摘要
利用具有强氧化性质的K2S2O8试剂作为研究对象,考察了对污泥重金属Pb、Zn、Cu、Cd的去除影响、脱水表现以及处理前后污泥性质的变化.结果表明:在起始pH值为2.0,反应时间1h,温度25℃,投加1.34g/g SS的K_2S_2O_8,可改善污泥的脱水性能.其中,滤饼含水率可由82.6%降至74.8%;污泥比阻由6.70×10~8S^2/g下降至5.43×108S2/g.K_2S_2O_8氧化处理污泥,可使污泥絮体快速分解,上清液COD从15.2mg/L增至187.0mg/L;TN从6.03mg/L增至22.7mg/L;TP则由8.15mg/L变为12.7mg/L;污泥TSS相应降低了9.4%.污泥重金属去除率随着投加量的增加而增加,当K2S2O8投加量达到2.01g/g SS时,污泥重金属Pb、Zn、Cu、Cd去除率可分别达到63.90%、87.10%、86.40%以及84.25%.当投加量大于2.01g/g SS,各重金属去除率趋于稳定.低pH值能够提高污泥中重金属的去除率.K2S2O8与污泥反应后,污泥重金属转移到上清液中,对上清液投加0.075%的Ca O,pH值提高,可以相应去除上清液中16.95%的Pb、54.70%的Zn、58.90%的Cu以及21.95%的Cd,TN和TP含量也明显降低.
The objectives of the study were to investigate the effects of the strong oxidizing agent-potassium persulfate on heavy metal removal,dewatering performance and characteristic of sludge.The results showed that sludge dewatering performance was improved,the moisture content of sludge cake was decreased from82.6%to74.8%,specific cake resistance was reduced from6.70×108S2/g to5.43×108S2/g under the condition(2for initial pH,1h for reaction time,25℃for temperature,1.34g/g SS for K2S2O8dosage).K2S2O8could effectively promote decomposition of the sludge floc.As a result,COD in the sludge supernatant was increased from15.2mg/L to187.0mg/L,TN in the sludge supernatant was increased from6.03mg/L to22.7mg/L,TP in the sludge supernatant was increased from8.15mg/L to12.7mg/L,and TSS in the sludge supernatant was decreased by9.4%.The removal rates of tested heavy metals increased with increasing oxidant concentration,when the dosage of K2S2O8was2.01g/g SS,the removal rates of Pb,Zn,Cu and Cd in sludge could reach63.90%,87.10%,86.40%and84.25%,respectively.The removal rates of heavy metals had been basically stable when the dosage was greater than2.01g/g SS.However,the efficiency of removal could increase with decreasing pH within a certain range.The heavy metals in the sludge were transferred to the supernatant after K2S2O8oxidation.Then,calcium oxide of0.075%concentrations was added to the supernatant,the pH value in the supernatant increased,as a result,the contents of heavy metals could be removed by16.95%for Pb,54.70%for Zn,58.90%for Cu,and21.95%for Cd in supernatant,respectively,the TN and TP in the liquid could be obviously improved.
作者
张维宁
肖智华
马彬
曾清如
ZHANG Wei-ning;XIAO Zhi-hua;Ma Bin;ZENG Qing-ru(College of Resources and Environment, Human Agricultural University, Changsha 410128, China;Rural Ecosystem Health Laboratory of Hunan Dongting Lake Area,Human Agricultural University, Changsha 410128, China)
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2017年第12期4605-4613,共9页
China Environmental Science
基金
国家重大研发计划(2016YFD0800304)
关键词
过硫酸钾
氧化反应
重金属
城市污泥
脱水性
potassium persulfate
oxidation
heavy metals
municipal sludge
dewatering performance
