DJB to order study with eye on sewage masterplan 2041

The Delhi Jal Board (DJB) is set to commission a study with an eye to overhaul the Capital’s 10,720km sewage network and the 38 sewage treatment plants in the city, with a target year of 2041, officials aware of the matter said on Sunday.

The water utility has now invited expressions of interest from experts, agencies, and consulting firms, admitting an increase in complaints of sewer overflow and blockages after the unprecedented growth in the Capital’s population in recent years has severely overloaded the city’s existing sewer system.

The process for hiring consultants is likely to be completed by November 5.

“At present, about 83% of Delhi’s population is connected to the sewerage network,” a senior DJB official said.

DJB’s current sewage masterplan (SMP), with a target year of 2031, was finalised a decade back, in 2014, and aimed to provide sewerage facilities to all unsewered areas of Delhi by 2031, officials said. Its goals included improving sanitation conditions, improving water quality in the Yamuna, and bringing clean water to under-served communities.

Under the existing SMP, DJB in 2022 adopted a minimum 300mm diameter for sewer lines. “Replacements of sewer lines are being carried out in piece-meal by the maintenance wing but it was felt that there is a need for adoption of a comprehensive and planned approach for up-gradation in the existing sewer network. The objective of the next plan will be to have a sustainable network for design year 2041,” the official quoted above said.

The official clarified that the 2041 study will exclude the scope of work covered in SMP-2031 for unsewered areas.

Ashok Bhasin, who heads the North Delhi Residents Welfare Federation, said agencies keep making plans but no change is seen on ground. “The areas with old pipelines which were laid in the 1950s and 60s continue to suffer from leakages, backflows. They keep making plans and waste public money but nothing is achieved on ground. First they should focus on implementing 2031 sewage plan. Single storey houses have turned to 4-5 storey buildings but the infrastructure has not been upgraded,” he said.

DJB supplies around 1,000 million gallons per day of potable water to more than 20 million people of Delhi through a network of nine water treatment plants (WTP), 123 underground reservoirs (UGRs), and around 15,600 km of water lines. The agency also maintains a network of 10720km of internal and peripheral sewer lines, and 200km of trunk sewers.

The DJB official quoted above explained that the 2041 study will focus on three themes — analysing the 10,720km sewer network, identify deficiencies and vulnerable points in the existing sewer network, and prepare a detailed design report based on present and projected population for 2041.

“The study will propose the augmentation of the existing sewer network and assess the adequacy of sewage treatment plant and pumping station capacities. it will also project how many STPs and SPSs we will need,” the official said.

Diwan Singh, water and drainage expert and environmental activist who organised the Yamuna Satyagrah for rejuvenating the river and other water bodies in the city, said that the sewage system has direct link with the health of the river, and more than 50% of the existing STPs don’t meet the required treatment parameters or are underperforming.

“DJB needs to focus on maintenance of existing infra as well. We are stuck in a catch-22 situation in which unplanned growth of city is taking place and we have run out of the optimum sustainable levels. City growth needs to be checked and regulated along with improvement in infrastructure,” he said.