[Performance of micro-aerobic continuous treatment system for sulfate-ridden antibiotic wastewater at varied influent...

Performance of a lab-scale micro-aerobic continuous treatment system for sulfate-ridden antibiotic wastewater, i.e., the treatment efficiencies, sludge SVI values and DHA activities, and the contents of yeasts and bacteria in sludge, were investigated at 14-18 degrees C when varied influent loadings COD of 2-21 kg/(m3 x d) were used. At an influent loading COD of 2 kg/(m3 x d), bacteria were preponderant in the microbial community in the sludge with a content of 96%, the sludge had MISS, DHA activity (TF/MISS x t), and SVI levels of 300 mg x L(-1), 4 300 mg/ (g x h), and 35 mL x g(-1), respectively,the system achieved a COD removal of 13%. When the influent loadings went up to 5 and 10 times higher than that at the first phase, i.e., 9 and 21 kg/(m3 x d), it was yeasts' turn to be preponderant in the sludge with contents of 67% and 71%, respectively, the MISS levels amounted to 2 300 and 1 500 mg x L(-1) respectively, the DHA activity (TF/MLSS x t) of 9 600 and 10 800 mg/(g x h), and the SVI values of 160 and 110 mL x g(-1), were achieved individually, the COD removal was greatly improved up to 40%-50%. It showed that influent loadings had remarkable influence on the treatment performance and microbial community structure of the system.