AWWA MTC53650

As membrane separation systems become more prevalent in the water treatmentindustry, a sound monitoring method will be needed to ensure the integrity of themembrane barrier. In this study, integrity is defined as "in perfectcondition" or operating as intended by the manufacturer. Reverse osmosis (RO) andnanofiltration (NF) membranes are intended to have a low rate of salt passage.One would expect that a barrier that excludes dissolved salts would also performwell as a microbiological barrier. However, the effluent from RO and NF membranesystems is so pure that it is difficult to measure anything in real-time thatwould indicate a small breach in integrity. A good integrity monitoring methodshould be: user friendly for municipal water treatment system operators;acceptable to membrane specialists and regulators; and, reflect some realseparation phenomena that can be correlated with a cause of microbiologicalbreak-through. Microfiltration (MF) and ultrafiltration (UF) systems aremonitored with particle counters, pressure hold and vacuum tests. These may bemodified for use with RO and NF systems. Also on-line total organic carbon (TOC)analysis, UV monitoring, particle monitoring and dye challenges may be useful forthe tighter membrane systems. In this study these methods are compared toperformance monitoring and Pseudomonas aeruginosa (P. aeruginosa) counts todetermine whether any of the methods would be suitable for integrity monitoring. Includes 9 references, tables, figures.