15 6 – 24.5
pH 8.2 7.1 – 9.5
DO, mg/L 6.7 0.9 – 9.5
BOD, mg/L 25 7 – 70
SS, mg/L 47 6 – 171
Ammonia, mg/L 3.1 0.001 – 29
Faecal coliform / 100 mL 5500 90-230000
It should be noted that Dong Hoi City is located in the tropical area in the Central
region of Viet Nam. There are two main seasons: winter (from October to March) and
summer (from April to August). In winter, there is more rainfall than in other regions
in Northern Viet Nam. Summer is characterized by hot and dry weather. Frequently
there are Southwest winds flowing from Lao country and increasing hard living
conditions for peasants. It is considered as one of the most severe region in Viet
Nam.
Based on the statistic data from Quang Binh Meteorology Center, the yearly average
temperature was about 25.1o
C (Highest: 40.1o
C, and Lowest: 7. 8o
C). Therefore, the
pond effluent data could refer from the data in the column of 90% sample in the
above Table 2.
4.2 What affects pond effluent quality
Amount of sunlight
Wind
Amount of BOD entering the pond
Amount of water entering the pond system (retention time)
Temperature (season)
Any toxic chemicals entering the pond system
Excess oil and grease
19. Pond shape
Nature: range of bacteria, algae, plants, animals in the pond
Some of these factors can cause problems, either by markedly reducing effluent
quality, causing odours, or even killing the pond’s biological processes.
4.3 Upgrading the quality of oxidation pond effluents
The algae-laden nature of oxidation pond effluents and their associated suspended
solids and BOD, much of which is associated with algae itself, does on occasions
cause problems with the effluent discharge into small watercourses, streams and
rivers where the algae itself exerts a BOD in the receiving water.
The above issues may result in the removal of some of the algae to give a clearer
effluent with lower BOD and SS. Also, there is an increasing need in a number of
situations to further reduce the possible levels of disease-causing microorganisms in
the effluent being discharged.
The above has resulted in increasing attention being paid to methods for upgrading,
or polishing, pond effluents. There are a number of methods available and each has
its own particular features that can apply in any particular instance.
These methods for upgrading oxidation pond effluents include such procedures as:
Re-arrangement of pond layouts to include more cells, longer travel paths
Various introduced aeration techniques
Rock and other types of effluent filters
Land treatment methods including overland flow and wetlands
Land disposal methods
Additional disinfection techniques
Various combinations of the above and other methods
4.4 Some impacts of pond effluent on the environment
So how does an oxidation pond effluent effect the environment? As mentioned
above, if dilution in a waterway receiving the effluent is not great enough, the BOD
and SS of the effluent might enrich the stream unacceptably, leading to growth of
nuisance algae and slimes, and possibly serious effects on stream life. Water colour
and clarity might also be affected for some considerable distance, well beyond what
could be described safely as a zone of reasonable mixing.
20. Levels of ammonia in pond effluents can be high, requiring far greater dilutions on
order to prevent adverse effects on aquatic life.
Proper design, operation and maintenance will ensure that these potential problems
do not occur.
5. Practice and problems in process control
Although stabilization ponds are simple devices for wastewater treatment, the basic
objectives should be upheld for providing an effective treatment according to design
specifications and not creating objectionable conditions or public health hazards in
the vicinity or downstream of the receiving waters. Common practices in process
control and some problems associated with them are discussed in this section.
Remedies for the control problems are also included.
5.1 Staging of ponds
A common practice in stabilization ponds with mixing is to fractionate the total
design volume to smaller ponds. The validity of belief in increasing the treatment
efficiency by the staging of ponds has been examined previously in this chapter.
Staging of ponds also is not an economical mode of land use because a single pond
occupies less land area per unit volume.
In addition, the staging of ponds adds to the construction costs in excavation,
interconnecting pipes or channels, and requires more maintenance.
