Ten Years from Design to Start-up at Sac Sewer: What's Changed and What's the Same?

Presentation Description: This talk will delve into novel technologies and concepts for biological nutrient removal (BNR) process through a series of case studies. The foundational case study will be the recently completed Sacramento Regional County Sanitation District (Regional San) BNR Basins which was awarded the American Academy of Environmental Engineers and Scientists (AAEES) Grand Prize for Design in 2022. Specific challenges to design were posed by the intersection of extreme influent dynamics, stringent effluent limits, and challenging carbon to nitrogen ratios, alongside drivers for energy efficiency, process resiliency, and ease of operation. To efficiently address these challenges without undue risk; cutting edge modeling and applied research of the day were applied to design.

Design features and operation will be discussed and then compared to several case studies which materialized during Regional San’s design, construction, and commissioning period. Common challenges and solutions will highlight how the understanding of some processes have advanced considerably while other core elements of successful BNR design are largely unchanged. Other case studies include:
•Trinity River Authority achieved intensification while improving nutrient removal and energy efficiency through low dissolved oxygen (LDO) operations. Operational optimization to stabilize settleability and LDO impacts on process kinetics and ecology will also be discussed in relation to the WRF study on low energy BNR (WRF 5083).
•The installation of Fluence membrane aerated biofilm reactor (MABR) modules into the existing May'an Zvi facility in Israel increased the rated capacity, reduced effluent nitrogen and phosphorus discharges, and decreased net energy use; while requiring no additional volume.
•Charlotte Water’s McAlpine Creek tested and implemented a strategic combination of primary and secondary sludge fermentation to stabilize performance and substantially reduce chemical requirements. Improved understanding of the carbon production potential of fermentative processes will be presented in relation to the WRF study on RAS fermentation (WRF 4975).
Comparing the foundational Regional San BNR upgrade with these related projects will paint a more comprehensive picture of the trajectory of BNR than possible by looking at one case alone. This will emphasize the importance of applied research to the evolution of evermore sustainable and effective water resource recovery processes.