Process water treatment with membrane contactors

Abstract

The recirculation of process water from the digested sludge dewatering of municipal wastewater treatment plants (WWTP) results in an additional load for the plant in terms of nitrogen. A full-scale membrane contactor facility with pretreatment was installed at Münster WWTP. Nitrogen removal efficiencies of approx. 74 % were achieved. In addition to pH, temperature and volumetric flow, the solids removal by pretreatment of the process water has a significant influence on stable operation. Nitrogen could be recovered as an ammonium sulfate solution (nitrogen content approx. 2,7 % N).