Full-scale study on dynamic state membrane bio-reactor with modified intermittent aeration

In order to evaluate the performance of a newly developed dynamic state membrane bio-reactor (MBR) with MIA, a full-scale plant with the capacity of 210 m3/d was operated for treating sewage. Due to the MIA, the effect of residual oxygen could be completely removed during the non-aeration period and recycle ratio could be reduced to 1 recycle-to-influent ratio. Even though the plant was operated in winter season, stable performance could be achieved (BOD, CODcr, SS, TN, TP and E. coli removal efficiency; 98.2, 95.2, 99.8, 72.7, 71.4 and 99.9%, respectively). Therefore newly developed dynamic state MBR with the MIA can be one of the useful biological nutrient removal (BNR) processes for stable nutrient removal.

Performance of the full-scale dynamic state MBR with MIA was investigated for 200 days of operation. The full-scale MBR plant applied MIA showed the stable treatment on treating sewage. The removal efficiency of CODcr, TN, TP, SS and E. coli were 95.2, 72.7, 71.4, 99.8 and 99.9% respectively. Also, due to the MIA during the non-aeration period, an adverse effect on remaining DO was successfully removed by dividing aeration period into non-aeration, aeration and non-aeration for denitrification and recycle ratio could be remarkably reduced to 1–1.5 recycle-to-influent ratio. Applied the membrane was continuously operated without out-line chemical cleaning by only in-line air scrubbing for 200 days.