dewats decentralised natural waste water treatment system
DESCRIPTION
Natural treatment for waste/grey waterTRANSCRIPT
Decentralised waste water treatment systemsDecentralised waste water treatment systemsAuroville Centre for Scientific Research
Decentralised waste water treatment principles and devices
Treatment for organic wastewater from domestic and industrial sources
Treatment of wastewater flows from 1-1000 m3/d
Achievement of discharge standards
Tolerance to inflow fluctuationMinimal dependence on external energy, minimal maintenance
Using gravity instead of pumps, avoiding valves
Aiming towards reliable and long-lasting devices
Priority given to anaerobic technology in warm climatesand aerobic technology in cold climates
Reuse of wastewater
Pre-treatment deviceSettler
Pre-treatment
Settler
1st treatment
Baffled tank reactor
Anaerobic filter
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD
457
0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
Planted gravel filter
Polishing pond
Pre-treatment is done in a Settler
A device which separates the liquid from the solid, retention time is only 2 hours. Pollution reduction is around 30%
First treatment takes place in a Baffled Tank
A device with several identical chambersthrough which the effluent moves from top to bottom.Retention time is 24 hours.Pollution reduction is around 80%
Natural treatment of waste water occurs by channeling the effluent through several devices:
Second treatment takes place in a anaerobic filter
A device filled with a filter material (cinder) throughWhich the effluent moves from top to bottom.
Retention time is around 8 hours.Total pollution reduction is around 90%At this stage CPCB standards are metbut the effluent still has an odour
Third treatment takes place in a planted gravel filter
A structure filled with gravel material and planted with water resistant plants, who provide oxygen to the passing effluent.Retention time is 1½ day.Pollution reduction is around 90%
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
RawSewage
OutletSettler
OutletBaffledReactor
OutletGravelFilter
OutletPond
BOD5
COD 0
200
400
600
800
1000
1200
Post treatment takes place in polishing pondsfitted with aquatic plants and fishes.It is through this device that the water transformsfrom a lifeless state into living water again.
Ponds with aquatic plants are an efficient way to combine wastewater treatment,landscaping, aesthetics and water reuse, the pond can also act as a storage device.
Underground anaerobic process Above ground level aerobic process
CPCB standards are met at this point, except for the smell control
Overview of the different devices
Surya Nivas, 2003 – 12 users
Samasiti, 2009 - 25 PE
Solar Kitchen, 1998 – 40 m³
Surya Nepal Pvt Ltd(subsidiary of ITC)
125 m³/day
Surya Nivas, Nepal60 m³ /day
Kadambadi settlementNagipattinam
Post Tsunami Dewats projects
Vortex systemsfor waste water treatment
ATS – Algal Turf Scrubbers Treating toxic waste water
Algal are grow in shallow basins for cleaning water pollution, including heavy metals
In the process Biomass is grown and harvested for Energy - gas methane/ethanol/butanol - Bio-diesel – bio-aviation fuel
Note: solar energy absorption by algal is 45 to 50%, increase in biomass doubles/24 hrs, during the process algal absorbs CO2 and gives off oxygen
ATS needs Start up investment Land area is required for installing the basins
Integrating ATS – Algal Turf Scrubbers
the use of algae for cleaning toxic
waste water
Auromode
“And justify the light on Nature’s face.”