This document is a thesis submitted by Balwinder Singh to Thapar Institute of Engineering & Technology in partial fulfillment of a Master of Engineering degree in Environmental Engineering. The thesis, supervised by Dr. Anita Rajor and Dr. A.S. Reddy, examines the determination of biochemical oxygen demand (BOD) kinetic parameters and evaluation of alternate methods. It includes chapters on literature review, materials and methods, results and discussion, and conclusions. The study evaluates six common methods for estimating BOD kinetic parameters using results from serial BOD testing of various water and wastewater samples.
Analysis BOD is an important parameter in identifying the extend of pollution in a water body. This presentation explains the various methods of BOD analysis as per the APHA manual
Biochemical oxygen demand (BOD) AND Chemical Oxygen Demand PDFchetansingh999
BOD and COD are common measures of water pollution. BOD measures the amount of dissolved oxygen needed by microorganisms to break down organic matter over 5 days. COD measures the amount of oxygen required to chemically oxidize organic and inorganic compounds. While both measure organic compounds, COD is less specific as it measures all chemically oxidizable material. BOD only measures biologically oxidizable organic matter. Calculations of BOD and COD involve measuring dissolved oxygen levels before and after incubation over 5 days or chemical oxidation. COD uses a chemical oxidation process while BOD relies on microbial decomposition.
Deals with the measurement of organic matter concentration in water and wastewater. BOD, BOD kinetics and COD tests are discussed at length. Further, as part of the ultimate BOD measurement, other associated tests like Dissolved Oxygen and Ammonical, Nitrate and Nitrite forms of nitrogen are also discussed.
This document discusses chemical oxygen demand (COD) testing. COD testing measures the amount of organic matter in water by determining the oxygen required to chemically oxidize the matter. Potassium dichromate is commonly used as the strong oxidizing agent. The COD test procedure involves refluxing a water sample with dichromate and sulfuric acid, then titrating the remaining dichromate with ferrous ammonium sulfate to determine the COD level in mg/L. COD testing provides faster results than biochemical oxygen demand (BOD) testing and oxidizes a wider range of compounds, though the results do not directly correlate to 5-day BOD levels.
Details about Biochemical Oxygen Demand(BOD) with solved examples. Extra examples are given for homework. You can contact me for details on pratik1516@gmail.com.
Wastewater has physical, chemical, and biological characteristics. Physically, it contains solids like total suspended solids and total dissolved solids that affect turbidity. Chemically, wastewater has parameters like pH, alkalinity, nitrogen, and phosphorus. Common methods to measure organic content include biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC). Biologically, wastewater contains organisms like bacteria, algae, protozoa, and viruses, some of which can be pathogenic.
This document discusses key concepts related to waste water treatment including biochemical oxygen demand (BOD), chemical oxygen demand (COD), and dissolved oxygen (DO). BOD measures the amount of oxygen required by microorganisms to break down organic matter in water. COD determines the oxygen required to oxidize organic compounds. DO refers to oxygen dissolved in water that aquatic life requires. The document outlines typical values and measurement methods for BOD, COD and DO in waste and natural waters. It also describes the nature of waste water pollutants and an overview of waste water treatment processes.
Analysis BOD is an important parameter in identifying the extend of pollution in a water body. This presentation explains the various methods of BOD analysis as per the APHA manual
Biochemical oxygen demand (BOD) AND Chemical Oxygen Demand PDFchetansingh999
BOD and COD are common measures of water pollution. BOD measures the amount of dissolved oxygen needed by microorganisms to break down organic matter over 5 days. COD measures the amount of oxygen required to chemically oxidize organic and inorganic compounds. While both measure organic compounds, COD is less specific as it measures all chemically oxidizable material. BOD only measures biologically oxidizable organic matter. Calculations of BOD and COD involve measuring dissolved oxygen levels before and after incubation over 5 days or chemical oxidation. COD uses a chemical oxidation process while BOD relies on microbial decomposition.
Deals with the measurement of organic matter concentration in water and wastewater. BOD, BOD kinetics and COD tests are discussed at length. Further, as part of the ultimate BOD measurement, other associated tests like Dissolved Oxygen and Ammonical, Nitrate and Nitrite forms of nitrogen are also discussed.
This document discusses chemical oxygen demand (COD) testing. COD testing measures the amount of organic matter in water by determining the oxygen required to chemically oxidize the matter. Potassium dichromate is commonly used as the strong oxidizing agent. The COD test procedure involves refluxing a water sample with dichromate and sulfuric acid, then titrating the remaining dichromate with ferrous ammonium sulfate to determine the COD level in mg/L. COD testing provides faster results than biochemical oxygen demand (BOD) testing and oxidizes a wider range of compounds, though the results do not directly correlate to 5-day BOD levels.
Details about Biochemical Oxygen Demand(BOD) with solved examples. Extra examples are given for homework. You can contact me for details on pratik1516@gmail.com.
Wastewater has physical, chemical, and biological characteristics. Physically, it contains solids like total suspended solids and total dissolved solids that affect turbidity. Chemically, wastewater has parameters like pH, alkalinity, nitrogen, and phosphorus. Common methods to measure organic content include biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC). Biologically, wastewater contains organisms like bacteria, algae, protozoa, and viruses, some of which can be pathogenic.
This document discusses key concepts related to waste water treatment including biochemical oxygen demand (BOD), chemical oxygen demand (COD), and dissolved oxygen (DO). BOD measures the amount of oxygen required by microorganisms to break down organic matter in water. COD determines the oxygen required to oxidize organic compounds. DO refers to oxygen dissolved in water that aquatic life requires. The document outlines typical values and measurement methods for BOD, COD and DO in waste and natural waters. It also describes the nature of waste water pollutants and an overview of waste water treatment processes.
Deals with UASB reactors for the primary treatment of sewage, stabilization of sludge and removal of BOD. Various components of a UASB reactor are described and design details are included. Modifications to UASB such as UASB ponds, Anaerobic baffle reactors, migrating blanket reactors are also described here.
Lecture notes of Environmental Engineering-II as per Solapur university syllabus of TE CIVIL.
Prepared by
Prof S S Jahagirdar,
Associate Professor,
N K Orchid college of Engg and Technology,
Solapur
This document describes an experiment to determine the biochemical oxygen demand (BOD) of a lake water sample. BOD measures the amount of dissolved oxygen needed by microorganisms to break down organic matter in water over 5 days. The results show increasing BOD readings over time. There are two types of BOD tests - seeded and unseeded. Seeded tests add microorganisms, while unseeded rely on microorganisms already present. High BOD effluent discharged into rivers can reduce oxygen levels and harm aquatic life. BOD testing helps evaluate sewage treatment plant performance and water quality.
There are three major biological wastewater treatment techniques: attached growth processes, suspended growth processes, and combined processes. Attached growth processes involve microorganisms attached to an inert medium that convert wastewater organic matter into gases and cell tissue. Suspended growth processes involve microorganisms maintained in suspension within the wastewater reactor through mixing as they consume organic matter. Combined processes use both attached and suspended growth approaches.
This document provides information about biochemical oxygen demand (BOD) including:
1. BOD is a measure of the oxygen used by microorganisms to decompose organic waste in water. A high BOD level indicates a large amount of decomposable organic waste.
2. The key difference between biochemical oxygen demand and biological oxygen demand is that BOD measures oxygen used to oxidize inorganic materials like sulfides in addition to decomposing organic matter, while biological oxygen demand only measures oxygen used for decomposing organic substances.
3. BOD tests are used to determine pollution levels, design treatment methods, and evaluate treatment plant performance by measuring how much oxygen is depleted during the decomposition of organic matter.
The document discusses trickling filters, which are used in sewage treatment to remove suspended solids and dissolved organic loads from wastewater. Trickling filters use microbial populations attached to a filter media to break down organic matter. They consist of a rotating arm that sprays wastewater over a rock or plastic media, with wastewater collected below for further treatment. Trickling filters can be designed as low or high rate systems, with high rate filters having greater organic loading, hydraulic loading, and recirculation ratios compared to low rate filters. Operational issues include ponding, odors, and fly nuisance that can occur if the filters become anaerobic or clogged.
This document provides an introduction to physical-chemical water treatment. It discusses the instructor, Hans van Leeuwen, and his background and research interests in wastewater treatment and bioengineering. It then covers various topics related to water treatment including ozone applications, exotic species in ports, human technological development, pollution, waterborne diseases, dissolved oxygen, biochemical oxygen demand, oxygen depletion in streams, and uses the Streeter-Phelps model to analyze an example of oxygen sag in a river.
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 document discusses various methods for treating wastewater, including removing nitrogen, phosphorus, and heavy metals. It describes the biological processes of nitrification and denitrification for removing nitrogen. Nitrification converts ammonia to nitrates while denitrification converts nitrates to nitrogen gas. Phosphorus can be removed through chemical precipitation or biological removal by certain bacteria. Heavy metals are removed using physico-chemical methods like adsorption, ion exchange, reverse osmosis, and electrodialysis.
The document discusses wastewater treatment processes for removing nitrogen. It describes the forms of nitrogen found in wastewater and explains why nitrogen needs to be treated. The nitrogen cycle and key processes like nitrification, denitrification, and biological nitrogen removal are summarized. Physicochemical and biological approaches to secondary treatment are compared.
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
This document discusses rotating biological contactors (RBCs), which are fixed film, aerobic biological reactors used for wastewater treatment. RBCs use rotating discs to bring wastewater into contact with oxygen and microorganisms to reduce organic matter. Key parameters that control RBC performance include organic and hydraulic loading rates, biomass levels, disc speed, dissolved oxygen, staging, temperature, and disc submergence. Design considerations for RBCs include using multiple treatment stages, corrugated discs to maximize surface area, and hydraulic retention times of 0.7-1.5 hours. RBCs have advantages of simple operation, low energy use, and process stability, but lack flexibility and can be sensitive to
Chemical characteristics of sewage and their testing Ankit Gola
The document discusses the chemical characteristics of sewage and their testing. It describes various tests that are carried out to determine characteristics like total solids, suspended solids, pH, chloride content, nitrogen content, fats/greases/oils, sulphides/sulphates, dissolved oxygen, chemical oxygen demand (COD), and biochemical oxygen demand (BOD). These tests help indicate the stage of sewage decomposition, its strength, and the type of treatment required to make it safe.
The document discusses biochemical oxygen demand (BOD) and its importance as a measure of water quality. BOD is defined as the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a water sample over a 5 day incubation period at 20°C. A higher BOD indicates a higher level of organic pollution. BOD is used to assess the effectiveness of wastewater treatment plants and provides an indication of overall water quality. The standard BOD test involves measuring the dissolved oxygen in a sample before and after 5 days, with the difference representing the oxygen consumed during decomposition of organic compounds.
BOD measures the amount of dissolved oxygen required by aerobic organisms to break down organic matter over 5 days, while COD measures the oxygen required to chemically oxidize organic compounds using a strong chemical oxidant. BOD uses a biological oxidation process that is slower but measures naturally degradable organics, while COD uses a chemical oxidation process that is faster but measures all organics including those not degraded biologically. COD values are typically higher than BOD and are used to measure pollution from industrial sources.
BOD measures the amount of oxygen required by bacteria to decompose organic matter in sewage over 5 days. High BOD indicates more bacteria and organic matter, risking anaerobic conditions. BOD is usually lower than COD since not all organic matter is biodegradable. COD measures oxygen required to chemically oxidize all organic matter and is faster than BOD, making it better for industrial waste. Both tests determine organic pollutant levels, but COD captures a wider range and does not differentiate biodegradable and non-biodegradable matter.
