Treatment of high-strength domestic wastewater by two-stage MBfR processes

A two-stage MBfR system with anaerobic and aerobic process was established to treat domestic wastewater (including sanitary wastewater and urine wastewater) and meet the plant nutrient solution recycling requirements for controlled ecological life support system (CELSS). The effects of hydraulic retention time (HRT) and urine concentration on organic removal and nitrogen conversion efficiency were studied. When HRT≥1 d, TOC removal ratio is not affected by HRT with removal rate above 90% and the effluent concentration below 15 mg/L. When HRT=1 d, the nitrification capability of the system was optimal, volumetric removal rate was 0.418 kg N/(m3•d). When HRT ≥2 d, the nitrogen conversion efficiency was more stable. The developed system could treat the 1 /5 concentration urine wastewater at the highest level. At this time, TOC removal ratio was 94.3%, with the effluent concentration below 20 mg/L. The nitrification efficiency of the system was 90.6%, and volumetric removal rate was 0.409 kg N/(m3•d). The developed two-stage MBfR system could effectively achieve the organic removal and nitrogen conversion of the domestic wastewater in CELSS. The research results can provide reference for the design and operation of domestic wastewater microbial treatment system in CELSS. © All Right Reserved.