title: Enhancement stabilization of heavy metals (Zn, Pb, Cr and Cu) during vermifiltration of liquid-state sludge.
abstract: This paper illustrated the potential effect of earthworms on heavy metal stabilization after vermifiltration of liquid-state sludge. Significant enhancement of organics degradation in sludge caused an increase of heavy metal concentrations in VF effluent sludge. However, the analysis of heavy metal chemical speciation indicated earthworms made unstable fractions of heavy metals transformed into stable fractions. Further investigation using principal component analysis revealed that transformations of heavy metal fractions were mainly due to the changes in sludge physico-chemical properties of pH, soluble chemical oxygen demand and available phosphorus. The bioassay of earthworms indicated that only zinc was accumulated by earthworms because the unstable fraction was its main chemical speciation. Furthermore, risk analysis demonstrated that earthworm activities weakened heavy metal risk due to the formation of stable fractions although their total concentrations increased. These results indicated that earthworms in vermifilter had a positive role in stabilizing heavy metals in sewage sludge.
authors: Key Laboratory of Yangtze River Water Environment, Ministry of Education, State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Jian
authors: J
authors: Yang
authors: Key Laboratory of Yangtze River Water Environment, Ministry of Education, State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Chunhui
authors: C
authors: Zhao
authors: Key Laboratory of Yangtze River Water Environment, Ministry of Education, State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: xmy5000@163.com.
authors: Meiyan
authors: M
authors: Xing
authors: Key Laboratory of Yangtze River Water Environment, Ministry of Education, State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors: Yanan
authors: Y
authors: Lin
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D001681:Biological Assay; D057919:Biological Oxygen Demand Analysis; D002857:Chromium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry*; D009835:Oligochaeta / Q000378:metabolism*; D010758:Phosphorus / Q000737:chemistry; D012306:Risk; D012722:Sewage; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D012989:Soil Pollutants; D002857:Chromium; D010758:Phosphorus; D007854:Lead; D003300:Copper; D015032:Zinc
keywords: Earthworm; Heavy metal; Sewage sludge; Stabilization; Vermifiltration