SU0004688 SSNL - Laserfiche WebLink

Home Browse Search

L ..s NLS§33 To quantify the anticipated nitrogen concentration for use in the nitrate loading \` calculations from the built-out West Lathrop Business Park project, effluent sample test results were obtained from another comparable commercial facility. These analytical test results (three total tests) were averaged to provide the concentrations found in Column 2, in Table 6 below. In addition, septic tank effluent concentrations from various researchers that have been published in Small and Decentralized Wastewater Management Systems, by Crites and Tchobanoglous are found in Columns 3 and 4. These two columns illustrate the effect effluent filtration has on certain constituents of the effluent, particularly BOD and TSS. Column 5 illustrates septic tank effluent concentrations for the constituents listed that have been determined by the U.S.E.P.A. TABLE 6 Laboratory Crites and Crites and U.S.E.P.A. ANALYTE Analysis of Tchobanoglous: Tchobanoglous: Commercial Septic With Effluent Filter Without Effluent Filter System Effluent Ammonia Nitrogen(NH,-N) 103 mg/L 40 mg/L 40 mg/L 6-18 mg,I. Organic Nitrogen 10 mg/L 28 mg/L 28 mg/L 30-82 mg/L Nitrate BDL BDL BDL BDL Total Nitrogen 113 mg/L 68 mg/L 68 mg/L 35-100 mg(L Total Suspended Solids 72 mg/L 80 mg(L 30 mg/L 200-290 mg/L (TSS) Biochemical Oxygen 21 mg/L 180 mg/L 130 mg/L 200-290 mg/L Demand(BOD,) PH 7.7 N/A N/A N/A Total Alkalinity 983 mg/L 60-120 mg/L 1 60-120 mg/L N/A B. CALCULATED NITRATE-NITROGEN LOADING NLS§3.3 The calculated or estimated nitrate-nitrogen impact to the soil and ultimately to the groundwater is difficult to determine due to the number of variables involved. These variables include 1.) Variability in wastewater flows, nitrogen concentrations and dilution effects that may occur from the showers and dishwasher, 2.)Impact from previous on-site agricultural operations, 3.) upgradient nitrate sources from agricultural farmland, 4.) Changes in groundwater directional flow and elevation, 5.)Denitrification potential of the underlying soil, which appears to be substantial, and 5.)Rainfall recharge. As noted in Table 5, the Total Nitrogen(TN) content is substantially higher in the tested septic tank effluent than in the other published sources. Therefore, as a safety factor, the Total Nitrogen of 113 mg/L will be used in the nitrate loading calculations,below. Various scientific methods are used to estimate nitrate-nitrogen loading. This study uses the Hantzsche/Finnemore Formula to predict the average concentration of nitrate-nitrogen in effluent recharge water: 15 Chesney Consuldng