Investigation of the cyclic separation of dioxins from municipal solid waste incineration fly ash by using fat.

It is necessary to detoxify municipal solid waste incineration fly ash (MSWIFA) to facilitate resource utilization. The current research focused on the treatment of heavy metals in MSWIFA which is relatively well-developed, while dioxins (PCDD/Fs) need to be treated with more referable programs. Based on the excellent lipophilicities of dioxins, readily available, nontoxic, harmless, and easily treatable animal fats have been used to separate the dioxins from MSWIFA samples, thereby reducing the toxic equivalence of the MSWIFA. The experimental results indicated that animal fats significantly reduced the toxic equivalence of untreated, water-washed, and acid-washed MSWIFA samples, with reductions in the dioxin toxicity equivalence of up to 70%. Furthermore, in studies of heavy metal leaching, water washing followed by pig fat (FP) separation was identified as the optimal approach for the separation of dioxins from MSWIFA. Under the optimal conditions, the toxicity due to dioxins was reduced by over 70% after separation from MSWIFA with recycled animal fats. The environmental and economic benefits of this treatment option were analyzed on this basis. • The dioxins in MSWIFA can be separated by fat. • MSWIFA with low toxicity equivalent and low heavy metal leaching can be obtained. • The net dioxin content can be reduced to around 20 ng TEQ/kg after multiple cycles. • The separation of dioxins by FP can obtain significant economic benefits. [ABSTRACT FROM AUTHOR]