Membrane bioreactor incorporated with biofilm carriers and activated carbon for enhanced biological nitrification of urine

Abstract

Long hydraulic retention time (HRT) of a membrane bioreactor (MBR) for the nitrification of source-separated urine remains one of the major challenges of which reduces energy efficiency and increases footprint. In this study, a powdered activated carbon (PAC) incorporated MBR with biofilm carrier addition was operated to investigate their effects on the enhancement of nitrification rates and their HRT. The presence of biofilm carrier in the MBR reduced restabilisation time and the start-up period by 26 % and 18 %, respectively. The combination of biofilm carriers and PAC showed a significantly higher nitrification rate of 304 ± 73 mgN/L·d compared to 194 ± 60 mgN/L·d for the conventional MBR (control), which significantly helped reduced HRT during urine treatment. This study therefore shows that PAC and biofilm carrier incorporated MBR is more compact and high-performing contributing to commercial applications and helping achieve circular economy of nutrients.