Thermal Behavior of Cd During Sludge Incineration: Experiments and Thermodynamic Equilibrium Model

Abstract

Experiments and thermodynamic equilibrium calculations were performed to investigate the behavior of Cd during sewage sludge incineration. The chemical equilibrium calculations indicated that chlorine significantly increased the volatilization of Cd in the form of CdCl2. In addition, SiO2-containing materials can function as sorbents for stabilizing Cd. The effect of PVC added to the sludge on the migration of Cd in the sludge was greater than that of NaCl. As the temperature increased, both organic and inorganic chlorides reduced the Cd distribution in the bottom ash. The chloride concentration, and the incineration time exhibited insignificant changes in Cd emission. With the addition of either NaCl or PVC into the sludge, the phases of Cd present in the bottom slag were primarily present in the form of silica-alumina oxides or multi-metal oxide, which could inhabit the Cd volatilization.

Environmental risk assessment in livestock manure derived biochars

“…47 Cadmium chloride, produced by the combination of Cd and chloride, is the major Cd species in the vapor phase during pyrolysis. 48,49 In this study, the bioavailability and ecotoxicity of Pb in livestock-manure-derived biochars was reduced aer pyrolysis. This result may be due to Pb make up more chlorides than other elements.…”

Thermodynamic equilibrium predictions of zinc volatilization, migration, and transformation during sludge co‐incineration

“…For example, “Treatment and Pollution Control Technology Policy for Sludge in Municipal Wastewater Treatment Plant” adopted by the Ministry of Environmental Protection of China incentivizes the use of sludge as a fuel in co‐incineration by thermal power plants, and cement and brick kilns. However, the complexity and variability of fuel components (e.g., sludge, coals, and municipal solid waste—MSW) in co‐incineration have led to the emissions of pollutants with strong toxicity such as heavy metals (HMs), organic pollutants, and acid gases (Li, Zhang, Shao, & He, ; Li et al., ; Liu, Fu, et al., ; Yu et al., ) whose migration, transformation, and emission patterns have drawn worldwide attention (Han, Hwang, Kim, Park, & Kim, ; Liu, Huang, et al, ; Liu, Huang, Sun, & Xie, ; Liu, Zeng, et al., ).…”