DHI’s study identifies pathways to 100% energy self-sufficiency at one of India’s largest STPs, delivering energy savings, higher biogas production and clean water to benefit 2.3 million residents

 

The Coronation Pillar sewage treatment plant (STP) in Delhi treats up to 318 MLD of wastewater using energy-intensive biological processes, with aeration and internal recirculation consuming over 80% of total electricity. Low solids concentration and short retention times also limit anaerobic digestion and biogas recovery. As part of the Indo-Danish collaboration on sustainable wastewater management, DHI supported the Embassy of Denmark in India and the Delhi Jal Board by applying advanced, plant-wide modelling with WEST to identify practical ways to cut energy use while boosting renewable energy production. 

 

Serving an estimated 2.3 million residents across North Delhi, the STP protects waterways and public health. The study provides a roadmap to transform one of India’s largest STPs into an energy self-sufficient facility, demonstrating how urban infrastructure can deliver sustainability and social impact.

 

Challenge

The Coronation Pillar STP aimed to significantly reduce its high energy consumption and increase on‑site renewable energy production while maintaining reliable treatment and regulatory compliance. Although the plant is already capturing biogas and using it to produce a portion of its electricity, overall energy neutrality remained low, and the operator lacked a holistic, data‑driven approach to identify which operational or investment measures would deliver the greatest impact.

At the same time, the plant’s high energy demand has increased its operational costs and overall carbon footprint. Improving energy efficiency and recovering renewable energy were therefore essential — both for more sustainable, cost‑effective operations and for supporting Delhi’s broader wastewater management efforts and protecting the receiving Yamuna River.

 

Solution

Together with the client and plant operator, DHI evaluated multiple optimisation scenarios targeting both increased biogas production and reduced energy consumption. The work combined on‑site investigations, analysis of operational and monitoring data and development of a detailed plant‑wide process model using WEST, with the results distilled into a practical, phased roadmap towards energy self‑sufficiency.

 

The key strength of the solution was the use of integrated, dynamic wastewater process modelling to assess operational and investment options across the entire treatment plant. Conventional trial-and-error operational changes or isolated equipment upgrades would not have provided a reliable understanding of system-wide impacts. The process modelling approach allowed DHI to quantify trade‑offs between energy savings, biogas production and effluent quality before any changes were implemented – all without disrupting plant operations.