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Staff Report -7— Waiver 7— Waiver of WDRs for Small Food Processors to treat the high BOD, salt, and nitrogen concentrations in winery wastewater to levels that will not degrade the underlying groundwater. Despite a request for input in the 25 March 2003 letter to the winery mailing list, the industry has not provided any rationale as to how this could happen either. Without sufficient treatment in the soil beneath a leachfield, untreated waste will migrate into the groundwater and cause degradation. Staff has reviewed available literature to see if septic tanks/leachfields are recommended as a method for the treatment and/or disposal for food processing wastewater. Neither the US EPA' nor the California League of Food Processors recommends this type of system. A septic tank performs in essentially the same way as a sedimentation pond, and can reduce the BOD concentration significantly in wastewaters high in settable solids. However, sedimentation systems alone are ineffective in treating wastewater primarily composed of dissolved BOD, such as winery wastewater 3. Additionally, unless such systems are specifically sized and designed to allow adequate solids settling during peak or slug flows,effluent quality will be variable 1,Z. In any case, dissolved solids (TDS)will not be removed by a septic tank. The Central Coast Regional Board's General Order allows a waiver for wineries using leachfields for disposal as long the discharger can "provide proof'that the depth to groundwater at the disposal area is greater than 100 feet. The Regional Board typically requires that such proof be provided in a report prepared and stamped by a California Registered Engineer or Geologist. The professional would review such items as well logs, sources of springs, depth to bedrock,the potential for perched groundwater, and the potential for fractured flow, and provide an opinion based on their professional expertise. The need to provide data stamped by a registered professional is a standard requirement for other dischargers, and would therefore be expected from wineries documenting the depth to groundwater. Many small wineries in the foothill counties are in areas with shallow soils and fractured bedrock. It seems unrealistic that many, if any, sites could provide proof that there is at least 100 feet to first groundwater beneath their leachfield. It should also be pointed out that this waiver is intended to be a simple tool for both the discharger and staff. The minimal one-time filing fee provided with the RWD does not permit staff to review in-depth analyses of groundwater conditions. That review is more appropriate in the development of site-specific WDRs. Staff of the Central Valley Regional Board have discussed the discharge of winery wastewater with staff from the Central Coast and North Coast Regional Boards. Neither of these Regional Boards has required a winery with a septic tank/leachfield disposal system install groundwater monitoring wells to determine whether this disposal method is degrading groundwater. It appears that the Central Valley Regional Board has required the most groundwater monitoring at wineries (although USEPA 1977.Pollution Abatement in the Fruit and Vegetable Industry,Basics of Pollution Control/Case Histories (EPA-625/3-77-0007-V.1). x Brown and Caldwell,et al.,2002. Manual of Good Practice,Land application of Food Process/Rinse Water, California League of Food Processors,Sections 8.1.3 and 8.2. 3 Storm,David R.,2001.Winery Utilities Plan,Design,and Operation,Aspen Publisher,Inc.,Gaithersburg,MD,pp 201-204 and 227-235.