Water is the life line of all living beings on earth. Water is required not only by human beings but also by all living beings. The responsibility of conservation of water begins with all of us.


Why should we conserve water?
The Earth is pretty much a “closed system” which neither gains nor loses any matter, including water. This means, the same volume of water that existed on Earth millions of years ago still exists. Moreover, only about 0.768% of the entire water in the universe can be made available for human consumption with great difficulty. However, the demand of water is increasing due to population explosion and increase in usage of appliances that consume more water. Moreover, discharge from industries and faulty / inefficient sewage water treatment has lead to pollution of our rivers and lakes. Purification of water for drinking purpose and pumping of water to our taps costs money. Therefore, conserving water means saving money!




What are the steps to be taken to conserve water?
Water used by us for our daily activities like drinking, cooking, washing, toilet, gardening, etc., comes from basically 3 types of sources:

• Surface water like rivers, lakes, tanks, ponds
• Ground water like open wells, bore well
• Rainwater which is the purest of all the sources.
  

Keeping in view of the scarcity of water supplied by the municipal authorities and the necessary water supply of 150 Litres per day per capita (as per the Norms stipulated by Central Public Health Engineering and Environmental Organisation for Class I cities), developers can design the following:

• Rainwater Harvesting
• Drinking Water Treatment Plant
• Wastewater Treatment Plant
• Dual Water Supply Scheme for all households

What is Rainwater Harvesting?
The collection of rain water, its filtration and infiltration into recharge wells is called as rain water harvesting. Rain Water Harvesting cab be provided for collection of rain water in individual households, multistoreyed buildings as well as whole layout so that maximum collection of rain water take place. Stormwater drains have been properly designed to channel rain water into scientifically sited recharge wells so that the ground water is recharged without water logging the area or underground sumps (where water quantity is very low). The rain water harvested per year depends largely on the rainfall, efficient drainage system as well as the natural drainage of the area.




How can drinking water be treated?
In Eco-friendly Infrastructure (where potable water is not supplied by the civic bodies), drinking water treatment plant is designed keeping two criteria in mind, namely,

• No water supply from the municipal authorities
• Water quality as per the IS 10500 standards to be maintained

In most places, there is no surface water available in the vicinity which can provide adeqate water supply of good quality, hence providing groundwater (bore well water) for drinking purpose is the only solution. The groundwater is tested in the area to ascertain whether it is of potable quality, depending on which the type of treatment is finalised. Moreover, proper care of the groundwater well along with the proper treatment of borewell water so that proper quality is always monitored and maintained. Water from the bore well is pumped to an under-ground sump. Before pumping it to an overhead tank the water passes through a filter and is chlorinated so that any bacterial contamination is removed.



How can waste water be treated?
Water after its use is discarded with a notion that it is of no use. However, normal wastewater is about 0.1% solids and 99.9% water. Fresh wastewater is usually gray in colour and has a musty but not offensive odour. It is only the untreated wastewater that turns septic and is black in colour and
has a disagreeable odour. Black solids start floating on the surface and throughout the liquid if proper treatment on time is not carried out. The water treatment plant has been designed:

• To make dirty water clean (to attain standards of drinking water)
• To reduce the amount of dirty water that man puts back into his environment
• To prevent pollution and disease (transmission of water-borne disease)
• To keep water sources clean for domestic use and recreational purposes (preserve aquatic environment)

A network of pipes, pumps and pump stations collect and transport wastewater to the treatment plant. The envisaged infrastructure segregates totally the sanitary sewer and storm runoff. Sanitary sewer is piped to centralised sewage treatment plant while storm sewer is channellised to recharge wells for rainwater harvesting. The wastewater treatment devices localize and confine the natural degradation processes to a restricted, controlled, suitable area and provide favorable conditions for the acceleration of the physical and biochemical reactions. The treatment plants consists of following:

• Preliminary treatment
  The preliminary treatment protects the operation of the wastewater treatment plant by removing any constituents which can clog or damage pumps, or interfere with subsequent treatment processes.
• Primary Treatment
  Primary treatment is designed to remove organic and inorganic solids by the physical processes of sedimentation and flotation.
• Secondary Treatment
  The secondary treatment process consists of the biological treatment of wastewater by utilizing many different types of microorganisms in a controlled environment to remove the organics in the wastewater. Subsequently, the microbial biological mass generated is separated by final clarification (in secondary settling tank) from the wastewater to ensure a proper degree of treatment within effluent and water quality standards.
• Filteration of Wastewater
  After the secondary settling, waste water is passed through a sand filter and activated carbon column to ensure that most of the bacteria and metals are adsorbed.
• Disinfection of Wastewater
  To prevent the spread of waterborne diseases and to minimize public health problems, the destruction of pathogenic organisms in wastewater is done by disinfecting treated water by chlorine. This step along with filteration ensures that the treated water is safe to be sent back to household for use in toilets and for gardening.
• Sludge Handling and Disposal
  Sludge drying beds are provided which dry the sludgefrom primary and secondary settling tank. The dried sludge will be mixed with compost and used in gardening as it contains nutrients need by plants.

What is Dual Water Supply Scheme?
Bangalore Water Supply and Sewerage Board (BWSSB) in their recent stipulation have made sewage Treatment Plants (STPs) mandatory for new layouts and have decided that 150 litres/ capita/day (LPCD) would consist of 30 LPCD of drinking water and 120 LPCD of treated water. However, for the benefit of the residents and considering the general prevailing perceptions of people towards recycled or treated water, planning can be done for 50:50 supply of potable (borewell) and treated (recycled) water. For all the drinking and cooking purpose, pure water (potable) will be supplied. Only for toilet and gardening purpose will treated wastewater be supplied (though the treated wastewater is of drinking water quality). Every site can be provided with pre-built chambers on the road side edge inside the site with:

• Terminations for Sanitary network for future hookup by the site owners.
• Terminations for Dual Water Supply network for future hookup by the site owners: Potable Water and Treated Water.