AWWA JAW36161

A prefabricated dual-stage filtration system was installed as a demonstration project under the USEPA Small System Technology Initiative at Freestone, California, a community of approximately 70 people. The filtration system proved to be a cost-effective compliance option for this small water system, which had a long history of microbiological contamination and boil-water orders. Dual-stage filtration of a source water that averaged monthly turbidities of 4.25-23 ntu consistently produced water with turbidity concentrations well below 0.5 ntu. Using an advanced telemetry device that relayed key operating data to his office 13 mi. from the plant site, the operator was able to successfully operate and maintain the equipment working an average of 13 hours/month (including travel time and state-mandated weekly site visits). The overall cost for the dual-stage filtration system at Freestone was $7.56/1,000 gal (3.8 m3), 42 percent less than the estimated cost for a similarly sized coagulation-filtration system for this site. Transferring ownership of the system to Sonoma County was a key factor in the success of this project. Includes 10 references, tables, figures.