Wastewater treatment encompasses the removal of contaminants from domestic and industrial wastewater to minimize pollution and produce reusable effluent and sludge. The treatment process typically includes primary, secondary, and tertiary stages, utilizing methods such as mechanical, biological, and chemical treatments. Additionally, various specialized treatments are required for specific industries, with advancements like constructed wetlands and water recycling being implemented to enhance environmental sustainability.

1. Waste Water Treatment

2. Waste Water Treatment
Usually refer to sewage treatment, or domestic wastewater
treatment
process of removing contaminants from wastewater, both
runoff and domestic
Residences (kitchen, bathroom)
Commercial institution
Industrial institution (usually require specialized treatment
process)
SOURCE OF WASTE WATER

3. Purpose:
To manage water discharged from homes, businesses
, industries & to reduce the threat of water pollution.
To produce waste stream (effluent)
To produce solid waste (sludge)
To discharge or reuse them back into the
environment

4. How can it be treated?
Collected and transported via a network of pipes and
pump stations to a municipal treatment plant

5. Stages of water treatment
Primary
solids are separated
Secondary
dissolved biological matter is converted into a
solid mass by using water-borne bacteria
95% of the suspended molecules should be
removed
Tertiary
biological solids are neutralized then disposed,
and treated water may be disinfected chemically
or physically

6. Types of Treatment
Mechanical treatment
• Influx (Influent)
• Removal of large objects
• Removal of sand and grit
• Primary Sedimentation
Biological treatment
• Trickling bed filter
• Activated sludge
Chemical treatment
• Disinfection

7. Preliminary Treatment
- removes large objects and non-degradable materials
- protects pumps and equipment from damage
- bar screen and grit chamber
Bar Screen
- catches large objects that have
gotten into sewer system such as bricks,
bottles, pieces of wood, etc
Grit Chamber
-removes rocks, gravel, broken glass, etc.
Mesh Screen
- removes diapers, combs, towels, plastic bags,
syringes, etc.

8. Treatment stages - Primary Treatment
typical materials that are removed during primary treatment include
fats, oils, and greases (eg. FOG)
sand, gravels and rocks (eg. grit)
larger settleable solids including human waste, and floating
materials

9. Primary treatment reduces the suspended solids and the B.O.D.
of the wastewater.
From the primary treatment tanks water is pumped to the
trickling filter for secondary treatment.
Secondary treatment will further reduce the suspended solids
and B.O.D. of the wastewater.
Wastewater Treatment

10. Treatment stages - Secondary Treatment or
Biological Treatment
Degrade biological content (dissolved organic matter) of the
sewage
Ex: human waste, food waste, soaps, detergent
Added bacteria and protozoa into sewage.3 different approaches
Fixed film system
Suspended film system
Lagoon system

11. Three approaches
 Fixed Film Systems
grow microorganisms on substrates such as rocks, sand or plastic
wastewater is spread over the substrate
Ex: Trickling filters, rotating biological contactors
Spread wastewater over
microorganism
made of coke (carbonised coal),
limestone chips or specially
fabricated plastic media
Optimize their thickness by insect
or worm grazing
Trickling filters bed

12. Suspended Film Systems
stir and suspend microorganisms in wastewater settled out as a sludge
pumped back into the incoming wastewater Ex: Activated sludge,
extended aeration
Secondary Treatment or Biological Treatment
& Role of Microorganisms
Activated sludge
Mixed community of microorganisms .Both aerobic and anaerobic bacteria may
exist. Biological floc is formed

13. 5 physical components of Activated
Sludge process
Aeration tank
oxygen is introduced into the system

14. Aeration source
ensure that adequate oxygen is fed into the tank
provided pure oxygen or compressed air

15. Secondary clarifiers
activated-sludge solids separate from the
surrounding wastewater

16. Activated sludge outflow
line
Pump activated sludge back
to the aeration tank
Effluent outflow line
discharged effluent into bay
or tertiary treatment plant
Activated sludge

17. Lagoon Systems
hold the waste-water for several months
natural degradation of sewage
Usually reeds are preferred

18. 1. a
2. Methanogenic Bacteria : These
bacteria, also refered to as
methanogens
Or methane formers are responsible for the
conversion of acetic acid and
Hydrogen to methane and
carbondioxide.The most important
methanogens
belong to the genera Methanobacterium,
Methanobacillus, Methanococcus
Role of Microorganisms….
A consortium of anaerobic microorganisms work together for degradation
Of sludge(or sewage) organic matter. They may be categorized into two types
1. Acid-Forming bacteria :Also known as acidogens or non-methanogenic
Bacteria. They bring out the hydrolysis of macromolecules (e.g.carbohydrate) to
simple substrates (e.g.monosaccharides), and the latter to acids e.g. Clostridium sp,
Lactobacillus sp, E.coli

19. Tertiary Treatment
Remove disease-causing organisms
from wastewater
There are four major processes
under the Tertiary Treatment
1. Solids removal
2. Biological nitrogen removal
3. Biological phosphorus removal
4. Disinfection
There are 3 different disinfection
process
1. Chlorination
2. UV light radiation
3. Ozonation

20. BIOLOGICAL NITROGEN REMOVAL
NITRIFICATION: Ammonia(NH4+)
Nitrosomonas
Nitrite
Nitrobacter
Nitrate
DENITRIFICATION: Nitrate(NO3-)
Nitrite
Nitric oxide
Nitrous oxide
Nitrogen gas

21. Biological Phosphorous Removal
The phosphorus enriched supernatant that comes out of the
phosphorus Stripper is treated with lime to precipitate the
phosphorus .The resultant Liquid supernatant can be returned to
the aeration tank for further treatment.

22. Chlorination
Most common
Advantages: low
cost & effective
Disadvantages:
chlorine residue
could be harmful to
environment

23. UV light radiation
Damage 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

24. Ozonation
Oxidized most pathogenic microorganisms
Advantages: safer than chlorination fewer disinfection
by-product
Disadvantage: high cost

25. Waste Water Treatment of some Industries
(Dairy)
Dairy facilities
Shed facilities
(washing of herd,
Milking, manure)
Anaerobic pond treatment
Aerobic Pond treatment
Treated
water

26. Waste Water Treatment of some Industries
(Distillery)
Organic matter
Bacterial oxidation
Acids, Alcohols,
Aldehydes,ketones
New Bacterial cells
Bacterial Oxidation
CO2,CH4,
NH3,H2S etc

27. Waste Water Treatment of some Industries
(Tannery)
Biological Acidification
Anaerobic sludge
Blanket reactor
Processing of
sulfide
sulfur
SLUDGE
SLUDGE
NaHS

28. Summary

29. Disposal of wastewaters from an industrial plant is a difficult and
costly problem. Most petroleum refineries, chemical and Nuclear
plants ,Dairy and Tannery plants have onsite facilities to treat their
wastewaters so that the pollutant concentrations in the treated
wastewater comply with the local and/or national regulations
regarding disposal of wastewaters into community treatment plants
or into rivers, lakes or oceans. Constructed wetlands are being used
in an increasing number of cases as they provided high quality and
productive on-site treatment. Other Industrial processes that
produce a lot of waste-waters such as paper and pulp production has
created environmental concern leading to development of processes
to recycle water use within plants before they have to be cleaned
and disposed of. Treated wastewater can be reused as drinking
water, in industry (cooling towers), in artificial recharge of aquifers,
in agriculture and in the rehabilitation of natural ecosystems.
Conclusion