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WASTE DISCHARGE REQUIREMENTS ORDER NO. • 2 '
<br /> CITY OF LATHROP AND METROPOLITAN LIFE INSURANCE COMPANY
<br /> CROSSROADS TREATMENT PLANT NO. 1, SAN JOAQUIN COUNTY
<br /> 6. Waste Discharge Requirements (WDRs) Order No. 94-198, adopted by the Board on 24 June 1994,
<br /> prescribes requirements for the Discharger's municipal wastewater treatment plant and the discharge
<br /> of treated effluent to evaporation/percolation ponds. The Discharger has evaluated the available
<br /> land areas described in Order No. 94-198 and determined they are inadequate for the anticipated
<br /> long term wastewater flow rate. The 18 May 2001 RWD proposes new land application areas;
<br /> therefore, Order No. 94-198 is inadequate and requires an update.
<br /> Existing Facility and Discharge
<br /> 7. The wastewater treatment facility and evaporation/percolation ponds areas cover approximately 12.2
<br /> acres. The wastewater treatment plant consists of approximately 2.2 acres, while the existing ponds
<br /> (including berms and roadways) consist of approximately 10.0 acres.
<br /> 8. Wastewater treatment processes include influent pumping, mechanical screening, grit and grease
<br /> removal, extended aeration, and clarification. Effluent is currently discharged to three 2.4 acre
<br /> evaporation/percolation ponds for disposal. Solids collected from the mechanical screens, grit, and
<br /> grease removal processes are hauled to a local landfill for disposal. Waste activated sludge is
<br /> dewatered by a polymer bag process or dried on concrete lined sludge drying beds, and disposed at
<br /> a permitted landfill.
<br /> 9. Based on flow monitoring data collected by the Discharger from January 2000 to February 2001, the
<br /> average dry weather flow to the wastewater treatment plant is currently 70,000 gallons per day
<br /> (gpd). Based on self monitoring data collected by the Discharger over the same period, the
<br /> treatment facility effluent quality is summarized below:
<br /> Date Flow d BOD (mg/1) TDS (mg/1) TSS (mg/l TN(me/1) pH
<br /> 1/00 45,000 2.2 1,100 15.1 1.6 7.1
<br /> 2/00 54,000 2.6 1,200 14.6 2.1 7.1
<br /> 3/00 70,000 1.0 1,500 6.5 1.0 7.1
<br /> 4/00 61,000 1.8 1,400 6.5 1.0 7.0
<br /> 5/00 56,000 3.2 1,200 12,0 2.4 7.1
<br /> 6/00 67,000 2.6 1,200 9.5 1.0 7.1
<br /> 7/00 75,000 7.8 1,300 13.5 3.6 7.1
<br /> 8/00 79,000 4.3 1,300 9.6 3.2 7.1
<br /> 9/00 79,000 1.6 1,200 5.3 2.3 7.0
<br /> 10/00 72,000 1.3 1,100 4.0 5.8 7.0
<br /> 11/00 79,000 1.3 1,300 4.8 2.9 7.3
<br /> 12/00 82,000 2.9 NR 7.0 8.1 NR
<br /> 1/01 80,000 6.8 1,200 10 10.3 7.7
<br /> 2/01 84,000 2.6 NR 7.9 4.4 7.6
<br /> Average 70,000 3.0 1,250 9.0 3.6 7.2
<br /> BOD denotes Biochemical Oxygen Demand, TDS denotes Total Dissolved Solids, TSS denotes Total Suspended
<br /> Solids, TN denotes Total Nitrogen,gpd denotes gallons per day,mg/1 denotes milligrams per liter.
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