The Delhi Jal Board (DJB) will rope in private firms to purchase raw biogas generated during sewage treatment, as the water utility looks to commercially utilise gas produced from sludge digestion rather than allowing it to be flared or left underutilised, senior DJB officials said.
To begin with, the DJB will initiate this process at two of its 37 sewage treatment plants for which expressions of interest have been invited.
The project covers the Keshopur Phase-I sewage treatment plant (STP), which is being upgraded from 12 million gallons per day (MGD) to 18 MGD, and the Yamuna Vihar Phase-II STP, which has a capacity of 15 MGD (68 million litres per day). The agencies are likely to be hired by November, an official said.
DJB operates 37 Sewage Treatment Plants across Delhi. The city generates nearly 1,000 Million Gallons per Day (MGD) of sewage every day, while the Capital’s sewage treatment capacity currently stands at 814 MGD.
A senior DJB official said that under the proposed arrangement, private buyers will purchase untreated, unpurified biogas directly from the plants and set up their own facilities to process and utilise it for power generation or as vehicle fuel.
“The possible uses include purification, compression, bottling, conversion into bio-compressed natural gas (bio-CNG) and power generation,” the official added.
The utility
The DJB will supply raw biogas at designated delivery points and provide land within the STP premises on a lease or licence basis.
“The selected firms will have to bear the cost of designing, installing, operating and maintaining their facilities, besides obtaining the necessary statutory approvals and clearances,” the official added.
The utility currently uses part of the biogas generated at some STPs for captive power generation and internal use. In the Keshopur Phase-I plant, biogas is currently being flared. At Yamuna Vihar Phase-II, biogas generation is 18,173 cubic metres per month, and the gas is also flared. The Keshopur plant design allows biogas generation capacity of 257.26 cubic metres per hour.
The project report also provides indicative daily gas-generation figures for the upgraded 18-MGD plant, ranging from 10,436 to 13,045 cubic metres, based on different volatile suspended solids assumptions. DJB officials said the exercise is intended to assess market interest, technical capabilities and the commercial terms that potential buyers are willing to offer.
“We will shortlist eligible companies based on the responses and subsequently issue a detailed request for proposals (RFP). The same process can be replicated in other STPs,” the official said.