Biological Nutrient Removal (BNR) is a process used for nitrogen and phosphorus removal from wastewater before it is discharged into surface or ground water.To control eutrophication in receiving water bodies, biological nutrient removal (BNR) of nitrogen and phosphorus has been widely used in wastewater treatment practice, both for the upgrade of existing wastewater treatment facilities and the design of new facilities.
The biological oxygen demand (BOD) measures the amount of dissolved oxygen needed by aerobic organisms to break down organic matter in water. Water with a high BOD cannot replenish oxygen fast enough to support aquatic life, potentially causing suffocation. BOD is normally measured over 5 days, with polluted water having a BOD above 5 parts per million. Thermal pollution degrades water quality by changing the ambient temperature, such as from careless discharge of heated water by industries or removing shading vegetation.
This document is a memorandum submitted by Plaintiffs' attorneys in support of a motion for a temporary restraining order against Defendants. It summarizes the arguments made in previous filings and addresses issues raised in the State's opposition memorandum. Specifically, it argues that the Attorney General's Opinion No. 13-1 misinterprets the meaning and intent of Article I, Section 23 of the Hawaii Constitution regarding the definition of marriage. It also argues that federal justiciability standards of an actual controversy, ripeness, and standing do not apply given that this involves a matter of great public importance under Hawaii law. The memorandum aims to demonstrate the Plaintiffs have a likelihood of success on the merits in their request for a declaratory judgment on the meaning of
Deals with UASB reactors for the primary treatment of sewage, stabilization of sludge and removal of BOD. Various components of a UASB reactor are described and design details are included. Modifications to UASB such as UASB ponds, Anaerobic baffle reactors, migrating blanket reactors are also described here.
Lecture notes of Environmental Engineering-II as per Solapur university syllabus of TE CIVIL.
Prepared by
Prof S S Jahagirdar,
Associate Professor,
N K Orchid college of Engg and Technology,
Solapur
This document describes an experiment to determine the biochemical oxygen demand (BOD) of a lake water sample. BOD measures the amount of dissolved oxygen needed by microorganisms to break down organic matter in water over 5 days. The results show increasing BOD readings over time. There are two types of BOD tests - seeded and unseeded. Seeded tests add microorganisms, while unseeded rely on microorganisms already present. High BOD effluent discharged into rivers can reduce oxygen levels and harm aquatic life. BOD testing helps evaluate sewage treatment plant performance and water quality.
There are three major biological wastewater treatment techniques: attached growth processes, suspended growth processes, and combined processes. Attached growth processes involve microorganisms attached to an inert medium that convert wastewater organic matter into gases and cell tissue. Suspended growth processes involve microorganisms maintained in suspension within the wastewater reactor through mixing as they consume organic matter. Combined processes use both attached and suspended growth approaches.
This document provides information about biochemical oxygen demand (BOD) including:
1. BOD is a measure of the oxygen used by microorganisms to decompose organic waste in water. A high BOD level indicates a large amount of decomposable organic waste.
2. The key difference between biochemical oxygen demand and biological oxygen demand is that BOD measures oxygen used to oxidize inorganic materials like sulfides in addition to decomposing organic matter, while biological oxygen demand only measures oxygen used for decomposing organic substances.
3. BOD tests are used to determine pollution levels, design treatment methods, and evaluate treatment plant performance by measuring how much oxygen is depleted during the decomposition of organic matter.
The document discusses trickling filters, which are used in sewage treatment to remove suspended solids and dissolved organic loads from wastewater. Trickling filters use microbial populations attached to a filter media to break down organic matter. They consist of a rotating arm that sprays wastewater over a rock or plastic media, with wastewater collected below for further treatment. Trickling filters can be designed as low or high rate systems, with high rate filters having greater organic loading, hydraulic loading, and recirculation ratios compared to low rate filters. Operational issues include ponding, odors, and fly nuisance that can occur if the filters become anaerobic or clogged.
This document provides an introduction to physical-chemical water treatment. It discusses the instructor, Hans van Leeuwen, and his background and research interests in wastewater treatment and bioengineering. It then covers various topics related to water treatment including ozone applications, exotic species in ports, human technological development, pollution, waterborne diseases, dissolved oxygen, biochemical oxygen demand, oxygen depletion in streams, and uses the Streeter-Phelps model to analyze an example of oxygen sag in a river.
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 document discusses various methods for treating wastewater, including removing nitrogen, phosphorus, and heavy metals. It describes the biological processes of nitrification and denitrification for removing nitrogen. Nitrification converts ammonia to nitrates while denitrification converts nitrates to nitrogen gas. Phosphorus can be removed through chemical precipitation or biological removal by certain bacteria. Heavy metals are removed using physico-chemical methods like adsorption, ion exchange, reverse osmosis, and electrodialysis.
The document discusses wastewater treatment processes for removing nitrogen. It describes the forms of nitrogen found in wastewater and explains why nitrogen needs to be treated. The nitrogen cycle and key processes like nitrification, denitrification, and biological nitrogen removal are summarized. Physicochemical and biological approaches to secondary treatment are compared.
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
This document discusses rotating biological contactors (RBCs), which are fixed film, aerobic biological reactors used for wastewater treatment. RBCs use rotating discs to bring wastewater into contact with oxygen and microorganisms to reduce organic matter. Key parameters that control RBC performance include organic and hydraulic loading rates, biomass levels, disc speed, dissolved oxygen, staging, temperature, and disc submergence. Design considerations for RBCs include using multiple treatment stages, corrugated discs to maximize surface area, and hydraulic retention times of 0.7-1.5 hours. RBCs have advantages of simple operation, low energy use, and process stability, but lack flexibility and can be sensitive to
Chemical characteristics of sewage and their testing Ankit Gola
The document discusses the chemical characteristics of sewage and their testing. It describes various tests that are carried out to determine characteristics like total solids, suspended solids, pH, chloride content, nitrogen content, fats/greases/oils, sulphides/sulphates, dissolved oxygen, chemical oxygen demand (COD), and biochemical oxygen demand (BOD). These tests help indicate the stage of sewage decomposition, its strength, and the type of treatment required to make it safe.
The document discusses biochemical oxygen demand (BOD) and its importance as a measure of water quality. BOD is defined as the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a water sample over a 5 day incubation period at 20°C. A higher BOD indicates a higher level of organic pollution. BOD is used to assess the effectiveness of wastewater treatment plants and provides an indication of overall water quality. The standard BOD test involves measuring the dissolved oxygen in a sample before and after 5 days, with the difference representing the oxygen consumed during decomposition of organic compounds.
BOD measures the amount of dissolved oxygen required by aerobic organisms to break down organic matter over 5 days, while COD measures the oxygen required to chemically oxidize organic compounds using a strong chemical oxidant. BOD uses a biological oxidation process that is slower but measures naturally degradable organics, while COD uses a chemical oxidation process that is faster but measures all organics including those not degraded biologically. COD values are typically higher than BOD and are used to measure pollution from industrial sources.
BOD measures the amount of oxygen required by bacteria to decompose organic matter in sewage over 5 days. High BOD indicates more bacteria and organic matter, risking anaerobic conditions. BOD is usually lower than COD since not all organic matter is biodegradable. COD measures oxygen required to chemically oxidize all organic matter and is faster than BOD, making it better for industrial waste. Both tests determine organic pollutant levels, but COD captures a wider range and does not differentiate biodegradable and non-biodegradable matter.
Biological Nutrient Removal (BNR) is a process used for nitrogen and phosphorus removal from wastewater before it is discharged into surface or ground water.To control eutrophication in receiving water bodies, biological nutrient removal (BNR) of nitrogen and phosphorus has been widely used in wastewater treatment practice, both for the upgrade of existing wastewater treatment facilities and the design of new facilities.
The biological oxygen demand (BOD) measures the amount of dissolved oxygen needed by aerobic organisms to break down organic matter in water. Water with a high BOD cannot replenish oxygen fast enough to support aquatic life, potentially causing suffocation. BOD is normally measured over 5 days, with polluted water having a BOD above 5 parts per million. Thermal pollution degrades water quality by changing the ambient temperature, such as from careless discharge of heated water by industries or removing shading vegetation.
This document is a memorandum submitted by Plaintiffs' attorneys in support of a motion for a temporary restraining order against Defendants. It summarizes the arguments made in previous filings and addresses issues raised in the State's opposition memorandum. Specifically, it argues that the Attorney General's Opinion No. 13-1 misinterprets the meaning and intent of Article I, Section 23 of the Hawaii Constitution regarding the definition of marriage. It also argues that federal justiciability standards of an actual controversy, ripeness, and standing do not apply given that this involves a matter of great public importance under Hawaii law. The memorandum aims to demonstrate the Plaintiffs have a likelihood of success on the merits in their request for a declaratory judgment on the meaning of
The document discusses the biochemical oxygen demand (BOD) test procedure for determining the amount of dissolved oxygen consumed by microorganisms while decomposing organic matter in water samples over a 5 day period. It provides background on BOD and dissolved oxygen, lists the necessary supplies and reagents, and describes the steps to conduct the BOD test and calculate results to evaluate water quality. A 5-day duration is used for the BOD test because most of the biodegradable organic matter will be degraded within 5 days if sufficient microorganisms and oxygen are present.
This document provides information about measuring biochemical oxygen demand (BOD). It discusses the significance of BOD testing, describing it as a measure of the oxygen demand of organic matter in water samples through biochemical reactions with microorganisms. The standard BOD test procedure and BIS (Bureau of Indian Standards) procedure are outlined. Other parameters for measuring organic matter like COD and TOC are also introduced and compared to BOD. Sources of error in BOD tests and methods to address them are explained. Equations to model BOD progression as a first-order reaction and calculate BOD values at different time points are presented.
This document discusses various organic and inorganic compounds found in water. It covers topics like biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids. For BOD and COD, it explains the test procedures and calculations used to measure levels of each compound. It also discusses how temperature affects BOD reaction rates. Inorganic compounds are classified as metals or non-metals. The document provides details on measuring parameters that indicate levels of organic pollution in water samples.
This document appears to be a project report submitted by Priyanka Bhatti to Gujarat University on her summer training with Marwadi Shares and Finance Pvt. Ltd., a leading financial company in India. The report includes an introduction to the company, an overview of different departments within the company, and an analysis of the current market scenario. It discusses the history of stock markets in India and provides details about Marwadi's vision, services, and departments like DP, trading, HR, and accounts. The report aims to document Priyanka Bhatti's learning experience during her summer training at Marwadi Shares and Finance Pvt. Ltd.
Pan card declaration letter format. (1)Unnikkrishnan
The document is a self declaration from a sole proprietor stating that they own a business called M/s. [blank] under their name Mr. [blank] located at [blank] with a PAN number [blank] and Service Tax number [blank].
The document discusses important contaminants of concern in wastewater treatment including suspended solids, nutrients, priority pollutants, refractory organics, heavy metals, and dissolved inorganics. It then describes characteristics of industrial wastewater such as physical characteristics (total solids, odors, temperature, color, turbidity), chemical characteristics (organic and inorganic matter), and biological characteristics. Finally, it outlines common wastewater treatment methods including mechanical, physical, chemical, physio-chemical, biological, and auxiliary operations like disinfection.
SIP REPORT ON INCOME TAX PLANNING WITH RESPECT TO INDIVIDUAL ASSESSEEMonika Kadam
This document is a student project report on income tax planning for individual assessees in India. It includes sections on an introduction to income tax law in India, objectives of the report, profiles of the student and guiding institution. It also includes literature review sections summarizing key concepts from the Income Tax Act of 1961 regarding residential status, sources of total income, and concepts used in tax planning like evasion and avoidance. Tables of content and acknowledgments are provided.
