An innovative accelerated carbonation process for treatment of incineration bottom ash and biogas upgrading

• Published in: Waste management (Elmsford) Vol. 144; pp. 203 - 209
• Main Authors: Yao, Zhiyi, Prabhakar, Arun Kumar, Cadiam Mohan, Babu, Wang, Chi-Hwa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.05.2022
• Subjects: CO2 sequestration; Heavy Metal Locking; Incineration Bottom Ash; Leaching; Sustainability; CO2 sequestration; Incineration Bottom Ash; Leaching; Sustainability; Heavy Metal Locking; CO sequestration
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2022.03.033

•A new strategy for combining accelerated carbonation with biogas purification.•Leached heavy metals could be significantly reduced after accelerated carbonation.•An integrated design to evaluate the large-scale accelerated carbonation process.•Environmentally friendly and economically feasible accelerated carbonation process. Incineration is the main technology used for the management of municipal solid waste, in parallel to various recycling programs. However, incineration should not be considered as the final step for waste management as the ash still needs to be treated and disposed properly. In this work, an innovative accelerated carbonation of incineration bottom ash (IBA) using simulated biogas composition from anaerobic digestion processes (a mixture of CH4 and CO2) has been applied to lower the leaching of heavy metals from the carbonated IBA and its associated toxicity. Various temperatures and reaction times were explored for carbonation optimization and it was found that the carbonation at 25 °C for 8 h was the optimal reaction condition by taking into account the degree of carbonation and time constraint. The mineral content, functional groups, thermal stability, leaching patterns and ecotoxicity of both raw IBA and carbonated IBA were tested. It was found that carbonated IBA leached out less heavy metals than the raw IBA due to the locking of heavy metals in the calcite matrix. Cost-benefit analysis was also conducted on the industrial-scale process with a capacity of processing 10 tons of IBA per day. The results indicated that the proposed process had great economic potential.