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Upgrading to a New Cost-Effective Disinfection Solution

Weaverville CSD converts an existing gas chlorine system to a safer, turnkey hypochlorite system


The Weaverville Community Services District (CSD) is a publicly owned municipal water agency located in Weaverville, California. The facility needed to retrofit an existing building and switch from a gas feed system to an onsite hypochlorite system. The conversion from gas to hypochlorite is a trend being seen in many Northern California districts as regulations on chlorine gas increase.

Weaverville CSD wanted to convert their exisitng gas chlorine system to a safer and more effective hypochlorite system; but because of small ppd requirements and a remote location, bulk hypochlorite delivery was determined to be too expensive. The facility general manager, Wes Scribner began evaluating onsite technologies as a cost saving alternative to meet plant capacity requirements. Traditionally, on-site generation systems have been too expensive for customers with lower chlorine demands to recognize a significant return on investment. Evoqua's OSEC® L system was selected for the project meeting the facility's small footprint but also offered a turnkey solution that was cost-effecitve and easy to operate and install.


The OSEC L system is a low capacity bipolar brine-based hypochlorite generator. It is an inherently safe alternative to chlorine, sodium hypochlorite and calcium hypochlorite; the OSEC L system does not require handling of any hazardous chemicals. The generator produces a dilute hypochlorite solution <1.0 wt% concentration using saturated brine (salt), water and electricity in an electrochemical process. With an embedded process controller the system is fully automated and can work in batching or direct feed operation modes. The compact, easy to operate design allows plant operators to reduce downtime and long service intervals. The footprint is 50% smaller versus other on-site generators and NEMA 4X rated components minimize corrosion and provide a safe long-life disinfection solution with low life-cycle costs.

" The unit is clean, simple, and professional. We really appreciate the modular design, allowing it to fit into a challenging space. We are happy to be the first customer to install the new OSEC® L system and have been bragging about it! "


Since adding the OSEC L system, the Weaverville CSD has been able to address their move away from gas and has realized significant savings by sourcing their salt through local hardware stores. They also no longer need to transport chemicals to their remote location, saving additional cost and effort. “With the increasing regulations on chlorine gas, it has worked out well for us.“ said Scribner. “We look forward to installing another unit at our other treatment plant.“