Development of a bench-scale immersed ultrafiltration apparatus for coagulation pretreatment experiments

The purpose of this paper is to present results of a project that focused on developing a standardized bench-scale apparatus and operating procedures for immersed ultrafiltration (UF) membrane systems to assess integrated process designs (e.g., coagulation-UF) under controlled laboratory conditions. The integrated test apparatus, termed Immersed Ultrafiltration Enhanced Coagulation (IUEC), was designed using a hollow-fiber, outside-in UF module immersed in a single compartment water preparation and filtration tank equipped with aeration mixing capabilities for coagulation and flocculation process evaluations. Bench-scale experiments were conducted with alum on a low turbidity surface water source to evaluate system performance of the integrated IUEC apparatus compared to a standard jar test unit. The experiments were evaluated by measuring the removal of natural organic matter and zeta-potential analysis from water collected from a conventional mechanically-mixed process with a manual transfer to a UF membrane system and comparing these results to the IUEC system. The results of this study demonstrated that using the single-compartment IUEC apparatus can provide water quality data that is congruent with those obtained through conventional methods that rely on use of standard jar tests.