Unlocking Value of Sludge - Landscape Assessment and Pathways towards circularity
May 2025
The rising urgency to address climate change and urban sanitation challenges demands innovative approaches to used water management. This study critically examines the untapped potential of sewage sludge as a circular resource in India's domestic liquid waste sector. With used water contributing to over 7–10% of national methane emissions and significant power consumption, the study emphasizes the integration of sludge-based resource recovery as a strategic pivot toward energy-efficient, self-sustaining sewage treatment plants (STPs). Through comprehensive data analysis, field visits, stakeholder interviews, and a market landscape assessment across cities with a population of 1 - 5 lakh, the research identifies methane capture, biofertilizer production, and electricity generation as viable pathways for circularity. It highlights the policy gaps, technical constraints, and economic challenges hindering large-scale adoption, while drawing lessons from global best practices. The findings underscore that enhancing the regulatory framework and creating an enabling environment through policy reforms, provision of fiscal incentives, and investing in infrastructure with a vision of circularity can reduce dependency on fossil fuels, enhance urban resilience, and foster climate mitigation. The study provides recommendations to create an enabling environment for enhancing sludge reuse and scalable business models that bridge sanitation and sustainability, reinforcing sludge as not waste, but wealth.
