The effects of activated biochar addition on remediation efficiency of co-composting with contaminated wetland soil

Abstract

Unreasonable disposal of organic wastes has caused great problems, including occupying land, affecting organoleptic feeling and causing environmental re-contamination. By incorporation of biochar as raw material into co-composting with agricultural organic matter, it not only can the wastes recycling be realized, but also can the remediation efficiency of multi-element contaminated soil be improved to reach land reclamation. Activated biochar was added for investigating the influences on physico-chemical properties of soil during composting. The concentrations of available metals and arsenic in soil were detected on great reduction in the treatment of biochar-blended composting. Based on the stronger adsorption and microbial activity induced by biochar, the initial content of available PAHs in wetland soil decreased to remain about 3.03% and 5.47% below the control (9.47%) in co-composting added with activated and fresh biochar, respectively. It was related to the observation with improved microbial number as well as optimized fungi/bacteria gene copy number ratio by activated biochar addition, which is conducive to vegetation replanting of contaminated land. The feasibility of applying biochar into co-composting with contaminated soil was confirmed by not only the high remediation efficiency but also the sustainable recycling of agricultural waste.