Wastewater treatment involves removing contaminants from domestic and industrial wastewater through physical, biological, and chemical processes before the water is discharged or reused. The treatment process begins with removing solids and floats through primary treatment, uses microorganisms to break down organic matter in secondary treatment, and may use disinfection like chlorination in tertiary treatment to remove pathogens. Sludge from the treatment plant is further processed through aerobic or anaerobic digestion, composting, or incineration to reduce its volume and kill pathogens. Properly treated effluent can be reused for irrigation or discharged into local waterways.

1. Wastewater Treatment
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Ms.T.Bhuvaneswari , CARE Group of
Institututions

2. Contents• Waste water
• Ill effects of waste water
• Contaminants of waste water
• What is waste water treatment
• Need for treatment
• Where does waste water come from
• Domestic waste water
• Flush Toilet
• Industrial waste water
• Types of treatment
• Stages of treatment
• Effluent used for
• Sludge treatment
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Ms.T.Bhuvaneswari , CARE Group of
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3. Waste water
• water that has been adversely affected in
quality by man-made influence
• originate from a combination of domestic,
industrial, commercial or agricultural activities
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4. Contaminants in waste water
• Biological contaminants – pathogens
• Floating Solids – papers , sticks, leaves,rags
• Dissolved Solids – Total solids
• Suspended solids – fine particles
• Inorganic matter – Flouride , nitrate
• Colours , odours , taste
• Nutrients – Nitrites , phosphates
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Ms.T.Bhuvaneswari , CARE Group of
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5. Ill effects of waste water
• Caused by Bacteria: typhoid, cholera,
dysentery,fever , vomitting
• Caused by virus:Hepatitis A, polio
• Excess of Nitrogen: Blue baby syndrome
prevents the normal uptake of oxygen by the
blood in young babies
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6. • Cadmium – High blood sugar, reduced
immunopotency, and anemia
• Chromium - skin ulcer, convulsions, kidney
failure and liver damage
• Fluoride - dental and skeletal fluorosis such as
yellowing of teeth, bending of spinal cord
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Ill effects of waste water
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7. What is wastewater treatment
• Process of removing the undesirable
chemicals and biological contaminants from
domestic wastewater and Industrial waste
water
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Ms.T.Bhuvaneswari , CARE Group of
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8. Need for treatment
To remove pollutants from waste water for its
recycling.
To promote health concern and public
hygiene.
To preserve aquatic life
To promote recreation and quality of life
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Ms.T.Bhuvaneswari , CARE Group of
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9. Where does wastewater come from?
• Residences (kitchen, bathroom)
• Institutions (College, theatres,auditorium)
• Industries (leather , dyeing , chemical
industries ….)
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Ms.T.Bhuvaneswari , CARE Group of
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10. Domestic waste water
Where does
the water from
the washer go?
When you flush the
toilet where does
the contents go?
By gravity flow, the waste is on its way to your local collection
and then to the wastewater treatment plant!
WWTP
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Ms.T.Bhuvaneswari , CARE Group of
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11. Flush toilet
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12. Flush toilet
• A flush toilet is a toilet that disposes of human
liquid waste and solid waste
• Flush toilets usually incorporate an "S", "U",
"J", or "P" shaped bend that causes the water
in the toilet bowl to collect and act as a seal
against sewer gases
• When a toilet is flushed, the wastewater flows
into a septic tank or sewage system and from
there to a sewage treatment plant
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13. Types of toilet
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Squat toilet Western
toilet
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14. Flush tank
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15. Types of trap
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16. Function of Trap/bend
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•A trap is a bent sanitary fitting which always remains full of
water.
• It‘s function to prevent the passage of foul gases or air
through it.
•The effectiveness of the trap usually depends on the water
seal.
•A properly installed “P” trap will always maintain a water
seal.
•If you have an “S” trap drain and you notice odors in the
room , you can run the water slowly for a short time to fill
the “S” trap to maintain a water seal so the sewer gases can
no longer escape to the home.
Ms.T.Bhuvaneswari , CARE Group of
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17. Working of flush toilet
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The ballcock or float valve is often used to regulate the filling of a
tank or cistern. When the fluid level drops, the float descends,
levering the valve opening and allowing more fluid to enter. Once
the float reached the 'full' position, the arm presses the valve shut
again.
Ms.T.Bhuvaneswari , CARE Group of
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18. Industrial wastewater
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19. Effects of waste water on animals
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20. Contaminants from Industry
• Waste water from High energy battery
industry contains Lead ,Cadmium, nickel .
• Waste water from Textile and leather
industries contains Sulphates ,
Chromium,Calcium
• Waste water from Paper and Paper board
industries contains Solids,Chlorinated organic
compounds
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21. How can it be treated?
• Waste water from domestic, industrial
,commercial centers are collected and
transported via a network of pipes and pump
stations to a sewage treatment plant
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Ms.T.Bhuvaneswari , CARE Group of
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22. Types of treatment
• Physical treatment
Removal of large objects – Bar Screen
Removal of sand and grit - Grit chamber
Primary Settling tank
• Biological treatment
Removal of organic and micro organism
- Trickling bed filter
• Chemical treatment
Removal of Bacteria – Disinfection process
Removal of Colour, odour, taste - Activated Carbon
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23. Stages of water treatment
• Primary treatment involves physical sedimentation of
particulates.
• Secondary treatment involves physical and biological
treatment to reduce organic load of wastewater.
• Tertiary or advanced treatment involves chemical
treatment to reduce odour, disease causing
organisms
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24. Preliminary treatment
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Primary and Secondary treatment Process
Ms.T.Bhuvaneswari , CARE Group of
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25. Primary treatment
• Typical materials that are removed during
primary treatment include
– fats, oils, and greases
– sand, gravels and rocks
– larger settleable solids including human waste,
and
– Floating materials includes papers,rags,sticks etc
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26. 26
Bar Screen Grit Chamber
Primary Settling Tank
Ms.T.Bhuvaneswari , CARE Group of
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27. Secondary treatment
• Degrade biological content (dissolved organic
matter) of the sewage
– Ex: human waste, food waste, soaps, detergent
• By adding bacteria and protozoa into sewage
for decomposition
• 3 different approaches
– Fixed film system
– Suspended film system
– Lagoon system
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28. Three approaches
• Fixed Film Systems
– grow microorganisms on substrates such as rocks,
sand or plastic
– wastewater is spread over the substrate
– Ex: Trickling filters
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29. • Suspended Film Systems
– stir and suspend microorganisms in wastewater
– settled out as a sludge
– Ex: Activated sludge
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30. Aeration system
– Oxygen is introduced into the system naturally or
manually
– Lagoons : Hold the waste-water for several months
Natural degradation of sewage
– Aerator : Oxygen is introduced manually using motors
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AeratorLagoons
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31. Tertiary treatment
Process for removing colour,odour, disease-
causing organisms from wastewater
• Activated Carbon Process
• Different disinfection process
– Chlorination
– UV light radiation
– Ozonation
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Ms.T.Bhuvaneswari , CARE Group of
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32. Chlorination
• Most common
• Advantages: low cost
& effective
• Disadvantages:
excess residual
chlorine could be
harmful to
environment
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Ms.T.Bhuvaneswari , CARE Group of
Institututions

