The pollution hazards of heavy metals were investigated in sewage sludge collected from four wastewater treatment plantsin Nanchang City,China,including Honggutan(HGT),Chaoyang(CY),Qingshanhu(QSH)and Xianghu(XH).Conta...The pollution hazards of heavy metals were investigated in sewage sludge collected from four wastewater treatment plantsin Nanchang City,China,including Honggutan(HGT),Chaoyang(CY),Qingshanhu(QSH)and Xianghu(XH).Contamination/riskcharacteristics of heavy metals(Cu,Pb,Zn,Cd,Cr and Ni)were evaluated based on their leachable content,total content andchemical speciation.The sewage sludge from QSH contained higher total contents of heavy metals(except Pb)than those from HGT,XH and CY.The total contents of Cd and Ni were mostly beyond standard.Cu,Cr and Pb were predominantly present in potentialeffect and stable fractions.Zn and Ni showed higher bioavailability.Cd presented roughly uniform distribution into four fractions.The leaching contents of heavy metals almost exceeded the threshold values,especially for Zn and Ni.The potential ecological riskindexes of heavy metals in sewage sludge were4263.34?7480.26,indicating very high risks.Cd contamination is the major concern.展开更多
Liquefaction of sewage sludge(SS)in ethanol-water cosolvents is a promising process for the preparation of bio-oil/biochar products.Effect of the combined use of ethanol and water on the distribution/transformation be...Liquefaction of sewage sludge(SS)in ethanol-water cosolvents is a promising process for the preparation of bio-oil/biochar products.Effect of the combined use of ethanol and water on the distribution/transformation behaviors of heavy metals(HMs)contained in raw SS is a key issue on the safety and cleanness of above liquefaction process,which is explored in this study.The results show that pure ethanol facilitates the migration of HMs into biochar products.Pure water yields lower percentages of HMs in mobile/bioavailable speciation.Compared with sole solvent treatment,ethanol-water cosolvent causes a random/average effect on the distribution/transformation behaviors of HMs.After liquefaction of SS in pure water,the contamination degree of HMs is mitigated from high level(25.8(contamination factor))in raw SS to considerable grade(13.4)in biochar and the ecological risk is mitigated from moderate risk(164.5(risk index))to low risk(78.8).Liquefaction of SS in pure ethanol makes no difference to the pollution characteristics of HMs.The combined use of ethanol and water presents similar immobilization effects on HMs to pure water treatment.The contamination factor and risk index of HMs in biochars obtained in ethanol-water cosolvent treatment are 13.1-14.6(considerable grade)and 79.3-101.0(low risk),respectively.In order to further control the pollution of HMs,it is preferentially suggested to improve the liquefaction process of SS in ethanol-water mixed solvents by introducing conventional lignocellulosic/algal biomass,also known as co-liquefaction treatment.展开更多
基金Project(20151BAB213024)supported by the Natural Science Foundation of Jiangxi Province,ChinaProject(GJJ14302)supported by the Scientific Research Fund of Jiangxi Provincial Education Department,ChinaProject(YC2015-S186)supported by the Jiangxi Province Innovation Foundation for Postgraduate,China
文摘The pollution hazards of heavy metals were investigated in sewage sludge collected from four wastewater treatment plantsin Nanchang City,China,including Honggutan(HGT),Chaoyang(CY),Qingshanhu(QSH)and Xianghu(XH).Contamination/riskcharacteristics of heavy metals(Cu,Pb,Zn,Cd,Cr and Ni)were evaluated based on their leachable content,total content andchemical speciation.The sewage sludge from QSH contained higher total contents of heavy metals(except Pb)than those from HGT,XH and CY.The total contents of Cd and Ni were mostly beyond standard.Cu,Cr and Pb were predominantly present in potentialeffect and stable fractions.Zn and Ni showed higher bioavailability.Cd presented roughly uniform distribution into four fractions.The leaching contents of heavy metals almost exceeded the threshold values,especially for Zn and Ni.The potential ecological riskindexes of heavy metals in sewage sludge were4263.34?7480.26,indicating very high risks.Cd contamination is the major concern.
基金Project(21707056) supported by the National Natural Science Foundation of ChinaProject(20151BAB213024) supported by the Natural Science Foundation of Jiangxi Province,ChinaProject(GJJ14302) supported by the Scientific Research Fund of Jiangxi Provincial Education Department,China
文摘Liquefaction of sewage sludge(SS)in ethanol-water cosolvents is a promising process for the preparation of bio-oil/biochar products.Effect of the combined use of ethanol and water on the distribution/transformation behaviors of heavy metals(HMs)contained in raw SS is a key issue on the safety and cleanness of above liquefaction process,which is explored in this study.The results show that pure ethanol facilitates the migration of HMs into biochar products.Pure water yields lower percentages of HMs in mobile/bioavailable speciation.Compared with sole solvent treatment,ethanol-water cosolvent causes a random/average effect on the distribution/transformation behaviors of HMs.After liquefaction of SS in pure water,the contamination degree of HMs is mitigated from high level(25.8(contamination factor))in raw SS to considerable grade(13.4)in biochar and the ecological risk is mitigated from moderate risk(164.5(risk index))to low risk(78.8).Liquefaction of SS in pure ethanol makes no difference to the pollution characteristics of HMs.The combined use of ethanol and water presents similar immobilization effects on HMs to pure water treatment.The contamination factor and risk index of HMs in biochars obtained in ethanol-water cosolvent treatment are 13.1-14.6(considerable grade)and 79.3-101.0(low risk),respectively.In order to further control the pollution of HMs,it is preferentially suggested to improve the liquefaction process of SS in ethanol-water mixed solvents by introducing conventional lignocellulosic/algal biomass,also known as co-liquefaction treatment.
