Full Description

A dynamic model was developed to describe the competitive adsorption oftrace organic compounds by powdered activated carbon (PAC) in a PAC/membranefiltration system. Two major competitive mechanisms caused by natural organic matter (NOM), directcompetition for sites and pore blockage were considered. The model accurately predictedatrazine removal in the presence of 1,4-dichlorobenzene (p-DCB) and poly(styrenesulfonate) (PSS), which represented the strongly competing and the pore blocking NOMfractions, respectively. The model was applied to investigate the effects of importantdesign and operating parameters such as the length of membrane cleaning interval,manner of membrane cleaning (backwash or hydraulic flushing), PAC type, dose, anddosing scenarios on the removal of trace organic compounds. Atrazine removal wasfound to be affected by the membrane cleaning interval (MCI) more than by the hydraulicretention time (HRT). It was also found that a long MCI was not necessarily beneficialfor the adsorption of trace organic compounds when low PAC doses were used. Theoptimal membrane backwash interval for trace organic compound removal should bedetermined based on the NOM characteristics of the influent water, the PAC dose and thebackwash or hydraulic flushing water quality. The type of adsorbent was also veryimportant. It should be selected based on the NOM characteristics of the influent water. Includes 10 references, tables, figures.

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Edition: Vol. - No. Published: 03/05/2003 Number of Pages: 18File Size: 1 file , 310 KB