This document appears to be a student's summer internship report on their project studying Coca Cola's marketing strategies and distribution channels in India. It includes sections on the company profile of Coca Cola, objectives of the project, distribution channels, the soft drink market in India, competitive arena, SWOT analysis, research methodology, and recommendations. The student declares this is their original work conducted as a summer intern at Coca Cola Beverage Pvt Ltd under faculty guidance.
Activated Sludge Process and biological Wastewater treatment systemKalpesh Dankhara
The document discusses biological wastewater treatment, specifically for removing biochemical oxygen demand (BOD) and nitrogen. It covers the types of pollutants found in wastewater, biological treatment methods, microorganisms involved, and the activated sludge process. Key aspects of the activated sludge process discussed include aeration basins, clarifiers, mixed liquor suspended solids, food to mass ratio, recycle and waste sludge streams, and sludge retention time.
The document provides details for establishing a jeans manufacturing small-scale industry called JRV Jeans Mills in Gujarat, India. It includes information on the location, management structure, production process, machinery requirements, raw material sources, sales projections, costing, and implementation schedule. The unit plans to produce 30,000 jeans annually and targets a sales revenue of Rs. 88 lakhs in the first year by selling different styles and sizes of jeans at varying price points to the local Gujarat and Maharashtra markets.
Marketing research project on nike shoesRohit Kumar
This document appears to be a marketing research project report submitted by Kunal Madaan to his professor, Ms. Kangan Jain, at Keshav Mahavidyalaya, University of Delhi. The report analyzes consumer behavior towards Nike footwear in India. It includes declarations of original work, certificates of supervision, acknowledgements of assistance, an executive summary of the report's contents, background on the problem being examined, and profiles of Nike and the Indian footwear industry.
IRJET- Design and Fabrication of a Micro-Respirometer to Measure the Short-Te...IRJET Journal
This document describes the design and fabrication of a micro-respirometer to measure the short-term respiratory quotient (RQ) of wastewater samples. The researchers developed a low-cost respirometer using locally available materials to determine oxygen consumption rate, carbon dioxide evolution rate, and RQ of wastewater samples. They tested wastewater samples from various sources covering a range of chemical oxygen demand levels. Samples from a pharmaceutical industry showed the highest carbon dioxide evolution rate and RQ above one. A mixed wastewater sample showed the highest RQ for low-range samples. The respirometer allows wastewater treatment plant operators to assess influent wastewater characteristics to inform plant operation.
The third inter-laboratory analytical quality control exercise was conducted for surface water laboratories in India. 35 laboratories participated by analyzing standard samples for 9 parameters. The performance of laboratories varied widely across parameters. Only 16 laboratories reported results for all 9 parameters. 4 laboratories could not analyze any parameter accurately. The highest performance was for conductivity and sodium analysis while the lowest was for boron. Systematic errors affected results more than random errors for most laboratories and parameters as indicated by result clusters in specific quadrants of Youden plots. Overall, the exercise revealed opportunities to improve accuracy for many laboratories and parameters.
Performance evaluation of Effluent Treatment Plant of Dairy IndustryIJERA Editor
Dairy industry is among the most polluting of the food industries in regard to its large water consumption. Dairy
is one of the major industries causing water pollution. Considering the increased milk demand, the dairy
industry in India is expected to grow rapidly and have the waste generation and related environmental problems
are also assumed increased importance. Poorly treated wastewater with high level of pollutants caused by poor
design, operation or treatment systems creates major environmental problems when discharged to the surface
land or water. Various operations in a dairy industry may include pasteurization, cream, cheese, milk powder
etc. Considering the above stated implications an attempt has been made in the present project to evaluate one of
the Effluent Treatment Plant for dairy waste. Samples are collected from three points; Collection tank (CT),
primary clarifier (PC) and Secondary clarifier (SC) to evaluate the performance of Effluent Treatment Plant.
Parameters analyzed for evaluation of performance of Effluent Treatment Plant are pH, TDS, TSS, COD, and
BOD at 200C The pH, TDS, TSS, COD and BOD removal efficiency of Effluent Treatment Plant were 26.14 %,
33.30 %, 93.85 %, 94.19 % and 98.19 % respectively.
This document summarizes a study evaluating the performance of an effluent treatment plant (ETP) for a dairy industry in India. Samples were collected from three points in the ETP - the collection tank, primary clarifier, and secondary clarifier. The ETP achieved removal efficiencies of 26.14% for pH, 33.30% for TDS, 93.85% for TSS, 94.19% for COD, and 98.19% for BOD. The treated effluent met standards for discharge set by the Gujarat Pollution Control Board. The ETP was effective at removing pollutants and bringing wastewater characteristics in line with regulatory requirements for reuse or discharge.
IRJET- Synthesis and Utilization of a Biodegradable, Novel Carbohydrate-based...IRJET Journal
This document summarizes research on the synthesis and analysis of a novel biodegradable carbohydrate-based polymer and its application in liquid laundry detergent formulation. Key points:
1) A polymer was synthesized from liquid glucose, citric acid, borax, and other ingredients. Its properties like viscosity, surface tension, and biodegradability were analyzed.
2) The polymer was found to be biodegradable based on a BOD/COD ratio of 0.6944 from biodegradation testing.
3) A liquid laundry detergent was formulated using the polymer and tested. Analysis showed it had comparable properties to a commercial detergent in terms of foaming, surface tension, and stain
Utilization of pre aerated sludge in activated sludge processeSAT Journals
Abstract The research was carried out with Pre aerated Sludge in Activated Sludge Process to observe the effect of Pre-aerated Sludge on BOD, COD , Phosphate, Nitrate, MLVSS mainly in treatment of dairy wastewater. The experimental process involves the conventional Activated Sludge Process (ASP) in which microorganisms are kept in suspension by mixing and aerating the wastewater. The study is to be conducted by following two methods: 1) utilizing non pre-aerated sludge and 2) utilizing pre-aerated sludge. In the first method the dairy wastewater measuring five liters and 400 ml of non-pre-aerated sludge is filled in the aeration tank and was aerated in the aeration tank where air (or oxygen) was supplied for regular intervals of 30, 60, 90, 120 minutes respectively and samples are collected before aeration and at regular intervals. In the second method the dairy wastewater measuring five liters and 400 ml of pre aerated sludge (with 20, 40 and 60 minutes pre-aeration) are filled in aeration tank. This tank is aerated for regular intervals of 30, 60, 90, 120 minutes respectively. The samples are collected before aeration and at regular time intervals. The sludge is to be not recycled to the aeration tank. Testing of different parameters like BOD, COD, Phosphate, Nitrate and Mixed liquor volatile suspended solids was carried out on the samples aerated with different aeration time, with and without pre-aerated sludge and consequent results are to be found. By utilization of pre-aerated sludge, the concentrations of various parameters to be considered for study are to be found decreased when compared with the values of concentration without using pre-aerated sludge. It will be very clear that removal of various parameters from wastewater is effective up to the optimum period for pre-aeration beyond this period removal of various parameters from wastewater will not be effective. Keywords: Activated Sludge Process, BOD, COD, Phosphate, Nitrate, MLVSS.
IRJET- Design of Leachate Bioreactor for Dilkap CollegeIRJET Journal
This document describes a study conducted to design a leachate bioreactor for Dilkap College in Maharashtra, India. Specifically:
- Researchers created a model tank containing layered gravel, soil, food waste from the college canteen, and additional soil to treat leachate generated from the waste.
- The leachate collected from the model would be used in an anaerobic bioreactor to convert it into methane gas, which could then be used as an energy source.
- The document reviews several other studies on leachate treatment methods, such as using solar photocatalysis and membrane bioreactor technologies to reduce leachate pollution and convert it into usable fuels.
Seba Salem Rawashdeh seeks a position utilizing her 2 years of experience in ISO/IEC 17025 laboratory accreditation and testing water samples. She has worked at the Prince Faisal Centre for Dead Sea research in Jordan, maintaining their quality management system and conducting tests such as TDS, TSS, pH, COD, BOD. She is skilled in using laboratory equipment like AAS, IC, GC-MS, FTIR and has certificates in ISO/IEC 17025, internal auditing, and laboratory test validation.
IRJET- Study on Increasing the Efficiency of the Existing Sequential Batch Re...IRJET Journal
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The comparative study of waste water and purified water present in sewage tre...IRJET Journal
This document summarizes a study comparing the quality of waste water and purified water from a sewage treatment plant in Bhusawal city, India. Laboratory tests were conducted to analyze various physical and chemical parameters, including total suspended solids, chloride content, pH, and dissolved oxygen. The results showed improvements in water quality after treatment, with reductions in total suspended solids from 220 to 7 mg/L, chloride content from 260 to 159.95 mg/L, and increases in dissolved oxygen from 0.1 to 7.9 mg/L. The pH also increased from 5.8 to 6.65 after treatment. The findings indicate that the sewage treatment process effectively reduced pollutants and improved water quality, suggesting
The document reports the findings of the third inter-laboratory analytical quality control exercise conducted by the Central Ground Water Board in Bhopal, India in June 2002. Thirty-eight water quality testing laboratories participated in the exercise. Laboratories were provided two synthetic water samples to analyze for nine parameters and their results were compared to reference values. Overall laboratory performance was mixed, with only one laboratory accurately analyzing all nine parameters. Conductivity, chloride, and total hardness saw the highest response rates, while boron saw the lowest. The report includes graphs comparing each laboratory's results to acceptable ranges and concludes some laboratories exhibited mostly random errors while others showed systematic errors. Recommendations are made to improve laboratory analytical capabilities.
This lab course focuses on practicing basic water quality analysis methods. Students will determine quality parameters of water and wastewater samples using gravimetric, volumetric, and spectrophotometric techniques. Parameters tested include alkalinity, hardness, solids, BOD, COD and more. The course aims to provide hands-on experience in laboratory procedures for water and wastewater treatment. Students will be assessed based on lab reports, quizzes, a midterm exam, and a final exam.
This lab course focuses on practicing basic water quality analysis methods. Students will determine quality parameters of water and wastewater samples using gravimetric, volumetric, and spectrophotometric techniques. Parameters tested include alkalinity, hardness, solids, BOD, COD and more. The course aims to provide hands-on experience in laboratory procedures for water and wastewater treatment. Students will be assessed based on lab reports, quizzes, a midterm exam, and a final exam.
This lab course focuses on practicing basic water quality analysis methods. Students will determine quality parameters of water and wastewater samples using gravimetric, volumetric, and spectrophotometric techniques. Parameters tested include alkalinity, hardness, solids, BOD, COD and more. The course aims to provide hands-on experience in laboratory procedures for water and wastewater treatment. Students will be assessed based on lab reports, quizzes, a midterm exam, and a final exam.
This lab course focuses on practicing basic water quality analysis methods. Students will determine quality parameters of water and wastewater samples using gravimetric, volumetric, and spectrophotometric techniques. Parameters tested include alkalinity, hardness, solids, BOD, COD and more. The course aims to provide hands-on experience in laboratory procedures for water and wastewater treatment. Students will be assessed based on lab reports, quizzes, a midterm exam, and a final exam.
Analysis of Waste Water Treatment in Kaduna Refining and Petrochemicals Corpo...IJERA Editor
This document summarizes a study analyzing waste water treatment at the Kaduna Refining and Petrochemicals Corporation (KRPC) in Nigeria. Key findings include:
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2) The KRPC laboratory is limited in the types of tests it can perform to monitor treated waste water discharged into receiving rivers. Many pollutants require more advanced instruments not available.
3) A comparison showed that while some treated effluent values met Nigerian guidelines, several important parameters could not be tested for and their levels remain unknown due to insufficient
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2016 ISCN Awards: Campus Planning and Management SystemsISCN_Secretariat
1) The project aims to develop anaerobic digester prototypes to reduce food and garden waste from three university canteens through co-digestion, and wastewater reuse systems for two buildings on campus.
