Simultaneous removal of phosphorus and foulants in a hybrid coagulation/membrane filtration system

At many wastewater treatment plants, chemical addition is required to meet the requirements for discharge of phosphorus. Membrane filtration is an attractive option for removing the chemically precipitated phosphorus, but that process can be impeded by fouling of the membrane by effluent organic matter (EfOM). In the current study, membrane fouling and ortho-P removal were explored in hybrid adsorbent/membrane systems dosed with alum and/or a new aluminum-based adsorbent (heated aluminum oxide particles, HAOPs). HAOPs prevented fouling more effectively than alum did, even though the two adsorbents removed similar amounts of EfOM. The HAOPs were particularly effective when they were pre-deposited on the membrane (as opposed to being mixed into the feed upstream). On the other hand, alum removed ortho-P more efficiently than HAOPs did. Combining both adsorbents in a single membrane system takes advantage of the most attractive features of each, accomplishing good ortho-P removal while simultaneously minimizing fouling. In addition to being potentially applicable directly, the results demonstrate the potential benefits of using multiple coagulants and/or adsorbents in a single hybrid membrane system.