Abstract: Filter media for a biological aerated filter (BAF) were prepared with blast furnace dust as the main material, and with clay and sodium silicate as chemical additives. Through the orthogonal experiment, the optimal preparation condition was obtained, which is 79% blast furnace dust, 15% clay, 6% sodium silicate and 600℃ calcination. The filter media have the characteristic of lower density, higher compression strength and larger specific surface. Soy sauce wastewater was treated in BAF by adopting this kind of filter media. When the hydraulic retention time (HRT) is 4 hour, air-water ratio is 6∶1, and the height of filter media is 100cm, the removal rate of COD, NH3-N and chroma is 70.3%, 74% and 60%, respectively. This method incorporates the concept of circular economy and explores a new pathway to utilize the resources of blast furnace dust.

Key words: soy sauce wastewater , biological aerated filter, filter media, blast furnace dust