AWWA MTC53651

With recentadvances in membrane treatment technologies, reverse osmosis (RO) has quicklydeveloped into a mature and reliable technology utilized in a variety of waterand wastewater applications. Despite these advances, RO membranes are prone tobiological fouling (biofouling), which ultimately limits the cost-effectivenessof this advanced treatment process. In an effort to slow the progression ofbiological fouling, chlorine and other oxidizing agents are routinely introducedin the feedwater. While this practice is generally effective, it can result indegradation to thin-film composite (TFC) polyamide RO membranes, which aresusceptible to attack by strong oxidizing chemical agents. As a result, membraneperformance can be quickly compromised. Newly designed polymer membranes arecontinually being designed to withstand the harsh chemical environmentsassociated with continual addition of chlorine and other oxidizing agents used tosuppress membrane biofouling. A chemically tolerant RO membrane wouldsubstantially reduce or possibly eliminate the costs associated with expensivepretreatment processes and frequent membrane cleanings. An experimental TFCmembrane, created by an interfacial reaction between one of the six possiblestereoisomers of cyclopentanetetracarboxylic (CPTC) acid chloride andm-phenylenediamine (MPD), has been developed to withstand prolonged operation onchlorinated feedwaters. Evaluations were conducted using flat-sheets of membranefed with secondary municipal wastewaters pretreated by a five-stage clarificationprocess. Experimental and commercial TFC membranes were evaluated for comparativepurposes. Results from membrane permeate flux and salt rejection measurementsindicate that the CPTC membranes exhibited chlorine resistance and low foulingpropensities when compared to commercial composite membranes. These findings havepromoted continued field evaluations of the CPTC membrane, which will also bepresented and discussed. Includes 6 references, tables, figures.