A Biological Aerated Filter with Blast Furnace Dust (BFD-BAF): Fe-C Inner-Electrolysis Enhanced Operation and Mechanism Investigation

Blast furnace dust (BFD) is a solid waste containing iron and carbon produced during iron and steel smelting, and will cause serious pollution to the environment if safe disposal cannot guaranteed. In this study, a novel filter (BFD-filler) was prepared using BFD and applied to treat domestic wastewater in biological aerated filter (BAF). The operation optimization of the reactor and the mechanism of BAF enhancement by inner-electrolysis were investigated. The results showed that the removal rates of chemical oxygen demand (COD) and NH4+-N by BFD-BAF were 95.93 % and 96.96 %. This is 26.38 % and 23.16 % higher than the conventional process and the start -up time is reduced by 13.3 %. The iron ions produced during the inner-electrolysis stimulated the growth and metabolism of microorganisms and could promote the stability of biofilm. The addition of BFD-filler affected the bacterial community of microorganisms in BAF and enhanced the bacterial abundance and specificity. Therefore, BFD-filler is suitable as a carrier for microbial attachment and immobilization and has great potential for application in BAF.