title: Use of organic acids in the composting of municipal solid waste: a pilot-scale study.
abstract: Compost made from municipal solid waste (MSW) contains heavy metals that can interfere with the use of organic amendment in soil. In order to find effective ways to reduce the potential risk of heavy metals, we have investigated a novel approach by use of organic acid during MSW composting. Citric and oxalic acid dissolutions (0.25 mol x (-1)) were used at determined ratios (kg dried MSW: cm(3) acid). Cr and Ni concentrations were similar in compost, independent of acid contribution. By contrast, Cu concentrations decreased by 63% (at citric acid ratio 1:15), 65% (at citric acid ratios 1:20 and 1:40) and 83% (at oxalic acid ratio 1:40); furthermore, Pb concentrations reduced by 71% (at citric acid ratios 1:20 and 1:40 and at oxalic acid ratio 1:40) and Zn concentrations reduced by 67% (at citric acid ratios 1:10 and 1:20) and 70% (at oxalic acid ratio 1:40). The total metal mass decreased by an average of 12% in the compost fraction, whereas the total percentage of the residual fraction increased by an average of 20%. The acid addition in the studied ratios improved compost quality without negatively influencing biostabilization.
authors.affiliation: Departamento de Biologiá Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain. arosray@upo.es
authors.forename: A
authors.initials: A
authors.lastname: Rosal
authors.forename: A F
authors.initials: AF
authors.lastname: Chica
authors.forename: M A
authors.initials: MA
authors.lastname: Arcos
authors.forename: M
authors.initials: M
authors.lastname: Dios
mesh_terms: D019343:Citric Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis*; D019815:Oxalic Acid / Q000737:chemistry*; D010865:Pilot Projects; D012722:Sewage; D012987:Soil / Q000032:analysis* / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D012987:Soil; D019343:Citric Acid; D019815:Oxalic Acid