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Design Criteri rencor <br /> Using Equation B3 from Appendix B provides the alkalinity demand for this project: <br /> 5 mg/L alkalinity <br /> Alkalinity Demand = 160 mg/L TKN x = 800 mg/L <br /> 1 mg/L TKN <br /> Using Equation B4 from Appendix B provides the alkalinity need for the project: <br /> Alkalinity Need = 800 mg/L + 100 mg/L— 120 mg/L = 780 mg/L <br /> These equations show that alkalinity addition is required for this system. <br /> Design Specifics <br /> Tankage Requirements <br /> Depending on the size of the facility,distributed tankage or a small gravity collection system to primary tankage is typically used.For systems with <br /> gravity collection,especially in areas with significant rainfall,an adjustment to the per capita flow may be necessary. <br /> Schools fall within Application Type 3 in Appendix A;therefore total primary tank recommendations call for a minimum of 3 days' retention at <br /> maximum day design flow.Since a pre-anoxic tank will be used due to the nitrogen reduction requirement,two days of primary tankage will be <br /> recommended with an additional one-day pre-anoxic tank situated at the treatment site. <br /> Table 3A-3:Sample Tank Sizing Recommendations(With Flow Equalization) <br /> Source Equalized Design Daily Flow(gpd) Recommended Minimum Tank Size(gallons) <br /> Grease Tankage 2,100' 6,300 <br /> Primary Tankage 10,500 21,000 <br /> EQ Tank 10,500 10,500 <br /> Pre-Anoxic Tank 10,500 10,500 <br /> 1 st Stage Recirculation Tank' 10,500 7,875 <br /> Post-Anoxic Tank 10,500 5,250 <br /> 2nd Stage Recirculation Tank3,4 10,500 2,625 <br /> Discharge Tank 10,500 2,100 <br /> 'Grease flow estimated at 20%of Design Flow <br /> 2 Only for AX100 Systems;volume included in AX-Max Systems <br /> 3 Sized at 25%of Design Flow(see page 17) <br /> °Only for AX100 Systems;volume included in AX-Max Systems <br /> Since the system is required to treat for organic constituents and provide nutrient reduction,it would be configured as shown in Figure 3A-1. <br /> Alkalinity Feed Carbon Feed <br /> Pre-Anoxic Return Line <br /> Primary EQ Pre- 1st Stage Post- 2nd Stage Discharge <br /> Treatment Tank Anoxic AdvanTex Anoxic AdvanTex <br /> Figure 3A-1.Treatment Configuration for Organic Constituents <br /> When using Flow Equalization,all calculations are performed with the Equalized flow considered as the Design Average Day Flow.Calculations for <br /> Maximum Day Design Flow are unnecessary. <br /> Orenco Systems°•800-348-9843•+1 541-459-4449•www.orenco.com NDA-ATX-1 <br /> Rev.8,©10/20 <br /> Page 35 of 38 <br />