title: Biostabilization enhancement of heavy metals during the vermiremediation of sewage sludge with passivant.
abstract: The present study revealed the effects of fly ash (FA) and phosphoric rock (PR) on stabilization of sewage sludge (SS) after vermicomposting for 60 days. The earthworms in all vermibeds showed significant increases in tissue metal; however, the bioconcentration factors (BCFs) of all investigated metals (except Zn) differed among treatments. Additionally, significant differences were observed in the final system weight and SS+Passivant weight reduction among treatments, but not in the percentage reduction of total system weight and organic matter (OM). pH decreased from the initial levels, eventually reaching neutrality. Significantly greater earthworm heavy metals content, growth and reproduction rates and BCFs were observed, while a decreased percentage of total heavy metals concentration and a proportional decrease of extractable metals (except Cu and Zn) were observed in treatments mixed with FA and PR. Furthermore, significant linear correlations between BCFs and a reduction in percentage concentration of total metals (Cu, Pb, Cd and As) were shown, as well as BCF-Cu and relative proportional changes in extractable Cu. These results indicate that vermicomposting with proportions of FA and PR is better for stabilization and remediation of SS in a short period of time.
authors.affiliation: Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, 8 Jiang Wang Miao Street, Nanjing 210042, PR China.
authors.forename: Longmian
authors.initials: L
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
authors.forename: Yimin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jianying
authors.initials: J
authors.lastname: Chao
authors.forename: Yuexiang
authors.initials: Y
authors.lastname: Gao
authors.forename: Xingzhang
authors.initials: X
authors.lastname: Luo
authors.forename: Jibiao
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001151:Arsenic / Q000378:metabolism* / Q000633:toxicity; D060729:Coal Ash / Q000633:toxicity; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity; D019216:Metals, Heavy / Q000378:metabolism* / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects / Q000502:physiology*; D012098:Reproduction / Q000187:drug effects; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D060729:Coal Ash; D004785:Environmental Pollutants; D019216:Metals, Heavy; D001151:Arsenic