No more filth

A wastewater treatment system promises to rid Indian cities of disease and pollution

Last Updated: Saturday 04 July 2015

in Delhi, it is estimated that everyday nearly 2,160 million litre of wastewater flows out of residences, educational establishments, offices, hospitals, hostels, hotels, industries, and other sources. Nearly 50 per cent of this wastewater carries food leftovers, excreta water, urine and other human and organic wastes.

A new low-cost wastewater treatment system can be useful in clearing a lot of choked drains and stink and thereby bring a significant decrease in diseases. All it would require is the active participation of residents, service organisations, offices, institutions and food and agricultural industries. Together, they just need to install and manage the low maintenance wastewater treatment system (lomwats) in their own premises against their daily wastewater outflow, before letting it out into the common sewer or drainage.In Delhi, lomwats is operated by Sulabh International Institute of Technical Research and Training (siitrat).

lomwats can clean up this filth at an amazingly low cost ranging from Rs 1.57 lakh to Rs 1.77 lakh per plant. "Nowadays, even a well equipped bathroom fitted with tiles, jacuzzi, bathtub, and telephonic showers catering to two to five persons cost around Rs 1.5 lakh, while a lomwats plant that treats human waste of 200 and more students of a hostel at Delhi's Jamia Millia Islamia University costs just Rs 1.60 lakh. Besides treating the wastewater, the plant working here also supplies bio-gas to the hostel kitchen for cooking," tells D P Singhal of siitrat.

Each lomwats plant has the capacity of treating one lakh litre of wastewater daily and therefore, is best suited for small and medium sized institutions, slum areas, housing colonies and industries that generate wastewater. The combined strength of 21,600 such plants in Delhi can directly clean up all the sewer lines and drainages that lie unattended in the city.

Working on a simple process of filtration of wastewater, using different chambers divided by beds of cinder, a lomwats plant lets out 80-85 per cent clean water free of organic wastes. "Although the process can only treat human and other organic wastewater, it adds great value to the wastewater treatment needs of a city where a major part of it is of human and organic nature." Says N K Mandal, a researcher working at siitrat on lomwats project in Delhi. "The perforations on the cinder pebbles act as a convenient breeding ground for the anaerobic microbes that work to decompose the organic wastes in water, releasing biogas and organic manure as the end products," says Mandal.

The project is being funded by the European Union (eu) and coordinated by Bremen Overseas Research & Development Association (borda) of Germany in both India and China. lowmats pilot plants built in these countries are being closely monitored for test results, so that further improvements can be made in their design and functions while replicating them on a large scale. The eu has sanctioned Rs 40 lakh through borda for building such plants at Delhi, Auroville (Pondicherry) and Kottayam (Kerala) in India, between October 1994 and October 1997.

In Delhi, out of eight plants to be built during this period, six have already been completed, although one at Mathur Food products in Noida, is not yet operational due to the non-payment of minimum polluter's share of Rs 50,000 towards the total cost of the plant. As per the current lowmats project, the polluter has to pay a minimum share fixed by borda towards the total construction cost of the plant. For the plant at Salwan public school in south Delhi, the school management paid Rs 20,000 towards the total cost of Rs 1.57 lakh for the plant, while the remaining Rs 1.37 lakh was borne by the eu.

Speaking on lomwats technology, Singhal says, "It is very much indigenous as it's the result of many years of work done by us and others in India on pollution-free public sanitation." He cited the example of the school at Goyla village at Najafgarh, west Delhi, where, the plant was built by the Chengdu Energy Environment International Corporation of China, based on their biogas septic tank know-how as a part of the current lomwats project.

The costs of different pilot plants commissioned so far in the Delhi region vary between Rs 1.57 lakh to Rs 1.77 lakh. "The test results of lomwats plants have been more than encouraging," tells Mandal, emphasising that in all plants installed so far, 80-85 per cent cleansing efficiency has been recorded, with the construction and maintenance costs amounting to minimum. He informed that borda and its regional partners will publish a report in this regard by the end of the current year.

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