Lessons Learned During Four Years of Operation of a Ceramic Membrane System for Drinking Water

The drinking water source for many municipalities is a lake or reservoir that is at a much higher elevation than the treatment plant, and the water must first be stored before pumping through the treatment system in order to prevent over-pressurization of the equipment. One such facility is the Basin Creek Water Treatment Plant in Butte, MT, where the overflow on the source reservoir is 175 feet above the plant. The Basin Creek Reservoir contains some of the most pristine water in all of Montana; for over 100 years, treatment consisted solely of chlorine addition for disinfection. But in 2011, a pine beetle infestation added extra organic material to the reservoir, which combined with the chlorine to form disinfection byproducts slightly above the required levels. As a result, the State mandated that the water be filtered prior to disinfection. The City and its engineer, HDR Engineering, looked at the filtration alternatives and determined that a low-pressure membrane system would be the best choice, not only for lowering the organics in the water but also for removing harmful pathogens. Proposals were requested and their 20-year life cycle costs were compared. The City decided to go with a ceramic membrane system because it was able to handle the higher inlet pressure, had a 20-year warranty, and generated much less wastewater. The full-scale plant was constructed and placed on-line in May of 2017, designed to handle up to 7 MGD and undergo a clean-in-place (CIP) every six months. The system is currently operating at more than 99.8% recovery, generating less than 14,000 gallons of wastewater per day. In addition, drinking water is typically provided to the City using only the head from the reservoir with no pumping required, which results in an enormous power savings. While the system has operated nearly flawlessly over its first four years of operation, there have been several challenges: both primary and recovery systems have experienced high TMPs on certain occasions, one of the primary trains failed its air integrity test, some of the valve actuators failed, to name a few. This session describes the ceramic membrane system, gives the system performance since startup, and discusses some of these challenges and the lessons learned.

This presentation is available to AMTA Members only.