Despite the disadvantage of pond fractionation, it adds to the operational flexibility
by recirculation, minimizes upset and nuisance, and maximizes stability. This is a
trade off between a less expensive, simple-in-operation unit and a more expensive,
reliable, sophisticated pond system. The decision usually is in favor of staging the
pond if the system is designed for:
efficient treatment of raw or primary wastewater to produce an effluent
quality compatible with other types of secondary treatment process, and
flexibility in being able to switch operations from series to parallel or their
combinations so that various organic and hydraulic loadings can be
accommodated as seasonal load changes.
5.2 Pond recirculation
Recirculation can be practiced for a single pond or multiple-pond system. It dilutes
the wastewater influent and incorporates some photosynthetic oxygen to the feed
21. zone so that odors and anaerobic conditions can be avoided. For n number of ponds
in a series, the dilutioncan be expressed as:
in which Sd is the substrate concentration in the diluted wastewater entering the first
pond, So is the influent substrate concentration, r is the recycle ratio or the ratio of
recycled flow rate R to influent flow rate Q, and S is the effluent substrate
concentration from the nth pond. As r increases, Sd becomes smaller and the
incoming organic load is spread more evenly throughout the pond system. The
overloading of the first eliminated completely. Because the design incorporates low
head losses in interconnecting pipes and channels, recirculation can be accomplished
with high volume, low-head propeller pumps. Siphon discharge flap gates can be
recommended. An auxiliary pump with an air eductor maintains the siphon. Siphon
breaks are provided to insure positive backflow protection. Multiple or variable-
speed pumps can be used to adjust the recirculation rate to seasonal load changes.
5.3 Pond mixing and aeration
Mixing and aeration are accomplished concurrently when compressed air diffusers or
mechanical aerators are used. In high-rate aerobic ponds in which intermittent
mixing is recommended to eliminate a sludge build-up at the bottom, only a high-
volume, low-head propeller pump is needed because aeration is not necessary in the
pond operation.
Where aeration is of prime consideration, diffused aeration is used in ponds deeper
than 3 m. The advantage of diffused aeration is that air can be distributed evenly
over the entire pond of any geometry. It is preferable to mechanical aeration in
northern areas, because ice build-up in the latter might be excessive. Proprietary
devices have been developed to introduce compressed air through slits in piping laid
on the pond bottom. Bubble-gun aerators also combine good mixing characteristics
with aeration. Diffused aeration is also advantageous in that tapered aeration can be
incorporated easily so that air supply can be more efficiently used to meet the
oxygen demand at different locations of the pond.
Mechanical aerators are generally divided into two types: cage aerators and the more
common turbine and vertical-shaft aerators. The former are suitable for shallow
ponds of 1.5 m depth or less, while the latter require a minimum depth for
economical use that depends on the horsepower of the unit. The cage aerator
appears to have a greater pumping capacity than the propeller aerator, because it
does not recycle much the volume pumped.
Mechanical aerators can be installed on platforms in a fixed position or the floating
type can be mounted out in the pond, and spaced about to provide even distribution.
Floating cage aerators may be mounted either in the pond or directly off the dike
slopes. When mounted off the dike slopes, they can be close to the pond inlets.
Better oxygen supply on the inlet side and easy access for maintenance and repair
22. are the advantages of such arrangements. Oxygen saturation in tap water at a given
temperature and altitude, as given in Table 3.
Table 3. Solubility of oxygen (mg/L) at various temperatures and elevations
5.4 Odor problem
It was mentioned that anaerobic zones in stabilization ponds can generate odorous
compounds such as H2S and mercaptans that escape the pond. The oxygenated upper
layer normally serves as a protective shield in keeping these odorous end products of
anaerobic decomposition from escaping the pond. This is because the compounds
are chemically or biochemically oxidized and rendered innocuous before they reach
the surface. During periods of upset, i.e., when high H2S concentration exists, algal
growth and the associated oxygen production may be inhibited. Odorous compounds
may reach the atmosphere as a result.