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3) An education program teaches staff and students about the 3Rs (Reduce, Reuse, Recycle) to increase sustainable waste management on campus.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
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I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
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Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
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Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
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the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
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and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
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1. DETERMINATION OF BOD KINETIC PARAMETERS AND
EVALUATION OF ALTERNATE METHODS
A Thesis submitted to
THAPAR INSTITUTE OF ENGINEERING & TECHNOLOGY, PATIALA
in partial fulfillment of the requirements
for the award of degree of
MASTER OF ENGINEERING
in
ENVIRONMENTAL ENGINEERING
by
BALWINDER SINGH
Under the supervision of
Dr. ANITA RAJOR Dr. A. S. REDDY
DEPARTMENT OF BIOTECHNOLOGY & ENVIRONMENTAL SCIENCES
THAPAR INSTITUTE OF ENGINEERING & TECHNOLOGY
(DEEMED UNIVERSITY)
PATIALA – 147 004
June, 2004
2. CERTIFICATE
This is to certify that the thesis entitled, “ Determination of BOD Kinetic Parameters
And Evaluation of Alternate Methods” submitted by Balwinder Singh in partial
fulfillment of the requirements for the award of Degree of MASTER OF
ENGINEERING in ENVIRONMENTAL ENGINEERING to Thapar Institute of
Engineering & Technology (Deemed University), Patiala, is a record of student’s own
work carried out by him under our supervision and guidance. The report has not been
submitted for the award of any other degree or certificate in this or any other
university or institute.
(Dr. Anita Rajor) (Dr. A. S. Reddy)
Department of Biotech. & Env. Sciences,
Thapar Institute of Engg. & Tech.,
Patiala – 147004
Lecturer (Selection Grade)
Department of Biotech. & Env. Sciences,
Thapar Institute of Engg. & Tech.,
Patiala – 147004
(Dr. Sunil Khanna) (Dr. D. S. Bawa)
Professor & Head,
Department of Biotech. & Env. Sciences,
Thapar Institute of Engg. & Tech.,
Patiala – 147004
Dean (Academic Affairs),
Thapar Institute of Engg. & Tech.,
Patiala – 147004
3. DECLARATION
I here by declare, that the thesis report entitled, “Determination of BOD Kinetic
Parameters And Evaluation of Alternate Methods” written and submitted by me to
Thapar Institute of Engineering & Technology (Deemed University), Patiala, in
partial fulfillment of the requirements for the degree of MASTER OF
ENGINEERING in ENVIRONMENTAL ENGINEERING. This is my original
work & conclusions drawn are based on the material collected by me.
I further declare that this work has not been submitted to this or any other university
for the award of any other degree, diploma or equivalent course.
BALWINDER SINGH
4. ACKNOWLEDGEMENT
I wish to express my deep gratitude to Dr. A. S. Reddy, Lecturer (Selection Grade),
Department of Biotech. & Environmental Sciences, Thapar Institute of Engg. &
Technology, Patiala for his invaluable guidance, inspiration, valuable suggestions,
encouragement during the entire period of present study. I will not hesitate to express
sincere thanks to Dr. Anita Rajor for providing the constant encouragement and
making the lab work possible under her able guidance.
I am highly thankful to Dr. Sunil Khanna, Head, Department of Biotech. &
Environmental Science for granting permission for the use of departmental labs.
Lastly, I am thankful to my colleagues, friends and family members for bearing with
me and providing me all moral help during the entire period of my work.
BALWINDER SINGH
5. CONTENTS
CONTENTS PAGE. NO.
Certificate i
Acknowledgement ii
Declaration iii
List of tables iv
List of Figures v
Chapter: 1 Introduction
1.1 Background information and objectives of the study
1.2 Overview of the contents of the report
1.3 Importance of the study
1 – 5
Chapter: 2 Literature Review 6 – 11
Chapter: 3 Materials and Methods 12 – 33
3.1 Introduction
3.2 Sampling
3.3 Serial BOD testing
3.4 Estimation of BOD kinetic parameters
3.4.1 Method of Moments
3.4.2 Least Squares Methods
3.4.3 Thomas Graphical Method
3.4.5 Iteration Method
3.4.6 Fujimoto Method
3.5 comparison of different methods of estimation
7. LIST OF TABLES
Table Name Page No.
2.1 Typical values of k and L0 of various waters 9
4.1 BOD results of River Satluj sample (SAT-7) 35
4.2 BOD results of East Bein River (EB-4) 35
4.3 BOD results of Treated Municipal Sewage 36
4.4 BOD results of Treated Distillery Effluents 36
4.5 BOD results of Treated Dairy Effluents 37
4.6 BOD results of Treated Textile Effluents 37
4.7 Duration of lag observed in serial BOD test 38
4.8 BOD kinetic parameters values for SAT-7 40
4.9 BOD kinetic parameters values for EB-4 41
4.10 BOD kinetic parameters values for Treated Municipal
Sewage
42
4.11 BOD kinetic parameters values for Treated Distillery
Effluents
43
4.12 BOD kinetic parameters values for Treated Dairy
Effluents
44
4.13 BOD kinetic parameters values for Treated Textile
Effluents
45
4.14 Sum of absolute differences between observed and
expected BOD values
47
4.15 Results discarded from the method evaluation 49
4.16 Suitability of methods for different samples 50
8. LIST OF FIGURES
Figure No. Name Page No.
1.1 Fate of biodegradable organic matter, during BOD test 2
3.2 Moore’s diagram for n=7 days 18
3.3 Thomas method for SAT-7 (IV) 24
3.4 Daily Difference method for SAT-7 (IV) 27
3.5 Fujimoto method for SAT-7 (IV) 32
4.1 - 4.4 Method comparison for SAT-7 (sample I – IV) 52 – 53
4.5 - 4.8 Method comparison for EB-4 (sample I – IV) 54 – 55
4.9 - 4.11 Method comparison for Sewage (sample I – III) 56 – 57
4.12 - 4.14 Method comparison for Distillery Effluent (sample I –
III)
57 – 58
4.15 - 4.17 Method comparison for Dairy Effluent (sample I – III) 59 – 60
4.18 - 4.20 Method comparison for Textile Effluent (sample I – III) 60 - 61
9. CHAPTER: 1
Introduction
1.1 Background information and objectives of the study:
Biodegradable organic matter is one of the important pollution parameter for water
and wastewater. Being heterogeneous (suspended colloidal and dissolved forms) and
being composed of a wide variety of compounds, it is very difficult to have a single
direct method for estimating its organic matter concentration in any water or
wastewater sample. Because of this reason, indirect methods, like BOD, COD, etc.
are dependent upon for the measurement of organic matter concentration. These
methods measure the organic matter concentration through estimating the amount of
oxygen required for its complete oxidation.
Methods like COD are quite accurate and take very less time for estimating the
organic matter concentration. But they cannot differentiate biodegradable organic
matter from non-biodegradable organic matter. Further, COD is not capable of
accurately estimating volatile organic matter and organic matter with nitrogen bases.
Because of these reasons, BOD is preferred over COD.
In the BOD test microorganisms are used for bio-oxidation of the organic matter in
the presence of oxygen. The amount of oxygen utilized in the bio-oxidation process is
measured and expressed as organic matter concentration in terms of oxygen. This
method actually estimates the amount of biodegradable organic matter rather than the
total organic matter present in water or wastewater sample. In this method, the sample
is diluted to appropriate level, seeded with sufficiently acclimatized microbial
populations, aerated and then filled in the air proof BOD bottles and incubated under
favaourable conditions. Through measuring the initial and final dissolved oxygen
present in the incubated sample, the amount of oxygen consumed in the bio-oxidation
process is estimated. Fig.1.1 shows the fate of biodegradable organic matter during
the incubation in the BOD test.
10. Microorganism
Biodegradable
Organic Matter
CO2 + H2O + Metabolic energy
Fig. (1.1): Fate of the biodegradable organic matter, during incubation in the BOD
test.
Organic Matter
Non-Biodegradable
Organic Matter
Synthesized
microbial biomass
Residual biomass
CO2+H2O+NH3+Metabolic
energy
NO3
O2
Microorganisms
O2
Auto oxidation by
microorganisms
O2
Bio-oxidation
Biosynthesis
11. The bio-oxidation process is rather slow and complete bio-oxidation takes a quite
long time (over 25 days). This necessitates incubation of the sample for quite long
time for getting the total biodegradable organic matter concentration. In practice,
incubating the sample, for such a long time, is not feasible and even if feasible, since
the results cannot be real time measurements; their utility is very limited. To avoid
this long incubation period a compromising approach is followed. In this approach
the sample is incubated for relatively short period of 5 days for getting major portion
of the organic matter bio-oxidized. The obtained results are extrapolated through
using a mathematical model [BOD kinetics model, y = L0 (1-e-kt)]. Use of this BOD
kinetics model requires prior knowledge of the BOD kinetic parameters (k & L0). The
required kinetic parameters for the water or wastewater in question are obtained
through laboratory experimentation (through conducting serial BOD test, wherein the
BOD exerted of the incubated sample is measured at regular intervals). Results of the
serial BOD test are used in estimating kinetics parameters with the help of one of the
multitude methods available.
Accuracy and reproducibility of BOD testing is not very satisfactory. Hence
estimation of the kinetic parameters which uses serial BOD test results is prone to
become much more inaccurate. For getting satisfactory results selection of
appropriate method of calculation of kinetic parameters is very important. Present
study is actually concerned with evaluation of the commonly used alternative
methods of kinetic parameters estimation. In the present study the following six
methods have actually been evaluated:
1. Method of Moments
2. Method of Least Squares
3. Thomas Graphical Method
4. Daily Difference Method
5. Iteration Method
12. 6. Fujimoto Method
For evaluating these methods, results are obtained from serial BOD testing for 7 days,
of the following samples have been used:
1. Satluj river water sample
2. East Bein river water sample
3. Treated Municipal sewage sample
4. Treated Distillery effluent
5. Treated Dairy effluent
6. Treated Textile effluent
1.2 Overview of the contents of the report:
This M.E. dissertation includes five chapters. Chapter 1 is introduction. In this
chapter after giving brief background information on BOD and BOD kinetics,
objective of the study is introduced. This chapter also includes overview of the
contents of the thesis and importance of the present study.
In Chapter 2, review of published literature on BOD, BOD kinetics and methods for
BOD kinetic parameters estimation is presented.
In the Chapter 3, the approach followed for achieving the objective of the study is
presented. In addition to this, this chapter also includes a brief overview on the
commonly used methods of BOD kinetic parameters estimation.
Chapter 4 includes the results of the study and discussion. The results mainly include
three components, the serial BOD test results, the estimated BOD kinetic parameters,
and results of evaluation of the alternate methods of kinetic parameters estimation. In
the discussion, it has been shown, which of the method is most appropriate and why.
13. The report concludes with Chapter 5, wherein the study is summarized, limitations of
the study are highlighted and scope for further study is brought forward.
1.3 Importance of the study:
Design, operation and control of biological treatment units require knowledge of
ultimate BOD whereas the BOD test gives 5 days BOD value or 3 days BOD value.
BOD tests are usually conducted at 20ºC, whereas temperature in the biological
treatment units can be different. These situations make BOD kinetics and BOD
kinetic parameters estimation very important. Very few laboratories actually perform
BOD kinetic parameters studies and ultimate BOD is found through thumb rules,
which is undesirable. In the light of these, the present study proves very important.
The study brings about the fact that all methods of kinetic parameters estimation
cannot be appropriate for all conditions. One has to sensibly select appropriate
methods for estimating the kinetic parameters.
