内源Fe^(2+)活化过硫酸盐联合生物炭增强厌氧消化污泥脱水性能的研究  

Study on enhancing dewaterability of anaerobiclly digested sludge by indigenous Fe^(2+)-activated persulfate combined with biochar as skeleton builder

作　　者：白杨 吴铮 张文 彭道平 黄涛 BAI Yang;WU Zheng;ZHANG Wen;PENG Dao-ping;HUANG Tao(School of Materials and Environmental Engineering,Chengdu Technological University,Chengdu 611730,China;Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]成都工业学院材料与环境工程学院,成都611730 [2]西南交通大学地球科学与环境工程学院,成都611756

出　　处：《安全与环境学报》2023年第3期855-863,共9页Journal of Safety and Environment

基　　金：四川省国际科技合作与交流研究计划项目(2019YFH0058)。

摘　　要：为实现厌氧消化污泥脱水性能提升,利用厌氧消化污泥内源Fe^(2+)活化过硫酸盐(PDS)联合核桃壳生物炭开展其脱水性能调理,并探讨了作用机理。结果表明,调理体系在pH值为6、PDS质量浓度为6.2 g/L、生物炭投加量为25.6 g/L、粒径范围125~150μm条件下,低压抽滤后泥饼含水率为70.3%,厌氧消化污泥的毛细吸水时间(CST)降低至114.7 s,CST降低率达到81.3%,脱水性能明显提升。在调理过程中,PDS氧化污泥中含铁矿物释放内源Fe^(2+),进一步活化PDS生成·SO_(4)^(-)和·OH,降解胞外聚合物(EPS),释放结合水,显著增强厌氧消化污泥脱水性能;生物炭能够吸附EPS中的亲水性有机物,并提供骨架支撑作用,实现脱水性能进一步提升。对抽滤后泥饼重金属分级提取结果表明,调理体系能够明显削弱污泥固相重金属的环境浸出能力,并降低其浸出毒性;环境效益成本比值(BCR)结果表明提出的联合调理手段可行性较强,需进一步研究实现工业化应用。This study investigated the improvement performances and mechanisms of anaerobically digested sludge(ADS)dewaterability and the transformation behavior of heavy metals(HMs,including As,Cu,Cd,Cr,Pb,Zn,and Ni)by joint conditioning of indigenous Fe^(2+)-activated peroxydisulfate(PDS)oxidation and walnut shell biochar(WS-BC).Experimental results showed that the joint conditioning was the most effective when the initial pH was 6,the concentration of PDS was 6.2 g/L,RS-BC particle size and dosage were 125-150μm and 25.6 g/L,respectively.Under this condition,the moisture content(MC)after low-pressure filtration was 70.3%,the capillary suction time(CST)was 114.7 s,and the CST reduction(CSTR)was as high as 81.3%,which implied an excellent improvement of sludge dewatering.For the improvement mechanism,indigenous Fe^(2+) is released upon the interaction between PDS and iron mineral within ADS,rather than the dissolution of iron bound to organic matter.Then the decomposition of extracellular polymeric substances(EPS)by the PDS activation products,·SO_(4)^(-) and·OH,the bound water within EPS was released as free water,which is easily removed.The content of protein and polysaccharide in EPS decreased dramatically after adding WS-BC,and the adsorption of hydrophilic maters by WS-BC achieved further dewatering performance.·SO_(4)^(-) was the major contributor to enhancing ADS dewaterability.Additionally,the micromorphology results showed that WS-BC established a rigid skeleton structure for water drainage,which ensures the mechanical dewatering performance after conditioning.After sequential extraction of HMs from conditioned sludge cake via Tessier’s method,indigenous Fe^(2+)-activated PDS oxidation can improve immobilization of As,Cu,Cd,Cr,Pb,Zn and Ni,which were transformed into residual fractions mostly.Toxicity Characteristic Leaching Procedure(TCLP)results showed that the leaching toxicity reduced dramatically.Therefore,the joint application of indigenous Fe^(2+)-activated PDS oxidation and WS-BC can be a feasible w

关 键 词：环境工程学 厌氧消化污泥 污泥脱水 过硫酸盐 内源Fe^(2+)活化 

分 类 号：X705[环境科学与工程—环境工程]