Other sources of odor are the end-products of the metabolism of certain blue-green
algae, diatoms and pigmented flagellates, and also the oil products released by dead
algal cells. These sources are highly unpredictable and generally are not considered a
major odor problem.
The most common method used to evaluate odour nuisances is an odour panel,
includes a group of people, typically eight or more, divided equally between men and
women. Samples of odourous gas are collected, diluted several times, and delivered
to the odour panel for sniffing. The average person can report the presence or
absence of an odour with more certainty than its characteristics or objectionability.
23. Table 4 presents specific odourous compounds, their odour threshold numbers and
characteristic smells.
Table 4 - Typical odourous compounds, odour threshold concentrations
andcharacteristic smells
5.5 Algae problem
The suspended solids concentrations in the ponds effluent could be higher than those
of activated sludge or trickling filter processes unless a physical solid-separation step
is included in the pond system. Because the discharge of suspended solids
contributes BOD and nutrients to receiving waters, a reasonable amount of solids
removal from the effluent is desirable and, in fact, is required by regulations for high-
quality receiving waters. Algal cells in the effluent constitute only a part of the
suspended solids. Even in high-rate aerobic ponds, algal production is only 50% to
60% of the effluent’s suspended solids. Any physical or chemical separation process
will remove both algal cells and other microbial solids.
Many processes have been investigated for the removal of algal cells from suspended
solutions. Algal cell could be removed by using ion exchange columns or sand
filtration. These processes are not economical. It would be advisable to find a market
for algae harvested from stabilization ponds. The harvested algae can be used as a
livestock feed because it has high nutrient and protein content, and it is reported to
be highly acceptable to livestock. Another potential use of the cultivated algae is to
produce biomass to be used for distilling alcohol fuels, or producing methane gas.
24. 5.6 Insect problem
With improper control or lack of consideration in design, stabilization pond
environments often become a nuisance and public health hazard. Of primary
importance are the breeding places that ponds and their effluents can provide for
mosquitoes. Many of the predominant species of mosquitoes found in ponds are the
primary vectors of encephalitic diseases.
Their breeding takes place in any pond that provides a protected area for oviposition.
Egg rafts and larvae can be found along the shoreline in vegetation, in water-filled
gullies created by wheels of mowing equipment at the water’s edge, in some
overflow structure, in floating sludge that is allowed to accumulate in corners.
Overflow boxes also harbor mosquito egg rafts and larvae because when water is not
flowing through such boxes they provide a quiet place for oviposition. Emergent
vegetation also provides a site for oviposition. Mosquito breeding is extremely heavy
where overflow water is allowed to drain across a flat area before reaching a
drainage ditch. The swampy areas with vegetation are ideal places for breeding by
providing cover and food. Screens on effluent boxes, careful construction, and proper
maintenance can eliminate all of these problems.
Certain midges breed prolifically in stabilization ponds, with adults becoming a
nuisance around residential areas because of their intolerable numbers. The problem
is one of nuisance rather than of health hazard, although mechanical transmission of
pathogen by midges is also possible. Emergent vegetation also has significant
influence on the occurrence of many aquatic insects other than mosquitoes. The
most obvious is the increase in the number of beetle larvae and adults, dragonfly
naiads, and Hemiptera. Near shore and shallower water where sponge-like algal mats
are found are places showing dense populations of midge larvae. At a distance
greater than 1.5 to 2.4 m from shore and about 0.75 m in depth these algal mats and
the dense populations of midges associated with them are seldom found. An
effective control of mosquito breeding therefore is also effective for other insects.
These problems could be appeared during operation of the Duc Ninh Wastewater
treatment plant. Each of these could affect the performance of the system. Besides,
they can affect to the operator and population around (i.e. insect, mosquito).
Therefore, checking and maintenance during operation must be done frequently.
