Delhi to have sludge treatment plants at all STPs in 2 yrs: Satyendar Jain

Grappling with sludge disposal issues, Delhi will have a sludge treatment facility at all the 35 sewage treatment plants within two years, Delhi Water Minister Satyendar Jain said on Tuesday.

The Delhi government is constructing once such a sludge treatment plant of 200 tonne capacity on the premises of the Kondli sewage treatment plant (STP). It will be completed by March 31.

Sewage sludge is the solid, semi-solid, or slurry residual material that is produced as a by-product of sewage treatment processes. It is removed using a scraper and then transferred to a tank where it is decomposed by anaerobic bacteria to produce biogas.

Even after this, the residue of the sludge remains which often reaches landfill sites where it poses a threat of seeping into the soil.

Also, it fills natural pores of the soil and disallows freshwater during the rains to recharge the underground aquifers. This, in turn, becomes a big contributor to land pollution and a threat for the health of people residing around the area.

Jain said the Delhi Jal Board's (DJB) STPs produce 700-800 tonnes of sludge a day which will be treated using modern technology and converted into a resource.

At the plant being built at Kondli STP, the sludge will be dried using hot air and converted to biochar. After the plant becomes operational, only five per cent residue will be left, according to a DJB statement.

The residue will be further used in making tiles and conditioning the soil. This is the first hybrid annuity model project of the DJB where 40 per cent cost will be incurred by the technology provider.

This project will have a 15 years operation and maintenance period, which implies that the maintenance will be taken care of by the agency concerned for 15 years.

Within two years, all STPs in Delhi will have an independent sludge treatment plant so that there is no dependency on MCD in the future, the statement quoted Jain as saying.

The minister said similar solutions will be implemented at the 13 common effluent treatment plants in industrial areas.