Grey water recycling and reuse has many benefits but also poses some risks if not done properly. Treated grey water can be used for applications that don't require drinking water quality, such as toilet flushing and irrigation, in order to reduce fresh water usage. However, precautions must be taken to ensure the treated grey water is hygienically safe and not a source of odors or contamination. Separate plumbing is required for grey water and factors like the treatment system used, existing infrastructure, and end use of the water must all be considered to safely implement grey water recycling.

1. Grey Water
Recycling & Reuse
By
K.V. RAMAN
MANAGING DIRECTOR
NATURE HAS GIVEN US CLEAR & CLEAN WATER
LET US RETURN BACK THIS, AS WE RECEIVED IT!

2. WATER OF FACTS!
• GROWING POPULATION NEEDS MORE FRESH WATER
• INDUSTRIAL GROWTH – NEEDS MORE WATER
• AGRICULTURE GROWTH – NEEDS MORE WATER
• UNPREDICTABLE RAINFALL – WATER SCARCITY
• LESS GROUND WATER RECHARGE – WATER SCARCITY
• OVER DRAWING FROM GROUND WATER SOURCE
• POOR / CONTAMINATED GROUND WATER QUALITY –
HIGHER TREATMENT COST
• HIGH COST OF TANKER WATER – Rs.70/m3 ( location
dependent)

3. What will happen if we
don’t act now?
1. Threat to our existence!
2. Quality of life affected!
3. Threat to business !- e.g – Closure / Migration of
business/ Limitation of expansion / Higher Capex &
Opex
4. Limitation on agriculture growth for want of water!

7. Why Grey Water Recycling??
• Treated grey water will act as a substitute to those application
which do not require drinking water quality so directly it will
reduce & save fresh water requirement.
• Grey water recycling is not dependent on season or variability
of rainfall and as such is a continuous and a reliable water
resource.
• As the treated water is high in nutrient Content(i.e. Nitrogen,
Phosphorous) we can use it for irrigation purpose, so it will
lead to an increase in agricultural productivity.
• Grey water recycling will reduce load on Sewage treatment
plant therefore tangential benefit is there.
• Infiltration of treated Grey water will help to increase ground
water table level.

8. What are benefits of grey water recycling?
Water saving potential :
• Each person water requirement is 135-150 lit/day so grey water
generated will be about 72 lit/day. we can recycle about 60 lit/day
which cost around Rs.21/- . Each person can save Rs.21/- per day.
It will reduce water bill so financial saving on price of water.
• Environmental benefits :
• Reduction in generation of waste water will reduce potential of
environmental pollution.
• Reduction in surface and ground water pollution.
• Sustainable Development.
• Treated water is valuable resource for landscaping and plant
growth especially in arid climates(Low rainfall).
• It is rich in phosphorous, potassium, and nitrogen, making it a
good nutrient or fertilizer source for irrigation.

9. What is Grey water & its Source???
• Grey water is all wastewater that is discharged from a house,
excluding black water (Toilet Wastewater).
• It includes waste water from Showers, Bathtubs Sinks,
Kitchen, Floor Cleaning, Dishwashers, Laundry tubs&
Washing machines.
Low-load
Showers, bathtubs
hand washbasins
Grey Water
High-load
Kitchen (dish
washers),
washing machines

10. What Grey Water Contains??
• Grey water generation is dependent on living standard of people
& it’s a result of personal hygiene, detergents used, cosmetics
used as well as dirty cloths,.
• Grey water contain Soap, Shampoo, Toothpaste, Food scraps,
Cooking oils, Detergents and Hairs, Kitchen waste, water from
Floor Cleaning.
• Dishwashing & Floor cleaning mainly contain phosphorous ,
Sodium Bicarbonate.
• Kitchen waste contribute to Organic loading so increase in BOD
Load. 12.5 % Bathing
56 % Washing
Machine & floor
Cleaning
31 % Kitchen waste

11. Grey Water Characteristics
Parameter Unit Raw Grey water
(range)
Suspended Solids mg/L 10-100
Turbidity NTU 20-100
BOD5 mg/L 50-150
Ammonia mg/L 1-10
Total Phosphorous mg/L 0.5-5
Sulphate mg/L 10-50
pH mg/L 6.5-8.5
Total Hardness as
CaCO3
mg/L 30-150
Conductivity µs/cm 150-500
TOC mg/L 50-100

12. Other
applications:
- car washing
- fire fighting
- industrial use
Grey Water Recycling
Surface &
Ground
water
Recharge
Gardening ,
Irrigation
Toilet flushing,
Washing
machine

13. What are the Factors Influencing Grey Water Reuse??
• Budget: It is dependent on which type of treatment we are
providing. It may vary from low cost to expansive treatment.
• Existing plumbing: Grey water & Black water collection
pipes should be separate.
• Existing garden area: Availability of space & choice of plant
is main aspect to calculate watering requirement.
• Elevation of garden beds: if Garden bed is having slope then
we can directly through gravitational force use treated water
for gardening if not then we have to go for some extra units
like pipe n pumps.
• Storage :We can have ready made tanks for storage of raw
grey water.
• Space : Sufficient space should be available to install plant.

