Novel Mass Bio System (MBS) and its potential application in advanced treatment of coal gasification wastewater

In this study, a Novel Mass Bio System (MBS), a suspended biologically activated carbon granular carrier cubic particle with 2-5mm side length and 1.02-1.08 specific gravity was developed for advanced treatment of coal gasification wastewater. A laboratory scale anaerobic AnaEG (advanced anaerobic expanded granular sludge bed)-primary aerobic BioAX (a novel environmental biotechnological aerobic process with internal circulation)-MBS aerobic fluidized bed nitrification bioreactor-MBS expended bed denitrification bioreactor-secondary aerobic BioAX reactor system was operated over a period of 260 days. With an influent concentration of chemical oxygen demand (COD) 3000 mg L-1, total phenol (TP) 300 mg L-1, and ammonium nitrogen (NH4+-N) 149 mg L-1, the effluent COD, TP, NH4+-N, could be decreased to 159 mg L-1, 6 mg L-1 and 0.12 mg L-1, respectively. The maximum removal efficiencies of COD, TP, and NH4+-N were respectively 94.7%, 98%, and 99.9%. With hydraulic retention time (HRT) of 36 h, methane content was 60% and methane productivity was 0.11 L CH4/g COD. Pyrosequencing analysis showed the enrichment of 'rare microbes'. Contrary to expectation, nitrifying bacteria, Ohtaekwangia (Bacteroidetes) was the most abundant rare bacteria with 37.1% of the microbial community entrapped in MBS.