厌氧动态膜生物反应器处理冷轧平整液废水

Treatment of cold-rolling wastewater from iron and steel industry using an anaerobic dynamic membrane bioreactor

平整液废水作为碱性含油废水,一直是冶金行业较难处理的废水之一。搭建了一套厌氧动态膜生物反应器(An DMBR),通过梯级驯化的方式,处理COD为2 500 mg·L^(-1)左右的平整液废水。经过88 d的启动驯化,在膜通量为6 L·(m2·h)-1,HRT为2.5 d的条件下,出水稳定在500 mg·L^(-1)左右,甲烷产率约0.151 L·g-1,动态膜的一个运行周期可以分为成膜阶段、稳定阶段和堵塞阶段3个阶段。成膜阶段出水浊度随动态膜的逐渐形成而下降;而后动态膜形成,出水浊度稳定,为稳定阶段;最后为堵塞阶段,跨膜压差激增,出水浊度上升。同时对驯化及稳定运行阶段的污泥进行了微生物菌群分析,在细菌群落中主要的微生物菌群为Clostridia(梭状芽胞杆菌纲)、Bacteroidia(拟杆菌纲)、Anaerolineae(厌氧绳菌纲)、OP8_1和Spirochaetes(螺旋体纲),其中拟杆菌纲是处理平整液废水的优势细菌菌群。在古菌群落中,Methanolinea(甲烷绳菌属)和Methanosaeta(甲烷鬃毛菌属)为主要菌种,随着反应器的长期驯化和运行,甲烷鬃毛菌逐渐成为反应器中优势菌群。

Owing to its alkaline nature and association with oil-containing waste streams from iron and steel in- dustry, cold-rolling wastewater is very difficult to treat. In this paper, an anaerobic dynamic membrane bioreac- tor（AnDMBR） was designed to treat cold-rolling wastewater. To acclimatize the anaerobic sludge to the wastewater, wastewater was added into the reactor in a stepwise increasing mode. The AnDMBR was operated at the hydraulic retention time （HRT） of 2.5 d with membrane flux of 6 L· （m2 · h） -2. After the acclimation pe- riod of 88 days, the effluent could be maintained at about 500 mg·L-1 with the influent COD of 2 500 mg· L-1. The CH4 yield was 0. 151 L·g-1 The operation cycle of dynamic membrane filtration was divided into three stages as follows： formation stage, stable stage, and clogged stage. In the formation stage, the turbidi- ty of the effluent decreased as the dynamic membrane formed gradually. Afterward, the turbidity remained at a stable level as the dynamic membrane finally formed, and this period was called the stable stage. In the clogged stage, the transmembrane pressure increased dramatically and the turbidity of the effluent increased to some ex- tent. At the same time, the microbial communities in the anaerobic sludge of the different phases were investiga- ted. Clostridia, Bacteroidia, Anaerolineae, OP8i, and Spirochaetes were found to be the main bacterial classes in the reactor, among which Bacteroidia were the dominant class. Methanolinea and Methanosaeta were the main archael genera, with Methanosaeta becominz more dominant in long-term operations.