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A feasibility assessment of retrofitting a 25 year-old, 40 MGD surface water treatment plant(WTP) with membrane microfiltration is presented in this paper. Presently, this WTP employs raw waterozonation, lime softening, ferric sulfate flocculation, coagulation, sand filtration, fluoride additionand chlorine disinfection. Capital cost and operation and maintenance costs were evaluated. A20 year life cycle analysis was utilized to compare between "conventional" rehabilitation andmembrane filtration (MF) retrofit. The study recommended a MF retrofit over a "conventional"rehabilitation subject to pilot testing confirmation. Because of the superior and consistent qualityof MF permeate, several existing processes were deemed no longer needed and for some areduction in number of units. Significant saving in residuals management can be achieved withMF compared to the existing treatment processes.The study indicated that the MF with microfiltration/ultrafiltration (MF/UF) technology is feasible,and is competitive in cost compared to rehabilitation of the existing lime softening plant andgranular media filters if one considers the abandonment of the softening process and itsassociated solids handling costs. Instead of raw water ozonation for taste and odor problems, apermeate ozonation is recommended resulting in significant ozone dose reduction, which in turnreduces the capacity requirements and power demand on the ozone generation equipment.Although the feasibility study included the evaluation of split flow water softening using lowpressure reverse osmosis, the discussion is not included in this paper.A pilot plant demonstration is definitely recommended in order to verify the technology, determinethe design parameters values, and confirm the need for and level of pretreatment required. Includes tables, figures.

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Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 18File Size: 1 file , 230 KB