Fates of heavy metals, S, and P during co-combustion of textile dyeing sludge and cattle manure

The co-combustion of textile dyeing sludge (TDS) and cattle manure (CM) may enhance circularity in terms of resource and pollution controls. However, the pollutant migrations and transformations of ashes and their characterization during the co-combustion are still unclear. This study aimed to quantify the transformation and migration behaviors of the co-combustion ashes, as well as the interactions involved via thermogravimetric experiments and thermodynamic simulations. The addition of TDS facilitated the conversions of Ni and Cr from the extractable form to the stable one, increasing their environmental safety. P dominated S for the reaction with Ca which promoted the generation of S-containing gas emission and apatite P. The reactions between the minerals in CM and Ca in TDS generated calcium silicate, decreasing the S-fixation ability of Ca, while increasing the emission of S-containing gases. Our findings provide insights into the interactions among the minerals, the heavy metals, and the specific elements and their impacts on pollutant emissions, thus enhancing pollution control strategies.