Thermal hydrolysis of waste activated sludge at Hengelo wastewater treatment plant, the Netherlands

Oosterhuis, M, Ringoot, D, Hendriks, A, and Roeleveld, P

Water Science and Technology, 2014


The thermal hydrolysis process (THP) is a sludge treatment technique which affects anaerobic biodegradability, viscosity and dewaterability of waste activated sludge (WAS).

In 2011, a THP-pilot plant was operated, connected to laboratory-scale digesters, at the water board Regge en Dinkel and in cooperation with Cambi and MWH Global. Thermal hydrolysis of WAS resulted in a 62% greater volatile solids (VS) reduction compared to non-hydrolysed sludge. The pilot digesters could be operated at a 2.3 times higher solids loading rate compared to conventional sludge digesters.

By application of thermal sludge hydrolysis, the overall efficiency of the sludge treatment process can be improved.

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