14. CHAPTER: 2
Literature Review
An attempt has been made to review the available literature on BOD, BOD kinetics
and available methods for kinetic parameters estimation. In the nineteenth century the
performance of sewage treatment plants was measured mainly by the chemical
analysis related to the determination of various forms of nitrogen; as an index of the
state and progress of the oxidation of organic matter. Frankland, 1868 as referred by
William (1971) first observed that depletion of dissolved oxygen in the wastewater
containing organic matter was due to chemical reactions. He observed that depletion
of oxygen was dependent on the time of storage. Dupret 1884 as referred by William
(1971) recognized that oxygen depletions were due to the activity of microorganisms.
The classical equation for expressing the BOD process is:
Substrate + bacteria + O2 + growth factors 22 . H2O + increased
bacteria + energy -------------------------------------------------------------(2.1)
The royal commission on Sewage Disposal, 1912, chose an incubation period of five
days for the BOD test because that is the longest flow time of any British river to the
open sea. An incubation temperature of 20oC was chosen because the long-term
average summer temperature in Britain was 18.3oC (Nesarathnam,1998).
Adeney 1928 as referred by Jenkins (1960) defined the absolute strength of sewage as
the amount of dissolved oxygen required for its complete biochemical oxidation.
Winkler’s method was mostly used to determine the dissolved oxygen content in
water (Standard Method 1995). Bruce et.al, (1993) suggested headspace biochemical
oxygen demand (HBOD) test having three main advantages: the test does not require
sample dilution, oxygen demand determined with in a shorter period of time (24-
36hrs) that can be used predict 5-day BOD value and the experimental conditions
used in the HBOD test, more accurately reproduce the hydrodynamic and culture
15. conditions. Booki et.al, (2004) suggested the use of fibre optic probe to obtain oxygen
demands in 2 or 3 days in respirometric tests, and then 5-day BOD can be predicted
from the results.
While a standard BOD test procedure developed for certain effluents has been widely
accepted, disagreements regarding the basic mechanisms and kinetics of the test
continue to persist. In fact, a review of the history of the BOD test and the related
mathematical procedures leads to the conclusion that the only universally accepted
concept is that the basic reactions involved are biochemical in nature. The
controversies about BOD kinetics arises largely due to the fact that the distinction
between BOD as a test and BOD as a microbial metabolic process is frequently
overlooked. (The term process is used to refer to the series of cellular enzymatic
reactions, which bring about the conversion of given reactants to final products under
the constraints of the prevalent environmental constraints and factors)(William
E.1971).
Phelps (1953) has presented the developmental history of BOD test and its kinetics.
He after studying the simplified reaction system associated with eq. 2.1 suggested that
the velocity of the reaction varied directly as the concentration of the bacterial food
supply (substrate). The concentration of the substrate was rated in terms of oxygen
equivalents as indicated by the test. Nonetheless, Phelps realized the limitations of his
empirical monomolecular law and delineated them quite clearly. In essence, he
concluded that though there was no actual reason why BOD reaction should be
monomolecular, the approximation was sufficient for practical applications. He also
noted that there were instances where the approach was not applicable. Despite its
stochastic nature, the first order approach has been applicable under some
circumstances, and it is apparently an acceptable approximation of a more general
deterministic expression or expressions.
The BOD test is designed to determine the quantity of oxygen required by the biota of
the system to completely oxidize the biologically available organic material William,
(1971). The quantity of oxygen required is the sum of oxygen consumed by:
16. 1. The bacteria of the ecosystem with in the confines of the BOD bottle as they
utilize the organic material (substrate) to support synthesis and respiration.
2. The consumers (protozoa) as they ingest the bacteria as a food source to support
their growth and respiration.
3. The process of auto destruction of bacterial and protozoan biomass produced as a
result of the preceding two processes.
During the initial phase of the BOD process, substrate is assimilated by bacteria under
aerobic conditions and a major portion of the substrate is converted to biomass. When
bacterial production has reached a maximum, i.e. when the substrate concentration
has been reduced to essentially zero concentration, the bacteria will either enter the
auto destruction phase, or if protozoa are present, they will start utilizing the bacteria
as a food source. When essentially all the bacteria have been so consumed the
protozoa will enter an auto destruction phase. Conceptually then, the BOD test is
terminated when the concentration of bacteria and protozoa have returned to their
respective concentration which prevailed at the start of the test.
Gaudy (1972), Le Blanc (1974), Stones (1981) and Shrivastava (1982) have also
reviewed the BOD test. Studies of streeter and Phelps, 1925 as referred by Gaudy
(1972) led to the following first order equation (BOD kinetic model).
dL/dt = - kL
In integrated form
Lt = L0 e-kt
In other form BODt = L0(1 – e-kt) -------------------------------------------(2.2)
Where,
BODt = BOD exerted in ‘t’ days of incubation.
Lt = BOD exerted at any time ‘t’
17. L0 = Oxygen demand yet to be exerted at t=0 i.e. ultimate
BOD.
k = BOD reaction rate constant and its units are time-1.
t = Time of incubation.
Analysis of the above first order equation indicates two variables, rate constant k and
ultimate BOD, L0 are dependent on each other. If the rate of biochemical oxidation is
very high, the value BOD5 is essentially equal to the ultimate BOD. (Ramallho,
1983). Maity and Ganguly (2002) observed that experimental ‘k’ value is always
greater than the theoretical ‘k’ value by 18% and 24%, when the sample is tested at
20oC and at 27oC respectively. Shrivastava (2000) studied the effect of sewage and
indigenous seed on BOD exertion and found that with indigenous seed the BOD
values are observed more and kinetic study revealed that with indigenous seed the
ultimate BOD is more and value of rate constant is higher in both first order and
second order equations with sewage seed. Typical values of k and L0 are listed in
table 2.1 (Peavy, 1985)
Table: 2.1 Typical values of k L0 for various waters.
Water Type K (Day-1) L0 (mg/l)
Tap water 0.1 0 – 1
Surface water 0.1 – 0.23 1 – 30
Weak municipal waste water 0.35 150
Strong municipal waste water 0.40 250
Treated effluent 0.12 – 0.23 10 – 30
18. Reddy reported that kinetics of BOD exertion pattern involves the following:
(i) Mathematical modeling of the oxygen demand pattern of the sample being
incubated
(ii) Using such a mathematical model for extrapolating the results obtain and
finding out the rate constant and ultimate BOD.
There are different methods of estimation of kinetic parameters k L0. Before an
estimate of k L0 can be made a set of progressive long-term (10 to 15 days) BOD
data must be obtained (Merske et.al, 1972). The work of Berthouex et.al, (1971)
showed that the estimation of BOD constants is most accurate when longer BOD test
data, with the addition of nitrification inhibitors, are considered. To calculate k L0
from given series of BOD measurements is fundamentally a curve-fitting problem.
Reed et.al, (1931) published a paper on the statistical treatment of velocity data, that
is recognized as the most comprehensive and accurate approach to the estimation of
the velocity constants of the first order model for the BOD kinetics. However as this
method requires laborious calculations and therefore one is discouraged from
estimating k L0 (Merske et.al, 1972).
Fair (1936) proposed the log-difference method for the solution of the BOD equation,
but was difficult to be solved. The method involved the plotting of daily difference
between the BOD values versus time. Thomas (1937) developed the slope method
(graphical) and for many years this was the most used method for computing the
kinetics parameters. Thomas (1950) proposed a simple graphical approximation for
evaluation of the constants of BOD curve, which is based on similarity function.
Moor et.al, (1950) developed the method of moments, which became the most used
technique of solving BOD kinetics parameters. The method involves constructing of
Moore’ s diagram of åBOD/L0 versus k and åBOD/åBOD.t versus k for the
particular number of days for which the BOD data is available. Remo Navone (1960)
published a new method for calculating BOD constant for sewage. This method
simplified the calculation of these parameters. The least squares method involves
19. fitting a curve through a set of data points, so that sum of the squares of the difference
between the observed value and the value of the fitted curve must be minimum
(Metcalf Eddy, 2003). Fujimoto (1961), suggested an arithmetic plot between
BODt+1 versus BODt, and the intersection of this plot with line of slope 1 corresponds
to the ultimate BOD(L0).
Gurjar (1994) suggested a new simple method to determine first stage BOD constants
(k L0). Guillermo Cutrera et.al, (1999), compared the three methods (non linear
fitting, linear fitting Thomas method) for estimation of k L0 and found that non-linear
method of least squares results in smallest error.
Rai (2000) suggested a simplified method for determination of BOD constants. He
suggested the iteration method for estimation of k L0. Riefler and Smets. (2003)
compared the type curve method with least square error method to estimate biofilm
kinetic parameters observed that more accurate and precise estimates were
obtained with least square error method.
20. CHAPTER: 3
Materials And Methods
3.1 Introduction
In the study, serial BOD testing for BOD kinetics was conducted on six different
types of samples (treated municipal sewage, treated distillery effluent, treated textile
effluent, treated dairy effluent, water sample collected from river Satluj near village
Sangowal and water sample collected from river East Bein, a tributary to river satluj,
at Malsian village). The experiments were conducted in triplicate. Samples of the
river Satluj and the river East Bein were analyzed for BOD kinetics, during June to
Sept. 2003, and the samples from other four sources were studied during Oct. to Dec.
2003. Results of the serial BOD tests were used in evaluating different methods used
for estimating the BOD kinetics parameters (k and L0). Evaluation of the methods
was done through calculating and comparing the sum of the absolute differences
between the observed BOD and exerted BOD.
3.2 Sampling
Grab samples were collected from each of the six sources, once a month for three
months. In case of river water samples the sampling was done for four months. The
collected samples were brought to the laboratory in an insulated box. For avoiding
deterioration of the samples during transportation, the box containing the sample was
filled with ice cubes. In the laboratory the samples were retained in a refrigerator and
used in the BOD kinetics experimentation within 2 days time from the day of
collection.
21. 3.2 serial BOD testing
For estimating the BOD kinetics parameters, k and Lo, serial BOD measurements for
the first 7 days were made for the prepared samples incubated at 20C. That is, BOD1,
BOD2, ---and BOD7 were measured for the sample in question. BOD bottle method
described in Standard Method, 1995 Method No. 5210B, was used for these
measurements.
24 BOD bottles were used in the experiment for facilitating daily DO measurement in
triplicate, as a part of the BOD test. Dilution factor approximating to COD/6 was used
for diluting the sample. Aerated distilled water containing 1 ml per liter each of ferric
chloride solution, magnesium sulphate solution, phosphate buffer solution and
calcium chloride solution was used as dilution water. These solutions and the
solutions used in COD measurements and DO measurements were prepared as per the
procedure and strengths indicated in the Standard Method, 1995 under the
corresponding methods. In case of industrial effluents 1 ml per liter of acclimatized
seed was also added to this dilution water. Supernatant of settled secondary sludge
from the ETP of the same industry was used as acclimatized seed.
The sample in question was first tested for COD using the method given in Standard
Method, 1995 Method No. 5220-C. On the basis of the COD dilution factor was
found out and used in the preparation of the diluted sample for serial BOD test. 12
liter of diluted sample was prepared and after sufficient aeration the sample was
transfered into the 24 BOD bottles. While analyzing 3 of the bottles for initial DO,
rest of the bottles were incubated in a BOD incubator at 20oC for 7 days. Every day 3
of the incubated bottles were taken out and tested for DO while using the technique
given in Standard Method, 1995 Method No. 4500-O.C. BOD of the sample was
estimated by using the following expressions:
BODt at 20oC = DF [(DOis-DOfs)-(DOib-Dofb)(1-1/DF)]-----------------(3.1)
22. Where,
BODt = BOD exerted in ‘t’ days of incubation.
