Name :: Supabana Ghosh
Class :: X == > D
Roll No :: 47
Board Regn Numbr :: B114084140217
Current water shortages and the cost associated with freshwater
have made water reuse and recycling of major importance. Reused
water is currently used for non-potable purpose , such as
agriculture , landscape , public parks and golf course irrigation
, industrial process water etc. Benefits of reuse includes protection
of ecosystems and reduction and prevention of pollution. This
paper focus on the environmental & health considerations related
to utilization of treated water.
1.Waste water recycling helps you get the most from limited water supplies.
It's a low-cost, environmentally friendly way to create fresh water for
industry and agriculture & offers a wide range of treatment
technologies for reclaiming industrial waste water.
2.Waste Water & Process Technologies is on the forefront with a wide range
of recycling solutions
3.This also benefits You & Reduced stress on drinking water supplies
Flexibility to suit specific applications Affordable cost Low
* The dilution model; where a wastewater collection system exists but is infiltrated
by groundwater, rain and sand.
* The digester-dyke-pond model for concentrated effluent; to rebuild or
construct a collection system which separates wastewater from rainwater.
* The soil filter model, where large water surfaces are undesirable for social
reasons such as houses located very close to the treatment area.
Could stop lots of pollutants to enter the natural process
Could help nature to be cleaner and not plagued by weeds
Could remove Chemicals that could have been harmful for environment
Stops waste water seepage into natural water sources.
1. Smell .
2. Cuts into natural process where every other person's crap is some
3. Chemicals used could be harmful in long run.
4. Requires large area of land that could be permanently damaged.
5. Air born pollution and germs.
Thus,recycling of waste water has advantages as well as disadvantages but in
most cases it is useful like it could remove harmful chemical from the
What creates an increased water consumption?
* Population growth.
* Economic growth based on agriculture and industry.
* Increased standard of living.
How to improve the situation and create a sustainable
Rainwater harvesting in arid climates (for agriculture).
Wastewater treatment for reuse, particulary in agriculture.
Improve methods for watering.
Processing and venture in drought tolerance crops.
More efficient water use in the industry.
Improve the legal protection of water resources.
Hard Water & Soft
Identifying Hard and Soft Water
* Hard water is water containing a substantial amount of dissolved minerals like
calcium and magnesium.
* Soft water is water where the only ion is sodium.
* Hard water has a negative effect on plumbing and makes some cleaning materials
* Soap is ineffective on hard water and reacts with it to form insoluble salt known as
* Soft water may taste salty and not be safe to drink.
Effects of Hard Water
*Homes with hard water use more soap!
*More soap residue.
*Calcium and iron deposits can build up
in appliances and on faucets:
*Shortens their life span and adds to
* Water with very low concentrations of
* Soap lathers easily and is sometimes
difficult to rinse off.
How Can Hard Water Be Made Soft?
*The calcium and magnesium cations need to be removed to soften the water.
* This can be done by adding a solution of soda ash (sodium carbonate) Na2CO3 to
the water to remove the magnesium.
* You can use slaked lime (calcium hydroxide) Ca(OH)2 to remove the calcium.
* Ca+2 + Na2 + CO3 + H2O → CaCO3 + Na2 + H2O
* Mg+2 + Ca+2 + 2OH + H2O → Mg(OH)2 + Ca+2 + H2O
* The sodium in the first equation and the calcium in the second equation are
crossed out because they are unaffected by the reaction.
Water Hardness Rating
mg/L as CaCO3
Degree of Hardness
Moderately hard water
Very hard water
Hydroelectric power (often called hydropower) is considered a renewable energy
source. A renewable energy source is one that is not depleted (used up) in the
production of energy. Through hydropower, the energy in falling water is
converted into electricity without “using up” the water. Hydropower energy is
ultimately derived from the sun, which drives the water cycle. In the water
cycle, rivers are recharged in a continuous cycle. Because of the force of
gravity, water flows from high points to low points. There is kinetic energy
embodied in the flow of water.
Sizes of Hydropower Plants
* Large plants : capacity >30 MW
* Small Plants : capacity b/w 100 kW to 30 MW
* Micro Plants : capacity up to 100 kW
* Embankment or Earth
Types of Hydro Turbines:
Impulse turbines , Pelton Wheel , Cross Flow Turbines , Reaction turbines , Propeller
Turbines , Bulb turbine, Straflo, Tube Turbine, Kaplan Turbine , Francis Turbines , Kinetic
Popular Struggle & Movements
Popular struggle & Movements
Class X D
Narmada BachaoAndolan Women’s Movement
* Influence politics rather than directly take part in electoral
* They are loose organisations
* Make informal decisions and are flexible
* They depend on spontaneous mass participation
Fight against Privatization of Water
1) World Bank pressurised Government to give up control of Municipal
2) Sale of rights to a MNC for the City of Cochabamba.
3) Company raised the price of water 4 times.
4) 4 day general strike by Labour and Human Rights and Community
5) Government agreed to negotiate.
6) Power of the people forced MNC to flee & made Government to
concede to all demands.
Water supply was restored to municipality at old rates.
Together We Can
Water resources are sources of water that are useful or potentially
useful. Uses of water include agricultural, industrial , household
, recreational & environmental activities. The majority of human
uses require fresh water .
97 percent of the water on the Earth is salt water. However, only
three percent is fresh water ; slightly over two thirds of this is
frozen in glaciers and polar ice caps.The remaining unfrozen
freshwater is found mainly as groundwater, with only a small
fraction present above ground or in the air.
Broadly rainwater can be harvested for two purposes
•Storing rainwater for ready use in containers above or below ground
•Charged into the soil for withdrawal later (groundwater recharging)
Source: A Water Harvesting Manual For Urban Areas
Why Rain water be harvested
* To conserve & augment the storage of ground water , reduce water table depletion
, improve the quality of ground water , arrest sea water intrusion in coastal areas &
avoid flood & water stagnation in urban areas .
Rain Water Harvesting (RWH )– Methodologies
• Roof , Land based & Watershed based Rain Water Harvesting
• For Urban & Industrial Environment –
• Roof & Land based RWH
• Public, Private, Office & Industrial buildings
• Pavements, Lawns, Gardens & other open spaces
Rain Water Harvesting– Advantages
1. Provides self-sufficiency to water supply & reduces the cost for pumping of ground water &
Reduces soil erosion & flooding in urban areas.
2. Provides high quality water, soft and low in minerals & improves the quality of ground water
through dilution when recharged.
3. The rooftop rain water harvesting is less expensive & easy to construct, operate and maintain
4. In deserts , RWH is the only relief
8. In saline or coastal areas & Islands, rain water provides good quality water