Rainwater harvesting catching up in slums also

By Feroze Ahmed

CHENNAI, JULY 22. Rainwater harvesting (RWH) has caught the fancy of slum dwellers too. At Kuyil Thottam, a slum colony in Santhome, a section of the residents say henceforth they will depend less on supply from Metrowater tankers. The daily water requirements of these residents will be met instead by RWH systems installed in two of the apartment blocks.

The first system installed in November 1999 caters to the residents of an entire block storing 3,000 litres of treated water.

Water from the terrace, with a catchment area of 20 x 20 feet, is diverted through a pipe to a 200-litre filter tank below filled with fine sand, charcoal and pebbles in layers.

This helps to remove the impurities of the first flush of rains, and importantly, purifies the water. Charcoal is used specifically for its anti-bacterial properties, which helps in removing inorganic impurities.

A builder, who designed the system, Mr. R. Jeyakumar, says that most of the bacteria can be removed by passing water through 10 m of sand.

The treated water is collected in a 3,000-litre storage tank and can be drawn through community taps fixed below. The residents are responsible for the maintenance. Periodically, they add chlorine tablets or liquid and alum to the storage tank to keep the stored water free of bacteria.

Recently, another RWH system, known as the double-pipe method, was installed in another block to divert rainwater directly to the apartments for daily use.

The rainwater collected at the terrace is diverted to a pipe, where the first flush and silt settles at the blocked bottom. Eventually, the water rises and is diverted to eight apartments on either side, on four floors, through smaller pipes. These are connected to taps fitted with filters.

The double-pipe method, installed on an experimental basis, is a simplification of a RWH process that incorporates an overhead storage tank inside the apartments.

However, this method was not possible in the slum tenements owing to the weak structure of the buildings, which is not able to support even the pipes.

The first system faced some initial resistance from the residents who were reluctant to use water collected from the terrace. Gradually, during rains, the residents started using the collected water for drinking and kitchen purposes. A quality analysis report last year confirmed the water as potable.

The double-pipe method is yet to yield results, owing to a damage in the main pipe that has now been repaired.

The main hurdles faced in the implementation of the RWH system in Kuyil Thottam are the attitude of some of the dwellers. They refuse to take responsibility for its maintenance. They also expect to receive the benefits free without any contribution.

However, the residents are more receptive to the RWH installed here as they can realise its benefits immediately.

Mr. Jeyakumar said the Rotary Club, which installed the pilot system, hopes to provide RWH in the entire colony to benefit all the 350 families.

The Tamil Nadu Slum Clearance Board officials said RWH would be incorporated in all its multi-storey tenements as per the CMDA guidelines. The board's tenement recently inaugurated at Ambedkar Nagar on New Avadi Road has an integrated RWH system.

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Section  : Southern States
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