Influence of high temperature aerobic composting treatment on the form of heavy metals in pig manure

The influence of high temperature aerobic composting treatment on the change of heavy metal combined form in pig manure was studied using Tessier sequential extraction method. After aerobic composting treatment, the total concentrations of Pb, Cu, Zn, Ni, Cr, Cd, As in pig manure increased. The concentrations of residual forms increased generally; only the concentrations of sulfide and organic combined form As and Zn decreased. The concentrations of exchangeable form Cu, Zn, Cr and As decreased markedly. Composting treatment could decrease the distribution coefficients of exchangeable form and carbonate form Pb, Ni, Cu, Cr, Zn, As and Fe-Mn oxides combined form Pb, Cu, Cr and As. Therefore, it could decrease the effectiveness of heavy metals in pig manure. Composting treatment is a possible way to reduce the risk of heavy metal pollution in the utilisation of pig manure on land