Nutrients and Heavy Metals in Biochar Produced by Sewage Sludge Pyrolysis: Its Application in Soil Amendment
Taoze Liu1, Bangyu Liu2, Wei Zhang2
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1State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences,
Guiyang 550002, P.R. China
2Geography and Tourism Department of Guizhou Normal College,
Guiyang 550018, P.R. China
Pol. J. Environ. Stud. 2014;23(1):271–275
The production of sewage sludge has been sharply increasing by municipal sludge treatment plants in China. Sewage sludge is a difficult waste to manage not only due to the high quantities produced but also due to its high concentration of heavy metals and pathogens. The pyrolytic conversion of sewage sludge to biochar and then applied to the land is a sustainable management potion. Therefore, the aim of this work is to evaluate the characteristics of nutrients and heavy metals in biochar from sewage sludge pyrolysis, and pot experiments were carried out with different treatments consisting of infertile and contaminated soils. The results showed that the content of major plant nutrients (N, P, K) in sewage sludge biochar meets agricultural requirements. The concentrations of heavy metals (Cu, Pb, Zn, Cd, and Cr) were evidently increased in biochar, but those of available heavy metals were decreased. The sewage sludge biochar can improve soil fertility and enhance plant growth while not increasing plant uptake of heavy metals, and remedied contaminated soil by reducing the plant availability of heavy metals.