Grey Water

Management
 What is Grey water

Washing of
Wastewater from Kitchen Bathroom Cloth washing Grey water
utensil
Current Situation of GWM in villages
Current Situation of GWM in villages
 Considerations for GWM

• Key considerations during designing GWM

interventions –
• Amount of greywater
• Flow of greywater
• Discharge arrangements etc.
• Low capital and O&M cost
• Key considerations for site selection of
treatment of greywater –
• Nearest place from point of generation for HH
level
• Site selection for village level interventions
should be nearest to the point of reuse or point
of generation
 Quantification of Waste water generated

Theoretical Method-Population based

How Much Greywater is Produced at HH Level per

day?

Fresh water 55 LPCD

Source:
https://swachhbharatmission.gov.in/SBMCMS/write
Greywater 65% (36 LPCD) readdata/Portal/SLWM/Shrikant_Navrekar_GWM_P
PT.pdf
of fresh water per day
Practical Methods
1. Flow measurement test 2. Bucket Test
Characteristics of wastewater
Decision Matrix
Space at HH

Village as a whole small bore pipe

Community leach pit for group of
system/WSP/DEWATS/SBT/Phytori
houses
d /others
Household level (HH) Grey water treatment systems

Kitchen Garden Soak pit

Leach pit Magic Pit

 Intervention chain for Grey water Management

Collection Platform
Internal Pipe
Nahani Trap Silt Chamber
Kitchen, Bathroom, Cloth Slope
washing, Dishwashing

Conveyance system
Nahani Trap with Jali

Silt Chamber
Silt Chamber ( 600 x 450 mm)
Household level interventions - Leach Pit
 Household level interventions - Leach Pit
Site selection criteria & data
required for planning of HH
level leach pit:

 No. of family members at HH to

calculate quantity of waste water
generated
 Soil type: Permeable and semi
permeable soils , No hard strata
& water logged condition
 Ground water table : Minimum
2 meter below GL in all season
 Adequate Space availability- Yes
Feasible sites for HH level leach pit
 HH level treatment options
Type of Pit Soak Pit Leach Pit Magic pit Kitchen Garden

Feasibility Soils with good Permeable and semi Soils with good absorption Factors like variation in
absorption capacity permeable soils capacity water requirement of
plants as per species,
seasons, type of soil
Location of the pit should be such that storm water does not flow into the should be considered.
pit.
The bottom of the pit should be at least 1m above ground water table
Material Graded gravels & Bricks Graded Gravel Gardening tool
requireme Sand Cement Sand Seeds, saplings
nt Perforated earthen pot Sand Siltation tank Fertilizers, oil grease trap
Gunny bag, twigs, coir & Pesticides
O&M Cleaning of filter Cleaning of the pit Regular cleaning of All gardening O&M
requireme media every5-6 years every 3-5 years. siltation tank (2-3years) Cleaning of material
nt Cleaning of filter media 7- deposited near plant roots
8 years Alternative arrangement
during rainy season
 Community level grey water management interventions

Community level interventions

Cluster of households Village level

Technology: Technologies:
1. Community leach pit 1. Constructed wetland
2. Modified Community Leach Pit 2. DEWATS
3. SBT/Others
 Community Leach Pit
(for cluster of households/ stand posts /institution areas/etc.)
• This pit is constructed and operated on the same
principle as HH level leach pit

• Size of the pit is calculated based on population

dependent on pit and water supply rate

• Bottom of the pit should be at least 2 m above the

water table.

• Site selection for a community leach pit should be based

on the ground slope and optimal length of connecting
pipe

• A silt chamber is provided to arrest the entry of

suspended solids into the pit
 Community Leach Pit
Site selection criteria & data required for
planning of Community leach pit:

