Drinking Water Engineering and Science Discussions www.drink-water-eng-sci-discuss.net 1996-9473 1996-9481 2 2 2009 10.5194/dwesd-2-205-2009 http://www.drink-water-eng-sci-discuss.net/2/205/2009/ http://www.drink-water-eng-sci-discuss.net/2/205/2009/dwesd-2-205-2009.html http://www.drink-water-eng-sci-discuss.net/2/205/2009/dwesd-2-205-2009.pdf 205 229 2009-11-03 Optimized conditions for application of organic flocculant aids in water purification P. Polasek polasek@mweb.co.za Water & Wastewater Treatment Consulting Engineer, P.O. Box 61965, Marshalltown, 2107, South Africa The application of organic flocculant aid (OFA) to a system undergoing aggregation has a direct effect on the quality of purified water as well as the settleability of resultant agglomerates. The optimum conditions for OFA application exist when the formation of aggregates by means of destabilisation (aggregation – CPE) reagent reaches flocculation optimum, i.e. the measure of flocculation γ=1, prior to OFA addition. Such method of OFA application is called the Post-Orthokinetic Agglomeration (POA) process. The POA process results in the formation of the fastest settleable agglomerates and the best quality of purified water matching that attainable without the use of OFA. Recirculation of the sludge conditioned by OFA back to the process of particle aggregation was found undesirable as it adversely affects the purified water quality as well as the settleability of produced agglomerates. Hereit, F., Mutl., S., and Vagner, V.: The formation of separable suspension and the methods its assessment, J. Aqua, 29, 95–99, 1980. Polasek, P.: Methods and testing procedures for monitoring and evaluating waterworks performance, Proc. Int. Conf., Johannesburg, 1980a. Polasek, P.: HR clarifier performance results, Proc. Int. Conf., Johannesburg, 1980b. Polasek, P. and Mutl, S.: Acceleration of gravity separation process, J. Filtration, 5(1), 33–39, 2005a. Polasek, P. and Mutl, S.: High Rate Clarification Technology, Proc. IWA Spec. Conf., Particle Separation 2005, Seoul, South Korea, 2005b. Vostrcil, J.: The effect of organic flocculants on water treatment and decontamination of water by a floc blanket, VUV Praha, Prace a Studie No. 129, 1971.