Powered Activited Carbon-UF for Treating Micro-polluted Surface Water
|Keywords||PAC-UF system operating condition membrane filtration performance orthogonal test membrane flux model|
In recent years,during the survey of the Ganjiang River,it was found that some Ganjiang water was polluted. Water quality of some reached III water quality standards. In response to this situation, this thesis proposed the hybrid process adding powder activated carbon （PAC） to ultrafiltration （UF） membrane system and studied on the influencing factors, the removal efficiency, and the fouling characteristics of the PAC-UF system. In this paper, kaolin, humic acid and ammonium chloride were used to simulate the drinking water source in Nanchang. The main results included:By changing the amounts of PAC, the operating pressure, backwashing interval and backwashing time, the influence of them on the effluent water quality and process performance were studied. It was shown that turbidity was steady and always kept less. Furthermore, the UV254 and NH3-N removel rates would rise after adding more PAC and the membrane fouling would slow inapparently with more PAC. The membrane flux decreased and slowed with the operating pressure down. When the backwash interval was extensed, the pre-backwash membrane flux would become less and less. The longer backwash the better membrane flux recovery.The reactor performance under different operation conditions was evaluated and educed the optimal operating mode. It was indicated that the values of synthetic index would be smallest: PAC 200mg/L, working pressure 0.16Mpa , backwashing interval 30min and backwashing 1min.Under the optimal operating mode, the removal effect of PAC-UF and the the membrane fouling was studied. It was displayed that the effluent turbidity was kept less than 0.4NTU at all times when that of influent fluctuated from 25NTU to 100NTU. When the influent UV254 was ascendant, effluent UV254 was rise as well as the removal. The PAC-UF process could remove NH3-N effectively. Moreover, when the influent NH3-N was 0.7～1.3mg / L, its removal rate was higher than 50% and the effluent NH3-N was lower than 0.55mg/L.According to the characteristics of membrane cleaning, a mathematical multi-factor model of membrane flux was established. The model could predict the membrane flux and production of water after the system running for some time, determined the time up to a certain amount of water required and when the chemical wash. These effects could guide the membrane water production practices, and subsequent mass production of automatic control.