AWWA SOURCES59193

The full-scale operation of water reuse facilities, and delivery of recycled water to farms, by the Monterey Regional Water Pollution Control Agency began in April 1998. Depending on demand for the reclaimed municipal wastewater, up to 90,000 m³/day (24 million gal/d) can be treated and distributed to farmers to irrigate 5,000 hectares (12,000 acres) of food crops, including artichokes, lettuce, broccoli, and strawberries. The treatment train consists of primary sedimentation, biological secondary treatment (trickling filter/solids contact), coagulation, flocculation, dual-media filtration, and chlorine disinfection. Since 1988, the tertiary effluent has been monitored daily for total and fecal coliform bacteria and approximately three times per year for pathogenic organisms of concern, including total culturable virus, E. Coli 0157:H7, Legionella, Salmonella, Shigella, Cyclospora oocysts, Giardia cysts, Cryptosporidium oocysts, and helminth eggs. During five years of monitoring, the California Title 22 standard on total coliforms has been exceeded only five times. In terms of pathogens, only Cryptosporidium oocysts, Giardia cysts, and Cyclospora oocysts have been found in the final effluent. Cryptosporidium oocysts were detected in 39% and Giardia cysts and Cyclospora oocysts in 6% of the effluent samples, with maximum concentrations of 2.3, 0.3, and 0.034 cysts/L, respectively. These low concentrations are not believed to represent a health risk. Includes 16 references, tables.