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` Californiaonal Water <br /> 1 � �TQuality Cont Board <br /> Central Valley Region <br /> Ln lams Karl E. Longley,ScD,P.E.,Chair <br /> Se <br /> for Sacramento Main Office <br /> En nlal 11020$un Cen(er Drive N200 <br /> l 'n Phone(916)464-Rancho 1FAX <br /> (916)California 956770-6114 Arnold <br /> h"Ppll�yN, aterboards.cago(v/cent464-4 4 LI)Q� Schwarzenegger <br /> 3y 2007 ralvalMAY —4 PH 212.5 Caverna, <br /> lTFt x [PARTijglq-r <br /> Johnston <br /> ctor of Public Works <br /> �. of Ripon <br /> 259 N. Wilma Ave. <br /> Ripon, CA 95366 <br /> REQUEST FOR TECHNICAL REPORT, ARSENIC REMOVAL IMPACT ON WASTEWATER <br /> SYSTEM AND GROUNDWATER QUALITY, RIPON, SAN JOAQUIN COUNTY <br /> The California Department of Health Services has informed the Regional Water Board of the <br /> City of Ripon's proposed drinking water arsenic removal treatment system. We have been <br /> provided two documents on the planned water system improvements, as follows: <br /> 2 April 2007 Draft Engineering Report for the City of Ripon Well 9 Arsenic Treatment <br /> Process, prepared by Damon S. Williams Associates, LLC; and <br /> (Undated) Engineering Report for the City of Ripon Well 9 Arsenic Treatment <br /> Process, prepared by Damon S. Williams Associates, LLC. <br /> The 2 April 2007 correspondence stated the mass of arsenic discharged to the wastewater <br /> system is unlikely to significantly affect the City's wastewater system, but the report does not <br /> consider the potential impact on groundwater quality, nor does it consider further treatment to <br /> reduce the arsenic discharged to the wastewater system. In addition, the documents do not <br /> describe which wastewater system (industrial or domestic) the arsenic would be discharged to. <br /> Staff believes the water supply treatment is likely to significantly increase the total amount of <br /> arsenic discharged to the wastewater system because substantial amounts of water are used <br /> for irrigation at residences and businesses. Historically, that arsenic was not returned to the <br /> wastewater system. In addition, other chemicals used in the water supply treatment process <br /> or in associated cleaning activities will also be discharged to the wastewater system. By <br /> removing the arsenic in water supply treatment, the City is likely changing the wastewater <br /> %tcha�9P by increasing the total amount of arsenic discharged, adding new chemicals of <br /> concern to the discharge, and concentrating the discharge in the limited area that the <br /> wastewater system occupies. For those reasons, staff believes the change has the potential <br /> to degrade groundwater quality. <br /> The document states, "To ensure that the discharge standards are maintained, the City will <br /> continue to monitor the treated wastewater effluent according to the Revised Monitoring and <br /> Reporting Program..."but staff note that arsenic is not included in the Revised Monitoring and <br /> Reporting Program; it is unclear how the information obtained by performing the required <br /> California Environmental Protection Agency <br /> ped Recycled Paper <br />