Application of combined physicochemical and biological processes for enhanced treatment of avermectin fermentation wastewater

摘要

This paper aimed at developing the enhanced biological treatment processes for treatingnavermectin fermentation wastewater (AFW). After UASB treatment and chemical coagulation, thenpretreated AFW was subsequently flowed into a rCAA reactor (reactor with repeated coupling ofnaerobes and anaerobes using macroporous carriers) system for further pollutant degradation andnexcess sludge reduction. By the treatment with chemical coagulation, COD, total nitrogen andntotal phosphorus concentration of treated AFW were eliminated to 550–700mg/L, 130–160mg/Lnand 1mg/L, respectively, and the dark color of the wastewater was greatly bleached. After thisndecolorized wastewater was treated by the following rCAA bioreactor, the COD could be reducednto around 200–300mg/L, while the further decrease of COD less than 200mg/L was difficult. ThenBiolog analysis and OUR test for the water treated by rCAA bioreactor demonstrated that theneffluent from chemical coagulation contained some unknown compounds with low biodegradabilitynand would simplify the microbial community in the subsequent rCAA reactor.