AWWA WQTC57039

At the end of the 1980s and in the beginning of the 1990s, conventional treatment processes began to look limited in their capability to treat water supplies. Not only was there a continuing decline in raw water quality, but there was a substantial increase in both consumer standards and microbiological contaminants. It was realized that traditional methods of water treatment were often incapable of meeting water quality needs. At that time, new methods of water treatment, particularly innovations in pressure-driven membrane processes, were being introduced in the United States at full scale. Although membrane processes have been used successfully for many years in desalting brackish water and seawater, new kinds of membranes were being seen as capable of treating water for a wide range of other uses, particularly turbidity and microbial removal. The objective of this paper was to describe the increasing role that membrane technology has played the United States, particularly in terms of its use for meeting microbial regulations. Topics discussed include: advantages of low-pressure membranes; growth in membrane use; disinfection as an impetus for membrane use; clarification as an impetus for membrane use; and, strategies for integration into water treatment plants. Includes figures.