DOis = DO of the diluted sample immediately after preparation,
mg/l.
DOfs = DO of the diluted sample at particular day of
incubation, mg/l.
DOib = DO of seed control before incubation, mg/l.
DOfb = DO of seed control after incubation, mg/l.
DF = Dilution factor.
3.4 Estimation of BOD kinetic Parameters: Using the results obtained from serial
BOD test, BOD and time were plotted and through extending the smooth curve
passing through the data points to the x-axis time lag involved in the test was
estimated (fig. 3.1). On the basis of the lag obtained the first order BOD kinetic
equation was corrected as below:
BODt = L0 (1-e-k . (t-lag time))
The corrected kinetics equation was used in all the calculations, except in case of
method of moments, the original BOD kinetic equation and nomograph for n = 7days
was used. Using the results obtained from the serial BOD tests, BOD kinetics
parameters (k and L0) were estimated by the following six different methods, which
are commonly used:
(i) Method of Moments (Ramallho, 1983)
(ii) Least Squares Method (Metcalf Eddy, 2003)
(iii) Thomas Graphical Method (McGhee, 1991)
24. 4000
3500
3000
2500
2000
1500
1000
500
0
0 1 2 3 4 5 6 7 8
Time(days)
Fig. 3.1: Lag of 0.9 day in Textile sample-III
BOD(mg/l)
25. 3.4.1 Method of moments (Ramallho, 1983): This method involves use of Moore’ s
diagram which is actually a nomograph showing relationship between k , åBOD/L0
and åBOD/åBOD.t. From the series of BOD measurements for 7-days,
åBOD/åBOD.t was calculated and ‘k’ value and å BOD/L0 value corresponding to
this åBOD/åBOD.t value were read from the Moore’ s diagram specific to 7-days.
From the åBOD/L0 value obtained, L0 was calculated.
Moore’ s diagrams (fig. 3.2) are constructed through the following equations:
åBOD/L0 = n – [10-k(10-nk – 1)/(10-k-1)] ------------------------------------------(3.2)
åBOD/åBOD.t =
- - -
å å 10
[10 (10 1) /(10 1)]
ik
k nk k
i - n
i i
n
-
- - -
´
=
-
i - n
=
i 1
i 1
-----------------------------(3.3)
Where,
BODt = BOD exerted in time ‘t’ days of incubation.
n = No. of days of incubation for the serial BOD test.
k = BOD rate constant
L0 = Ultimate BOD.
The above expressions have been used for calculating åBOD/L0 and åBOD/åBOD.t
values for n = 7 days. These calculated values have been used for constructing the
required Moore’ s diagram.
27. Sample calculation: The kinetic parameters k and L0 of the River Satluj’ s fourth
sample [SAT-7 (IV)] were calculated as given below.
Step:1
Determination of åBOD and åBOD/åBOD.t values:
Dilution factor: 1:2 Incubation period:7days Incubation temperature:20oC
Incubation time
(days)
DO (mg/l) BODt (mg/l) BOD . t
0 8.2 --- ---
1 7.4 1.6 1.6
2 6.7 3.0 6.0
3 6.27 3.86 11.58
4 5.83 4.74 18.96
5 5.63 5.14 25.7
6 4.77 6.86 41.16
7 4.33 7.74 54.18
åBOD=32.94 åBOD.t=159.18
åBOD/åBOD.t = 0.207
Step:2
Reading k value and åBOD/L0 value corresponding to the åBOD/åBOD.t value
from the Nomograph.
k = 0.05/day
åBOD/L0 = 2.465
28. Step 3:
Estimation of L0 value
L0 = åBOD/(åBOD/L0) = 2.465/32.94 = 13.36 mg/l
3.4.2 Least Squares Method (Metcalf Eddy 2003): According to first order kinetics
dL/dt = - kLt
where,
Lt = L0 - yt
yt = BODt
dy/dt = k (L0 – yt)
dy/dt = kL0 – kyt
This is a linear equation. Through use of least squares method k L0 values in the
above linear equation can be found out. In the calculations the following equation are
used:-
Sxx = n åyt
2 – (å y)2 -----------------------------------------------(3.4)
Sxy = nåyt(dy/dt) – (åyt) (ådy/dt) ---------------------------------(3.5)
Slope (-k) = Sxy / Sxx ---------------------------------------------------------(3.6)
Intercept (kL0) =å (dy/dt)/n + kå(yt)/n -----------------------------------------------(3.7)
L0 = Intercept/(-slope) ----------------------------------------------(3.8)
Sample calculation:
The kinetic parameters k L0 of the river Satluj’ s fourth sample [SAT-7(IV)] were
estimated as follows:
29. Step 1:
Constructing the following table:
Time yt dy/dt = (yt+1 – yt-1)/2¨W yt
2 yt.dy/dt
1 1.60 1.50 2.56 2.40
2 3.00 1.13 9.00 27.0
3 3.86 0.87 14.90 3.34
4 4.74 0.63 22.47 4.88
5 5.14 1.07 26.42 5.50
6 6.86 1.30 47.06 8.92
7 7.74*
Sums 25.20 6.50 122.42 26.55
* Value not included in total and n = 6 is used.
Step 2:
Substituted the value computed in Step 1 in eq. (3.4) and (3.5).
Sxx = 99.48
Sxy = - 4.5
Step 3:
Calculated k and L0 by using eq. (3.6), (3.7) and (3.8).
k = 0.045/day
L0 = 28.17 mg/l
30. 3.4.3 Thomas Graphical Method (McGhee 1991): This is an approximate method.
It is based on the following equation:
(t/y)1/3 = 1/(2.3 kL0)1/3 + [(2.3 k)2/3/6 L0
1/3] . t --------------------------(3.9)
Plot of (t/y)1/3 versus t gives slope as (2.3 k)2/3/6 L0
1/3 and intercept as 1/(2.3 kL0)1/3.
The kinetics parameters are calculated as follows:
k = 2.61(slope/intercept) - -------------------------------------------------- (3.10)
L0 = 1/(2.3 k. intercept3) ----------------------------------------------------- (3.11)
Sample calculation:
The kinetic parameters k L0 of the river Satluj’ s fourth sample [SAT-7 (IV)] were
estimated as follows:
Step 1:
Constructing the following table:
Time (t) BODt (y) (t/y)1/3
0 0.00 ---
1 1.60 0.855
2 3.0 0.873
3 3.86 0.919
4 4.74 0.945
5 5.14 0.991
6 6.86 0.956
7 7.74 0.967
31. Step 2:
Plotted (t/y)1/3 versus ‘t’ (fig. 3.3) and found slope and intercept as given below:
Slope = 0.0205
Intercept = 0.8474
Step 3: From equation (3.10) and (3.11), obtained k and L0:
k = 0.063/day
L0 = 11.34 mg/l
33. 3.4.4 Daily Difference Method (Ramallho,1983):
According to first order equation:
y = L0 (1- 10-kt)
dy/dt = L0 (-10-kt )(ln10)(-k)
log(dy/dt) = log(2.303 kL0) – kt -----------------------------(3.12)
Plotting log (dy/dt) versus time (midinterval value of ‘t’ ) gives slope as –k and
intercept as log(2.303 kL0). Ultimate BOD (L0) can then be obtained by the following
equation:
L0 = 10(intercept) / 2.303 (k). -----------------------------(3.13)
Sample calculation:
The kinetic parameters k L0 of the river Satluj’ s fourth sample [SAT-7 (IV)] were
estimated as follows:
Step 1:
Constructing the following table:
Time (t) y (mg/l) dy/dt log dy/dt Midinterval value
of t
0 0 --- --- ---
1 1.60 1.60 0.204 0.50
2 3.00 1.40 0.146 1.50
3 3.86 0.86 - 0.066 2.50
4 4.74 0.88 - 1.056 3.50
5 5.14 0.40 - 0.398 4.50
6 6.86 1.72 0.236 5.50
7 7.74 0.88 - 1.056 6.50
34. Step 2:
Plotted Log (dy/dt) versus midinterval of time as shown in fig. (3.4) and obtained
slope and interval as follows:
Slope = - 0.033
Intercept = 0.1182
Step 3:
Calculated k and L0:
k = - slope = 0.033
L0 = 10(intercept)/ 2.303 (k) = 17.12 mg/l
36. 3.4.5 Iteration Method: R.K. Rai (2000) suggested an iteration method for the
analysis of time series of BOD data and found the results very close to that of least
squares method.
Procedure:
(i) Assumed the ultimate BOD (L0) equal to the last BOD value.
(ii) Calculated k from first order equation
y = L0(1 – e-kt) -----------------------------------------------------(3.14)
Using L0 as in step (i) and using first BOD data (y and t).
(iii) Calculated L0 from equation using k from step (ii).
(iv) Calculate k from equation using L0 from step (iii).
Repeated the calculation of k using just calculated value of L0 and the given
BOD data from start and L0 using just calculated value of k and the given
BOD data from last till all the given data are used up. The values of k L0
obtained in the last step are their correct values.
Sample calculation:
The kinetic parameters k L0 of the river Satluj’ s fourth sample [SAT-7 (IV)] were
estimated as follows:
Step 1:
Assumed L0 = 7.73 mg/l
Step 2:
Substituted L0 = 7.73 mg/l, y = 1.6 mg/l and t = 1 day in equation 3.13
obtained k = 0.232/day
37. Step 3:
Substituted k = 0. 232/day, y = 7.73 mg/l and t = 7 in equation 3.13
obtained L0 = 9.628 mg/l
Step 4:
Substituted L0 = 9.628 mg/l, y = 3.0 mg/l and t = 2 days in equation 3.13
obtained k = 0.187/day
Step 5:
Substituted k =0.187/day, y = 6.87 mg/l and t = 6 days in equation 3.13
obtained L0 = 10.19 mg/l
Step 6:
Substituted L0 = 10.19 mg/l, y = 3.87 mg/l and t = 3 days in equation 3.13
obtained k = 0.159/day.
Step 7:
Substituted k = 0.159/day, y = 5.13 and t = days in equation 3.13
obtained L0 = 9.35mg/l
Step 8:
Substituted L0 = 9.35mg/l, y = 4.73mg/l and t = 4 days in equation 3.13
obtained k = 0.176/day
38. Step 9:
The values of BOD constants are, therefore
L0 = 9.35mg/l and k = 0.176/day
3.4.6 Fujimoto method (Metcalf Eddy 2003): Using this method an arithmetic plot
was prepared of BODt+1 versus BODt. The value at the intersection of the plot with a
line of slope 1 corresponds to the ultimate BOD. The rate constant k was determined
from the following equation:
BODt = L0 (1-e-kt)--------------------------------------------- (3.15)
Where,
BODt = BOD exerted in time ‘t’ days of incubation.
L0 = Ultimate BOD
t = time (days)
Sample calculation:
The kinetic parameters k L0 of the river Satluj’ s fourth sample [SAT-7 (IV)] were
estimated as follows:
Step 1:
Prepared and arithmetic plot of BODt+1 versus BODt (fig. 3.5) using the following
table:
Sr.No. 1 2 3 4 5 6
BODt
(mg/l)
1.60 3.00 3.86 4.74 5.14 6.86
BODt+1
(mg/l)
3.00 3.86 4.74 5.14 6.86 7.74
39. Step 2:
Drew a line with slope of 1 on the same plot as constructed in step 1. The value at the
intersection of the two lines corresponds to ultimate BOD, L0 = 27 mg/l.
Step 3:
Determined the k value for 5th day data using equation 3.14.
