The document discusses the activated sludge process for treating wastewater. It begins with an overview that activated sludge involves aerating wastewater in tanks containing microorganisms that break down organic matter. The microorganisms are separated from the treated water, with some returned to the aeration tank and excess removed. It then provides details on the key components of activated sludge plants, including aeration tanks, clarifiers, recycled sludge, and wasted sludge. Various process parameters are defined that are important for monitoring and controlling the activated sludge process.
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
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.
The document describes the activated sludge process, which is the most common suspended growth process for municipal wastewater treatment. The process involves introducing air or oxygen into a mixture of wastewater and microorganisms to develop biological flocs that reduce organic content. Wastewater and microbes form mixed liquor that undergoes aeration and settling, with clarified effluent discharged and excess sludge wasted or returned. Common activated sludge process types include plug flow, complete mix, contact stabilization, and extended aeration. Design considerations include wastewater characteristics, effluent quality goals, and sludge production.
The document describes a trickling filter, which is a biological wastewater treatment process using attached growth of microorganisms on media to remove organic matter. Wastewater is distributed over the top of the media (such as gravel or plastic), where microbes grow as biofilms and degrade organics. The treated water exits through underdrains while air flow through the media supports the aerobic biofilms. Higher rate filters use recirculation and plastic media to achieve greater organic removal at smaller footprints. Proper design and operation are needed to control issues like ponding, flies, odors, and icing.
The document discusses various aerobic and anaerobic wastewater treatment processes. It begins by defining wastewater treatment as a process to convert wastewater into an effluent that can safely return to the water cycle with minimal environmental impact. It then describes several specific treatment processes, including activated sludge processing, trickling filters, rotating biological contactors, biofilters, aerobic and anaerobic stabilization ponds, and various anaerobic digestion methods like upflow anaerobic sludge blanket and expanded granular sludge bed processes.
Deals with what is activated sludge, mechanisms and kinetics of treatment, design of activated sludge process, secondary clarifiers and their design and bulking sludge, raising sludge and foaming of ASP.
The document summarizes various stages of wastewater treatment processes. It discusses preliminary treatment which removes solids, grit, and grease. Primary treatment uses sedimentation to remove 60% of suspended solids. Secondary treatment uses biological processes like activated sludge and oxidation ditches to remove organic matter. Tertiary treatment further removes nutrients and particles through processes like filtration and disinfection. The document provides details on the treatment units and processes involved at each stage of wastewater treatment.
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.
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
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.
The document describes the activated sludge process, which is the most common suspended growth process for municipal wastewater treatment. The process involves introducing air or oxygen into a mixture of wastewater and microorganisms to develop biological flocs that reduce organic content. Wastewater and microbes form mixed liquor that undergoes aeration and settling, with clarified effluent discharged and excess sludge wasted or returned. Common activated sludge process types include plug flow, complete mix, contact stabilization, and extended aeration. Design considerations include wastewater characteristics, effluent quality goals, and sludge production.
The document describes a trickling filter, which is a biological wastewater treatment process using attached growth of microorganisms on media to remove organic matter. Wastewater is distributed over the top of the media (such as gravel or plastic), where microbes grow as biofilms and degrade organics. The treated water exits through underdrains while air flow through the media supports the aerobic biofilms. Higher rate filters use recirculation and plastic media to achieve greater organic removal at smaller footprints. Proper design and operation are needed to control issues like ponding, flies, odors, and icing.
The document discusses various aerobic and anaerobic wastewater treatment processes. It begins by defining wastewater treatment as a process to convert wastewater into an effluent that can safely return to the water cycle with minimal environmental impact. It then describes several specific treatment processes, including activated sludge processing, trickling filters, rotating biological contactors, biofilters, aerobic and anaerobic stabilization ponds, and various anaerobic digestion methods like upflow anaerobic sludge blanket and expanded granular sludge bed processes.
Deals with what is activated sludge, mechanisms and kinetics of treatment, design of activated sludge process, secondary clarifiers and their design and bulking sludge, raising sludge and foaming of ASP.
The document summarizes various stages of wastewater treatment processes. It discusses preliminary treatment which removes solids, grit, and grease. Primary treatment uses sedimentation to remove 60% of suspended solids. Secondary treatment uses biological processes like activated sludge and oxidation ditches to remove organic matter. Tertiary treatment further removes nutrients and particles through processes like filtration and disinfection. The document provides details on the treatment units and processes involved at each stage of wastewater treatment.
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.
Tertiary treatment involves additional wastewater treatment processes beyond secondary treatment to further improve water quality before discharge or reuse. It typically includes nutrient removal through nitrification/denitrification or phosphorus precipitation, disinfection through UV, ozone, or chlorine, and filtration through sand filters, membrane filters, or activated carbon to remove remaining solids and chemicals. The goal of tertiary treatment is to remove nearly all organic and inorganic compounds to produce very high quality effluent suitable for sensitive reuse applications or discharge into the environment. Common tertiary treatment processes include nutrient removal, disinfection, ion exchange, membrane filtration, and sand or activated carbon filtration.
