The effects of branching and other physical properties of anionic polyacrylamides on the flocculation of domestic sewage

Authors

  • Alan J. Anthony,

    1. Civil Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
    Current affiliation:
    1. Bureau of Applied Technology, State Water Control Board, P.O. Box 11143, Richmond, Virginia 23230
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  • Paul H. King,

    1. Civil Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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  • Clifford W. Randall

    1. Civil Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Abstract

This investigation was undertaken to evaluate the effect of long-chain branching of anionic polyacrylamides on the flocculation of domestic sewage. The polyelectrolytes were polymerized using a redox couple, selectively hydrolyzed, and then characterized by means of light-scattering photometry. Coagulation tests were then employed to evaluate the synthesized polymers. The optimum polymer dose for suspended solids removal was used as the basis for evaluating each anionic polyacrylamide fraction with respect to its ability to flocculate domestic sewage. The results of this investigation indicated that as the weight-average molecular weight increased, the optimum polymer dose decreased. For polymers of similar molecular weights and differing radii of gyration, as the radius of gyration increased, the optimum polymer dose decreased, indicating that the “linear” polymers were more efficient in removing suspended solids than the “branched” polymers.

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