BOD5 = 5.14 = 27 (1-e-5k)
k = 0.042/day
41. 3.5 Comparison of different methods of estimation: The methods are compared by
plotting observed BOD values and expected BOD values during 7 days for six
different methods against time. Evaluation of different methods was done by
calculating the sum of absolute differences between the observed and expected BOD
values as follows:
D = ™ (oi – ei) /ei
Where, oi and ei are the observed BOD and expected BOD values calculated by using
estimated kinetic parameters by each method.
42. CHAPTER: 4
Results and Discussion
4.1 Introduction
This chapter includes, the results obtained from the serial BOD tests, the BOD kinetic
parameters estimation by different methods and the evaluation of different methods of
BOD kinetic parameters estimation through sum of the absolute differences between
the observed and expected BOD values during 7 days. Further, the results obtained
are discussed to indicate how far the BOD kinetic parameters estimation methods are
reliable and which of the methods has proved most appropriate in the present study.
4.2 Results
Results obtained from the serial BOD tests for 7 days of incubation and from the
COD tests on the following six different types of samples are presented in the tables
4.1 to 4.6.
1) Satluj river water sample
2) East Bein river water sample
3) Treated Municipal sewage sample
4) Treated Distillery effluent
5) Treated Dairy effluent
6) Treated Textile effluent
43. Table: 4.1 BOD results of River Satluj (SAT-7).
Days BODt(mg/l)
Sample I Sample II Sample III Sample IV
1 1.02 0.20 0.77 1.60
2 2.70 0.74 1.80 3.00
3 3.80 2.54 2.43 3.86
4 4.00 2.94 2.83 4.74
5 4.42 3.54 3.48 5.14
6 4.80 4.20 3.70 6.86
7 6.56 4.60 4.17 7.74
COD
(mg/l)
16.00 21.00 9.00 25.00
Table: 4.2 BOD results of East Bein river (EB-4).
Days BODt(mg/l)
Sample I Sample II Sample III Sample IV
1 6.60 2.60 5.50 10.00
2 15.20 13.30 23.25 21.50
3 28.20 23.60 31.75 51.50
4 35.00 28.60 38.25 61.50
5 44.60 33.30 49.25 71.50
6 49.33 37.00 57.50 88.50
7 62.00 39.30 62.50 95.00
COD
(mg/l)
176.00 115.00 350.00 727.00
46. The results obtained, from serial BOD tests were checked for involvement of any lag
phase and wherever there is a lag phase its duration was measured. Duration of lag,
obtained in serial BOD tests is given in table 4.7.
Table: 4.7 Duration of lag observed in serial BOD test.
Lag Values (day)
Samples Sample I Sample II Sample III Sample IV
River Satluj
0.5 0.85 0.35 Nil
(SAT-7)
East Bein
River (EB-4)
Nil 0.80 0.75 Nil
Treated
Municipal
Sewage
Nil Nil Nil ----
Treated
Distillery
Effluent
Nil Nil Nil ----
Treated Dairy
Effluent
Nil 0.20 Nil ----
Treated Textile
Effluent
Nil Nil 0.9 ----
47. BOD kinetics parameters (k and L0) calculated from the serial BOD test results using
the following six different methods of BOD kinetic parameters estimation, for each of
the samples on which serial BOD tests were conducted, are presented in the tables 4.8
to 4.13:
1) Method of moments
2) Least squares method
3) Thomas method
4) Daily difference method
5) Iteration method
6) Fujimoto method
COD values and BOD5 /COD values at 20oC are included in these tables.
48. Table: 4.8 BOD Kinetic Parameters Values for the Satluj River water (SAT-7)
* ‘k’ values are to base 10.
Kinetic Parameters Values
Sample I Sample II Sample III Sample IV
Methods
K L0 K L0 K L0 K L0
Moments* 0.067 9.27 0.00002 14430 0.067 6.51 0.05 13.36
Least squares 0.221 7.36 0.037 21.83 0.195 5.54 0.045 28.17
Thomas* 0.146 6.39 0.049 9.44 0.421 2.45 0.063 11.34
Daily Difference* 0.051 9.4 0.027 18.46 0.082 5.38 0.033 17.12
Iteration 0.414 5.25 0.160 7.42 0.248 4.75 0.176 9.35
Fujimoto 0.172 8.2 0.170 7.00 0.256 5.00 0.042 27.0
COD (mg/l) 16.0 21.0 9.0 25.0
BOD5/COD 0.276 0.169 0.395 0.206
49. Table: 4.9 BOD kinetic parameters values for the East Bein River water (EB-4):
* ‘k’ values are to base 10.
BOD Kinetic Parameters Values for the East Bein River water
Sample I Sample II Sample III Sample IV
Methods
K L0 K L0 K L0 K L0
Moments* 0.0001 38000 0.018 91.88 0.018 266 0.000 25372
Least squares 0.023 405.48 0.147 64.87 0.095 135.75 0.047 358.14
Thomas* 0.031 100.40 0.119 49.35 0.127 71.51 0.042 113.9
Daily Difference 0.007 490.58 0.134 46.0 0.073 89.74 0.025 264.65
Iteration 0.071 142.85 0.315 45.18 0.231 72.51 0.074 241.0
Fujimoto 0.022 430.0 0.282 48.0 0.208 84.0 0.136 145.0
COD (mg/l) 176.0 115.0 350.0 727.0
BOD5/COD 0.254 0.290 0.141 0.098
50. Table: 4.10 BOD kinetic parameters values for the treated Municipal sewage:
Kinetic Parameters Values
Sewage
Sample I Sample II Sample III
Methods
K L0 K L0 K L0
Method of moments* 0.206 38.50 0.212 193.43 0.014 917
Least squares 0.444 39.29 0.475 196.64 0.044 683.10
Thomas* 0.192 40.81 0.186 207.70 0.009 1365.26
Daily difference* 0.182 37.26 0.195 183.45 0.016 785.57
Iteration 0.335 41.22 0.499 188.16 0.092 346
Fujimoto 0.524 38.5 0.485 192 0.049 640
COD(mg/l) 125 160 180
BOD5/COD 0.286 1.094 0.78
* ‘k’ values are to base 10.
51. Table: 4.11 BOD kinetic parameters values for the treated Distillery Effluent:
Kinetic Parameters Values
Distellery
Sample I Sample II Sample III
Methods
K L0 K L0 K L0
Method of moments* 0.1 5578.30 0.192 2183.13 0.078 21384.83
Least squares 0.157 6839.22 0.412 2230.28 0.175 21264.28
Thomas* 0.117 5200.84 0.173 2327 0.077 21239.71
Daily difference* 0.063 6897.90 0.204 1998.10 0.081 20391.90
Iteration 0.227 5356.47 0.521 2141.98 0.196 19166.45
Fujimoto 0.082 10700 0.447 2170 0.172 21500.00
COD(mg/l) 5000 10000 13760
BOD5/COD 0.72 0.194 0.901
* ‘k’ values are to base 10.
52. Table: 4.12 BOD kinetic parameters values for the treated Dairy Effluent:
Kinetic Parameters Values
Dairy
Sample I Sample II Sample III
Methods
K L0 K L0 K L0
Method of moments* 0.072 267.0 0.083 109.70 0.083 55.35
Least squares 0.081 410.53 0.114 157.39 0.186 54.59
Thomas* 0.070 257.60 0.069 137.56 0.087 53.0
Daily difference* 0.045 290.80 0.047 174.64 0.180 39.0
Iteration 0.141 293.88 0.146 134.0 0.170 57.26
Fujimoto 0.094 38.20 0.186 120.0 0.455 3850.0
COD(mg/l) 200 100 80
BOD5/COD 0.718 0.708 0.458
* ‘k’ values are to base 10.
53. Table: 4.13 BOD kinetic parameters values for the treated Textile Effluent:
Kinetic Parameters Values
Textile
Sample I Sample II Sample III
Methods
K L0 K L0 K L0
Method of moments* 0.124 43.56 0.283 1730.13 0.058 6648.20
Least squares 0.228 47.81 0.703 1731.0 0.259 4706.95
Thomas* 0.125 43.41 0.231 1916.46 0.179 4232
Daily difference* 0.071 64.98 0.312 1686.38 0.145 3832.11
Iteration 0.329 41.00 0.83 1686.36 0.528 3631.11
Fujimoto 0.151 56.50 0.096 4300.0 0.455 3850.0
COD(mg/l) 720 1300 2000
BOD5/COD 0.042 1.266 1.628
* ‘k’ values are to base 10.
54. 4.3 Evaluation of Methods
For evaluating the methods used for estimating the BOD kinetic parameters, expected
BOD values against each of the observed BOD values were calculated with the help
of the first order BOD kinetics equation given below:
BODt = L0 (1-exp-kt)
In the above equation the BOD kinetic parameters (k and L0) estimated by the method
in question are used for calculating the expected BOD values. While using the
observed and expected BOD values, the sum of the absolute differences between the
observed and expected BOD values, while using the following equation:
k
D = åi = 1
(oi – ei) /ei
Where,
D = sum of the absolute differences between the
observed and expected BOD values
oi = is the observed BOD
ei = is the expected BOD
k = is the number of terms in the formula
The observed BOD values and expected BOD values for the six different methods
have been plotted against time (t) and shown in Figures 4.1 to 4.20. The chi-square
statistic obtained for each of the methods of BOD kinetic parameters estimation are
given in table 4.14, and are also indicated in the above figures.
56. 4.4 Discussion
For evaluating the methods used for estimating the BOD kinetics parameters, the
following criterion has been used:
Criterion-1: The method, for which the sum of absolute difference between the
observed and estimated BODs (through using first order BOD kinetics equation and
estimated BOD kinetic parameters) is minimum, should be the best method for BOD
kinetic parameters estimation. That is, if this sum is less than or equal to 0.35, then
one can say that the observed values are within the range of 0.95xBODexpected to
1.05xBODexpected.
Criterion-2: Criterion-1 for comparison has however not been applied on:
1. all those cases for which the calculated ultimate BOD (L0) is less than the
observed BOD7
2. all those cases for which the observed COD is less than the observed BOD7 or
calculated ultimate BOD (L0).
Details of the results rejected on the basis of the second criterion are indicated in the
table 4.15.
57. Table-4.15: Results discarded from the methods evaluation
Sample Methods
Satluj river water sample-1 Thomas method and Iteration method
Satluj river water sample-2 Moments method and Least Squares method
Satluj river water sample-3 Thomas method
Satluj river water sample-4 Least Squares method and Fujimoto method
East Bein river water sample-1 Moments method, Least Squares methods,
Daily difference method and Fujimoto method
East Bein river water Sample-4 Moments method
Treated municipal sewage sample-1 Daily difference method
Treated municipal sewage sample-2 All the six method
Treated municipal sewage sample-3 All the six method
Treated distillery effluent sample-1 All the six methods
Treated distillery effluent sample-2 Daily difference method
Treated distillery effluent sample-3 All the six methods
Treated dairy effluents sample-1 All the six methods
Treated dairy effluents sample-2 All the six methods
Treated dairy effluent sample-3 Fujimoto method
Treated textile effluent sample-2 All the six methods
Treated textile effluent sample-3 All the six methods
Method of Moments, Thomas method and Daily Difference method have used log to
base 10 in the estimations of BOD kinetics parameters. Hence the BOD reaction rate
constant (k) obtained by these methods need correction by multiplying with 2.303 in
order to make them comparable with the k values calculated by other methods.
58. After evaluating the methods according to the criterion-1 given earlier, suitability of
methods for different samples obtained is shown in the table-4.16.