Rotating Biological Contactors (RBCs) are fixed film, aerobic biological wastewater treatment systems that use rotating discs to reduce organic matter. RBCs grow microorganisms on the discs that break down organic pollutants. The objectives of RBC wastewater treatment are to manage industrial and domestic wastewater discharge to reduce water pollution threats without harming human health or the environment. RBCs have advantages like low space and energy requirements with reliable liquid/solid separation and low sludge production.
Distillery Industry Waste and Its TreatmentLakhan Kumar
This document summarizes the waste generated by distillery industries and methods for treating distillery wastewater. Distilleries producing alcohol from molasses generate 60-100 liters of wastewater per liter of alcohol in the form of spent wash, spent lees, and yeast sludge. The spent wash is hot, acidic, and high in organic matter. Biological treatment methods like anaerobic digestion followed by aerobic processes like activated sludge or trickling filters are commonly used to treat the wastewater before disposal in water courses or on land. The treated effluent must meet standards for biochemical oxygen demand and total dissolved solids before disposal.
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.
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.
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 sequencing batch reactors (SBRs) for wastewater treatment. SBRs perform the stages of treatment - equalization, biological treatment, and clarification - sequentially in a single tank. Key advantages are that SBRs require less space than traditional systems using separate tanks for each stage, and can achieve high removal rates of various pollutants. The SBR process involves repeated fill, react, settle, decant, and idle phases in the single tank reactor.
The document summarizes several biological treatment processes used for waste water treatment including suspended growth processes like activated sludge and fixed film processes like trickling filters, fluidized bed reactors, rotating biological contractors, and upflow anaerobic sludge blanket reactors. It describes the basic mechanisms and configurations of each process as well as their advantages and applications.
Sludge dewatering is a prior process to manage the sludge. The dewatering requires to decrease the volume of sludge for easy handling. It has two methods: Conventional and advance.
this presentation gives you a quick glimpse of Sludge Dewatering process and method.
This document discusses the treatment of water for drinking purposes. It outlines the microorganisms commonly found in domestic water supplies and describes the multi-step water treatment process. The primary treatment involves coagulation, flocculation and sedimentation to remove solids. Secondary treatment uses filtration to remove remaining particles. Tertiary treatment employs disinfection methods like chlorination and ozonation to kill microbes. The overall process aims to produce potable water that is safe for human consumption.
This document discusses sludge processing and disposal. It defines sludge as organic matter that settles in sedimentation tanks during wastewater treatment. Left untreated, sludge decomposition causes foul odors and pollution. The document outlines various sludge treatment processes including thickening to reduce moisture, anaerobic and aerobic digestion to reduce volume and pathogens, and dewatering through methods like drying beds and centrifugation. The main objectives of sludge treatment are digesting organic matter, destroying pathogens, and achieving safe and odor-free disposal, such as through incineration, application to agricultural land, or ocean disposal.
The document discusses aerobic and anaerobic digestion processes used in wastewater treatment. Aerobic processes use oxygen and include activated sludge systems, lagoons, trickling filters, and aeration. Anaerobic digestion breaks down organic matter without oxygen to produce methane and carbon dioxide. It includes anaerobic sludge digestion and Imhoff tanks. Both processes use microorganisms and require proper operation and maintenance to effectively treat wastewater.
Trickling Filter
A trickling filter is a type of wastewater treatment system.
• A trickling filter , also called trickling biofilter, biofilter, biological filter and biological trickling filter , is a fixed-bed, biological
reactor that operates under (mostly) aerobic conditions.
CH-3. Anaerobic treatment of wastewaterTadviDevarshi
Anaerobic treatment process, Effects of pH, temperature and other parameters on anaerobic treatment, Concept of anaerobic contact process, anaerobic filter, anaerobic fixed film reactor, fluidized bed and expanded bed reactors and up flow anaerobic sludge blanket (UASB) reactor.
Upflow Anaerobic Sludge Blanket (UASB) Treatment of SewageAravind Samala
TREATMENT OF SEWAGE BASED ON UASB PROCESS. Up flow anaerobic sludge blanket process (UASB),was developed by Lettinga and his co-workers in Holland in the early 1970's
Anaerobic granular sludge bed technology refers to a special kind of reactor concept for the "high rate" anaerobic treatment of wastewater.
The major objectives of the UASB process is:
Pre sedimentation anaerobic wastewater treatment and final sedimentation including sludge stabilization are essentially combined in one reactor making it most attractive high-rate wastewater treatment option.
To produce by products like Methane enriched biogas and nutrient rich sludge.
