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Kinetics of biochemically driven metal precipitation in synthetic landfill leachate
Author(s) -
Samaranayake Rajika,
Singhal Neresh,
Lewis Gillian,
Hyland Margaret
Publication year - 2002
Publication title -
remediation journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 27
eISSN - 1520-6831
pISSN - 1051-5658
DOI - 10.1002/rem.10060
Subject(s) - chemistry , methanogenesis , propionate , precipitation , carbonate , metal , sulfate reducing bacteria , leachate , environmental chemistry , chemical oxygen demand , inorganic chemistry , nuclear chemistry , sulfate , methane , environmental engineering , organic chemistry , wastewater , physics , meteorology , engineering
This study investigates the effectiveness of using metal sulphide and carbonate precipitation mechanismscombined with a landfill‐derived mixed bacterial population. The study was conducted under controlledsubstrate conditions in anaerobic batch reactors. High chemical oxygen demand (COD):sulphate ratios,butyrate, propionate, and acetate were used anaerobically by bacteria for growth with associated sulphatereduction as well as sulphide and carbonate generation. Propionate and butyrate degradation occurred duringsulphate reduction by sulphate‐reducing bacteria while acetate degradation was associated withmethanogenesis by methanogenic bacteria. Using low COD, sulphate ratios showed limited acetate utilization, butsulphate reduction still occurred. Precipitation of Cd, Cu, Zn, Ni, and Fe sulphides occurred quickly and wascompleted in 15 to 30 days, while Ca, Mn, and Mg carbonates formed after 40 to 50 days and some soluble metalremained even after 120 days. The rate of metal precipitation was in the order ofCd>Cu>Zn>Ni>Fe>Mn>Mg>Ca. Bacterially mediated metal precipitation occurred slower than thatrecognized for chemical precipitation. These findings suggest that contaminant transport models based on chemicalequilibrium metal behaviors may over‐predict metal removal by bio‐precipitation. © 2002 WileyPeriodicals, Inc.