6. Maintenance
Proper maintenance of your pond system is essential for efficient treatment.
To properly maintain the pond, the following factors should be concerned:
Litter control
Accumulated material on the wave bands
25. Floating material control
Odour control
Weed control
Vegetable control on the banks
Bank maintenance
Control structure maintenance
Seepage control
Toxic material control
6.1 Litter control
Domestic sewage has significant amount of plastic and other litter type material that
can cause littering problems around oxidation ponds if it has not been previously
removed by appropriate screens.
Therefore, the raw sewage should be screened out before sewage enters the
oxidation ponds. Once in an oxidation pond, much of this plastic material which floats
or is neutrally buoyant accumulated on the wave band or banks. It is often
concentrated in certain areas or corners of the pond by the wind patterns on the
pond. Once on the wave band it often dries particularly if the top water level of the
pond varies.
6.2 Accumulated material on the wave bands
Accumulated material also includes fat and grease deposits, any floating accumulated
sludge materials and windblown vegetation and other materials.
Methods of periodically cleaning will depend on the degrees of accumulation, the
size of the pond and the equipment that may be available.
Options include hand clearing, hosing back into the pond to accumulate on the
bottom or lower down the bank below the water level, removal by mechanical
means.
If there is a significant build up of material below the water level on the wave bands,
then lowering the pond water level and letting the material dry and the removing by
an excavator with a swamp bucket has been shown to be an effective methods of
removing this material.
26. 6.3 Floating material control
This should not occur in a normally well operated pond but from time to time it does.
Often floating sludge will break up itself and resettle. Other methods include hosing it
to break up if it is near the banks, or mixing the pond by boat to get more water
movement that will help it break up and sink.
Mechanical floating or fixed aerators, stirrers of bubble aeration also assists by more
movement of the pond liquid.
6.4 Odour control
Ponds may occasionally five off odours, no matter how well operated and
maintained. Bad odours are an indication that something is out of balance and you
should determine and correct the causes of the odours.
Usually odours are caused by:
Anaerobic conditions in the pond
By the growth of the blue-green algae.
Either of these conditions could be caused by:
Extensive cloud cover, which reduces the amount of sunlight and therefore
the amount of dissolved oxygen;
Toxic waste that killed a portion or all of the bacteria;
A sudden large inflow of high strength organic waste; and
Floating sludge mats.
Any one of these conditions can upset the balance between bacteria, oxygen, algae
and food and should be corrected.
To remove odours, there are two methods which could be used:
The first method is to add oxygen to the pond by mechanical methods by:
Using a portable pump, to spray the pond contents into the air
Installing portable aeration equipment in the ponds
Recirculating secondary effluent if it has a higher DO
27. Using a motorized boat to stir up and aerate the top layer of the pond
The second method concerning odour problems is a chemical method:
The chemical method for correcting odour problems uses sodium nitrate,
which is a source of oxygen. This chemical can be added in quantities of 5 to
15% by weight of the influent BOD.
If the ponds are small, spread the nitrate evenly throughout the pond by
scattering it in all directions from the edges of ponds, for very large ponds use
a boat to reach the central areas of the pond.
Break up any floating scum, septic sludge or blue-green algae mats. Repeated
attempts to break up the scum may be necessary because the mat may tend
to reform. If it is possible, it may be enough to let the cell rest by cutting of
any flow to that cell until it corrects itself.
An algae bloom is a sudden and extreme algal growth. It consists mostly of
blue-green algae. The growth of blue-green algae may be caused by pond
overloading, lack of sunlight in the wastewater, pond turnover, shutdown or
other reason. The blue-green algae give off a characteristics odour. However,
most of the odour is caused by the ‘just as sudden’ die-off of the bloom. This
large amount of dead algae makes a very high BOD loading on the pond. As a
result, the dissolved oxygen is used up, the pond becomes anaerobic and
odour problems are created.