Tertiary treatment is needed to further treat effluents beyond secondary treatment levels before discharge or reuse. It aims to remove additional contaminants like nutrients, pathogens, toxins, and dissolved solids. Common tertiary treatments include nutrient removal processes like nitrification/denitrification, ion exchange, and membrane technologies such as reverse osmosis. Phosphorus removal can be achieved through physical filtration, chemical precipitation, or biological enhanced biological phosphorus removal. Ammonia removal is typically done through air stripping or biological nitrification followed by denitrification. The document provides details on various tertiary treatment processes and their operating mechanisms.
Sewage and wastewater contain organic and inorganic matter, gases, and microorganisms. The organic matter can undergo aerobic or anaerobic decomposition. Aerobic decomposition occurs in the presence of oxygen and forms stable end products. Anaerobic decomposition occurs without oxygen and forms gases and simpler compounds. The characteristics of sewage include physical properties like color and temperature, chemical properties like pH and dissolved oxygen, and biological indicators like BOD and COD that measure decomposability. Proper treatment of sewage is necessary to remove pathogens and pollutants before disposal or reuse of water.
The document discusses wastewater management and treatment. It describes how wastewater contains pollutants and needs to be treated before discharge. The treatment process typically involves primary, secondary, and sometimes tertiary steps. Primary treatment removes solids through screens and sedimentation. Secondary treatment uses microbes to break down organic matter, often through activated sludge treatment or trickling filters. Tertiary treatment can further remove nutrients and pathogens through methods like filtration or disinfection. The goal of treatment is to make wastewater safe to release into the environment while minimizing environmental impacts.
Tertiary treatment involves additional wastewater treatment processes beyond secondary treatment to further improve water quality before discharge or reuse. It typically includes nutrient removal through nitrification/denitrification or phosphorus precipitation, disinfection through UV, ozone, or chlorine, and filtration through sand filters, membrane filters, or activated carbon to remove remaining solids and chemicals. The goal of tertiary treatment is to remove nearly all organic and inorganic compounds to produce very high quality effluent suitable for sensitive reuse applications or discharge into the environment. Common tertiary treatment processes include nutrient removal, disinfection, ion exchange, membrane filtration, and sand or activated carbon filtration.
Rotating Biological Contactors (RBCs) are fixed film, aerobic biological wastewater treatment systems that use rotating discs to reduce organic matter. RBCs grow microorganisms on the discs that break down organic pollutants. The objectives of RBC wastewater treatment are to manage industrial and domestic wastewater discharge to reduce water pollution threats without harming human health or the environment. RBCs have advantages like low space and energy requirements with reliable liquid/solid separation and low sludge production.
Distillery Industry Waste and Its TreatmentLakhan Kumar
This document summarizes the waste generated by distillery industries and methods for treating distillery wastewater. Distilleries producing alcohol from molasses generate 60-100 liters of wastewater per liter of alcohol in the form of spent wash, spent lees, and yeast sludge. The spent wash is hot, acidic, and high in organic matter. Biological treatment methods like anaerobic digestion followed by aerobic processes like activated sludge or trickling filters are commonly used to treat the wastewater before disposal in water courses or on land. The treated effluent must meet standards for biochemical oxygen demand and total dissolved solids before disposal.
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.
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.
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 sequencing batch reactors (SBRs) for wastewater treatment. SBRs perform the stages of treatment - equalization, biological treatment, and clarification - sequentially in a single tank. Key advantages are that SBRs require less space than traditional systems using separate tanks for each stage, and can achieve high removal rates of various pollutants. The SBR process involves repeated fill, react, settle, decant, and idle phases in the single tank reactor.
The document summarizes several biological treatment processes used for waste water treatment including suspended growth processes like activated sludge and fixed film processes like trickling filters, fluidized bed reactors, rotating biological contractors, and upflow anaerobic sludge blanket reactors. It describes the basic mechanisms and configurations of each process as well as their advantages and applications.
Sludge dewatering is a prior process to manage the sludge. The dewatering requires to decrease the volume of sludge for easy handling. It has two methods: Conventional and advance.
this presentation gives you a quick glimpse of Sludge Dewatering process and method.
This document discusses the treatment of water for drinking purposes. It outlines the microorganisms commonly found in domestic water supplies and describes the multi-step water treatment process. The primary treatment involves coagulation, flocculation and sedimentation to remove solids. Secondary treatment uses filtration to remove remaining particles. Tertiary treatment employs disinfection methods like chlorination and ozonation to kill microbes. The overall process aims to produce potable water that is safe for human consumption.
This document discusses sludge processing and disposal. It defines sludge as organic matter that settles in sedimentation tanks during wastewater treatment. Left untreated, sludge decomposition causes foul odors and pollution. The document outlines various sludge treatment processes including thickening to reduce moisture, anaerobic and aerobic digestion to reduce volume and pathogens, and dewatering through methods like drying beds and centrifugation. The main objectives of sludge treatment are digesting organic matter, destroying pathogens, and achieving safe and odor-free disposal, such as through incineration, application to agricultural land, or ocean disposal.
