Effects of Co-composting of Municipal Solid Waste and Pigeon Pea Biochar on Heavy Metal Mobility in Soil and Translocation to Leafy Vegetable Spinach.

An experiment was conducted to study the effects of co-composted products of municipal solid waste (MSW) and pigeon pea biochar (PPB) on heavy metal mobility in soil and its uptake by spinach. Application of municipal solid waste biochar co-compost (MSWBC) significantly (p ≤ 0.05) reduced the heavy metal content in spinach leaves and roots compared to municipal solid waste compost (MSWC) amended soil. The percent decrease in spinach leaf following the application of MSWBC-10% PPB compared to MSWC was 20.62%, 28.95%, 36.02%, 41.88%, 41.50%, and 41.23% for Cu, Cd, Pb, Cr, Ni, and Zn, respectively. The dry matter yield of spinach and soil organic carbon (SOC) content in soil amended with MSWBC-10% PPB was significantly increased by 32.75% and 47.73%; and 17.62% and 27.45% relative to control and MSWC amended soil. The study concludes that co-composted product, MSWBC, stabilized heavy metals in MSW, reduced their uptake by spinach and thus making it a viable option for safe disposal of MSW.