Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
The term solid waste management mainly refers to the complete process of collecting, treating and disposing of solid wastes. In the waste management process, the wastes are collected from different sources and are disposed of. This process includes collection, transportation, treatment, analysis and disposal.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
L13 -SECONDARY TREATMENT OF SEWAGE OXIDATION PONDS.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).
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
Lecture Notes of Environmental Engg-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
The term solid waste management mainly refers to the complete process of collecting, treating and disposing of solid wastes. In the waste management process, the wastes are collected from different sources and are disposed of. This process includes collection, transportation, treatment, analysis and disposal.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
L13 -SECONDARY TREATMENT OF SEWAGE OXIDATION PONDS.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).
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
Lecture Notes of Environmental Engg-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
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
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).
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
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).
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
What are Oxidation Ponds ?
Oxidation Pond is an open, flow through earthen basin of controlled shape specially design and constructed to treat sewage and bio-degradable industrial waste by natural processes involving bacteria and in many instances algae.
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).
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
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).
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
The study of the source of disposal is important because the amount of treatment required to be given to sewage depends very much upon the source of disposal, its quality, and capacity to tolerate the impurities present in the sewage effluents, without itself getting potentially polluted or becoming less useful.
Water Pollution
Water pollution occurs in many different forms, is produced in a variety of ways, and has a range of effects on the biological and physical environment. Consider some common examples:
A river dashing down a steep mountainside cuts into its rocky bed and carries away sand, silt, and pebbles. When the river reaches flat ground, it deposits these materials on the river bottom.
A farmer spreads herbicides, pesticides, and fertilizer on her land, knowing the increase in crop value this practice will produce. During the next rain, some of those chemicals are washed away into the nearest lake, where they remain suspended for weeks or months.
A small crack develops in an underwater pipe that carries oil from an offshore drilling rig to a holding tank on land. Crude oil seeps out of the crack and into the ocean, where marine plants and animals are exposed to its toxic effects.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
L5 -Water Quality Criteria and Paremeters.pptxPRACHI DESSAI
Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. This treatment is crucial to human health and allows humans to benefit from both drinking and irrigation use.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
2. STREAM STANDARDS AND EFFLUENT
STANDARDS
Effluent standards: effluent standards refer to the quality of
water coming from a pipe or outfall. They are based on
economics than on absolute protection of the stream.
Easy to control.
Detailed stream analyses are not required.
They do not establish an overall level of pollutant loading for
a given water body.
Ratio of wastewater to stream flow is not considered.
Treatment is obligatory irrespective of the size of industry.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 2
3. STREAM STANDARDS AND EFFLUENT
STANDARDS
Stream Standard: Standard of the water in a particular water course to which a sewage treatment
plant is discharging into. If a stream standard exists the Effluent standard for a particular WWTP
is set by working back from the Stream standard.
They are based on establishing classification of quality for a stream.
The quality of the receiving water is regulated to maintain established stream classification.
Prevention of excessive pollution/ Loading is limited to what the stream can assimilate No
consideration of type and location of industry.
Allows public to establish goals for present and future water quality.
Confusion of zone of different classification.
Controversy over proportion of stream to be reserved for future usage (municipal, industrial,
agriculture etc.)
Opposition from industry/ public to change the established classification
A detailed stream analysis is required to determine the level of wastewater treatment required
to maintain the health of the ecosystem
Cost of treatment may affect the survival of industry
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 3
4. OXYGEN SAG CURVE
SELF PURIFICATION OF RIVER WATER
It is a natural process of rivers, lakes or canals to recover the rate of dissolved oxygen values of the
highest concentration of oxygen which is one of the best indicators of water quality.
FACTORS AFFECTING SELF PURIFICATION
1. DILUTION: When sufficient dilution water is available in the receiving water body where the waste
water is discharged, the DO level in the receiving stream may not reach to zero.
2. CURRENT: When strong water current is available , the discharge waste water will be thoroughly
mixed with stream water preventing deposition of solids. In small current the solid matter from the
waste water will get deposited at the bed following decomposition and reducing DO.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 4
5. OXYGEN SAG CURVE
FACTORS AFFECTING SELF PURIFICATION
1. TEMPERATURE: The quantity of DO available in stream water is more in cold temperature than in
hot temperature. Also, as the activity of micro organisms is more at the higher temperature, hence , the
self purification will take less time hot temperature than in winter.
2. SUNLIGHT: Algae produces oxygen in presence of sunlight due to photosynthesis. Therefore, sunlight
helps in purification of stream by adding oxygen through photosynthesis.
3. RATE OF OXIDATION: Due to oxidation of organic matter discharged in the river DO depletion
occurs. This rate is faster at higher temperature and low at lower temperature. The rate of oxidation of
organic matter depends upon chemical composition of organic matter.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 5
6. OXYGEN SAG CURVE
Deoxygenation curve: In a polluted stream, the DO
content goes on reducing due to decomposition of
volatile organic matter.
