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MEMORANDUM Page 2 of 7 No' <br /> Holly Commerce Center Buildings A& B <br /> Tracy, CA �N S I E G F R I E D <br /> III. Septic Tank Volume <br /> Septic Tank Volume (TV) Using the County Disposal Systems Equation 4.1.12 for determining volume of <br /> septic tanks: <br /> For ADF<1,500 Gallons/Day, TV= 1,200 gallons (Base Tank Capacity) +ADF <br /> For ADF>1,500 Gallons/Day, TV= 1,125 gallons + 0.75 ADF <br /> For each building, the minimum allowable septic tank size as determined by the County Disposal Systems <br /> Equation is reported in Table B below. The minimum County Tank Volume is then used to calculate the <br /> detention time as calculated by the following equation: <br /> Detention Time (days) = Tank Volume".70 (Reduced Volume due to sludge)/ADF <br /> Note our office uses a reduction of 30% of tank volume which is lost over time due to sludge. <br /> For buildings A & B, a traditional septic tank is proposed with a separate lift station to lift the liquid into the <br /> leach field. The proposed septic tank is specified as the smallest standard septic tank that meets the <br /> required minimum tank volume as calculated by the County. Detention time is then recalculated for the <br /> actual septic tank size specified. <br /> Table B: Septic Tank Volume <br /> Min. <br /> Working <br /> Min. Volume for 1 <br /> Calculated Tank Detention Detention Day <br /> Volume (CTC) County Time per Tank Volume Time based Retention <br /> min County Used (TV) on TV (gallons) <br /> Building ADF (gallons) (days) (gallons) (days) ADF/0.70 <br /> A 320 1,520 3.33 2,000 4.38 458 <br /> B 320 1,520 3.33 2,000 4.38 458 <br /> IV. Filter Bed Calculations <br /> Building A: <br /> Traditional Leach line Requirements = (CTC+ADF) "Soil Factor <br /> _ (1,520 gallons+ 320 gallons) "0.25 <br /> =460 ft <br /> SF at soil effluent=460 "4 (Soil Bed Factor) = 1,840 sq. ft. <br /> Due to high ground water elevations and limited space for a large leach field a filter bed will be deployed <br /> using the Soil Acceptance Rate as a basis for design: <br /> Stockton San Jose Sacramento Modesto <br /> 3428 Brookside Rd. 111 N. Market St.,#300 109 Scripps Drive 100 Sycamore Ave,#100 <br /> Stockton, CA 95219 San Jose, CA 95113 Sacramento, CA 95825 Modesto, CA 95354 <br /> t:209.943.2021 t:408.754.2021 t: 916.520.2777 t: 209.762.3580 <br /> F:\17projects\17017 Holly Sugar Industrial\Civil\Septic Sizing-Prelim\17017 Sanitary Sewer Design Criteria Memo Buildings A&B <br /> Rev 1.docx <br />