14. How do I collect Grey water??
• Identification of water : Separation of the drinking water ,
grey water ,Black water pipes and clear labeling of the taps
and devices should be there for reuse.
• Diversions systems : Grey water can not be stored more than
24 hour. It has to be treated through filtration & disinfection.

15. What is Grey water reuse concept??
• Safety & Hygiene : Treated grey water should be hygienically
Safe i.e. absence of E-Coil bacterial and viruses.
• Identification : Separate Grey water Plumbing & Labeling
should be there and avoid cross connection between drinking
water and grey water.
• Segregation between low & High Strength : Water from
baths, showers and hand washbasin which is less polluted
should be collected separately from high concentrated kitchen
waste & washing machines
• Direct reuse : We can use low concentrated grey water
directly for Toilet Flushing & Irrigation
• Treatment system: Grey water treatment should be Simple,
Low Cost & Ecofriendly & Reliable and easy to operate and
maintain

16. Grey water Treatment Technologies
 Dependent On
• Planned site
• Available space
• User needs
• Investment and maintenance costs

17. Proposed Process

18. CAPEX & OPEX
CAPACITY 75 KLD
POWER @ Rs.14 / Kwh 516110
CHEMICAL PAC & CLO2 @ 5 K/month 60000
CONSUMABLES - CARBON/Year 35000
MAINTENANCE @ 3% of Capex 125000
LABOUR @ Rs.40K /Month 480000
TOTAL OPEX 1216110
WATER PROCESSED /DAY in m3 75
WATER PROCESSED /YEAR (365 DAYS) in m3 27375
COST OF FRESH TANKER WATER /m3 70
COST OF FRESH TANKER WATER /YEAR 1916250
CAPEX 8000000
SIMPLE RETURN ON INVESTMENT
TOTAL SAVINGS BY WAY OF WATER PURCHASE 1916250
OPEX 1216110
NETT SAVINGS/YEAR 700140

19. Contribution
• Rs.40,000/ flat towards Capex when
200 residential units are considered
which is just the cost of a refrigerator
/ LCD TV /or a high end washing
machine.

20. What are treated grey water parameter should be??
A) Hygiene requirements (bathing water quality )
Sr No Parameter Standards
1 Total coliforms < 10.000 / 100 ml
2 E. coli < 1.000 / 100ml
3 Pseudomonas aeruginosa < 100 / 100 ml.
4 Faecal Streptococci 0 / 0.1 ml;
5 Candida albicans 0 / 0.1 ml;
6 Staphylococcus aureus 0/1 ml
7 Legionella sp. 0 / 10 ml;
8 BOD7 < 5 mg/l;
9 Oxygen Saturation > 50%;
10 UV-Transmission at 254nm (1 cm)  60%

21. B) Technical requirements
• Grey water Should not be source of bad odour. It must be free
from colour & Suspended Solids.
• Grey water pipe should be permanently colour coded &
Labeled.
• There should not be a Cross connection between Drinking and
Treated water.
• Municipal Waste water should not enter in grey water
recycling system.
• All mechanical equipment and treatment unit should be easily
accessible for cleaning , repair & maintenance
• Skilled Installation of treatment plant should be done to avoid
errors.
• Storage reservoirs should be away from direct sunlight to
avoid possible growth of Algae.
How to install Grey water treatment system?

22. What are the precautionary care one should
take while using treated grey water?
Health aspects:
• System overload should be avoided.
• Less polluted grey water sources such as from showers,
bath tubs and hand washbasins should be preferred for
treatment and reuse over kitchen or laundry grey water
• Grey water should not be stored but used immediately
or within 24 hours
• When used for gardening, grey water should be applied
to the subsurface to avoid any contact with the grey
water.
• Grey water should not be applied to fruits and
vegetables that are eaten raw.
• When used to water the garden or for irrigation, no
sprinklers should be used

23. thank you