Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China; School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China.
Chemosphere. 2014 Aug;109:14-9. doi: 10.1016/j.chemosphere.2014.02.053. Epub 2014 Apr 5.
Microbial growth is a big issue of concern in the use of reclaimed water. In this study, the variation of microbial growth potentials of municipal secondary effluents after coagulation was evaluated by measuring assimilable organic carbon (AOC). Surprisingly, the AOC levels increased significantly (55-667%) after coagulation with poly-aluminum dosages of 60 mgL(-1) for the samples investigated in this research. By ultrafiltration membrane fractionation, the microbial growth potentials of the fractions with different molecular weight (MW) were measured. The results revealed that the maximum cell densities of microbial growth in secondary effluents were lower than those in their fractions with MW<10kDa. Meanwhile, the organic component with MW>10kDa in biological treated effluents was proved to have an inhibitory effect on microbial growth. Therefore, the removal of those high MW organic matters was the main reason for the increase of microbial growth potential in secondary effluents during coagulation. Furthermore, polysaccharides and/or proteins in secondary effluents were easily removed by coagulation and were thought to be the possible key organic substances affecting the microbial growth potential during coagulation. It is suggested that post treatments would be needed after coagulation to maintain the biological stability of reclaimed water.
微生物生长是再生水使用中一个令人关注的大问题。在本研究中，通过可同化有机碳（AOC）的测量来评估市政二级出水在混凝后微生物生长潜力的变化。令人惊讶的是，在所研究的样本中，当使用 60mg/L 的聚合氯化铝剂量进行混凝时，AOC 水平显著增加（55-667%）。通过超滤膜分级，测量了不同分子量（MW）级分的微生物生长潜力。结果表明，二级出水中微生物生长的最大细胞密度低于其 MW<10kDa 的级分。同时，生物处理废水中 MW>10kDa 的有机成分被证明对微生物生长具有抑制作用。因此，在混凝过程中，去除那些高分子量的有机物是导致二级出水中微生物生长潜力增加的主要原因。此外，混凝容易去除二级出水中的多糖和/或蛋白质，被认为是影响混凝过程中微生物生长潜力的可能关键有机物质。建议在混凝后进行后处理以维持再生水的生物稳定性。
