Full Description

The application of ultrafiltration (UF) and microfiltration (MF) membrane processes to treatsecondary and/or tertiary treated wastewater for reuse purposes is gaining popularity in theUnited States and the world today. This is a result of the continuing depletion of fresh drinking watersupplies and the development of regulations and guidelines associated with reclaimed waterproduction. Membrane processes provide an effectivemeans of meeting these demands because of their ability to remove solids as well as microbialcontaminants including viruses by size exclusion. Inaddition, this technology requires small footprints and minimal chemical addition, in comparisonwith conventional wastewater reclamation processes.The performance of UF/MF membrane processes can be affected by operating conditions andfeed water characteristics. Several key operational conditions that control membraneperformance include operating flux, backwash frequency, and pretreatment processes, such as coagulation. Furthermore, UF/MF productivity can be significantlydeteriorated by membrane fouling, which results from the mass loading of solid, organic andmicrobial contaminants present in the feed water. The optimization of suchconditions is essential to achieving the productivity and filtrate water quality necessary for waterreclamation. The main intent of this study was to assess the effect of various operating conditions on theperformance of capillary fiber UF membranes during the reclamation of tertiary treatedwastewater. Specifically, a series of pilot experiments were conducted using a small-scale UFsystem to investigate the effect of operating flux, backwash frequency, and in-line coagulationpretreatment on membrane productivity and removal efficiency. Accordingly, membraneproductivity was assessed by monitoring the temperature corrected mass transfer coefficient(MTC) of water with respect to filtration time. The rejection capability of the UF system wasevaluated by measuring the feed and filtrate concentrations of solid (turbidity and particlecounts), organic (UV254 and TOC), and microbial (total coliform and heterotrophic plate counts)parameters under varying operating conditions. Based on pilot experimental data, fundamentalmechanisms of productivity decline and contaminant removal during ultrafiltration of tertiarywastewater were delineated for future process optimization. Includes 27 references, tables, figures.

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Edition: Vol. - No. Published: 05/01/2001 Number of Pages: 22File Size: 1 file , 320 KB