Study On Degradation Of Phenol-containing Wastewater In High Concentration SBR

The activated sludge coming from membrane bioreactor (MBR) was acclimated and cultured in an asynchronous manner with different kinds of substrates respectively to fit sequencing batch reactor (SBR) with high concentration activated sludge, aiming at the degradation of phenol-containing wastewater. The first one was using only glucose as substrate during the acclimation period, then adding gradually phenol to SBR system during the culture period. Compared with the first one, the second one was having peptone as additional substrate during both the acclimation and culture period. The results obtained from the second one were found to be better than that from the first one by measuring settleability of activated sludge, effluent COD and effluent phenol concentration, and observing microorganism. According to the second one, the settleability of activated sludge was in the range of normal values and prolific microorganism kept appropriate proportion between bacteria and protozoa, metazoa. The effluent was of low COD (between 30mg/L and 40mg/L) and very low phenol concentration far better than the national discharge standard.HPLC was employed to measure effluent phenol concentration in different time of the culture period. At the beginning of the culture period, effluent phenol concentration was 64.1μg/L while influent contained phenol of 21mg/L. The degradation of phenol was improved along with the culture going on. And the system could maintain effluent phenol concentration below HPLC detection limit value of 10μg/L while the highest influent phenol concentration was 252mg/L.During the mature period of activated sludge, DO and OUR in SBR system were checked respectively and were used to analyze the role of peptone in the phenol degradation system. It was found that peptone can weaken glucose effect and stabilize substrate degradation rate. In addition, the growth of high concentration activated sludge was observed by determining microbial apparent yield coefficient Y and sludge ageθc. The results showed that the microbial apparent yield coefficient using phenol as its substrate was minimal, while that using glucose, peptone and phenol as its substrate is little different from the one using glucose and phenol as its substrate. Moreover, the sludge age of the two latter was in the range of the normal values reported in the literature.