6.5 Weed control
Plants around of in the pond cause problems. Therefore, the control of weeds is one
of the main tasks in pond maintenance.
Some plants have large roots that will puncture the seal and cause leakage problems.
Plants that grow to the surface promote concentration of scum and sludge mats and
therefore encourage insect breeding. If the plants are dense in the pond, the sunlight
will not penetrate deep enough and the DO in the top layer will not be mixed or
distributed by wind action. This will result in a low DO level.
Surface weeds, like duckweed, can cause problems. Although very often confused
with algae, it is actually a small three-leaved plant that looks like clover leaf.
Duckweed floats on the wastewater surface and has long hair-like roots hanging
down into the water. It is green during its normal growth periods, and will turn
brownish-yellow as it dies off. Duckweed grows in large amounts and rapidly. It will
completely cover the wastewater surface in the pond if not controlled. This would
reduce the amounts of sunlight received by the pond and consequently reduce the
growth of the algae and the production of DO in the pond.
28. Besides reducing sunlight, duckweed poses a threat when it dies off. It will cause a
high oxygen demand in the pond in the same way as it would when being killed off by
herbicides.
There are a number of ways to control duckweed and other surface weeds.
If the area of coverage is not extensive, a few ducks may be able to control
the growth. Ducks will eat duckweed.
If the pond is exposed to a clean sweep of the wind, duckweed usually will not
flourish.
On small systems, the operator can skim off the duckweed.
Duckweed removed from the pond should be buried to prevent odour and insect
problems.
Submerged or bottom-roots weeds can also cause problems. Generally, bottom-
rooted water weeds should not be a problem, as long as the wastewater depth in the
pond is not lower than 0.6 m during the summer. If the water level has to be lowered
below this level, the ponds should be continuously inspected for plant growth that
may be developing.
There will be a constant cause damage to the pond seal, reduce mixing in the cell,
and possibly reduce algae activity. There are several ways to control plant growth.
The removal method must be adjusted in terms of the amount of plant growth and
the time of year.
Pull the weeds out. When the weeds are young, they should be pulled out
before they become established.
Cut and drown the weeds. It the water level in the pond is low or can be
lowered, the weeds can be cut off. Immediately after they are cut, the water
level should be raised about 0.8 - 1.0 m above the top of the cut weeds.
6.6 Vegetable control on the banks
Banks usually have a protective grass cover and some sort of wave band. Weeds
growing between racks in the concrete, or holes in the rubber, can de-stabilise the
wave band. Weeds on the banks can be removed by:
Hand or mechanically
Using chemicals
Removing the plants by hand or mechanically involves much more work but it is safer
for operator and the biological life in the pond and the receiving stream.
29. 6.7 Bank maintenance
Banks are constructed around the ponds to hold back the water and to allow access
to the pond for maintenance. The most important part in bank maintenance is to
make sure that they continue to hold back the water and do not develop any leaks.
Bank erosion can quickly damage the seal and cause wastewater to leak out. Erosion
of the bank is caused by:
Wave action
Surface run-off
Burrowing animals
Therefore, a regular inspection and maintenance routine must be kept to prevent
erosion of the banks. Certain areas are especially weak and easily affected by erosion.
Such areas include: around the control structures, in the corners, entrances to animal
burrows, the side slopes opposite the prevailing winds, are with insufficient
vegetation cover or with insufficient compaction of the bank during construction.
Erosion problems are generally more serious on large ponds due to increase wave
action.
If the action of wind and wave is likely to cause erosion of the bank’s inner slopes,
some form of wave band must be applied to prevent further damage. This is
necessary because once the erosion has begun, the entire bank can fail very quickly.
The wave band may be:
Concrete
Any other suitable and available material such as rubber or synthetic line
Do not use asphalt material, which weakens after a few year and has to be replaced,
or any other material that breaks up easily.
In addition, a good well mowed grass cover must be kept on all bank surfaces.
