超滤一体化装置处理低温期闽江水的效能研究

Efficiency of Integrated Ultrafiltration Equipment for Purification of Low-temperature Raw Water from Minjiang River

针对闽江水质特征，开发了混凝／沉淀／超滤一体化装置，并通过中试考察其在低温水质期对闽江水的净水效能。试验结果显示：在水温为9～15℃的低温水质期，一体化装置运行稳定之后，出水浊度平均为0．085NTU，远低于水厂传统工艺出水浊度；出水CODMn平均为1．34mg／L，对CODMn的平均去除率为58．8％；超滤对细菌的去除率可达99％以上，出水菌落总数最大不超过3CFU／mL。低温水质时期系统的平均产水率为95．9％；恢复性化学清洗（CIP）能够有效缓解膜污染，提高超滤膜的过滤性能，CIP之后的出水浊度显著改善，膜通量提高了11．9％。水温会影响超滤膜的过滤性能，11．0℃时的膜比通量为14．4℃时的88％左右，水温越低，超滤系统的膜比通量就越小；通过缩短过滤时间或增加反冲洗时间可以提高超滤膜通量，增加系统的反冲洗时间对提高系统通量的效果更好，且耗电量的增加量也相对较小。

Aimed at the water quality characteristics of Minjiang River, an integrated equipment of coagulation/sedimentation/ultrafihration was developed, and its purification efficiency of this river water at low temperature period was investigated in pilot-scale experiments. The results showed that when the e- quipment operated stably at low temperature period of 9 to 15 ℃, the average turbidity of the effluent was 0. 085 NTU, which was much lower than that of the effluent from the conventional process in the plant. The average CODMn was 1.34 mg/L and the average removal rate was 58.8%. The removal rate of bacte- ria by uhrafiltration was more than 99%, the total number of bacterial colonies was less than 3 CFU/mL and the average water yield rate was 95.9%. Cleaning in place （CIP） could effectively alleviate the foul- ing and improve the performance of membranes. After CIP, the effluent turbidity was significantly im- proved, and membrane flux increased by 11.9%. The temperature of water had an effect on the perform-ance of ultrafltration membrane. The specific membrane flux at 11.0 ℃ was 88% of that at 14.4℃. When the temperature was lower, the specific membrane flux was lower. Shorting filtration time or in- creasing backwash time could increase membrane flux. Increasing backwash time was more effective and had less increment in the power consumption.