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A. <br /> RATE OF CALIFORNIA—HEALTH AND WELFARE AGENCY GEORGE DEUKMEa414, Governor <br /> DEPARTMENT OF HEALTH SERVICES - <br /> 31 E. CHANNEL STREET, ROOM 270 <br /> STOCKTON, CA 95202 <br /> (2" 948-7697 - <br /> November 2. , 1987 <br /> Mr. Steve Woodard <br /> Little Potato Slough Mutual Water Company <br /> 14900 W. Highway 12 <br /> Lodi, California 95240 <br /> MODIFICATION OF SURFACE WATER TREATMENT FACILITIES <br /> Since the Little Potato Slough Mutual Water Company is currently <br /> in the process of designing equipment and facilities to improve <br /> the water treatment, you should be aware of changes in the <br /> surface water treatment regulations which will affect surface <br /> water treatment plants in the near future. <br /> The Department is currently developing new regulations for the <br /> treatment of surface waters for domestic use. The regulations <br /> are being developed in response to Federal requirements embodied <br /> in the Safe Drinking Water Act amendments of 1986. The draft <br /> regulations require that all surface waters be given complete <br /> conventional treatment which includes coagulation, flocculation, <br /> sedimentation, filtration, and disinfection or equivalent <br /> treatment provided that the equivalency of the non-conventional <br /> treatment is demonstrated in conformance with criteria set forth <br /> in the regulations. The draft regulations also include <br /> performance standards which must be met by surface water <br /> treatment trains, reliability requirements and operational <br /> requirements. The regulations will apply to all existing surface <br /> water treatment plants as well as new treatment facilities. <br /> Therefore, any measures taken by purveyors currently designing <br /> treatment processes -to assure that an optimum level of water <br /> quality improvement is achieved will prevent the need for <br /> retrofitting and redesigning facilities to upgrade the level of <br /> treatment to meet new regulatory performance standards. <br /> Although the regulations have not yet been adopted, the <br /> guidelines currently require a 1000 fold removal and inactivation <br /> of giardia cysts and a 10, 000 fold removal and inactivation of <br /> enteric viruses. Similarly, the guidelines include a turbidity <br /> standard for rapid sand and direct filters as follows: <br /> a) never to exceed (undetermined as yet NTU <br /> b) not to exceed 0.2 NTU 50% of the time <br /> c) not to exceed 0. 3 NTU 75% of the time + �1��7 <br /> d) not to exceed 0. 5 NTU 95% of the time ; � <br /> ENVIRUMt`•�S�RV CESTH <br /> F ERMII/ <br />