The document discusses aerobic and anaerobic digestion processes used in wastewater treatment. Aerobic processes use oxygen and include activated sludge systems, lagoons, trickling filters, and aeration. Anaerobic digestion breaks down organic matter without oxygen to produce methane and carbon dioxide. It includes anaerobic sludge digestion and Imhoff tanks. Both processes use microorganisms and require proper operation and maintenance to effectively treat wastewater.
Trickling Filter
A trickling filter is a type of wastewater treatment system.
• A trickling filter , also called trickling biofilter, biofilter, biological filter and biological trickling filter , is a fixed-bed, biological
reactor that operates under (mostly) aerobic conditions.
CH-3. Anaerobic treatment of wastewaterTadviDevarshi
Anaerobic treatment process, Effects of pH, temperature and other parameters on anaerobic treatment, Concept of anaerobic contact process, anaerobic filter, anaerobic fixed film reactor, fluidized bed and expanded bed reactors and up flow anaerobic sludge blanket (UASB) reactor.
Upflow Anaerobic Sludge Blanket (UASB) Treatment of SewageAravind Samala
TREATMENT OF SEWAGE BASED ON UASB PROCESS. Up flow anaerobic sludge blanket process (UASB),was developed by Lettinga and his co-workers in Holland in the early 1970's
Anaerobic granular sludge bed technology refers to a special kind of reactor concept for the "high rate" anaerobic treatment of wastewater.
The major objectives of the UASB process is:
Pre sedimentation anaerobic wastewater treatment and final sedimentation including sludge stabilization are essentially combined in one reactor making it most attractive high-rate wastewater treatment option.
To produce by products like Methane enriched biogas and nutrient rich sludge.
Tertiary treatment is needed to further treat effluents beyond secondary treatment levels before discharge or reuse. It aims to remove additional contaminants like nutrients, pathogens, toxins, and dissolved solids. Common tertiary treatments include nutrient removal processes like nitrification/denitrification, ion exchange, and membrane technologies such as reverse osmosis. Phosphorus removal can be achieved through physical filtration, chemical precipitation, or biological enhanced biological phosphorus removal. Ammonia removal is typically done through air stripping or biological nitrification followed by denitrification. The document provides details on various tertiary treatment processes and their operating mechanisms.
Sewage and wastewater contain organic and inorganic matter, gases, and microorganisms. The organic matter can undergo aerobic or anaerobic decomposition. Aerobic decomposition occurs in the presence of oxygen and forms stable end products. Anaerobic decomposition occurs without oxygen and forms gases and simpler compounds. The characteristics of sewage include physical properties like color and temperature, chemical properties like pH and dissolved oxygen, and biological indicators like BOD and COD that measure decomposability. Proper treatment of sewage is necessary to remove pathogens and pollutants before disposal or reuse of water.
The document discusses wastewater management and treatment. It describes how wastewater contains pollutants and needs to be treated before discharge. The treatment process typically involves primary, secondary, and sometimes tertiary steps. Primary treatment removes solids through screens and sedimentation. Secondary treatment uses microbes to break down organic matter, often through activated sludge treatment or trickling filters. Tertiary treatment can further remove nutrients and pathogens through methods like filtration or disinfection. The goal of treatment is to make wastewater safe to release into the environment while minimizing environmental impacts.
Biotechnology in Microbiology- includes the how microbial associations are worked out in secondary treatment techniques like activated sludge process, trickling filters, rotating biological contractors, composting, bioremediation etc.
Conventional wastewater treatment involves primary, secondary, and sometimes tertiary treatment stages. Primary treatment uses settling tanks to remove solids. Secondary treatment uses microbes and oxygen to break down remaining organic matter. This usually involves an aeration tank and secondary clarifier. Tertiary treatment may further remove nutrients or other contaminants through methods like filtration, carbon adsorption, or phosphorus/nitrogen removal. Sludge from primary and secondary clarifiers undergoes anaerobic digestion to reduce pathogens and volume before disposal or reuse.
L11 -SECONDARY TREATMENT OF SEWAGE - TRICKLING FILTERS.pptxPRACHI DESSAI
Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes (called water reclamation).
The document provides an overview of wastewater treatment processes. It discusses the objectives of water treatment being to produce water that is safe, appealing, reasonably priced, and free of pathogens. The major operations discussed include physical processes like screening, mixing, and sedimentation as well as chemical processes like coagulation and biological processes like activated sludge. It then describes various treatment processes like primary treatment using sedimentation, pre-treatment involving screening and grit removal, and secondary/biological treatment using activated sludge or trickling filtration. Tertiary treatment methods like nutrient removal, disinfection, and filtration are also summarized. Finally, it discusses sludge treatment processes involving thickening and digestion.