 No. of HH & total family members to

calculate quantity of waste water
generated
 Soil type: Permeable and semi
permeable soils , No hard strata & water
logged condition
 Ground water table : Minimum 5 meter
below GL in all season
 Site should be at least 10 m away from
Existing challenges: ground water source
 Adequate Space availability- Yes
1. Waste water from Community water point
OR group of HH has no waste water
management arrangements
2. Its creating stagnant condition of
contamination nearby water body
3. Waste water direct connected to drain
without treatment contaminating water
body
Feasible sites for Community Leach Pit
 Sizing of Community Leach Pit
Consideration: Calculation Sheet of Community Level Leach Pit
• No. of No of Household 5 10 15
households
connected to the No of Population 25 50 75
pit/ Population Grey water generated (l/d) (Considering 65% of
dependent Water Supply @ 55 lpcd) 893.75 1787.5 2681
• Rate of water
Grey water generated (m3/d) 0.9 1.8 2.7
supply (55 lpcd)
• Rate of Required volume of leach pit (m3) 1.80 3.60 5.40
greywater effective depth of leach pit 1.8 1.8 1.8
generation (65%)
Area required 1 2 3
• Volume of the
pit is twice the Internal Diameter of leach pit 1.2 1.6 1.96
incoming flow External diameter of brickwork 1.7 2.1 2.46
• 5 members per
External diameter of PCC 1.9 2.3 2.66
household
Actual depth (effective depth +FB) 2.1 2.1 2.1
Silt Chamber Internal Size (900 mm X 600 mm)
Community Leach Pit & Silt Chamber
Community Leach Pit
 Modified Community Leach Pit

• In case of soils with low permeability, a sand

envelop of 300 mm is provided around the
leach pit.
• The sand envelop facilitates slow seepage of
water into the surrounding
• Size of cavities is reduced to 20-25 mm
instead of 40-45 mm
Feasible sites for Modified Community Leach Pit
Filter Chamber
Filter Chamber (In Drain Treatment)
 Filter chamber
Site selection criteria & data required for
planning of Filter chamber:

 No. of HH & total family members to

calculate quantity of waste water
generated
 Adequate space availability at drainage
(minimum 2m width & 4m in length)
 Series of filter chambers to provide after
each 15 HH coverage
 availability of adequate space for
provision of diversion to discharge
additional storm water during monsoon
Existing challenges:

1. HH waste water connected to drain and

no scope of HH level intervention
2. Non availability of adequate space for
end treatment & site not suitable for Note: This is an inline treatment technique to reduce the organic
community leach pit/modified leach pit loading intermittently, however it is recommended that some form of
(Waterlogged area & large Qty. of waste treatment is provided at the ultimate discharge point
water generated)
Feasible sites for Filter chamber
Diversion for additional storm water discharge
Diversion for additional storm water discharge
Community level grey water management interventions
Community level interventions

Village level

Technologies:
1. Constructed wetland
2. DEWATS
3. SBT/Others
Village Level Intervention Constructed Wetland
 Constructed wetland

Feasibility:
 Adequate space availability at end point
including space for provision of diversion

Data required for planning:

 No. of HH & total family members to
calculate quantity of waste water
generated OR actual data of Qty. of waste
water generated at outlet (Calculated from
Existing challenges:
flow measurement test OR bucket test)
 Water quality test report for BOD, COD,
1. HH waste water outlets connected with
PH & TSS parameters for water sample
drainage
collected at end point
2. No scope for community level
 Space availability (Length x Width)
intervention like community leach pit OR
Community modified leach pit
3. No permeable strata available
4. Waste water creating stagnant condition
at end point or contamination water body
Feasible sites for Constructed wetland
Horizontal flow Constructed Wetland
Cana Indica
Drawing of Constructed Wetland
 Decentralized Wastewater Treatment System (DEWATS)
• A DEWATS is a robust nature-based technology that uses a combination of different
treatment modules and is used to achieve the desired level of treatment.
Feasible sites for DEWATs
 Decentralized Wastewater Treatment System (DEWATS)

Feasibility:
 Adequate space availability at end point
including space for provision of diversion

Data required for planning:

 No. of HH & total family members to
calculate quantity of waste water
generated OR actual data of Qty. of waste
water generated at outlet (Calculated from
Existing challenges: flow measurement test OR bucket test)
 No. of septic tank overflow connected to
1. HH waste water outlets connected with drainage drain
 Water quality test report for BOD, COD,
2. No scope for community level intervention like
community leach pit OR Community modified leach pit PH & TSS parameters for water sample
3. No permeable strata available collected at end point
 Space availability (Length x Width)
4. Waste water creating stagnant condition at end point or
contamination water body
5. Overflow of septic tanks are connected to drains, BOD &
COD is high
Decentralized Wastewater Treatment System (DEWATS)
Data collection sheet
Thank You