Somewhere in Delhi....

The MCD has come up with a unique way to meet the growing water requirement to maintain its parks in south Delhi. After the civic agency started focusing on building a green capital, parks are getting special attention. But the depleting ground water level is not helping matters. So now, the MCD is planning to use sewer water to maintain parks. To achieve this, MCD is taking the help of National Environment Engineering Research Institute (NEERI), a government organization, in setting up a natural plant-based sewer water purifying unit in Chirag Dilli. Under this technology, also known as phytorid, sewer water is purified using special types of plants and stones. NEERI, which is a part of the Council for Scientific and Industrial research (CSIR), has submitted the project report to MCD. The plant, MCD sources said, will be installed on Chirag Dilli nullah and the treated water will be used for maintenance of 22 acres of land, including Millenium Park which is spread over 11 acres in Chirag Dilli. “There is an acute shortage of water in south Delhi. The ground water level is dismal. We have borewells, but most of them have dried up. Hence, we decided to try out this method of using purified sewer water for maintaining our parks,’’ said an MCD official. MCD needs just two lakh litre of water per day which is less than 1% of the total output of Chirag Dilli nullah. The flow in the nullah is 80-90 million litres per day. NEERI experts said to produce two litres of purified water, a small unit would suffice. The best part about this plant is that it doesn’t require any machinery. Therefore, maintenance cost is almost zero. “We have to make a small tank of 100 metres in length and three metres in depth. We will then fill it up with stones, some of which are treated with micro-bacteria, and plant water hyacinths, American pondweed, common arrowhead etc. These plants can survive in waterlogged areas and its roots extract impurities from water. When the impure water comes in contact with the roots and stones, the carbon content is oxidized. When carbon dioxide is extracted from the impure water, the treated water doesn’t have foul smell,’’ explained Dr Rakesh Kumar, head, NEERI (Mumbai). It takes 24 hours to purify impure water and make it ready for use. The sewer water is released at one end of the 100-metre tank and in 24 hours it slowly moves towards the other end and by then the impurities is completely treated. NEERI has installed the plant in several places like Mumbai, Pune, Nagpur, Nashik etc. A senior MCD official said: “It will cost MCD close to Rs 1 crore to set up the unit, but it will solve our water problems forever. We might expand this project and treat the entire nullah in the long run. The project should be approved soon. Usually sewer water is not preferred as the foul smell remains in the water. But this project solves that problem.’’

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