Use of biotechnology in the treatment of municipal wastes and hazardousindust...Sijo A
Industrial waste water is a type of waste water produced by industrial activity, such as that of factories, mills and mines.
It is characterised by its large volume, high temperature, high concentration of biodegradable organic matter and suspended solids, high alkanity or acidity and by variations of flow.
The treatment of wastes by micro-organisms is called biological waste treatment.
The document describes the chemical oxygen demand (COD) test, which is used to quantify the amount of chemically oxidizable organic material in wastewater. In the COD test, a strong chemical oxidizing agent is used instead of bacteria to oxidize organic compounds. The COD test measures total oxidizable organic material rather than just biodegradable material, so COD results are higher than biochemical oxygen demand (BOD) tests on the same samples. The document also provides an overview of primary, secondary, and advanced wastewater treatment processes and describes processes like activated sludge treatment and trickling filters used in secondary biological treatment.
The document provides background information on wastewater treatment. It defines wastewater and its components. It describes the functions of a wastewater treatment plant, which typically includes primary treatment to remove solids through screening and sedimentation, and secondary treatment using biological processes like activated sludge to break down organic materials. It outlines primary treatment methods like grit removal and sedimentation tanks, and secondary treatment options like activated sludge, trickling filters, and lagoons. It also discusses tertiary treatment and sludge treatment. The overall document aims to educate students on municipal wastewater treatment processes.
Municipal sewage treatment systems carry out various steps involved. These steps are primary treatment, secondary (or) biological treatment, and tertiary treatment.
This document discusses the treatment of municipal waste and industrial effluents through various biological processes. It describes the four main treatment processes: 1) preliminary treatment to remove solids, 2) primary treatment using sedimentation to remove settleable organic materials, 3) secondary or biological treatment using microorganisms to break down dissolved and suspended organic matter, and 4) tertiary or advanced treatment for additional removal of nutrients or contaminants. Key biological treatment methods discussed include activated sludge processes, trickling filters, and rotating biological contactors.
The document describes the operation of a wastewater treatment plant that serves an export processing zone. It details the multi-stage treatment process including primary treatment to remove solids, secondary treatment using oxidation ditches for biological BOD removal, tertiary treatment with UV disinfection, and sludge treatment including thickening and dewatering. It also provides an overview of treating different types of contaminants like organics, acids, alkalis, and toxins that may be present in wastewater. Diagrams illustrate the wastewater treatment process and components of the plant.
The document summarizes the three step municipal sewage treatment process:
1. Primary/mechanical treatment removes coarse solid materials through sedimentation.
2. Secondary/biological treatment uses aerobic and anaerobic microbial activity to break down organic matter, including through trickling filters, oxidation ponds, and the activated sludge process.
3. Tertiary/final treatment uses chemical treatment and chlorination to further purify the water before discharge.
This document provides an overview of the sewage treatment process. It begins with an introduction to sewage treatment and its importance. It then describes the various stages of treatment - preliminary (screening), primary (settling), secondary (trickling filters or activated sludge), tertiary (additional filtration), and solids processing (digestion or composting). The final effluent is disinfected before discharge while solids are disposed of in landfills. The document outlines the key objectives, processes, and equipment used at each treatment stage.
Activated sludge process in wastewater treatment plantMohamed Asfak
1) The activated sludge process is a commonly used secondary treatment method that uses aerobic bacteria and microorganisms to oxidize dissolved organic matter in sewage water into carbon dioxide and water.
2) It works by adding sludge from a previous batch, containing sewage-metabolizing microbes, to incoming sewage as an inoculum. This causes the organic matter to be incorporated into bacterial flocs over 4-8 hours of aeration.
3) The flocs are then settled and treated in anaerobic digesters, removing up to 95% of BOD through both aerobic oxidation and settling out of the flocs.
The document discusses wastewater treatment processes. It describes that wastewater contains a variety of pollutants from physical to biological contaminants. The size of treatment systems depends on sewage volume and anticipated flows. Common treatment methods include primary, secondary, and tertiary levels. Primary treatment involves screens, comminution, grit removal and sedimentation to remove solids. Secondary treatment uses biological processes like trickling filters, activated sludge, and oxidation ponds to further reduce organic matter. Tertiary treatment can achieve very high removal rates of 99% for drinking water quality effluent.
The document discusses sewage systems and sewage treatment processes. It begins by defining sewage and explaining why sewage systems are necessary to collect and transport wastewater from residential and commercial areas to treatment plants. It then describes the multi-step treatment process, including primary treatment to remove solids, secondary biological treatment to remove organic matter using microorganisms, and tertiary treatment for disinfection and removal of additional contaminants. The document provides details on various treatment methods and system components, such as screens, sedimentation tanks, aerators, lagoons, and sludge treatment. Case studies from Japan and the Philippines are also presented to compare sewage treatment approaches.
