Gurgaon: The city is planning to expand its sewage treatment capacity to 977 million litres a day by 2028.However, a sewage treatment plant (STP) can only treat “what reaches it,” water governance and sustainability expert Dr Fawzia Tarannum told TOI.Tarannum’s remarks come against the backdrop of a CAG audit finding that the city is struggling to get sewage into the treatment plants it already has.In March 2024, 63 MLD of sewage was not reaching the city’s existing STPs, with the audit noting that it was apparently being released untreated into drains.Treatment capacity cannot be used if the sewer network does not collect and carry wastewater to the plants.The city was generating 550 MLD of domestic sewage in areas under GMDA. Of this, 90 MLD was being treated and reused by colonisers within their premises, leaving 460 MLD to be treated through govt system.GMDA had an installed capacity of 415 MLD across 12 STPs, against the 460 MLD requiring treatment.Yet the average sewage reaching the plants was only 397 MLD, leaving 63 MLD outside the treatment system.CAG said this represented 14% of the sewage requiring treatment.GMDA told CAG that it had prepared an action plan after a detailed survey of drains involving MCG, HSVP, HSIIDC, PHED and HSPCB.It said measures had been taken to increase treatment capacity to 977 MLD by Dec 2028, enough for projected sewage generation of 800 MLD as well as sewage diverted from drains.The existing gap, however, raises a question over how effectively that additional capacity can be used if sewer connectivity does not expand alongside it.Tarannum told TOI, “Gurgaon’s problem isn’t simply a shortage of treatment capacity. It is a gap across the entire sewage chain that has not been adequately studied. If 63 MLD is not reaching the plants, adding more STPs without fixing sewer connectivity, pumping infrastructure and household connections risks creating underutilised capacity.”She said the city needed a scientific baseline before expanding treatment infrastructure.“A catchment-wise sewage balance showing what is generated, collected, conveyed and bypassed, along with an assessment of actual STP inflow against installed capacity, should determine how the proposed 977 MLD capacity is built,” Tarannum said.The problem is particularly evident at Jahajgarh, where GMDA approved a 20 MLD STP in March 2020.Only 5 MLD of sewage was reaching the plant because the required sewer infrastructure was incomplete.CAG said Rs 18.67 crore spent on the project remained largely idle, while the objective of treating 20 MLD remained unachieved.The audit attributed the problem to lack of coordination between GMDA and MCG.MCG manages internal sewer lines and household sewer connections, while GMDA manages master sewer lines and STPs.The Jahajgarh case therefore illustrates how gaps between the two parts of the network can leave treatment capacity unused.At Manesar, the problem was the delayed creation of treatment capacity.GMDA approved a 25 MLD STP for Manesar and Naharpur-Kasan in March 2020.After three unsuccessful tender attempts, the work was awarded in Jan 2022 for Rs 35.7 crore, with completion scheduled for Oct 2023.CAG found that delays in tendering and construction resulted in prolonged discharge of untreated wastewater from Manesar and Naharpur-Kasan into drains and open land.The environmental consequences are already visible. CAG found that only 12 of the city’s 16 STPs were meeting prescribed wastewater discharge norms. The three main drains carrying the city’s wastewater towards Yamuna recorded BOD levels of 88 mg/L in Leg I, 97 mg/L in Leg II and 106 mg/L in Leg III, against the prescribed 10 mg/L. Faecal coliform levels ranged from 1,816 to 3,310 MPN/100 ml, against the prescribed 100.The audit also found problems in MCG’s decentralised sewage treatment programme.Of 21 micro STPs planned under one package, only nine had been completed when auditors inspected them in Dec 2024.One had a stolen motor, three were partially functional and 12 remained incomplete after five years.CAG said Rs 11.9 crore spent on the incomplete plants remained largely idle.
