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<br />Stockton San Jose Sacramento Modesto <br />3428 Brookside Rd. 111 N. Market St., #300 900 Howe Ave., #200 100 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 /> <br />F:\17projects\17017 Holly Sugar Industrial\Civil\Septic Sizing - Prelim\17017 Holly Commerce Center E&E Nitrate Loading Memo <br />Ver 4.docx <br />APPENDIX B- UPDATED NITRATE LOADING ANALYSIS FOR <br />MICHAELS TI’S STAFF EXPANSION <br /> <br />I. Introduction <br />This nitrate loading analysis is intended to update the prior calculations provided for the E&E Trading <br />project when the staffing was anticipated to be closer to a maximum for 400 people per day. The building <br />is now being leased to Michaels and the staff loading will be different than originally anticipated therefore <br />a revised peak ADF has been established in the Sanitary Sewer Design and Operational Parameters <br />memo. The new maximum staff loading per day will be 700 people across three shifts of 8 hours each. <br />300 per shift for two shifts and then 100 people on the third overnight shift. <br /> <br />II. ADF Peak Flow and Annual Wastewater Generation <br />The ADF established in the Sanitary Sewer Design and Operational Parameters memo for a maximum of <br />700 employees per day is 4,900gpd, previously the peak ADF was 2,612.4gpd and was based upon a <br />maximum of 400 employees a day. Nitrate loading is calculated on an annual loading basis in accordance <br />with Attachment 1. The annual average volume of wastewater will be based on the following <br />assumptions: <br /> <br />1. Maximum occupancy will only be achieved Monday through Friday <br />2. Weekends will be assumed to be minimal staff at 25% of the maximum <br />3. There are assumed to be 10 holidays per year with minimal to no staffing <br />4. The peak ADF will not be achieved on a daily basis and therefore will be reduced by 20% to <br />better represent an average annual volume <br /> <br />Therefore, the annual average volume of wastewater is assumed to be: <br /> <br />W = (4,900 gpd x 80% x (5 dpw x 52wpy – 10 holidays))+(4,900 gpd x 80% x 25% x 2 dpw x 52wpy) <br />= 980,000 gals/yr + 101,920 gals/yr <br />= 1,081,920 gals/yr <br />= 144,631 cu-ft/yr x (1/43,560 ac-ft/cu-ft) <br />= 3.32 ac-ft/yr <br /> <br />III. Current and Future Changes, and Monitoring Plan <br />The currently proposed changes to the OWTS involve an increase in occupancy from 400 employees per <br />day to 700 employees per day. The change does not result in increased septic tanks or pumps, but does <br />increase the leach field size and the nitrate loading. See the sewer design memo for details. <br /> <br />As with the prior approvals the improvement plans include a flow monitor and sensor on the post septic <br />tank lift stations that lifts the effluent into the leach field. The project owner has volunteered to enter into <br />the County’s monitoring program and will report the waste flows as required. Please see note on detail 2 <br />on sheet C7.3. This flow monitoring will aid in validating that the design usage and actual usage are in <br />alignment. <br /> <br />To address the building use change potential, Siegfried has prepared and attached an exhibit that <br />designates the current and requested expansion of the leach field. If additional employee expansion is <br />desired by the owner a permit will be filed and any required modifications will be proposed at that time