Erosion may cause the following damage:
Wash away the parent or liner material
Form areas along the bank that are difficult for mainetance
All of these problems reduce the design life of the ponds. A properly applied wave
band will stop erosion, reduce the growth of large plants along the shallow area of
the bank and discourage animals from tunnelling into the bank.
30. 6.8 Control structure maintenance
Pay attention to the control structures at all times, make sure that they function
properly. Leakage and corrosion are the main causes that affect the control
structures.
Corrosion problems can be reduced by frequently lubrication of gates and vales and
by moving the gates and valves frequently. One method to reduce corrosion
problems is to replace the solid manhole covers on the structures with grated covers.
This will increase ventilation and greatly reduce the corrosion.
Leaks in structures are usually difficult to correct. Gaskets or sewer plugs can be used
to stop the leak. If necessary preplace the gates, slides or valves to eliminate
problems.
6.9 Seepage control
Inability to maintain adequate wastewater level in the pond is a great problem. Most
ponds have natural clay, bentonite or vinyl layers to prevent pond seepage. Usually a
percolation test of the pond bottom is done as part of the design and construction,
but if leakage occurs, it is unwise to believe that wastewater solids will seal the pond.
Wastewater affects the surrounding land, rivers, lakes and ground-water, causing
potential health hazards and pollution problems.
When considering the seepage problem, take into account the losses of water due to
evaporation first, then investigate for leakage. Seal damage can be caused by erosion,
roots, burrowing animals, heavy equipment, cattle and, it the ponds are allowed to
dry, by cracks.
Proper seal maintenance consists of preventive measures and of correcting existing
problems. It involves total care. The most common seal material used is natural clay.
Normally, the finished clay seal is at least 0.15 m thick. Membrane liners need proper
bedding material and a proper cover material. The cover material protects the liner
and at the same time anchors the liner down. Exposed liners are easily damaged by
animals, equipment, vandals and sunlight.
6.10 Toxic material control
The problem of toxic material in the influent can not be solved in the pond itself. Any
discharges to the sewage system are best controlled by eliminating them at their
source. Therefore, it is important to identify any waste source that may be
discharging toxic wastes.
31. 7. Monitoring and record keeping
7.1 Introduction
Operation of oxidation ponds requires regular laboratory tests to ensure proper
performance and to satisfy the requirements of the regulatory agency. At Dong Hoi, a
labroratory at the WWTP with basic analysis equipments will carry out these tests.
Each pond system is different. Even identical adjacent ponds receiving the same
amount often have different values of pH and the dissolved oxygen content at any
given time. For this reason, sampling and testing for each pond should be done
separately. Once the characteristics of each pond has been know, the performance of
the pond will be judged.
In a properly functioning facultative pond, the pH and DO values will be different
from season to season, day to day and hour to hour. There will also be a decline in
DO from the surface of the pond to the bottom. The DO level will be lowest in the
anaerobic region at the bottom. If the DO drops toward zero throughout the pond
and the pH drops below 7, this is an indication that algae are dying off and the pond
is going anaerobic. Measurement of the pond can warn of impending problems
because the middle DO will decrease before the surface DO.
This condition will frequently be indicated by the change in colour of wastewater
from green to grey. Sometimes odours develop too. Therefore, two tests, pH and DO,
are the most important laboratory tests for evaluation of ponds performance and
their operational control. Both tests can be performed with inexpensive colorimetric
test kits or more modern pH and DO meters with probes.
Other tests, important in judging pond performance, are the biochemical oxygen
demand (BOD), total suspended solids (SS), and coliform counts. However, these
tests are more difficult and time consuming, they also require some extensive
laboratory equipment which is not normally provided in small pond installations.
7.2 Problems with BOD and SS testing
The BOD and SS tests are two of the tests often used to monitor performance of an
oxidation pond. However, there is a major problem with these tests which must be
recognised, that is the tests do not distinguish between sewage BOD/SS and algae.
