Transparent exopolymer particles (TEP) have been associated with biological fouling in reverse osmosis (RO) systems, but their impact on ultrafiltration (UF) systems have only been investigated recently. TEP are very sticky substances and may serve as a binding agent for rejected particles and aid their adhesion to membrane surfaces during dead-end filtration. The aim of this study is to demonstrate the possible effects of different levels of TEP to the operational performance of the UF system treating seawater. Several RO plants with integrated membrane system (IMS) configuration were studied to assess the TEP removal efficiencies of UF pretreatments. Other pretreatment systems applied in these plants were also investigated including rapid sand filtration, biological activated carbon filtration (BACF) and in-line (coupled with UF) coagulation systems. To measure TEP removal by pre-treatment, p-TEP and c-TEP concentrations were measured over the pre-treatment processes of these plants. In this study a seawater UF-RO plant provided some evidence that TEP can actually foul UF systems. Non-backwashable fouling rate in the UF was found to coincide with TEP levels in the feedwater. The binding capability of TEP with other particles/colloids may have enhanced the formation of a membrane cake layer with high filtration and backwashing resistance. Recent studies found that estoration of membrane permeability by backwashing can be improved by application of in-line coagulation.
This presentation is available to AMTA Members only.
- Loreen Villacorte, MSc
- UNESCO-IHE, Institute for Water Education
- AMTA Annual Meeting, San Diego, CA
- San Diego Biennial
- Fouling, Ultrafiltration, Seawater