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11 Design For TN,TIN,and NO3-N discharge requirements of<10 mg/L,or for applications with primary treated effluent TN values of>150 mg/L and >80% nitrogen removal requirements, it will be necessary to integrate a two-stage AdvanTex system,followed by a denitrifying moving bed bioreactor(MBBRd),denitrification upflow filter,or other denitrification technology into the treatment process. Contact Orenco prior to designing a system to meet these requirements.See pH Effect on Nitrification and Temperature Effect on Nitrification and Denitrification in the Design Considerations section on page 19. Waste Stream O Primary Treatment AdvanTex Systems for the Advanced Removal of Ammonia Use for Systems with Permits Requiring Discharge Limits > O Pre-Anoxic Treatment 95% Removal of Ammonia or TKN •See Appendix A for sizing O For wastewater systems requiring ammonia removal due to restrictive ammo- ©Standard AdvanTex Treatment nia nitrogen (NH3 N)or TKN discharge limits(>95%removal),a Second •Sizing Equations 1.1,1.2,1.3 Stage AdvanTex system will be necessary following standard AdvanTex treat- 0 Second-stage ment.Figure 6 shows the typical configuration for discharge limits associated © AdvanTex Treatment with this level of treatment. •See Process Stage Section The nitrification occurring in the AdvanTex system is heavily influenced for applicability O O •Sizing Equations 2.1,2.2,2.3 by the alkalinity required to buffer the process(7.14 mg/L alkalinity per 1 mg/L of ammonia-N).pH levels of 7.5 to 8.5 are ideal for complete nitri- fication and should be buffered to remain above a pH of 7 for all applica- © 0 Alkalinity Feed System tions. Immediately preceding the AdvanTex treatment stage,a supple- Two installation options;pre- mental alkalinity feeder may be necessary to ensure sufficient alkalinity anoxic return line or just for nitrification to break down ammonia. before Standard AdvanTex 0 Treatment Using a pre-anoxic stage helps buffer pH,as denitrification in this stage will return as much as 50%of the alkalinity consumed during nitrifica- tion. In addition, readily available BOD is consumed in the pre-anoxic denitrification stage, reducing the BOD load to the secondary treatment Discharge unit. Most application types provide adequate carbon in the incoming Figure 6.Treatment Diagram for Advanced Removal of Ammonia stream to achieve denitrification and subsequent alkalinity return,but in the design it is best to ensure that there is enough alkalinity added with- out relying on this occurrence.As operational data becomes available for the specific treatment system—demonstrating the return of alkalinity through denitrification—alkalinity feed rates can be adjusted downward.See pH Effect on Nitrification and Temperature Effect on Nitrification and Denitrification in the Design Considerations section on page 19. Process Stages — AdvanTex Treatment Systems Primary Treatment Stage Purpose and Description: The primary treatment stage is designed to collect wastewater; segregate settleable and floatable solids(sludge and scum); accumulate,con- solidate and store solids; digest organic matter; and discharge primary-treated effluent. Passive,energy-free primary tankage provides the most cost-efficient method of primary treatment available for nonindustrial sewage; BOD removal of>50%and TSS removal of>90% (when using an effluent filter)are typically accomplished with passive primary treatment. The primary treatment stage can be configured in several ways, including single- or multiple-compartment tanks,single tanks with meandering baffles(partitions),or multiple tanks in series.Some systems may utilize solids separation devices. Primary treatment includes effluent screening, and effluent may be discharged to the secondary treatment stage via gravity or pump. Design Notes and Special Considerations: The volume and configuration of primary tankage or inclusion of other primary treatment devices(e.g.solids separation) is dependent on the system,the application type,and the expected waste strength.When using tankage for primary treatment,proper sizing ensures adequate volume for the development of the necessary microbial environments,appropriate sludge and scum storage,and surge volume. For recommendations on sizing of primary tankage,see Appendix A.The tank's structural soundness and watertightness are vital to the system's performance,and all tanks should be reviewed by the engineer and water-tested in the field after installation. Orenco Systems°•800-348-9843•+1 541-459-4449•www.orenco.com NDA-ATX-1 Rev.8,©10/20 Page 11 of 38