The invention relates to a
ferrihydrite (FH)-ultra-
filtration (UF) membrane combination process for removing trivalent
arsenic and dissolved organic matters (DOMs) in water, so as to control disinfection by-products (DBPs) and relieve membrane
pollution, belonging to the technical field of
water treatment. The process comprises the following steps: adding an adsorbent FH into a hollow
fiber UF membrane
filtration system, maintaining a suspension state by means of
aeration, providing a shearing force to reduce the enrichment of pollutants on the surface of the membrane, and separating out the adsorbent from the water by means of UF membrane
filtration. The process utilizes the trivalent
arsenic to bond with monoatomic or diatomic O on the surface of FH, and simultaneously enables the FH andthe DOMs to be subjected to a coordination exchange reaction so as to form a
coordination complex, so that 99.4% of the trivalent
arsenic, 80.2% of a
trihalomethane precursor and 90.4% of a haloacetic acid precursor are effectively removed, the concentrations of the arsenic and all the DBPs in
effluent reach the drinking water standard, and the safety of drinking water is accordingly guaranteed.Furthermore, FH adsorption pretreatment reduces the enrichment of the DOMs on the surface of the membrane and the absorption inside membrane pores, so that the
transmembrane pressure difference is reduced by 65.5%, and
membrane fouling is significantly alleviated.