In this study, biological treatment of copper-containing organic wastewater from TFT-LCD industry was investigated. N-methylformamide (NMF) and diethylene glycol monomethyl ether (MDG) were the main components in the copper-containing wastewater, therefore, biodegradations of NMF and MDG as well as the effects of copper on biodegradation were examined under anoxic and aerobic condition using batch tests and lab-scale A/O SBR. Under aerobic and anoxic condition, NMF and MDG could be successfully degraded without observable inhibition either on nitrification or denitrification at NMF and MDG concentrations up to 1000 mg/L and 800 mg/L, respectively. The ammonia released from NMF degradation under aerobic condition did not show observable inhibition on NMF degradation and the following nitrification as well even at initial substrate-to-biomass (S0/X0) of 0.28. By adding copper-containing wastewater, the results indicated that denitrification had a lower tolerance on copper than nitrification, and denitrification rate decreased by 39% at 5 mg/L of copper. Similarly, anoxic degradation of MDG was also affected by adding mg/L of copper, suggesting that the presence of copper might inhibit denitrification by slowing down the utilization of carbon source and nitrate reduction. Furthermore, the lab-scale A/O SBR was operated for more than 80 days by adding 0.5 mg/L of copper per day with sludge retention time (SRT) of 20 days. A/O SBR removal performance on NMF, MDG, COD and nitrogenous species removal was not affected, showing that microorganisms might be able to adapt the copper-containing environment under proper operation. A one-day shock loading of copper at 10 mg/L caused inhibition on denitrification and nitrification, but not NMF and MDG removal.

Biological treatment of copper-containing NMF/MDG organic wastewater from the TFT-LCD industry

2019 Fall National Meeting

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