The characteristics of backwash and concentrate discharges depend upon the quality of
the water being treated and the net recovery of the membrane system. This paper is to
indicate a design methods on the capacities of residuals treatment facilities in
membrane processes for drinking water. We operated a demonstration membrane plant with
a recovery rate of 90 percentage for designing G-water treatment plant. We
investigated on esign parameter (optimum coagulant dosage and surface loading rate
etc.) to design efficiently the residuals treatment facilities.The settling test was
conducted with 1m columns dosing PACl to kaolin and membrane residuals under the
experimental condition that discharge permit was under a 60mg/L. When the quantity of
membrane residuals was 1,575m3/day, the estimated results for 1st thickener
demonstrated the surface loading rate of 14.4m/day, detention time of 5.83hr, available
depth of 3.5m.
