AC25 Secondary Effluent Quality, Potable Reuse, and Nitrogen Removal: Considerations for Multi-Benefit Projects

CWEA Members: $35.00
Non-Members $45.00
CWEA Contact Hours: 1.0 contact hours towards CWEA Certifications: AWT

Presentation Description: Water reclamation facilities are facing a variety of new challenges, including the move toward potable reuse and new regulations to limit nitrogen discharges. This presentation explores the interactions between secondary effluent quality, potable reuse, and nitrogen removal.

Successful potable reuse requires high-quality, consistent secondary effluent. The first part of this presentation will discuss typical advanced treatment trains for potable reuse and identify the critical design parameters impacted by the secondary treatment processes. Key differences between secondary treatment types will be quantified. The evaluation documents higher concentrations and higher variability in non-nitrifying facilities for several key parameters for potable reuse design, including total organic carbon (TOC), ammonia, and nitrite. For non-nitrifying plants, average TOCs ranged from 14 to 27 mg-N/L; nitrifying plants averaged 10 mg-N/L or less. Some non-nitrifying plants routinely reported nitrite concentrations above 2 mg-N/L, and even the fully nitrified facilities occasionally reported nitrite concentrations above 1 mg-N/L and ammonia concentrations above 2 mg-N/L. Plants considering potable reuse should begin monitoring TOC and nitrite to provide data for advanced treatment design. Optimization or upgrades to secondary treatment may be necessary, depending on the advanced treatment goals and requirements. The presentation will help planners and designers understand the suitability and challenges of their secondary effluent for potable reuse.

Plants with new nitrogen limits are considering multi-benefit solutions incorporating recycled water and potable reuse to reduce nitrogen discharges. The second part of this presentation will discuss the impact of potable reuse on nitrogen discharges. A variety of upgrade scenarios for a conventional BOD-removal only plant upgrading to potable reuse will be considered, and the impact on nitrogen removal will be quantified. Scenarios considered include different secondary treatment types (conventional BOD-removal like trickling filter solids contact and nitrification/denitrification in activated sludge), different management of reverse osmosis concentrate (discharge of concentrate, return of concentrate to the plant influent, and separate treatment of concentrate), and a range of potable reuse flows. Although each plant situation is unique, the results will help planners and designers understand the feasibility of using potable reuse to reduce nitrogen discharges and the key factors that impact nitrogen discharges.

Learning Objectives:
Upon completion, participants will be able to list three secondary effluent quality parameters key to potable reuse design.
Upon completion, participants will be able to describe the suitability and challenges of their secondary effluent for potable reuse.
Upon completion, participants will be able to understand the key potable reuse design decisions that impact nitrogen discharges."

Registrants who view the live webinar to see the slides and hear the audio and then enter the correct attention check code (directions below)1.0  contact hours towards CWEA's Contact Hours. AWT

To receive your contact hours for viewing the live webinar, please note the one (1) attention check code that will be displayed during the webinar in the top left or right corner of the presentation for approximately 90 seconds.  Please enter this code in the Attention Check Code component under the "Contents" tab.  

Please note, all user activity of CWEA certification holders on the Online Wastewater Education Network is subject to the CWEA Code of Ethics standards for professional conduct and ethics. Certification holders should receive credit for a training only once within the same contact hour period. Any attempt to undermine the certification process may be subject to ethics procedures and possible sanctions. It is not possible to receive contact hours for both attending the live webinar and viewing the recording.  

Once you have entered the correct attendance check code, you will be able to create and download an electronic "Certificate of Completion" under the "Contents" tab.