Effect of waste-derived soil amendments on mitigating leaching impacts from municipal solid waste incineration (MSWI)...

This study explores modifying a sandy soil with a low solid to liquid partitioning coefficient (K_d) by adding amendments including iron-rich industrial slag byproducts and biochars, which contain sorption sites for trace metals present in MSWI ash leachate (notably Sb, cited as a concern for reuse applications). K_d values for Sb were determined for the sandy soil to be as low as 1.6 ± 0.1 L/kg. With amendments, K_d values varied from 1.4 ± 0.2 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% iron slag, to 990 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% magnetic solids. A blend of 20% magnetic solids showed orders of magnitude increase beyond 100% sandy soil. The biochars showed limited capacity to reduce leached Sb in the ash-derived leachate, which is likely due to negative surface charges of the biochars and Sb at basic pH. A risk assessment (US EPA IWEM) performed using experimental K_d for each blend suggests that using soil amendments could reduce leached concentrations at points of concern, which could open additional avenues for ash reuse.