Coagulation—ultrafiltration system for river water treatment

Abstract

The “in-line” coagulation—ultrafiltration hybrid process has been investigated using three different coagulants, viz. FeCl 3, Fe 2(SO 4) 3 and Al 2(SO 4) 3. The coagulants were dosed in the amounts of 2.4 mg Fe/dm 3, 2.8 mg Fe/dm 3 and 2.9 mg Al/dm 3, respectively. Surface water from the Czarna Przemsza river (Silesia region, Poland) was used as raw water. The ultrafiltration membrane module with capillary polyethersulphone membranes was applied. It has been shown that the application of coagulant “in-line” contributes to the improvement of the quality of water as a result of growth of the removal of organic matter. It has also been statistically proven that the proper choice of the coagulant is of significant importance for the degree of removal of organic matter from the water. The highest efficiency of the process was achieved when the aluminum coagulant was used. Furthermore, it has been shown that the application of “in-line” coagulation and ultrafiltration with the most proper coagulant restricts the fouling of the membranes, so that contaminations deposited on the membrane can easily be removed using deionized water.