Study on a in situ sludge yield reduction SBBR system by biological uncoupling

A in situ biological uncoupling metabolism sludge yield reduction system was constructed in SBBR. To induce uncoupled metabolism, aeration mode was introduced to a bench-scale SBBR(Sequencing-Batch Biofilm Reactor) process to investigate sludge yield and sewage treatment performance. It was found that when the aeration mode was aeration 30min/30min without aeration, uncoupling metabolism in the biofilm was enhanced, and a in situ biological uncoupling metabolism system was constructed with low sludge yield index(SYI) and effluent met the standard for discharge, under the conditions of temperature at 25°C, biofilm density at 45%, organic loading at 1.0 kgCOD/m3 · d, DO at 5mg/L. It was also revealed that when aeration modes were aeration 30min/30min without aeration, aeration 15min/15min without aeration, and continuous aeration respectively, the average sludge yield index were 0.03 kgMLSS/kgCOD · d, 0.07 kgMLSS/kgCOD · d and 0.08 kgMLSS/kgCOD · d respectively, compared with traditional activated sludge process, sludge yield index were reduced by 90%,77% and 73% respectively.