内、外压超滤膜在净水中的对比试验研究

Comparative Pilot Study on Water Purification with Inside-out and Outside-in Hollow-fiber Ultrafiltration Membrane Modules

针对水源水质特征,构建了微絮凝+超滤一体化装置,分别选取了内压式和外压式中空纤维超滤膜开展中试对比研究,探讨了两种超滤膜装置的处理效果、运行稳定性和产水回收率等。结果表明,内、外压超滤装置对浊度、CODMn、低浓度氨氮的去除效果均较好,出水水质均优于我国《生活饮用水卫生标准》(GB 5749—2006);内、外压式膜组件同步运行时的膜比通量(SF)都比较稳定,内压式膜组件的SF是外压式的两倍多,跨膜压差(TMP)受温度影响较外压式小,运行压力约为外压式的一半;单个过滤周期中内压式膜组件的SF衰减速率是外压式的3倍多;虽然大水流高强度冲洗以及酸碱交错化学增强反冲洗(CEB)的方式能够替代外压式的气擦洗,但也增加了耗药量并使得产水回收率较外压式低5%;当原水水质较好时,考虑SF、运行压力和能耗方面的优势,可优先选择内压式膜组件,但必须加强超滤前的预处理。

Integrative devices of miero-flocculation and ultrafiltration were built based on raw water characteristics, and an inside-out and an outside-in hollow-fiber membrane uhrafiltration modules were chosen to purify raw water in a pilot-plant test. The treatment performance, operation stability and fresh water recovery rate were discussed. The results showed that the removal effieiencies of turbidity, CODMn and low-concentration ammonia-nitrogen by the two types of uhrafihration devices were superior to those required by the Standards for Drinking Water Quality （ GB 5749 - 2006）. The specific fluxes （SF） of both ultrafihration modules during synchronous operation were stable, the SF of the inside-out ultrafiltra- tion module was more than double that of the outside-in membrane module, the TMP of the former ap- peared less influenced by temperature, and the operating pressure of the former was about one half of the latter. The decay rate of SF of the former was three times that of the latter in a single filtration cycle. Al- though high flow and high strength flushing and the acid-base chemical enhanced backwash （CEB） of theinside-out module could replace the gas washing of the outside-in module, but the chemicals consumption was increased, and the product water recovery rate of the former was 5 % lower than that of the latter. For the treatment of raw water in a good quality period, the inside-out membrane module would be the pre- ferred choice, considering advantages in terms of SF, operating pressure and energy consumption, and the pretreatment of uhrafihration should be noted.