电解耦合Fe^(2+)活化过硫酸盐强化污泥脱水及其机理

Enhancement and Mechnism of Electrolysis Coupled Fe~(2+)-activated Persulfate Oxidation for Excess Sludge Dewatering

采用电解(EC)耦合Fe^(2+)/过二硫酸盐(PDS)预处理剩余污泥,考察了电解时间、电压、PDS投加量和Fe^(2+)∶PDS(物质的量之比)对污泥脱水性能的影响,并通过测定胞外聚合物(EPS)、三维荧光光谱(EEM)和扫描电镜(SEM)观察等探讨其机理。结果表明,EC/Fe^(2+)/PDS可有效提高污泥脱水性能。当电压为25 V、PDS投加量为2 g/L、Fe^(2+)∶PDS=0.4、电解时间为30 min时,毛细吸水时间(CST)降低58.3%,泥饼含水率降为74.2%,上清液的SCOD达到367.8 mg/L。EC/Fe^(2+)/PDS体系可有效促进Fe^(3+)向Fe^(2+)的转化,提高Fe^(2+)和PDS的利用率,减少药剂用量;并且,可有效破解污泥絮体及EPS结构,将紧密结合型EPS(TB-EPS)中的蛋白质、多糖和类腐殖酸等物质降解和转移。相关性分析表明,CST与EPS总量相关性较强,污泥脱水性能最佳时EPS理论值为320 mg/L。

Electrolysis(EC)coupled Fe^(2+)/peroxydisulfate(PDS)was employed to pretreat excess sludge.The effects of electrolysis time,voltage,PDS dosage and Fe^(2+)to PDS molar ratio on sludge dewatering performance were investigated,and the mechanism was analyzed by means such as measuring extracellular polymeric substances(EPS),three-dimensional fluorescence spectrum(EEM)and scanning electron microscopy(SEM).EC/Fe^(2+)/PDS effectively improved the sludge dewatering performance.When the voltage was 25 V,the dosage of PDS was 2 g/L,the Fe^(2+)to PDS molar ratio was 0.4 and the electrolysis time was 30 min,the capillary suction time(CST)was reduced by 58.3%,the moisture content of sludge cake was decreased to 74.2%,and the SCOD of supernatant reached 367.8 mg/L.The EC/Fe^(2+)/PDS system effectively promoted the conversion of Fe^(3+)to Fe^(2+),improved the utilization rate of Fe^(2+)and PDS,and reduced the dosage of reagent.In addition,it effectively cracked the structure of sludge floc and EPS,and degraded and transferred proteins,polysaccharides and humic acids in tightly bound EPS(TB-EPS).The correlation analysis showed that CST had a strong correlation with total EPS,and the theoretical value of EPS was 320 mg/L when the dewatering performance was the best.