Novel sludge management options for a large UK water company

Thames Water is the largest water company in the UK. The company treats about 400,000 tonnes dry solids (tds) p.a. sewage sludge. The company's current strategic investment plans focus on improving treatment through enhanced digestion and reducing the wet mass of sludge recycled to land. Thames recognises sludge as a resource and is evaluating advanced options to unlock the full energy potential from sludge. Anaerobic digestion has been the foundation of sludge treatment and, in combination with combined heat and power, is the main process for recovering renewable energy in Thames Water and in the UK Water Industry. It is our view that sludge drying is an essential stage for advanced energy recovery process technologies such as pyrolysis or gasification. Efficient use of waste heat is critical to the economic and environmental sustainability of sludge management. Innovative technologies are a key part for the vision to convert a water company into a renewable energy provider.