Research Projects

Anaerobic digestate, the liquid effluent from the digestion of sewage sludge or the organic fraction of municipal solid waste (OFMSW), contains high concentrations of ammonium nitrogen (NH₄⁺-N), along with phosphate (PO₄³⁻) and potassium (K⁺)¹,². Although rich in nutrients and a potential source for fertiliser production, this digestate remains underutilised due to the lack of a formal market and public hesitance toward its use³. Its high nutrient load and low biodegradability also make biological treatment difficult. Typically, such streams are discharged into low-lying areas or rivers like the Yamuna, or in the case of sewage sludge supernatant, recirculated to the inlet of treatment plants, leading to nutrient pollution and increased operational costs. In this veneration, electroconcentration (EC) technology offers a sustainable, modular, and abiotic route for recovering both nutrients and hydrogen (H₂) gas from such waste streams⁴,⁵. The applicant successfully developed and operated an EC reactor at IIT Kharagpur, achieving 80% NH₄⁺-N removal (initial: 5.3 g/L) and 69% recovery efficiency. It also produced 5.4 m³ H₂/m³·day and the resulting concentrate contained 24.6 g/L NH₄⁺-N, 11.9 g/L K⁺, 5.5 g/L PO₄³⁻, 6.2 g/L SO₄²-, 12.24 g/L Na⁺, and 21.6 g/L Cl⁻. Further, a manuscript based on these results is currently under review in the Journal of Environmental Chemical Engineering (IF – 7.2). Also, the final product, i.e. organic fertiliser, is free of heavy metals and antibiotics, requiring only minimal post-treatment to comply with the latest Fertiliser Control Order (FCO) norms, making it a promising substitute for chemical fertilisers. This would benefit India’s agriculture-driven economy by reducing dependence on imported chemical fertilisers. Despite all these potentials, EC faces limitations such as high energy (~26 kWh/kg-N) demand and membrane fouling. Thus, the proposed project aims to overcome these challenges and develop a decentralised, scalable, plug-and-play EC set-up for nutrient and green H₂ recovery from OFMSW. Different parameters like chamber volume ratios and membrane-to-electrode area ratios will be tested to optimise reactor design. The optimised system will be operated in continuous mode using real OFMSW collected from a biomethanation plant (BPM) located at Sector 51, Noida, to assess its long-term performance, energy needs, and membrane fouling. To mitigate fouling, self-cleaning methods like polarity reversal and periodic chemical rinsing will be tested. The recovered fertiliser will be refined to meet FCO norms, and a comprehensive techno-economic analysis (TEA) and life cycle assessment (LCA) will benchmark the EC system against technologies like struvite precipitation, electrodialysis, and anammox. This work supports national goals, including the Fertiliser Self-Reliance Strategy, Water Reuse Roadmap, Net-Zero emissions by 2070, Swachh Bharat and Namami Gange by enabling circular, sustainable waste valorisation.