5. Water/Wastewater Terms
activated sludge: sludge particles produced by the growth of
microorganisms in aerated tanks as a part of the activated sludge process
to treat wastewater
aeration: exposing to circulating air; adds oxygen to the wastewater and
allows other gases trapped in the wastewater to escape (the first step in
secondary treatment via activated sludge process)
biochemical oxygen demand (BOD): a laboratory measurement of
wastewater that is one of the main indicators of the quantity of pollutants
present; a parameter used to measure the amount of oxygen that will be
consumed by microorganisms during the biological reaction of oxygen with
organic material
biosolids: sludge that is intended for beneficial use. Biosolids must meet
certain government specified criteria depending on its use (e.g., fertilizer
or soil amendment)
26-Mar-13 Activated Sludge Process 5
6. Water/Wastewater Terms
decomposition: the process of breaking down into constituent parts or
elements
domestic wastewater: wastewater that comes primarily from
individuals, and does not generally include industrial or agricultural
wastewater
effluent: treated wastewater, flowing from a lagoon, tank, treatment
process, or treatment plant
grit chamber: a chamber or tank used in primary treatment where
wastewater slows down and heavy, large solids (grit) settle out and are
removed
influent: wastewater flowing into a treatment plant
26-Mar-13 Activated Sludge Process 6
7. Water/Wastewater Terms
lagoons (oxidation ponds or stabilization ponds): a wastewater treatment method
that uses ponds to treat wastewater. Algae grow within the lagoons and utilize
sunlight to produce oxygen, which is in turn used by microorganisms in the lagoon to
break down organic material in the wastewater. Wastewater solids settle in the
lagoon, resulting in effluent that is relatively well treated, although it does contain
algae
municipal: of or relating to a municipality (city, town, etc.). Municipal wastewater is
primarily domestic wastewater.
primary treatment: the first stage of wastewater treatment that removes
settleable or floating solids only; generally removes 40% of the suspended solids and
30-40% of the BOD in the wastewater
secondary treatment: a type of wastewater treatment used to convert dissolved
and suspended pollutants into a form that can be removed, producing a relatively
highly treated effluent. Secondary treatment normally utilizes biological treatment
processes (activated sludge, trickling filters, etc.) followed by settling tanks and will
remove approximately 85% of the BOD and TSS in wastewater. Secondary
treatment for municipal wastewater is the minimum level of treatment required by
the EPA.
26-Mar-13 Activated Sludge Process 7
8. Water/Wastewater Terms
sedimentation: the process used in both primary and secondary
wastewater treatment, that takes place when gravity pulls particles to the
bottom of a tank (also called settling).
settling tank (sedimentation tank or clarifier): a vessel in which solids
settle out of water by gravity during wastewater or drinking water
treatment processes.
sludge: any solid, semisolid, or liquid waste that settles to the bottom of
sedimentation tanks (in wastewater treatment plants or drinking water
treatment plants) or septic tanks
tertiary treatment: any level of treatment beyond secondary
treatment, which could include filtration, nutrient removal (removal of
nitrogen and phosphorus) and removal of toxic chemicals or metals; also
called “advanced treatment” when nutrient removal is included
26-Mar-13 Activated Sludge Process 8
9. Water/Wastewater Terms
total suspended solids (TSS): a laboratory measurement of the quantity
of suspended solids present in wastewater that is one of the main
indicators of the quantity of pollutants present
trickling filter process: a biological treatment process that uses coarse
media (usually rock or plastic) contained in a tank that serves as a surface
on which microbiological growth occurs. Wastewater trickles over the
media and microorganisms remove the pollutants (BOD and TSS). Trickling
filters are followed by settling tanks to remove microorganisms that wash
off or pass through the trickling filter media.
turbidity: the cloudy or muddy appearance of a naturally clear liquid
caused by the suspension of particulate matter
wastewater: water that has been used for domestic or industrial purposes
26-Mar-13 Activated Sludge Process 9
10. Activated Sludge Process
Mixed Liquor Suspended Solids
Returned
Activated
Sludge
Waste Activated Sludge
26-Mar-13 Activated Sludge Process 10
11. Activated Sludge Process
The most common suspended growth
process used for municipal wastewater
treatment is the activated sludge process
26-Mar-13 Activated Sludge Process 11
12. Activated Sludge Plant
Activated sludge plant involves
• wastewater aeration in the presence of
a microbial suspension
• solid-liquid separation following aeration
• discharge of clarified effluent
• wasting of excess biomass
• return of remaining biomass to the
aeration tank
26-Mar-13 Activated Sludge Process 12
13. Activated Sludge
Activated Sludge serves two purposes
1. Reducing organic matter in wastewater by
using a complex biological community in
the presence of oxygen and converting
the organic matter to new cell
mass, carbon dioxide and energy
2. Producing solids capable of bio-
flocculating and settling out in the
clarifier to produce and effluent low in
Biochemical Oxygen Demand (BOD) and
Total Suspended Solids (TSS)
26-Mar-13 Activated Sludge Process 13
14. The Process
• In activated sludge process wastewater containing
organic matter is aerated in an aeration basin in
which micro-organisms metabolize the suspended
and soluble organic matter.
