Rain water harvesting & greywater management

1. RAIN WATER HARVESTING
& GREYWATER
MANAGEMENT
Vivek Kumar,
St. Vincent Pallotti College of
Engineering and Technology,
Nagpur

2. RAIN WATER HARVESTINGRAIN WATER HARVESTING

3. REASONS OF SHORTAGE OF
WATER
Population increase
Industrialization
Urbanization
(a) Increase in per capita utilization
(b) Less peculation area
In places where rain fed/ irrigation based crops are
cultivated through ground water
Decrease in surface area of Lakes, talab, tanks etc.
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4. REASONS OF SHOTRAGE OF
WATER
Deforestation
(i) Less precipitation
(ii) Absence of Barriers
(a) Rain drops checked by leaves of tree
(b) Water slowly descends through twigs & trunk
© Humus – acts as reservoir
(d) Tiny creatures – helps percolation
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1 hectare of forest-6-7 Lac ton of water
(after filtering) top layer can hold 1.2 Lac tons of water

5. WHAT IS THE SOLUTION ?
Rain water is the ultimate source of fresh water
Potential of rain to meet water demand is tremendous
Rain water harvesting helps to overcome water
scarcity
To conserve ground water the aquifers must be
recharged with rain water
Rain water harvesting is the ultimate answer
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6. WHY RAIN WATER BE HARVESTED
To conserve & augment the storage of
ground water
To reduce water table depletion
To improve the quality of ground water
 To arrest sea water intrusion in
coastal areas
To avoid flood & water stagnation in
urban areas
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7. WHAT IS RAIN WATER
HARVESTING ?
It is the activity of direct collection of rain water
Rain water can be stored for direct use or can be
recharged into the ground water aquifer
The roof catchment are selectively cleaner when The roof catchment are selectively cleaner when
compared to the ground level catchmentcompared to the ground level catchment
Losses from roof catchment are minimum
Built & Maintained by local communities
No Chemical contamination & only required
filtration
Available at door step with least cost
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8. THE TYPICAL ROOF TOP RAIN
WATER HARVESTING SYSTEM
COMPRISES
Roof catchment
Gutters
Down pipe & first flushing pipe
Filter Unit
Storage Tank
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9. ROOF CATCHMENT
The roof of the house is used as the catchment for
collecting rain water. The style construction and material
of the roof effect its suitability as a catchment, Roofs
made of corrugated iron sheet , asbestos sheet, Tiles or
Concrete can be utilized for harvesting the rain water
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10. GUTTERS
Gutters are channels fixed to the edges of roof all
around to collect & transport the rainwater from
the roof. Gutters can be made in semi-circular
and rectangular shape with cement pipe, plain
galvanized iron sheet, PVC pipes, bamboos etc.
Use of locally available material reduce the
overall cost of the system.
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11. DOWN PIPE
It is the pipe which carries the rainwater from
the gutters to the filter & storage tank. Down
pipe is joined with the gutters at one end & the
other end is connected to the filter unit of the
storage tank. PVC or GI pipe of 50mm to 75mm
(2 to”) are commonly used for down pipe. Bamboo
can be also used wherever available and possible
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12. FIRST FLUSH PIPE
Debris, dust & dirt collect on the roof during non
rainy periods when the first rain arrive. A first
flush system arrangement is made to avoid the
entering unwanted material into the Filter media
& storage tank. This is a simple manually
operated arrangement or semi-automatic system
with a valve below the ‘T’ junction
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13. FILTER UNIT
The filter unit is a container or chamber filled
with filter media such as coarse sand, charcoal,
coconut fiber, pebbles & gravels to remove the
debris & dirt from water that enters the tank.
The filter unit is placed over the storage tank or
separately. It may be of Ferro cement filter unit,
Aluminum, Cement rings or Plastic bucket etc.
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14. STORAGE TANK
It is used to store the water that is collected from the roof
through filter. For small scale water storage plastic
buckets, jerry cans, clay or cement jars, ceramic jars,
drums may be used. For larger quantities of water, the
system will require a bigger tank with cylindrical or
rectangular or square in shape constructed with Ferro
cement or cement rings or plain cement concrete or
reinforced cement concrete or brick or stone etc. The
storage tank is provided with a cover on the top to avoid
the contamination of water from external sources. The
storage tank is provided with pipe fixtures at appropriate
places to draw the water to clean the tank & to dispose of
extra water. A provision for keeping the vessel to collect
the water is to be made.
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15. SIZE OF STORAGE TANK
Based on
No. of person in the House hold
Per capita water requirement
No. of days for which water is required
Example
Drinking water requirement for a household with 5 family
members, period 8 months & 6 lpcd
= 5x 180x 6
= 7200 Liters
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16. GREYWATER GREYWATER
MANAGEMENTMANAGEMENT

17. GREYWATER DEFINITION
Greywater is wastewater generated by household
processes such as washing dishes, laundry and
bathing. Greywater is distinct from wastewater
that has been contaminated with sewage, which
is known as blackwater .

