低氧状态下生物膜法废水处理中丝状菌膨胀特性研究

Characteristic of filamentous bulking in biofilm reactor under low DO condition when treating wastewater

以生物接触氧化反应器处理模拟污水,考察了低氧状态下(DO的质量浓度为1.0～1.5 mg/L)丝状菌膨胀对生物接触氧化反应器的运行效果、生物膜活性及胞外多聚物的影响。结果表明:发生丝状菌膨胀后,系统COD去除率由正常运行时的88.2%下降到79.3%;生物膜活性普遍比正常运行期的要高,在第24天,两段氧化池生物膜活性都达到最大值,分别为165.48和163.04 mg[O2]/(g[MLVSS].h);生物膜EPS含量低于正常运行期,主要是由于EPS中多糖含量下降引起的。一段氧化池EPS由60.05 mg/g[MLVSS]降低到第26天的30.77 mg/g[MLVSS],二段氧化池EPS由34.84 mg/g[MLVSS]降低到第26天的26.88 mg/g[MLVSS];优势丝状菌种为021N型丝状菌和丝硫细菌。

Biological contact oxidation reactor was used to treat simulant wastewater, the intluence ol filamentous bulking on operation effect, biofilm activity and extracellular polymeric substances in the reactor under low DO condition（mass concentration of DO was 1.0-1.5 mg/L） was investigated. The results showed that： after the filamentous bulking occurred, the removal rate of COD decreased from 88.2% to 79.3%, the biofilm activity was higher than that in the normal operation period. The biofilm activity in the two stages of oxidation tank both reached the maximum value, which were 165.48 and 163.04 mg[O2]/（g[MLVSS]·h） respectively at the 24th day; The EPS content of the biofilm was lower than that in the normal operation period mainly because of the decrease of polysaccharide content in EPS. The EPS content decreased from 60.05 to 30.77 mg/g [MLVSS] in the first stage oxidation tank and from 34.84 to 26.88 mg/g [MLVSS] in the second stage oxidation tank at the 26th day; the preponderant filamentous bacterium were type 021N and Thiothrix sp..