The effluent from an oxidation pond contains large numbers of algae, which turn up
as suspended solids in the standard tests. A high SS result often means that the pond
is performing well.
Similarly, the BOD test will be significantly affected by the fact that algae use up
dissolved oxygen in the dark and produce it in light. Also, if the BOD test is done in
the dark, many algae will die and be broken down by bacteria, creating a large false
BOD value. This may have no bearing on the actual performance of the pond, nor
environmental impacts of the final discharge.
32. Care should be taken with the use and interpretation of these two tests, at best they
should be used only to indicate changes in pond performance over time, rather than
measure actual sewage treatment performance of potential environmental impact.
Sampling is important. If the samples are not taken properly, the test results will not
be accurate. Samples collected must represent the quality of the wastewater. There
are two kinds of samples:
Grab samples: a grab sample is one that is collected at one location and at
one instant. This is used for DO, faecal coliform count, pH.
Composite sample: several samples taken at regular intervals during specific
period of time. This is used for SS, BOD.
7.3 Where the sample should be taken from
Samples of raw wastewater should be collected in either the wet well of the lift
station or the inlet manhole at the pond site. Do not sample wastewater in the
bottom of the wet well basin because solids tend to settle immediately after entering
the wet well.
Take effluent samples from the outlet control structure during discharge. Samples
should be taken at the same time and location every day.
7.4 Frequency and location of laboratory samples
This sampling regime would be used for large pond systems. It can normally be
reduced for smaller pond system. The general program in Table 5 will be adjusted to
fit the needs of Duc Ninh WWTP and the regulation agency as TCVN 7222: 2002.
Table 5. Frequency and location of laboratory samples
Test Frequently Location
pH Daily Pond/influent
DO Daily Pond/effluent
Temperature Daily Pond
BOD Weekly Influent/effluent
Faecal coliform Weekly Effluent
Suspended
solids
Weekly Influent/effluent
DO and pH should be taken during the same time each day because conditions in the
pond change during this period.
33. DO measurements should be regularly recorded for surface, middle, and bottom
from a representative point away from the banks of the pond.
DO, pH and temperature are important indicators of the condition of a pond.
BOD, SS and the faecal coliform count indicate treatment efficiency. BOD is also used
to calculate pond loading.
BOD and solids concentration in the effluent will change with the time of day, the day
of the week and probably with the season.
Although the BOD of the influent is constantly changing, it is not generally necessary
to determine the BOD on a daily basis. Most ponds can be run successfully by taking a
BOD test once or twice a month on 3 samples taken during the daily low, average and
high flow periods. The average BOD calculated from these samples will show an
indication of the organic loading to the pond.
If the strength of the influent changes rapidly and significantly, more frequent
sampling may be necessary.
Other more specific tests may be required for discharge consent or other
requirements, e.g. nutrient (N, P) toxins, etc.
Finally, make and record observations daily or based on a regular inspection
programme:
Ponds appearance
Any odours
Unusual occurrences
Maintenance needs and actions taken
Weather
Other matters it would be useful to record
Record of when samples were taken for discharge consent monitoring
Record of duplicate testing on a sample of both on-site and laboratory
sampling is undertaken to confirm
Record of plant operators for period
34. 8. Discharge consents and conditions
Wastewater treatment engineering design has to provide solutions with equal
emphasis on three main issues with equal emphasis: odour removal, treatment and
sludge disposal. These summarizing issues and proposed treatments are presented
in the following sections.
8.1 Odour treatment
Most of domestic influents contain odour producing components such as ammonia
(NH3), hydrogen sulphide (H2S) and traces of mercaptans (sulfo-organic
compounds). The level of odour causing compounds depends on many factors the
most of which is the existence of septic sources within city sewer network.
Odours from raw influent are typically removed:
physically by air stripping , or
chemically by wet oxidation, or
biologically by absorption and bio-transformation into bio-flocs.
