Metal membranes for water treatment

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), acidic, low alkalinity and turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of using inorganic metal microfiltration membranes in a submerged membrane configuration with coagulation pretreatment for drinking water production. Variations in operating modes and conditions were tested, from dead-end operation to semi sequencing batch operation using air scouring and backwashing cycles for membrane cleaning and fouling control. Fluxes around 180 LMH at transmembrane pressures below 0,3 bar where achieved over production cycles in excess of 50 hours. Treatment efficiencies in general showed >95% color removal, ~85% UV removal, 65-75% TOC removal, >0.5 NTU turbidity and non-detectable suspended solids in the permeate. The initial results show that MF metal membranes combined coagulation pretreatment are a potential alternative to treating drinking water.