Bihar plans to build its largest sewage treatment plant in Patna, a 400 million (mn) litres per day (MLD) facility intended to prevent untreated wastewater from flowing into the Ganga. The project forms part of the Namami Gange programme following a recent review meeting. The urban development and housing department has directed the Bihar Urban Infrastructure Development Corporation to begin work on the scheme. Officials said the objective is to ensure that all city drains are tapped so that contaminated water is intercepted and diverted to the new plant for treatment before release into the river. The process will involve intercepting existing drains and directing flows to the STP where sewage will be treated and processed. Authorities emphasised use of interception and diversion to reduce the risk of untreated discharge. Surveys from Digha to Didarganj have identified proposed sites between Danapur and Patna City, with the final location subject to higher approval. The design phase will determine whether the facility will operate as a single 400 MLD unit or two 200 MLD units. Officials said the new infrastructure will connect drains in neighbourhoods including Digha, Kurji and Rajapur through an interception and diversion system. Planners intend to minimise public inconvenience by employing existing channels and avoiding fresh excavation in narrow streets where possible. The state currently manages 39 STPs with a total outlay of 77,520 mn Rs and plans to increase the number to 45 to treat nearly 1,100 MLD of sewage generated in towns along the Ganga. Of the existing projects, 21 are operational in districts such as Munger, Bhagalpur and Chhapra. The capital operates four plants in Beur, Saidpur, Karmalichak and Pahadi, while facilities in Digha and Kankarbagh remain partially functional. 13 STPs are under construction in districts including Motihari, Supaul, Jamui and Rohtas and are expected to be completed within two years; construction and commissioning typically take about three years. The urban development and housing department has prioritised tapping major drains and said strengthening wastewater management infrastructure across the state will remain a focus.