Dmf Wastewater Activated Sludge System The Sludge Organic Toxicity Distribution Law

This research was conducted to investigate the acute toxicity spatial distribution in the sludge treating hydrophilic toxic pollutants N,N-Dimethylformamide (DMF) with various influent concentration (40 mg/L,80 mg/L,120 mg/L and 200 mg/L) in SBR process. The effect of treatment time on the values of effluent COD. concentration of DMF in water and sludge phases and organic toxicity in a single operation cycle were analyzed. The adsorption degradation contribution extent to formation of organic toxicity in unacclimated inactivated sludge, unacclimated sludge and acclimated sludge were investigated as well.The effluent COD was about 300mg/L, the acclimated stage in each concentration was 30 days, operation cycle was 12 hours and dissolved oxygen was controlled from 2.0 mg/L to 3.0 mg/L. It was showed that the toxicity of sludge in each concentration stages fluctuated from relatively high level in the beginning to low-level in the end, the value of toxicity of sludge increased with that of initial DMF concentration, while the content of DMF was not detected. All these phenomena indicated that the toxicity of sludge phase was caused by DMF degradation products or the toxic substance secreted by DMF induction microbial cells and toxicity centered mainly in the inner extracellular polymeric substances (EPS) and intracellular zone.