It should be noted that the odour emitted from the raw influent pumping station,
the partial reduction of odour could be taken place during the screening and grit
removal steps inside the pre-treatment building. A multipurpose aerated grit
chamber will remove oil & grease, settle grit, and also strip odour. Contaminated air
and odour are then vented and treated by chlorine-oxidation scrubbing and bio-
filtration. The remaining traces of NH3 and H2S (including mercaptans) could be
absorbed into bio-flocs of the aerated lagoon step.
At Dong Hoi the odour and contaminated air come from wet well of pumping
station, pre-treatment building (screening and grit removal by aerated grit
chamber), septic tank sludge reception wet well, and certain parts of aerated
lagoon treatment step are collected and treated by chemical oxidation using
chlorine scrubbing (for NH3 and H2S removal) and a biofiltration step as absorption
on Ca(OH)2 and biodegradation on biomass fixed on wet organic support as peat
moss, compost bulk, soil-type media, etc., for traces removal.
8.2 Wastewater treatment
35. In order to comply with TCVN-7222:2002 standards (organic contents, nutrient N &
P, coliforms), wastewater will be treated through a chain of combined lagoons
consisting in mechanically-aerated basin, facultative naturally-aerated lagoons and
shallow maturation ponds using solar disinfection and nutrient removal. The main
objective of aerated lagoons in a combined system is to allow a flexibility to face
unexpected pollutant loads. Finally, maturation pond with low depth will offer
advantages of zero-cost solar disinfection while aquatic floating system and surface
flow wetland allow low-cost nutrient removal.
8.3 Sludge disposal
Settled sludge can be annually removed from the lagoon bottom and dried during
the dry season. Large amounts of liquid at relative low solid contents (2 to 3%) is
pumped to a reed bed-based dewatering system. Using their live growing roots,
reed plants can progressively increase the sand interstices of the filtration bed and
improve the filtrate flow.
At Dong Hoi, sludge from the wastewater treatment plant is dewatered in the reed
bed system. Dewatered sludge can be reused as compost for agriculture reuse or
city street urban greening purposes.
9. Some case histories
9.1 Septic tank cleaner problem
A wastewater pond system was used to receive septic tank sludge and grease from
the local community. There was only once access/dumping point for the tank
cleaning operator to use. The ponds were sited in a windless gully, with the results
that as island of sludge gradually formed near the dumping point, creating a major
odour problem and seriously reducing the performance of the pond.
9.2 Industrial overloading and excess grease problems
A two pond system for a town about 6000 people also received miliscreened waste
from a small meatworks. This coupled with an excessive grease content in the
meatworks waste, meant that atmospheric oxygen could not enter the ponds, which
regularly became anaerobic in summer.
36. 9.3 Butynol rubber bank collapse
A large pond with a butynol rubber liner was located in a windy situation. The liner
was not keyed in sufficiently at the top, with the result that spray and pond liquid
seeped down behind the liners, partially collapsing the bank. Further wind and wave
action worsened the problem considerably.
9.4 Concrete wave band cracking and breaking up by wave action erosion
A pond was only partly filled following construction and the water level was such that
the wave action on the banks caused erosion of the embankment immediately below
the lower edge of the concrete wave band. The wave band then lost support and
broke up in places.
9.5 Fat/oil slick over the first or primary pond surface
In a busy tourist town which had many restaurants and hotels establishment there
was a much higher than normal cooking oil and fat discharge in the sewage. The fat
and grease traps at these establishments were also not working effectively. This
resulted in a higher than normal discharge of cooking fat and oils to the ponds,
causing an oily film to form on the top layer of the first or primary pond. This had the
effect of reducing the natural aeration effects on the pond water surface. The film
and associated surface tension effects were most noticeable when compared to the
adjacent second pond especially when there was a breeze. At these times the first
pond still had a surface while the second was rippling from the breeze.