Table: 4.16 Suitability of methods for different samples:
Sample Level of
Significance
Moments Least
Squares
Thomas Daily
difference
Iteration Fujimoto
95% None of 3 None of 2 None of 2 1 of 4 1 of3 1 of 3
90% 2 of 3 1 of 2 2 of 2 None of 4 2 of 3 None of 3
Satluj river
water (4
samples)
80% 1 of 3 1 of 2 ---- 2 of 4 ---- None of 3
95% None of 2 None of 3 1 of 4 1 of 3 1 of 4 1 of 3
90% 1 of 2 None of 3 1 of 4 None of 3 1 of 4 1 of 3
East bein river
water (4
samples)
80% None of 2 2 of 3 None of 4 2 of 3 2 of 4 1 of 3
95% 1 of 1 1 of 1 None of 1 ---- None of 1 1 of 1
90% ---- ---- 1 of 1 ---- 1 of 1 ----
Treated
municipal
sewage (3
samples) 80% ---- ---- ---- ---- ---- ----
Treated
distillery
effluent (3
samples) 80% ---- ---- ---- ---- ---- ----
95% 1 of 1 1 of 1 None of 1 ---- 1 of 1 1 of 1
90% ---- ---- 1 of 1 ---- ---- ----
95% None of 1 None of 1 None of 1 None of 1 None of 1 ----
90% 1 of 1 1 of 1 1 of 1 None of 1 1 of 1 ----
Treated Dairy
effluent (3
samples)
80% ---- ---- ---- 1 of 1 ---- ----
95% None of 1 None of 1 None of 1 None of 1 None of 1 None of 1
90% 1 of 1 1 of 1 1 of 1 None of 1 1 of 1 None of 1
Treated
Textile
effluent
80% ---- ---- ---- 1 of 1 ---- 1 of 1
The results indicate that iteration method is best for estimating the BOD kinetic
parameters from the serial BOD test results. Daily difference method is worst of all.
59. 4.5 Conclusions
Method of moments has been found erroneous under the following two different
conditions:
ƒ When there is a lag phase in the serial BOD test (lag phase reduces the t value
(from 7 to 7-lag period) where as the nomogram used is specific for t=7 days)
ƒ When the sample is a river water sample or when it is thoroughly treated
effluent sample k value obtained by Method of Moments has been very low
and the L0 value very high (consistently higher than the sample’ s COD)
Results of the serial BOD tests have been observed to be not of that high accuracy
and dependable. Accurate results might have made the study much more useful.
The evaluation approach followed in this study has indicated that Iteration method is
the best and daily difference method the worst among the methods evaluated for
estimating BOD kinetics parameters from the serial BOD test results.
60. 7
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.1 Method comparison for SAT-7(I)
BOD(mg/l)
Observed BOD
Moments(0.83)
Least squares(1.13)
Thomas(0.62)
Daily diff.(2.98)
Iteration(0.64)
Fujimoto(1.59)
BOD = 6.56 mg/l
COD = 16 mg/l
Fig: 4.2 Method comparison for SAT-7 (II)
7
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8
Days
BOD (mg/l)
Observed BOD
Moments(0.15)
Least squares(0.18)
Thomas(0.37)
Daily diff.(0.17)
Iteration(0.30)
Fujimoto(2.59)
BOD = 4.60 mg/l
COD = 21.0 mg/l
61. 5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.3 Method comparison for SAT-7 (III)
BOD (mg/l)
Observed BOD
Moments(0.37)
Least squares(0.52)
Thomas(2.33)
Daily diff.(0.93)
Iteration(0.47)
Fujimoto(0.19)
BOD = 4.17 mg/l
COD = 9.0 mg/l
Fig: 4.4 Method comparison for SAT-7 (IV)
9
8
7
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8
Days
BOD (mg/l)
Observed BOD
Moments(0.44)
Least squares(0.78)
Thomas(0.41)
Daily diff.(0.93)
Iteration(0.50)
Fujimoto(1.43)
BOD = 7.74mg/l
COD = 25.0 mg/l
62. Fig: 4.5 Method comparison for EB-4 (I)
70
60
50
40
30
20
10
0
0 1 2 3 4 5 6 7 8
Days
BOD (mg/l)
Observed BOD
Moments(0.55)
Least squares(0.63)
Thomas(2.50)
Daily diff.(0.99)
Iteration(0.72)
Fujimoto(0.62)
BOD = 62.0 mg/l
COD = 176.0 mg/l
Fig: 4.6 Method comparison for EB-4 (II)
45
40
35
30
25
20
15
10
5
0
0 1 2 3 4 5 6 7 8
Days
BOD (mg/l)
Observed BOD
Moments(6.07)
Least squares(1.34)
Thomas(0.17)
Daily diff.(0.19)
Iteration(0.21)
Fujimoto(0.12)
BOD = 39.4 mg/l
COD = 115.0 mg/l
63. 70
60
50
40
30
20
10
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.7 Method comparison for EB-4 (III)
BOD (mg/l)
Observed BOD
Moments(0.75)
Least squares(1.72)
Thomas(0.45)
Daily diff.(1.27)
Iteration(1.05)
Fujimoto(0.66)
BOD = 62.50 mg/l
COD = 350.0 mg/l
Fig: 4.8 Method comparison for EB-4 (IV)
120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8
Days
BOD (mg/l)
Observed BOD
Moment(0.99)
Least squares(0.92)
Thomas(3.70)
Daily diff.(1.24)
Iteration(0.94)
Fujimoto(1.07)
BOD = 95.0 mg/l
COD = 727.0 mg/l
64. 50
40
30
20
10
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Observed BOD
Moments(0.32)
Least squares(0.34)
Thomas(0.40)
Daily diff.(0.67)
Iteration(0.73)
Fujimoto(0.31)
BOD = 37.8 mg/l
COD = 125.0 mg/l
Fig. 4.9 Method comparison for sewage-I
250
200
150
100
50
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.10 Method comparison for Sewage - II
BOD(mg/l)
Observed BOD
Moments(0.16)
Least squares(0.19)
Thomas(0.26)
Daily diff.(0.60)
Iteration(0.15)
Fujimoto(0.11)
BOD = 188.0 mg/l
COD = 160.0 mg/l
65. 200
180
160
140
120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Observed BOD
Moments(0.22)
Least squares(0.22)
Thomas(0.14)
Daily diff.(0.16)
Iteration(0.41)
Fujimoto(0.36)
BOD = 183.0 mg/l
COD = 180.0 mg/l
Fig: 4.11 Method comparison for Sewage-III
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
0 1 2 3 4 5 6 7 8
Days
Fig. 4.12 Method comparison for Distillery-I
BOD(mg/l)
Observed BOD
Moments(0.49)
Least squares(0.64)
Thomas(0.47)
Daily diff.(0.96)
Iteration(0.57)
Fujimoto(1.18)
BOD = 4650.0 mg/l
COD = 5000.0 mg/l
66. 2500
2000
1500
1000
500
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.13 Method comparison for Distillery II
BOD(mg/l)
Observed BOD
Moments(0.28)
Least squares(0.33)
Thomas(0.38)
Daily diff.(0.59)
Iteration(0.32)
Fujimoto(0.27)
BOD = 2062.0 mg/l
COD = 10000.0 mg/l
Fig: 4.14 Method comparison for Distillery-III
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Oserved BOD
Moments(0.15)
Least squares(0.09)
Thomas(0.06)
Daily diff.(0.07)
Iteration(0.20)
Fujimoto(0.10)
BOD = 14900.0 mg/l
COD = 13760.0 mg/l
67. Fig: 4.15 Method comparison for Dairy-I
200
180
160
140
120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Observed BOD
Moments(0.38)
Least squares(0.86)
Thomas(0.32)
Daily diff.(2.03)
Iteration(0.35)
Fujimoto(0.52)
BOD = 178.5 mg/l
COD = 200.0 mg/l
Fig: 4.16 Method comparison for Dairy-II
100
90
80
70
60
50
40
30
20
10
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Observed BOD
Moments(0.71)
Least squares(0.25)
Thomas(0.70)
Daily diff.(0.35)
Iteration(0.31)
Fujimoto(0.56)
BOD = 82.0 mg/l
COD = 100.0 mg/l
68. 45
40
35
30
25
20
15
10
5
0
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Fig: 4.17 Method comparison for Dairy-III
Observed BOD
Moments(0.38)
Least squares(0.36)
Thomas(0.36)
Daily diff.(0.93)
Iteration(0.37)
Fujimoto(0.95)
BOD = 38.2 mg/l
COD = 80.0 mg/l
50
45
40
35
30
25
20
15
10
5
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.18 Method comparison for Textile-I
BOD(mg/l)
Observed BOD
Moments(0.41)
Least squares(0.54)
Thomas(0.42)
Daily diff.(0.82)
Iteration(0.42)
Fujimoto(1.09)
BOD = 38.4 mg/l
COD = 720.0 mg/l
69. 2500
2000
1500
1000
500
0
0 1 2 3 4 5 6 7 8
Days
Fig: 4.19 Method comparison for Textile-II
BOD(mg/l)
Observed BOD
Moments(0.15)
Least squares(0.18)
Thomas(0.37)
Daily diff.(0.17)
Iteration(0.30)
Fujimoto(2.59)
BOD = 1693.6 mg/l
COD = 1300.0 mg/l
4500
4000
3500
3000
2500
2000
1500
1000
500
0
-500
0 1 2 3 4 5 6 7 8
Days
BOD(mg/l)
Observed BOD
Moments(1.47)
Least squares(1.37)
Thomas(0.74)
Daily diff.(1.74)
Iteration(0.73)
Fujimoto(0.69)
BOD = 3795.0 mg/l
COD = 2000.0 mg/l
Fig: 4.20 Method comparison for Textile-III
70. CHAPTER: 5
Conclusions
The present study on the evaluation of six different methods for BOD kinetic
parameters estimation, while using the serial BOD test results for treated industrial
effluents and river waters, has indicated that Iteration method is the best and Daily
difference method is the worst. This conclusion should be seen in the light of the
following limitations of the present study:
1. BOD and COD results indicate that some of the samples used in the study are not
in real sense treated effluents (at the time sampling the treatment plant might not
been working satisfactorily) (sewage samples 2 and 3, distillery effluent sample 3
and textile effluent sample 2 and 3).
2. In quite a few cases the testing has indicated that their BOD7 is greater than COD
– this indicates that the testing of the samples has not been that accurate. For
making the evaluation process acceptable the results of all such samples whose
BOD7 was obtained greater than the COD have not been considered.
3. In some of the cases in the serial BOD test, an initial lag phase was observed
(indicating that the seed used was not sufficiently acclimatized). For taking care
of this problem the BOD kinetic equation used has been appropriately modified.
But this modification has brought in certain errors affecting the evaluation
process.
4. Treated effluent samples have been used and for properly treated effluents k
values, as expected, have been found to be very low and wherever very low k
values are encountered the L0 was found to be higher than COD. Samples with
such cases have also been not considered in the evaluation process.
For the selection of appropriate method for BOD kinetic parameters, study has
indicated that the following aspects may be given due consideration:
71. ƒ Serial BOD test may be conducted accurately while using properly acclimatized
seed and the results may be crosschecked with COD test.
ƒ For each type of wastewater or water samples the methods may be separately
evaluated and selected on the basis of statistically significant number of serial
BOD tests (at least 7 samples may be tested).
ƒ Incubation period for serial BOD test was chosen as 7 days and this may be
followed because it can allow bio-oxidation of significant fraction of the organic
matter and nitrogenous BOD exertion may still not be significant. However in
case of treated effluent samples for avoiding nitrogenous BOD exertion
appropriate inhibitors may be used.
The present study has clearly indicated that Moments Method of kinetic parameters
estimation is not good for samples from surface water bodies and for thoroughly
treated secondary effluents. Keeping this in mind further work may be planned for
answering the question ‘which method is most appropriate under what conditions?
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