Pilot Evaluation of Ceramic Membranes in Surface Water Treatment with Coagulant Pretreatment

Results from a pilot scale study on the performance of ceramic membranes in treating high turbid waters are presented. Coagulation pretreatment using alum or ferric sulfate was found to improve permeate quality and increase permeate flux. In comparison with ferric sulfate, pretreatment with alum resulted in lower permeate turbidity. DOC removals between 45-65% are possible with coagulation. Ferric sulfate was more effective in reducing organic carbon concentrations. The highest permeate fluxes were observed with alum coagulation, at pH 6. The quality of the membrane permeate was similar to that achievable by packed bed filtration. Careful control of coagulant dose and pH is required to optimize performance of the process and may pose difficulties in full scale operation.