Effect of solution chemistry on assimilable organic carbon removal by nanofiltration: full and bench scale evaluation

    Authors

    I. C. Escobar; A. A. Randall; S. K. Hong;J. S. Taylor

    Abbreviated Journal Title

    J. Water Supply Res Technol.-Aqua

    Keywords

    assimilable organic carbon (AOC); biostability; nanofiltration; solution; chemistry; zeta potential; BIODEGRADABLE FRACTION; REVERSE-OSMOSIS; DRINKING-WATER; MATTER; GROUNDWATER; MEMBRANES; Engineering, Civil; Water Resources

    Abstract

    The effectiveness of nanofiltration (NF) to control assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC) the main indicators of biological stability of finished, potable water, was systematically investigated at the 30,000 m(3)/day NF membrane plant located in Southern Florida. one year of full-scale operation showed that nanofiltration effectively reduced BDOC but was not able to reject AOC. The insignificant AOC rejection observed was probably due to the low pH, high hardness, and high ionic strength (TDS) of the processing water, In order to verify this hypothesis, a series of well-controlled bench-scale experiments were conducted at simulated solution chemistries. The bench-scale study clearly demonstrated that AOC removal by NF membranes decreased markedly with decreasing pH (a 25% decrease in pH led to a 20% decrease in AOC removal), and increasing hardness (10-fold increase led to a 90% decrease in AOC removal) and ionic strength (a 25-fold increase led to a 50% decrease in AOC removal) These solution. environments repress the electrostatic repulsion between charged AOC compounds and membranes, resulting in low AOC rejection. Lastly, an empirical model was statistically developed based on bench-scale data and utilized to estimate full-scale performance, AOC removal predicted by the model showed good agreement with values observed in full-scale operation (R-2 = 0.98).

    Journal Title

    Journal of Water Supply Research and Technology-Aqua

    Volume

    51

    Issue/Number

    2

    Publication Date

    1-1-2002

    Document Type

    Article

    Language

    English

    First Page

    67

    Last Page

    76

    WOS Identifier

    WOS:000175088800001

    ISSN

    0003-7214

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