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Treatment and disposal of concentrate from nanofiltration (NF) and reverseosmosis (RO) membrane filtration processes is an important issue facing utilities in areasof scarce water supply. Feasible disposal options for membrane concentrate areultimately site specific and depend on the concentrate's quantity and quality. It has beenproposed that removal of trace pollutants such as arsenic from membrane concentratemay increase the number of disposal options or even allow for concentrate reuse.This paper presents results of an on-going study exploring chemical treatment ofmembrane concentrate, with emphasis on coagulation using iron chloride followed bysolid-liquid separation. Simplified concentrate solutions at ionic strengths representativeof NF/RO concentrate (0.2 and 0.7 M) were prepared in the lab using specific ratios ofmajor ions (e.g. sodium, bicarbonate, etc.). Removal of arsenic from these simulatedconcentrates was determined experimentally using small volume jar test procedures.Solids formed during treatment were separated from solution using 0.2 micron pore sizefilters. Removal of arsenic as functions of background matrix, natural organic matter (NOM) source, andcoagulant dose are presented. Includes 3 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 8File Size: 1 file , 240 KB