Ash characteristics during co-incineration with industrial organic solid waste in a large-scale municipal solid waste incinerator

Abstract In recent years, the co-incineration with industrial organic solid waste (IOSW) in municipal solid waste (MSW) incinerators has been an effective method for addressing MSW volume deficiencies and expediting IOSW disposal. However, co-incinerating IOSW raises several concerns, particularly regarding the altered characteristics of incineration ash. This study investigated the impact on ash characteristics at co-incineration ratios of 20%, 30%, and 40% in a 500 t/d MSW incinerator. IOSW consisted mainly of plastic, fabric, and leather, and it contained relatively high levels of chlorine, sulfur, and heavy metals. The findings indicated that co-incineration marginally affected the crystalline structure of ashes but altered the chemical composition of part ashes. Higher IOSW ratios reduced the Ca content to 5.80% and increased the concentrations of Cl, Na, and K in particulate matter (PM). The use of calcium-based agents to reduce acid gas concentrations lowered Cl, Na, and K in baghouse fly ash (BHFA). Heavy metal concentrations in superheater and economizer ash remained relatively stable, whereas the elevated levels of As, Cd, Pb, Zn, and Cu in PM with rising co-incineration ratios were attributed to increased temperatures and HCl concentrations. BHFA displayed reduced heavy metal content, likely due to dilution by deacidification agents. The leaching concentrations of Cr, Pb, Zn, and Cu in BHFA slightly increased, while those of As and Se decreased due to higher pH and reduction reactions. Most heavy metals in the leachate, except Pb, complied with regulatory limits. This investigation provides insights into ash characteristics at IOSW co-incineration ratios of up to 40% and offers guidance for subsequent treatment and disposal of fly ash.