ANALYSIS OF 10 YEARS OF VIRUS MONITORING DATA FROM LOS-ANGELES-COUNTY TREATMENT PLANTS MEETING CALIFORNIA WASTE-WATER RECLAMATION CRITERIA

Six tertiary treatment water reclamation plants were monitored monthly for enteric viruses for 10 years. Secondary treatment removed 99.8% of the detectable viruses. The virus concentrator and assay system detected low levels of native viruses in 74 out of 75 unchlorinated secondary effluent samples. Only 1 of 590 final effluent samples averaging 1 040 L (275 gal) was positive for enteric viruses. These results suggest that the California Title 22 treatment-based water reclamation standards assure reliable production of essentially virus risk-free effluents.