• Part of organic matter is synthesized into new cells
and part is oxidized to CO2 and water to derive
energy.
• In activated sludge systems the new cells formed in
the reaction are removed from the liquid stream in
the form of a flocculent sludge in settling tanks.
• A part of this settled biomass, described as
activated sludge is returned to the aeration tank
and the remaining forms waste or excess sludge
26-Mar-13 Activated Sludge Process 14
15. Activated Sludge Process
Variables
The main variables of activated sludge
process are the
• mixing regime
• loading rate
• flow scheme
26-Mar-13 Activated Sludge Process 15
18. The BOD Curve
The BOD determination involves
the measurement of the
dissolved oxygen used by
microorganisms in the
biochemical oxidation of organic
matter. The BOD test bottle is
incubated for 5 days at 20oC. A
typical BOD curve is shown in
Figure. The BOD5 of secondary
effluents consists of two major
components – a carbonaceous
demand resulting from the
oxidation of carbon and a
nitrogenous demand resulting
from the oxidation of nitrogen.
That is,
BOD5 = CBOD5 + NBOD5
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19. The Growth Curve
The growth curve has five distinct phases
These are:
1. Adaptation (Lag) Phase – This portion of the
curve represents the time required for the
organisms to acclimate themselves to the
organic material present in the wastewater.
The numbers of bacteria are not
increasing, however, a shift in the population
of the different species of bacteria in the
wastewater is occurring so that the bacteria
that can best utilize these organic materials
become predominate.
2. Log Growth Phase – Once the bacteria have
“adapted”, only the number of organisms
present limit the rate of growth. Because
bacterial cells reproduce by binary fission
(i.e., cell division – one cell divides and
becomes two, these two divide and become
four, then eight, sixteen … ), this is known as
logarithmic growth. Food is not a limiting
factor for growth in this phase, that is, for
each cell formed enough food is present to
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allow it to grow and divide.
20. The Growth Curve
3. Declining Growth Phase – In this
phase food becomes a limiting factor to
the growth of the bacterial cell mass
because not every bacterium that is
formed has the food required to grow.
4. Maximum Stationary Phase – Here
the available food is just sufficient to
keep the cell mass at a constant level
with a rate of growth equal to zero.
5. Endogenous (Cell Death) Phase –
When the supply of food becomes
insufficient to maintain the bacterial
mass at a constant level, the
microorganisms are forced to
metabolize their own protoplasm.
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21. Sludge Age
Therefore, an optimum
“sludge age” exists
which provide an
adequate separation of
the cell mass from the
liquid. For a specific
system the optimum
sludge age can be
determined by plotting
the sludge volume index
(SVI) versus the sludge
age
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22. Activated Sludge
The basic activated sludge process has
several interrelated components. These
components are
1. aeration tank
2. aeration source
3. clarifier
4. recycle
5. waste
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23. Activated Sludge
Aeration tank. A single tank or multiple tanks designed generally for either
complete mix or plug flow with a detention time of as little as 2 hours and
up to over 24 hours. The contents of the aeration tank are referred to as
mixed liquor.
Aeration source. Generally either diffused air or surface mechanical
aeration used to supply oxygen and mix the aeration tank contents.
Clarifier. A settling tank where the mixed liquor solids are separated from
the treated wastewater. Most treatment plants employ several secondary
clarifiers.
Recycle. Solids that settle in the clarifier and are returned to the aeration
tank.
Waste. Excess solids that must be removed from the system.
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25. Activated Sludge
A typical activated sludge
plant identifies the three
major control mechanism for
the activated sludge
treatment process
1. aeration rate
2. return sludge rate
3. waste sludge rate
Control of three variables in
addition to providing the
proper environment
(physical, chemical, biological
and nutritional requirements)
all lead to good sludge quality
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26. Mixed Liquor Suspended Solids
MLSS
• The combination of raw sewage and biological mass is commonly
known as Mixed Liquor.
• In all activated sludge plants, once the sewage (or industrial
wastewater) has received sufficient treatment, excess mixed
liquor is discharged into settling tanks and the treated
supernatant is run off to undergo further treatment before
discharge.
• Part of the settled material, the sludge (RAS), is returned to
the head of the aeration system to re-seed the new sewage
entering the tank.
