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This paper presents a study, funded by the Awwa Research Foundation (Water ResearchFoundation as of January 1, 2009), that explores the effects of organic nitrogen compounds(measured as dissolved organic nitrogen -- DON) on reversible and irreversible fouling of low pressure (LP)membranes as well as pretreatment conditions to optimize organic nitrogen removal andminimize membrane fouling. The paper presents initial data for experimental work with modelnitrogen containing compounds. One critical aspect of this research is the study of the impact of DON on membrane fouling for abench-scale system that imitates full-scale operation. Poly(vinylidene-fluoroethylene) (PVdF)based outside-in membrane samples were tested. The fiber has an inner diameter (ID) of 0.8 mm,outer diameter (OD) of 1.9 mm, and a nominal membrane pore size of 0.04 micron(manufacturer supplied data). The technique that was usedallowed the lower ends of the fibers to be loose, and for one end of the membranemodule to be open which obtained better removal of solids during backwashing. This pottingtechnique also makes it easier to remove a small piece of the hollow fiber for surface analyses.An air bubble test was conducted to check for membrane leakage on assembled modules prior totesting. The membrane system was built so that either vacuum or pressurizedoperational modes can be utilized. In this initial phase, tests were conducted using the vacuummode, which is the actual operation mode at pilot and full scales for the type of membraneutilized. Three separate pressure transducers were used to monitor the pressure at the inlet andoutlet to the membrane module and the backwash pressure. The membrane system was operatedat constant flux, dead-end filtration, with periodic backflushing and monitoring of TMP andpermeate volume. Chemical washing was conducted periodically. Includes table, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 7File Size: 1 file , 730 KB