复合重金属对生物除磷的短期及长期影响及机制

Short-Term and Long-Term Effects of Complex Heavy Metal on Biological Phosphorus Removal and Its Mechanism

构建了序批式活性污泥反应器(SBR),模拟污水生物除磷过程,探究重金属Cu及Cd复合胁迫对生物除磷短期及长期的影响。结果表明,短期影响时,Cu和Cd的复合胁迫降低混合液MLSS和MLVSS含量,出水COD、NH4+^-N和有机磷(OP)的去除效率分别下降至85.6%~87.5%、82.6%~86.5%84.5%~86.8%,显著低于空白组。长期影响时,Cu及Cd的复合胁迫同时降低出水COD、NH4+^N及OP含量。Cu及Cd复合胁迫降低了厌氧磷酸盐释放与好氧磷酸盐吸收量,降低了内聚物聚羟基脂肪酸酯的最大合成量,从而后续氧化分解吸磷能力下降;并且也降低了多聚磷酸盐激酶(PPK)和多聚磷酸盐酯酶(PPX)的活性。

Sequencing Batch Activated Sludge Reactor(SBR)was constructed to simulate biological phosphorus removal process of sewage,and the short-term and long-term effects of combined stress of heavy metals Cu and Cd on biological phosphorus removal were explored.The results showed that the combined stress of Cu and Cd reduced the content of MLSS and MLVSS,and the removal efficiencies of COD,NH4_+~N and OP decreased to85.6%~87.5%,82.6%~86.5%and 84.5%~86.8%respectively,which were significantly lower than those of the blank group.Long-term effects study found that the combined stress of Cu and Cd reduced the content of COD,NH4_+~N and OP in effluent simultaneously.The combined stress of Cu and Cd reduced the release of anaerobic phosphate and the adsorption of aerobic phosphate,and also reduced the maximum synthesis of polyhydroxyalkanoate esters,and consequently the subsequent oxidative decomposition and phosphorus uptake capacity decreased.The activity of polyphosphate kinase(PPK)and polyphosphate esterase(PPX)decreased under the combined stress of Cu and Cd.