Application of low pressure nanofiltration membranes for the recovery and reuse of dairy industry effluents

Abstract

This paper outlines the requirements for water reuse of dairy industry treatment plant effluents. Two alternative membrane processes are described. Nanofiltration (NF) membranes were applied to the existing treatment plant effluents in the first part of the study. NF membranes were used in different operating conditions. Successive batch runs had shown that serious membrane fouling appeared not to be a problem with treatment plant effluents. Excellent rejections have been achieved. It will be possible to recover approximately 90% of the treatment plant effluent for reuse. Heavy metal removal was also very high. In the second part of the study, two pass reverse osmosis (RO) membranes were applied to the raw wastewater of the dairy industry. RO experiments demonstrated that two-pass RO produce permeate of very good quality. Almost complete COD removals were achieved and flux values decreased slightly during the each RO run.