• Mixed Liquor is a mixture of raw or settled wastewater and
activated sludge within an aeration tank in the activated sludge
process
• Mixed Liquor Suspended Solids (MLSS) is the concentration of
suspended solids in the mixed liquor, usually expressed in
milligrams per litre (mg/l)
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27. Why Measure MLSS
• If MLSS content is too high
– The process is prone to bulking and the treatment system
becomes overloaded
– This can cause the dissolved oxygen content to drop with the
effect that organic matters are not fully degraded and
biological 'die off„
– Excessive aeration required which wastes electricity
• If MLSS content is too low
– The process is not operating efficiently and is wasting
energy
• Typcial Control band
– 2,000 to 4,000 mg/l
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28. RAS and WAS
• A proportion of the floc is called Return Activated Sludge
(R.A.S.) and is used to re-seed the process.
• Measuring the solids concentration of RAS allows the return
volume to be adjusted to keep the solids level in the aeration
basin within the control parameters
• Excess sludge which eventually accumulates beyond that
returned is defined as Surplus or Waste Activated Sludge
(SAS/WAS)
• This is removed from the treatment process to keep the ratio
of biomass to food supplied (sewage or wastewater) in balance
• Typical Range
– 4,000 to 6,000 mg/l
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29. Activated Sludge Parameters
The parameters in the diagram and a few
others that will be used for the activated
sludge calculations are summarized in the
list below.
• primary effluent flow rate, Qo, MGD
(m/day for S.I.)
• primary effluent biochemical oxygen
demand (BOD) concentration, So, mg/L
(g/m3 for S.I.)
• primary effluent suspended solids
conc., Xo, mg/L (g/m3 for S.I.)
• aeration tank volume, V, ft3 (m3 for S.I.)
• aeration tank MLSS (suspended solids
conc.), X, mg/L (g/m3 for S.I.)
• secondary effluent flow
rate, Qe, MGD, (m3/day for S.I.)
• secondary effluent susp.solids
conc., Xe, mg/L (g/m3 for S.I.)
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30. Activated Sludge Parameters
• secondary effluent biochemical oxygen
demand (BOD) concentration, Se, mg/L (g/m3
for S.I.)
• waste activated sludge flow rate, Qw, MGD
(m3/day for S.I.)
• waste activated sludge biochemical oxygen
demand (BOD) conc., Sw, mg/L (g/m3 for S.I.)
• waste activated sludge susp. solids conc., Xw
mg/L (g/m3 for S.I.)
• recycle activated sludge flow rate, Qr, MGD
(m3/day for S.I.)
• Food to Microorganism ratio, F:M, lb
BOD/day/lb MLVSS (kg BOD/day/kg MLVSS)
• Hydraulic retention time, HRT, hours (hours
for S.I.)
• Sludge retention time (also called sludge
age), SRT, days (days for S.I.)
• Volumetric loading, VL, lb BOD/day/1000 ft3
(kg BOD/day/m3 for S.I.)
• % volatile solids in the aeration tank mixed
liquor suspended solids, %Vol.
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32. Calculations
NOTE: F:M values will be the same for units of lb BOD/day/lb MLVSS.
Calculations with these design parameters can be made in U.S. units using
the following equations:
• V = [ (8.34*So*Qo)/VL ] (1000)
• VMG = V*7.48/1,000,000
• HRT = 24*VMG/Qo
• F:M = (8.34*So*Qo)/(8.34%Vol*X*VMG)
= (So*Qo)/(%Vol*X*VMG)
VMG is the tank volume in millions of gallons.
It is introduced for convenience in calculations, since the primary effluent
flow rate is given in MGD.
The 8.34 factor in the equations above is used to convert mg/L to
lb/MG, and the 7.48 is for conversion of ft3 to gallons.
Also, note that the primary sludge flow rate is typically very small in
comparison with the influent wastewater flow rate, so the primary effluent
flow rate, Qo, is typically taken to be equal to the plant influent flow rate.
26-Mar-13 Activated Sludge Process 32
40. Other Aerobic Treatment Units
Stabilization ponds: The stabilization ponds are open flow
through basins specifically designed and constructed to treat
sewage and biodegradable industrial wastes. They provide
long detention periods extending from a few to several days.
Aerated lagoons: Pond systems, in which oxygen is provided
through mechanical aeration rather than algal photosynthesis
are called aerated lagoons.
Oxidation ditch: The oxidation ditch is a modified form of
"extended aeration" of activated sludge process. The ditch
consists of a long continuous channel oval in shape with two
surface rotors placed across the channel.
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42. Assignment # 3
Due Date: Friday, 5rd April, 2013
• Each Group has to make an excel sheet in which detailed population
analysis for every decade will be done for one city from 2000-2100
• Based on that population, the water demand for the same city
• Assuming 100 gallons per capita per day
• Also incorporating temp change/climate change scenario
• Assuming additional 10 gallons per capita per day per 0.20 C increase
in temp.
• Refer to Urban Water Demand Model California
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44. Dredging
Dredging is an excavation activity or
operation usually carried out at least
partly underwater, in shallow seas
or fresh water areas with the purpose of
gathering up bottom sediments and
disposing of them at a different location.
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