Hydrocycloning Influent, Mixed Liquor or Return Activated Sludge for Best Grit Removal and Sludge Production Reduction

摘要

This paper explores grit removal from influent and activated sludge as a means to reducernsludge production of biological wastewater treatment plants (WWTPs). Experimentsrnwere carried out on a laboratory-scale (13 mm) hydrocyclone on sludge from eightrnWWTPs in Quebec (Canada) with different industrial loadings and combinations ofrnpreliminary and primary treatment. Full-scale hydrocycloning (50 mm) experiments werernperformed on sludge from a membrane bioreactor pilot plant treating municipalrnwastewater in Quebec and also at the Morongo Cannibal? WWTP (California, USA).rnResults indicated that hydrocyclone grit separation efficiency decreased with increasingrnfeed solids concentration. Grit separation efficiency of the 13 mm and 50 mmrnhydrocyclones seemed to be comparable. The best grit removal strategy (grit chamber atrnthe influent vs hydrocycloning sludge vs a combination of the two processes) should bernevaluated on a case-by-case basis as it will depend on grit characteristics and anrneconomic analysis, among other factors.