The rate of deoxygenation depends upon the
amount of organic matter remaining to be oxidized
at a given time as well as on
the temperature of reaction, hence at given
temperature, the curve showing depletion of DO
with time i.e. deoxygenation curve is similar to
the first stage BOD-curve.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 6
7. OXYGEN SAG CURVE
Reoxygenation curve: In order to counter the
balance of the consumption of DO due to
deoxygenation, atmosphere supplies O2 to
water and the process is called reoxygenation.
The rate at which the oxygen is supplied by
atmosphere to the polluted water depends
upon:-
The depth of receiving water
Condition of flow
Oxygen deficit
Temperature
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 7
8. OXYGEN SAG CURVE
Oxygen deficit:-
The oxygen deficit D at any time in a polluted river
stream is the difference between the actual DO
content of water at that time and the saturation DO
content at the water temperature.
Oxygen Deficit = DOsat–DOactual
In order to maintain clean conditions in a river
stream, the oxygen deficit must be nil and this can
be found out by knowing the rates of
deoxygenation and reoxygenation.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 8
9. FACTORS AFFECTING SELF
PURIFICATION
If Cs = Concentration of Sewage and Cr = Concentration of River, organic content, BOD,
suspended solids, dissolved oxygen in the sewage and river having discharge Qs = Discharge of
Sewage and Qr = Discharge of River respectively, the resulting concentration C of the mixture is
given by
𝐶 =
𝐶𝑠𝑄𝑠 + 𝐶𝑟𝑄𝑟
𝑄𝑠 + 𝑄𝑟
9
11. ZONES OF POLLUTION IN A
RIVER OR STREAM
A polluted stream undergoing self- purification can be divided into following four zones
Zone of degradation
Zone of active decomposition
Zone of recovery
Zone of clearer water
Zone of Degradation:
• This zone is found for a certain length just ahead of the point where sewage is discharged into the river.
• Water becomes dark and turbid with formation of sludge deposits at the bottom.
• Bacteria will start oxidation of the organic matter the DO is reduced to about 40 % of the saturation valve
• Oxygenation occurs but is slower than deoxygenating.
• These conditions are unfavorable to the development of aquatic life; and as such, algae dies out, but certain type
of fish may be present feeding on fresh organic matter. Moreover, certain typical bottom worms such as
limondrilus and Tubifex appear with sewage fungi.
11
12. ZONES OF POLLUTION IN A
RIVER OR STREAM
Zone of Active Decomposition
Heavy pollution.
Water becomes grayish and darker than in the previous zone.
DO concentration falls down to zero
Anaerobic conditions may set in with the evolution of gases like methane, carbon dioxide, hydrogen
sulphide, etc.. bubbling to the surface, with masses of sludge forming ugly scum layer at the surface.
Rate of deoxygenating becomes lesser than the re-aeration rate and DO again rises to the original level
(i.e. above 40 %)
In this region, the bacteria flora will flourish. At the upper end, anaerobic bacteria will replace aerobic
bacteria, while at the lower end, the position will replace aerobic bacteria, while at the lower end the
position will be reversed.
Protozoa and fungi first disappear then reappear. Fish life will be absent. Algae and tubifex will also
be absent. Maggots and Psychoda (Sewage fly) larvae will, however, be present in all but the most
septic sewage.
12
13. ZONES OF POLLUTION IN A
RIVER OR STREAM
Zone of Recovery
the river stream tries to recover from its degraded condition to its former appearance.
The water becomes clearer, and so the algae reappears while fungi decreases. BOD decreases and DO
content rises above 40 % of the saturation value; Protozoa, Rotifers, Crustaceans and large plants like
sponges, Bryozoans, etc.
The organic material will be mineralized to form nitrate, phosphate, carbonates, etc..
Zone of Clearer Water
the river attains its original condition with DO rising up to the saturation value.
Water becomes attractive in appearance, fish ( which requires at least 4 to 5 mg /l of DO) and usual
aquatic life prevails.
Some pathogenic organisms may still, however survive and remain present, which confirms the fact
that “ once the river water has been polluted, it will not be safe for drinking, unless it is properly
treated.
13
14. DILUTION NUMERICALS
The sewage of a town is to be discharged into a river stream. The quantity of sewage produced
per day is 8 million liters and its BOD is 250 mg/L. If the discharge in the river is 200 l/s and if
its BOD is 6 mg/L, find out BOD of Diluted water.
𝐻𝑖𝑛𝑡: 𝐶 =
𝐶𝑠𝑄𝑠 + 𝐶𝑟𝑄𝑟
𝑄𝑠 + 𝑄𝑟
14
15. DILUTION NUMERICALS
A waste water effluent 560 l/sec with a BOD = 50 mg/L, DO = 3 mg/L and temperature = 23ᵒC
enters a river stream where the flow is 28 cumecs, BOD = 4 mg/L and DO = 8.2 mg/L and
temperature is 17ᵒC. Determine the following after the mixing of sewage with the river stream
1. Combined Discharge
2. BOD
3. DO
4. Temperature
15