Comparision of cellulose acetate and nanofi ltration membranes for color removal from a norwegian lake

Abstract

Norwegian lake water treatment is dominated by cellulose acetate (CA) membranes, which serve approximately 3% of the population. The quality requirements for potable water are becoming stringent and Dow Water & Process Solutions has suggested nanofi ltration (NF) as a suitable technology replacement in cases where CA membranes fail to meet the quality limits. This paper discusses the operating experience of the fi rst CA plant retrofi t trial in Norway, where the treatment goal was to remove color, organic matter and bacteria from surface lake water to produce potable water for the community. The project has shown that nanofi ltration membranes can provide excellent water quality in terms of color, bacteria and an overall TOC rejection (98%). The end user reports a clear improvement in the water quality compared to CA membranes. The trial was executed with minimal modifi cations to the existing plant. This paper focuses on evaluating the feasibility of the current set up and gives recommendations on furth...