Comparison of decolorization of synthetic dyeing wastewater in an anaerobic sequencing batch reactor and a moving bed anaerobic sequencing batch biofilm reactor

فاقد چكيده فارسي

Azo dyes are toxic and xenobiotic compound used in textile industry which are carcinogen as well as mutagenic to various microbiological and fish species. In this study decolorization of synthetic dyeing wastewater including three commonly used azo dyes namely Black B, Red 3BSN and Black WNN in an anaerobic sequencing batch reactor (ASBR) and a moving bed anaerobic sequencing batch biofilm reactor (MBASBBR) was compared. The results showed that the higher biomass concentration in the AMBSBBR leaded to the higher COD removal efficiency, 63.6±12.7%. Although the color removal efficiency was better in the MBASBBR (64.8±6.2%), but the color calculation error due to the formation of aromatic amines, resulted in the same color removal efficiency at both reactors (in the range 53.9±1.3-75.8±1.1%). Probably due to the production of soluble microbial products in the ASBR, its effluent COD concentration was higher than its influent at some points. In the MBASBBR, the concentration of COD in the effluent was almost constant, and between 217±58 mg/l and 350±71 mg/l. The results of this paper also indicates that the azo bond reduction through anaerobic reaction phase was the main mechanism for decolorization of the three azo dyes present in the synthetic dyeing wastewater.