Full Description

Microfiltration and ultrafiltration, categorized as low-pressure membranes, are drawing attentionas new technologies for water purification systems. This is because they work as a complete barrier,mainly against Cryptosporidium. Furthermore, the removal of not only solid but also dissolvedcontaminants in raw water is eagerly desired. To meet this demand, hybrid systems combined withmembrane filtration are becoming increasingly important.NGK has been supplying users with unique ceramic membrane filtration systems combined withpre-coagulation that afford excellent energy saving, reduction of maintenance work, and stableoperation. However, both installation and operation cost would still be more desirable. The authorshave been testing means of achieving higher filtration flux operation while maintaining efficiency.This paper discusses the performance of high flux operation with certain devices.To achieve a high flux operation such as 250 gfd (= 420 L/msup2/sup/hr) against river surface water anddam water with direct filtration, the reduction of two kinds of transmembrane pressure (TMP) maybe the main breakthrough. On-site experiments led to the expectation that the daily changedTMP increase after BW would be reduced dramatically by the combination of acid chemicallyenhanced backwash (CEB), and that a TMP increase of one filtration cycle would be reduced byin-line flocculation. As a result, the hybrid system with pre-coagulation, in-line flocculation andceramic membrane filtration with acid CEB showed the possibility of high flux direct operation of250 gfd (= 420 L/msup2/sup/hr) with quite stable condition against organic contaminated river surface water. Includes 8 references, tables, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 10File Size: 1 file , 800 KB