33. UV light radiation
• Alter the genetic
structure of bacteria,
viruses and other
pathogens.
• Advantages: no chemicals
are used
• water taste more natural
• Disadvantages: high
maintenance of the UV-
lamp
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Ms.T.Bhuvaneswari , CARE Group of
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34. Ozonation (O3)
• Oxidises most pathogenic microorganisms
• Advantages: safer than chlorination
• Disadvantage: high cost in the production of O3
34Ms.T.Bhuvaneswari , CARE Group of Institututions

35. Activated Carbon treatment
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• More volatile organic compounds,odour ,
colour, taste problems can be effectively
removed
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37. What can effluent used for?
• discharged into a stream, river, bay, lagoon or
wetland
• used for the irrigation of a golf course, green
way or park
• If it’s sufficiently clean, it can be used for
groundwater recharge (at the place called
sanchetti, near Chennai the treated water is led
into borewell to recharge the ground water by
the Chennai corporation)
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38. Sludge treatment
• Primary sludge usually have strong odors
• Secondary sludge have high concentration of
microorganism
• Goals of treatments are:
– Reduce odors
– Remove water
– Reduce volume
– Decompose organic matter
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Ms.T.Bhuvaneswari , CARE Group of
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39. Sludge treatments
• Aerobic digestion
• Anaerobic digestion
• Composting
• Incineration
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40. Aerobic digestion
• Bacterial process – nitrobacter , Nitrosomanas
• In the presence of oxygen
• Consume organic matter and convert into
carbon dioxide (CO2)
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Ms.T.Bhuvaneswari , CARE Group of
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41. Anaerobic digestion
• Bacterial process – Pseudomonas,Aerobacter
• Absence of oxygen
• Consume organic matter, produce biogas,
which can be used in generators for electricity
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Ms.T.Bhuvaneswari , CARE Group of
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42. Composting
• Aerobic and anaerobic
process
• requires the correct
mix of carbon,
nitrogen, oxygen and
water with sludge
• Disadvantage :
Generate large
amount of heat and
ash
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Ms.T.Bhuvaneswari , CARE Group of
Institututions

43. Incineration
• Combustion of
organic substances
contained in waste
materials
• converts the waste
into ash, flue gas,
and heat.
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44. Sludge disposal
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Ms.T.Bhuvaneswari , CARE Group of
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