Cost estimates for membrane filtration and conventional treatment

Abstract

Membrane processes may offer small facilities a less expensive alternative for the removal of particles and organic materials. Costs of several ultrafiltration and nanofiltration processes are compared with the cost of conventional liquid‐solid separation with and without GAC adsorption for small facilities. Data on raw‐water quality, permeate flux, recovery, frequency of backflushing, and chemical dosage obtained from a pilot study were used with a previously developed model for membrane costs to calculate anticipated capital and operating costs for each instance. Data from the US Environmental Protection Agency were used to estimate conventional treatment costs. All of the membrane process calculations showed comparable or lower total costs per unit volume treated compared with conventional treatment for small facilities (<200,000 m 3 /d or about 5 mgd).