19. CHARACTERISTICS OF DIFFERENT
SOURCES OF GREYWATER
PRODUCTION
kitchen: kitchen greywater contains food residues, high amounts of oil
and fat, including dishwashing detergents. In addition, it occasionally
contains drain cleaners and bleach. Kitchen greywater is high in nutrients
and suspended solids. Dishwasher greywater may be very alkaline (due to
builders), show high suspended solids and salt concentrations.
bathroom: bathroom greywater is regarded as the least contaminated
greywater source within a household. It contains soaps, shampoos,
toothpaste, and other body care products. Bathroom greywater also
contains shaving waste, skin, hair, body-fats, lint, and traces of urine and
faeces. Greywater originating from shower and bath may thus be
contaminated with pathogenic microorganisms.
laundry: laundry greywater contains high concentrations of chemicals
from soap powders (such as sodium, phosphorous, surfactants, nitrogen)
as well as bleaches, suspended solids and possibly oils, paints, solvents,
and non-biodegradable fibres from clothing. Laundry greywater can
contain high amounts of pathogens when nappies are washed

20. Greywater GardensGreywater Gardens

•drain greywater (without any pre-
treatment) to swales or trenches,
which are filled with mulch
material;
•Sub-mulch or above the surface
of mulch application;
•periodical replacement of
decomposing mulch (wood chips,
bark chips, rice husk, etc.);
•simple greywater management
systems;
•direct utilisation of greywater;
•facilitate breakdown of organic
compounds and recover nutrients;

21. Advantages & Limitations of Greywater GardensAdvantages & Limitations of Greywater Gardens
ADVANTAGES LIMITATIONS
•no external energy required (no
pumping) due to gravity flow;
•not suitable for densly populated
areas with high greywater
production if space for establishing
greywater gardens is limited;
•hair, soap residues etc. will be
retained (at the point of greywater
application) by the mulch material;
•use of locally available organics
(e.g. rice husk, etc.) as mulch
material;
•no use of inorganic material (e.g.
gravel, perforated pipes, etc.) for
distribution of greywater;
•greywater garden can be
redesigned easily by simply
plowing the soil (organic material
will be mixed with the soil);

22. Examples of Greywater Gardens, India

23. Greywater Towers

24. Horizontal (HFCW) & Vertical Flow Constructed Wetlands (VFCW)


•preliminary treatment of greywater in e.g.
settlement tank for solid-liquid separation
(oil and fat, hair, lint, food residues, etc.);
•subsequent treatment of greywater in reed
beds also known as horizontal flow
constructed wetlands (HFCW) or vertical
flow planted gravel filters (VFPGF) also
known as vertical flow constructed wetlands
(VFCW);
•application of pretreated greywater happens
continously by gravity flow (HFCW) and
intermittently by means of siphons or (solar-
operated) pumps (VFCW);
•HFCW differ from VFCW as part of the
filter is permanently soaked and operated
aerobically, anoxically (no free oxygen
present but nitrates) and anaerobically;

25. Advantages & Limitations of HFCW and VFCW
HORIZONTAL FLOW CONSTRUCTED WETLANDS
ADVANTAGES LIMITATIONS
•feeding by gravity flow is possible;•required surface area;
•treated water is fit for non-potable
purposes (e.g. surface
application);
VERTICAL FLOW CONSTRUCTED WETLANDS
ADVANTAGES LIMITATIONS
•reduced surface area in
comparision to HFCW
•intermittent feeding requires either
a (solar-operated) pump or
sufficient vertical distance for
installation of siphon tank
•treated water is fit for non-potable
purposes (e.g. surface
application);

26. Sizing of Small-Scale Horizontal Flow Constructed Wetlands

27. Sizing of Small-Scale Vertical Flow Constructed Wetlands

28. Examples of VFCW, Nepal

29. Examples of HFCW, Nepal

30. THANK YOU
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