Pilot scale evaluation of SANI process for sludge minimization and greenhouse gas reduction in saline sewage treatment

摘要

This study reports on a pilot trial of the SANIns process (Sulfate reduction, Autotrophicndenitrification and Nitrification Integrated process) in Hong Kong. A pilot-scale SANI plantntreating saline sewage at 10 m3/day was scaled-up from a lab-scale system treating syntheticnsaline sewage. The plant consisted of a sulfate reduction up-flow sludge bed (SRUSB), an anoxicnbioreactor (BAR1) for autotrophic denitrification utilizing dissolved sulfide produced by thenSRUSB and an aerobic bioreactor (BAR2) for nitrification. The SANIns pilot plant was successfullynoperated for 225 days and achieved average COD, TSS, TN removal of 87, 87, and 57%,nrespectively. The ratio of MLVSS to MLSS in the SRUSB was stable at 0.7 and the average sludgenvolume index (SVI) was constantly below 110 ml/g. No sludge was purposely withdrawn fromnthe plant during 225-day plant operation. This was attributed to a very low observed sludgenyield (0.02 kgVSS/kgCOD removed) of the SRUSB reactor. DNA extraction, PCA amplificationnresults revealed that no methanogens were detected in the SRUSB. SANIns can reducen90% sludge production, 35% energy and 36% GHG compared to conventional biologicalnnutrient removal (CBNR) process.