this presentation is about how the water is polluted and how it can be treated and reused.Waste water can be treated and reused.

1. BY
Mr. SURYA PRAKASH J
FIRST YEAR
MECHANICAL ENGINEERING
S.K.P ENGINEERING COLLEGE
WATER TREATMENT
&
WASTE WATER
TREATMENT

2. TYPES OF TREATMENT
1.Water Treatment: prepares water for use in Homes,
businesses (drinking water).
2.Waste Water Treatment: prepares sewage/wastewater
to be returned to the environment.

3. 1.INITIAL STAGES
2.SECONDARY STAGES
3.FINAL STAGES
STAGES OF WATER TREATMENT

4. 1. Screening
2. Aeration
3. pH correction
INITIAL STAGES

5. 1.Screening - the removal of any coarse floating
objects, weeds, etc. from the water.
2.Aeration - dissolving oxygen into the water to
remove smell and taste, promote helpful bacteria to
grow, and precipitate nuisance metals like iron and
manganese.
3.pH correction - preparing for coagulation and to
help precipitate metals.
INITIAL STAGES

6. 4. Coagulation
5. Sedimentation
6. Pre-chlorination and De-chlorination
SECONDARY STAGES

7. SECONDARY STAGES
COAGULATION
4.COAGULATION - causes the sedimentation of suspended
solid particles through the addition of a coagulating agent
(usually aluminum sulphate and/or iron sulphate) to the raw
water along with a polymer to help form a floc.

8. 5.SEDIMENTATION - Floc settles out and is scraped and
vacuumed off the bed of large sedimentation tanks. Clarified
water drains out of the top of these tanks in a giant decanting
process.
SEDIMENTATION

9. PRE-CHLORINATION
AND
DE-CHLORINATION
6.Pre-chlorination and De-chlorination - mostly to kill algae
that would otherwise grow and clog the water filters. Also kills
much of the remaining unprotected bacteria.

10. 7. Filtration
8. Disinfection
9. pH adjustment
FINAL STAGES

11. FILTRATION

12. 8.Disinfection - water completely free of suspended sediment
is treated with a powerful oxidizing agent usually chlorine,
chlorine then ammonia (chloramine), or ozone.
1.A residual disinfectant is left in the water to prevent
reinfection.
2.Chlorine can form harmful byproducts (THMs)and has
suspected links to stomach cancer and miscarriages.
3.Many agencies now residually disinfect with Chloramine to
prevent formation of THMs.
9.pH adjustment - so that treated water leaves the plant in
the desired range of 6.5 to 8.5 pH units.
FINAL STAGES

13. Municipal Water Purification Plant

14. WASTEWATER TREATMENT
1.SEPTIC TANKS: typically treat small volumes of waste
(e.g., from a single household, small commercial/ industral).
2.WasteWater Treatment Plants(WWTP) : typically treat
larger volumes of municipal or industrial waste.

15. 1.Wastewater treatment systems take human and industrial
liquid wastes and make them safe enough (from the public
health perspective) to return to the aquatic or terrestrial
environment.
2.In some cases, wastewater can be clean enough for reuse
for particular purposes.
3.Wastewater treatment systems use the same purification
process that occurs in a natural aquatic system only faster
and in a controlled manner.
TREATMENT OBJECTIVES

16. SEPTIC TANKS

17. 1.Approx. 22 million systems in operation ( 30% of
US population)
2.Suitability determined by soil type, depth to water
table, depth to bedrock and topography
3.Commonly fail due to poor soil drainage
4.Potential contaminants: bacteria, heavy metals,
nutrients, synthetic organic chemicals (e.g. benzene)
SEPTIC TANKS

18. Sewage or wastewater is composed of sewage or
wastewater from:
 Domestic used water and toilet waste
 Rainwater
 Industrial effluent (Toxic industrial water is
pretreated)
 Livestock wastes
SEWAGE OR WASTEWATER
TREATMENT

19. 1. Pretreatment: Bar screening
Large rack with bars to remove large objects that can
damage equipment.
These objects are sent to landfills.
SEWAGE TREATMENT
MULTISTEP PROCESS
2.Primary Treatment: Settling Tanks
Primary Sludge: heavy solids that sink to the bottom -
removed and sent to solids treatment facility.
Light grease/oil float to top--skimmed off and sent to
solids treatment facility.
This takes several hours.

20. 2.Secondary Treatment: Final Clarifiers
Microbes fall to bottom and most get recycled back into
aeration tank to work on more waste.
Any excess microbes are removed and sent to solids
treatment.
TREATMENT OF LIQUIDS
1.Secondary Treatment: Aeration Tank
Biological Treatment.
Activated sludge: contains bacteria/protozoa that eat
organics in the liquid wastes.
Air bubbles pumped in to aid bacteria in digesting.

21. 3.Final Treatment: Disinfection
Chlorine: kills disease causing organisms.
Can react with organisms to form chlorinated hydrocarbons
that can cause cancer.
UV light or ozone: can be used instead of chlorine, but more
expensive.
Clean water is then sent to ocean, river, etc.

22. 1.Mainly anaerobic digestion.
2.Large tanks mix and heat solids.
3.Microbes eat solids and produce methane.
4.Excess water removed to reduce volume
before transport.
 Remaining solids: some are recycled as fertilizer
and some are sent to landfills.
 Methane: can be used as energy source.
TREAMENT OF SOLIDS

24. 1. Tertiary: Chemical and Physical.
2. Removes specific nutrients--such as phosphate,
nitrate.
3. Expensive! Not used in many systems.
ADVANCED SEWAGE TREATMENT
TERTIARY:PHYSICAL AND CHEMICAL

25. 1. Currently, treated wastewater, no matter how “clean” cannot
be directly mixed with treated raw water and supplied as
potable (from Latin potare = “to drink”) water (most places).
2. However, if a dual plumbing system is available,
wastewater can be piped into facilities for specific, approved
uses for which non-potable water is adequate (process water,
irrigation, sanitary use, etc.).
3. Dual plumbing systems in America are colored purple to
distinguish pipes, valves, taps, etc. from potable ones.
REUSING WASTEWATER

26. 1. Increasingly, treated wastewater is being used in Aquifer
Recovery and Storage projects, used to recharge and protect
groundwater that will ultimately be used for potable supplies.
2. In dual systems, the wastewater “gray water” can be used
for irrigation.
3. Treated wastewater is frequently used as sources of saline
intrusion barrier water.
INDIRECT USE OF WASTEWATER

27. 1.Through the two methods of water treatment , we can easily
purify the water .
2.And so, it will be useful for the drinking and domestic
purposes.
CONCLUSION