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w . <br /> Messrs. Hill and Machado - 2 - 9 <br /> 2 - <br /> 9 May 2003 <br /> Treated MEGS Combined <br /> Constituent Wastewater Wastewater Wastewater Change <br /> TDS 717 mg/L 891 mg/L 734.8 mg/L 2.48 % <br /> Nitrate <0.1 mg/L 264 mg/L 264 mg/L NA % <br /> Sodium 154 mg/L 240 mg/L 163 m o <br /> Chloride 195 mg/L 104 mg/L 185,7 g/ 5.71 uo <br /> Arsenic 0.00825 ug/L 0.036 ug/L 0.01 ug/L <br /> 4.76 00 <br /> Boron 0.48 mg/L 0.4 mg/L 0.47 g/ 21.21 % <br /> �L -2.08 % <br /> Based on the data submitted the discharge will result in increases of TDS, nitrate, sodium, and arsenic. <br /> _Wastewater Quality Trends <br /> Review of the domestic wastewater treatment system's Total Dissolved Solids (TDS) concentration <br /> trend in the time period from 1999 to 2002 indicates TDS concentrations have increased from 655 to <br /> 736 mg/L. Because inorganic dissolved solids are not treated in the City's wastewater system it is <br /> anticipated that the TDS will be discharged to groundwater. Addition of industrial wastewater, <br /> including the MEGS wastewater, will further increase the TDS concentration in the effluent. <br /> Groundwater Monitoring Data <br /> The City has collected only limited groundwater data until recently when the Monitoring and Reporting <br /> Program Order No. 94-263 was revised to include additional groundwater analytes. Groundwater <br /> monitoring data collected in the first quarter 2003 monitoring event indicates groundwater flows to the <br /> north; however, because of the limited data, an evaluation of the impact of wastewater application on <br /> groundwater quality is not possible at this time. Based on the concentrations of Nitrogen as N reported <br /> in Wells MW-1, MW-3, MW-4, and MW-5, which all exceed the Water Quality Objective (10 mg/L) <br /> groundwater quality degradation has already occurred. <br /> Well No. Units Nitrogen as N Sodium Chloride TDS <br /> MW-1 mg/L 25 80 140 720 <br /> MW-2 mg/L 7.9 110 150 690 <br /> MW-3 mg/L 13 130 130 720 <br /> MW-4 mg/L 50 140 160 910 <br /> MW-5 mg/L 18 140 170 720 <br /> MW-6 mg/L 8.5 140 180 700 <br /> Wastewater Character Material Chane Determination <br /> California Water Code Section 13260(c) requires: <br /> Every person subject to subdivision (a) shall file with the appropriate regional board a report of <br /> waste discharge relative to any material change or proposed change in thecharacter, locatio <br /> or volume of the discharge. n, <br /> The term "material change" is defined in Section A.4.d of the Standard Provisions and Reporting <br /> Requirements for Waste Discharge Requirements (Standard Provisions), dated 1 March 1991 as: <br /> V llin lauymn Noltl%mlhCbnnilSnl IapmnWpan WW %Machado 2 Ma,I11 Jpc <br />