Staff reporter

The project will be designed to treat 2,000 litres of used water

Chennai: The Chennai Mathematical Institute, spread across five acres in Siruseri, proposes to implement a grey water recycling system in its premises.

The project, in its first phase, would be designed to treat about 2,000 litres of used water. Grey water refers to waste water produced after cleaning, washing and bathing. The treated water could be used for gardening or ground water recharge.

Grey water is easier to treat than black water or water from toilets. This is because black water is loaded with pathogens that are difficult to get rid of through a simple treatment system.

Sultan Ahmed Ismail, Managing Director of Ecoscience Research Foundation, who designed the project for the Chennai Mathematical Institute, said that root zone treatment would be used to treat the grey water.

The principle behind the system is quite simple. Grey water is allowed to flow through a horizontal filter that is three metres long, two metres wide and 30 centrimetres deep. The water is passed through a filter of pebbles and gravel.

The water also passes through a reed bed, which is slightly sloped so that the water flows easily.

Root zone treatment

The reed bed is crucial to the water treatment. The best plants to use for the reed bed include Canna (kal vaazhai), Banana and Colocasia (a yam). The plants keep the soil partially aerobic by pumping atmospheric oxygen to the roots, where some micro organisms live.

These bacteria help in the break down on any suspended solids in the grey water.

Once the first phase of the project is fully operational, Mr. Ismail also proposes to treat black water through a more elaborate technology.

A composting shed for solid waste management is also being planned.

Chennai Mathematical Institute is an autonomous institution for teaching and research in Mathematical Sciences.

It is supported by the Department of Atomic Energy.

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