College of Geography and Environment, Shandong Normal University, Jinan 250358, PR China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
J Hazard Mater. 2023 Aug 5;455:131615. doi: 10.1016/j.jhazmat.2023.131615. Epub 2023 May 12.
This study investigated the efficiency of fecal sludge conditioning using peroxydisulfate (PDS) activated by zero-valent iron (ZVI). For fecal sludge obtained from public toilets in a densely-populated rural area in China, the ZVI/PDS coupling greatly improved its dewaterability as well as the supernatant quality in terms of organic matter and nutrient contents. The capillary suction time (CST) and supernatant turbidity of fecal sludge can be reduced up to 97% and 73% respectively in 10 min by the combination of 0.15 g/g TS ZVI and 0.2 g/g TS PDS. Protein removal, especially for tightly and loosely bound extracellular-polymeric-substance (EPS), is more linearly correlated to CST reduction than polysaccharide removal. Fecal sludge dewatering was improved by the hybrid functions of radical oxidation and iron coagulation. The ZVI/PDS treatment produced larger and looser flocs, probably because 1) surface ionic and hydrophilic groups of fecal sludge were reduced, 2) surface charge was neutralized, and 3) secondary structures of EPS proteins were altered by the radicals. The excellent fecal sludge dewatering was related to strengthened particle hydrophobicity and reduced sludge viscosity and compressibility. The results highlight that the ZVI/PDS combination is potentially an effective conditioning approach for fecal sludge from public toilets.
本研究考察了过一硫酸盐（PDS）在零价铁（ZVI）作用下对粪便污泥调理的效果。对于从中国人口密集的农村地区公共厕所中获得的粪便污泥，ZVI/PDS 耦联大大提高了其脱水性能以及上清液中有机物和营养物的含量。在 10 分钟内，组合使用 0.15g/g TS ZVI 和 0.2g/g TS PDS 可使粪便污泥的毛细吸水时间（CST）和上清液浊度分别降低 97%和 73%。蛋白质的去除，特别是紧密结合和松散结合的胞外聚合物质（EPS）的去除，与 CST 降低的线性相关性比多糖的去除更强。自由基氧化和铁混凝的协同作用改善了粪便污泥的脱水。ZVI/PDS 处理产生了更大、更松散的絮体，这可能是因为 1）粪便污泥的表面离子和亲水基团减少，2）表面电荷中和，以及 3）自由基改变了 EPS 蛋白质的二级结构。优异的粪便污泥脱水与增强的颗粒疏水性以及降低的污泥粘度和可压缩性有关。结果表明，ZVI/PDS 组合是公共厕所粪便污泥的一种有效的调理方法。
