Direct ultrafiltration performance and membrane integrity monitoring by microbiological analysis. (15th October 2015)

• Record Type: Journal Article
• Authors: Ferrer, O.; Casas, S.; Galvañ, C.; Lucena, F.; Bosch, A.; Galofré, B.; Mesa, J.; Jofre, J.; Bernat, X.
• Is Part Of: Water research. Volume 83(2015)
• Page Start: 121
• Page End: 131
• Publication Date: 2015-10-15
• Subjects: Ultrafiltration -- Integrity -- Bacteriophages -- Enteroviruses -- Noroviruses; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2015.06.039
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: The feasibility of substituting a conventional pre-treatment, consisting of dioxi-chlorination, coagulation/flocculation, settling and sand filtration, of a drinking water treatment plant (DWTP) by direct ultrafiltration (UF) has been assessed from a microbiological standpoint. Bacterial indicators, viral indicators and human viruses have been monitored in raw river, ultrafiltered and conventionally pre-treated water samples during two years. Direct UF has proven to remove bacterial indicators quite efficiently and to a greater extent than the conventional process does. Nevertheless, the removal of small viruses such as some small bacteriophages and human viruses (e.g. enteroviruses and noroviruses) is lower than the current conventional pre-treatment. Membrane integrity has been assessed during two years by means of tailored tests based on bacteriophages with different properties (MS-2, GA and PDR-1) and bacterial spores ( Bacillus spores). Membrane integrity has not been compromised despite the challenging conditions faced by directly treating raw river water. Bacteriophage PDR-1 appears as a suitable microbe to test membrane integrity, as its size is slightly larger than the considered membrane pore size. However, its implementation at full scale plant is still challenging due to difficulties in obtaining enough phages for its seeding. Graphical abstract: Highlights: Direct UF appeared as a suitable alternative to a DWTP conventional pre-treatment. Direct UF ensured the removal of >5 log10 units of bacteria and viruses >60 nm. Direct UF guaranteed 3 log10 units removal of viral indicators and viruses <40 nm. Naturally occurring somatic coliphages are suitable to monitor UF virus performance. Bacillus spores and PDR-1 appeared as suitable microbes to monitor membrane integrity.