Co-composting solid biowastes with alkaline materials to enhance carbon stabilization and revegetation potential.

Abstract

Co-composting biowastes such as manures and biosolids can be used to stabilize carbon (C) without impacting the quality of these biowastes. This study investigated the effect of co-composting biowastes with alkaline materials on C stabilization and monitored the fertilization and revegetation values of these co-composts. The stabilization of C in biowastes (poultry manure and biosolids) was examined by their composting in the presence of various alkaline amendments (lime, fluidized bed boiler ash, flue gas desulphurization gypsum, and red mud) for 6months in a controlled environment. The effects of co-composting on the biowastes' properties were assessed for different physical C fractions, microbial biomass C, priming effect, potentially mineralizable nitrogen, bioavailable phosphorus, and revegetation of an urban landfill soil. Co-composting biowastes with alkaline materials increased C stabilization, attributed to interaction with alkaline materials, thereby protecting it from microbial decomposition. The co-composted biowastes also increased the fertility of the landfill soil, thereby enhancing its revegetation potential. Stabilization of biowastes using alkaline materials through co-composting maintains their fertilization value in terms of improving plant growth. The co-composted biowastes also contribute to long-term soil C sequestration and reduction of bioavailability of heavy metals.