AWWA MTC57642

Water treatment facilities across the United States are upgrading their facilities, and as a result, may be considering MF/UF technology as an option. There are many reasons for this trend including: regulatory requirements (both existing and future). The future is now with respect to low-pressure membrane treatment (microfiltration (MF) and ultrafiltration (UF)). The market has become increasingly competitive, which results in exceptionally cost-effective treatment facilities, especially when considering the quality of the finished water. As the market has become more competitive, membrane system suppliers are becoming more aggressive with their applications as well as with their overall design. There is limited long-term installation information for most of these systems; however, the operating (and piloting) results for most of these systems are very exciting. Based on the available data, it appears that "traditional" membrane designs (i.e. those over a year or so old) may have been very conservative. This is due to the limited operational data at that time as well as membrane module warranties that place a significant risk on the supplier should the membranes not perform or foul at a quicker rate than expected. As a result, engineers and vendors correctly opted for conservative membrane system designs. However, since the competition in the MF/UF marketplace has increased significantly over the past few years, membrane suppliers are becoming more aggressive with their designs, which have translated into much more costeffective membrane systems. However, as the suppliers are developing more aggressive designs, proper engineering evaluations, effective procurement documentation and clearly defined purchase and warranty contracts are more critical than ever to ensure a quality installation at the lowest possible cost to a public water system. Membranes can fit in a variety of applications. They can be used post-filtration as a final polishing step; they can be used to replace existing gravity filters; and, depending on raw water quality, they can be used in lieu of an entire conventional treatment facility. The evaluation of the best membrane application for a specific water system is a balance of costs vs. risk tolerance. A number of water treatment facilities across the United States are facing facility upgrades and low-pressure membranes will undoubtedly be one of the many options considered. A number of site-specific issues must be addressed at individual facilities, and, to date, little industry guidance is available to public water systems when considering membrane technology and its most costeffective application point. Accordingly, this paper highlights some of the issues that should be addressed, which are based on a real-life example recently experienced in Lancaster, Pennsylvania.