The June Lake Water Treatment Plant (WTP), located in the high Sierra Nevada region east of Yosemite, provides high quality drinking water with a new packaged microfiltration (MF) membrane system. The WTP serves the community of June Lake, CA, and is primarily used to help meet additional drinking water demands during the summer tourist season.
The district began the project with the goal of improving the plant’s reliability and performance, meeting future regulations and expanding its capacity.
“Our former pressure filter system wasn’t going to meet the new state water quality requirement for turbidity,” said Mindy Pohlman, General Manager of the June Lake Public Utility District. “Since we draw our water directly from the lake, polymers don’t have enough time to react with the particles in the water. With the membrane filtration system, the process doesn’t require chemicals for particle removal and it provides the most assurance of meeting future, potentially more stringent regulations. It gives us the highest water quality of the three alternatives we looked at.”
The new plant has an initial capacity of 200 gallons per minute (gpm), which the District plans to upgrade to an ultimate capacity of 400 gpm. The plant improvements included a new package membrane filtration system and modifications to the existing building and pumping systems. The upgrades increased system capacity, reduced chemical usage and provided higher quality drinking water than the former pressure filter plant.
Kennedy/Jenks Consultants designed the project. Because the plant is in a remote location, the district reduced project costs by coordinating the construction with in-house staff instead of using a general contractor. Additional costs savings were realized by raising the roof of the existing plant building to accommodate the membrane equipment instead of constructing a new plant building.
Membrane Alternative
The first phase of the plant improvements was completed by modifying the building and installing a Siemens/Memcor XS48 packaged MF skid in the building where the existing pressure filter had been housed. The building measures 20-ft. by 22-ft. When the system was installed, it was one of the first of Memcor’s small packaged systems to be installed in California. The new 200 gpm plant currently uses one MF membrane skid with the associated pipes and valves. When the district is ready to expand the plant to its ultimate 400 gpm capacity, additional membrane modules can be added to the skid. This will allow the district to double plant capacity without expanding the physical footprint of the plant.
Other Plant Upgrades
To transfer raw water from June Lake to the plant, the raw water pumps were retrofitted with new motors and variable frequency drives. After the water passes through the membranes, the filtered water goes to a small tank that serves as a wet well for new booster pumps. There the water is disinfected and lifted by booster pumps to a storage tank where it is stored for distribution.
A new submersible pump station was constructed outside the plant building to pump spent backwash and neutralized cleaning solutions from the membrane treatment process to the district’s wastewater plant for treatment and disposal.
Locating the new plant equipment within the existing plant building was a challenge. Also, plant construction had to be completed between Labor Day and Memorial Day when the district could use an alternative water supply and the June Lake WTP could be shut down. The district removed all the existing plant equipment shortly after Labor Day and worked through the fall and winter on the plant construction. The new plant was up and running in time for tourist season the next spring.
Conclusion
Package membrane systems are ideal for small water systems like June Lake because they produce high quality water with low operations and maintenance requirements. The new membrane filtration system has been producing high quality water for the community of June Lake since the spring of 2005.
“The plant is working very well,” Pohlman said. “It produces water that is less than 0.05 NTU. We’ve been very happy with it.”
The Kennedy/Jenks Consultants project team that worked on the June Lake WTP project included Todd Reynolds, PE, BCEE; Andrew de Boer, PE; and Lily Zhu, PE. Reynolds can be reached at [email protected].
