Laserfiche WebLink
WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2007- 4 <br /> CITY OF TRACY AND LEPRINO FOODS COMPANY <br /> LAND DISCHARGE UNITS OF THE TRACY WASTEWATER TREATMENT PLANT <br /> SAN JOAQUIN COUNTY <br /> Constituent Units Average Maximum <br /> Nitrate-N mg/L 5t2t 7 <br /> Nitrite-N mg/L 4(2) 5 <br /> Arsenic Ng/L ND(2) 6.9 <br /> Manganese Ng/L 51'2) 91 <br /> (1) Leprino influent to Pond 2. <br /> (2) Average of Ponds 1 through 5. Actual constituent concentrations vary from pond to pond. <br /> 10. The City utilizes sand sludge drying beds for dewatering its anaerobically digested sludge. <br /> The Facility includes 12 drying beds with a total surface area of approximately 8.2 acres. <br /> The drying beds use an underdrain system to return residual liquid to the plant sewer <br /> pump station, which is returned to the facility headworks. However, the beds are not lined <br /> to prevent seepage to groundwater. Therefore, discharges from the sludge drying beds <br /> are regulated by this Order. <br /> 11. The City stores the dried biosolids onsite in an unlined pond prior to final disposal to a <br /> landfill. There is the potential for seepage to groundwater during rainfall events. <br /> Therefore, discharges from the biosolids storage area are regulated by this Order. <br /> Site-Specific Conditions <br /> 12. Driller's logs from wells in the vicinity of the industrial holding ponds show alternating <br /> sands and clays with no predominance of fine- or coarse-grained deposits. Depth to <br /> groundwater ranges from 14 to 18 feet below ground surface (bgs) near the industrial <br /> ponds. Groundwater flows to the north. <br /> 13. As shown on Attachment E (which is attached hereto and made part of this Order by <br /> reference), the City has installed five groundwater monitoring wells around its unlined <br /> industrial storage ponds. These are the only groundwater monitoring wells at the Facility. <br /> Additional groundwater studies or monitoring wells may be required to determine if the <br /> sludge drying beds, biosolids storage area, and/or Leprino's pretreatment lagoons are <br /> adversely affecting groundwater quality. Provisions E.1.b. requires the Discharger to <br /> ensure the groundwater monitoring network includes one or more background monitoring <br /> wells and a sufficient number of monitoring wells downgradient of every treatment, <br /> storage, and disposal unit that does or may release waste constituents to groundwater. <br /> Basin Plan, Beneficial Uses, <br /> and Regulatory Considerations <br /> 14. The Water Quality Control Plan for the Sacramento River and San Joaquin River Basins, <br /> Fourth Edition, revised August 2006 (hereafter Basin Plan) designates beneficial uses, <br />