When a Detour Becomes a Shortcut: Going Full-scale with Partial Denitrification/Anammox as an Alternative Strategy for Mainstream Deammonification and Incorporating Biological Phosphorus Removal

The specific objective of this project is to pave the way for full-scale applications of shortcut N removal processes, by increasing nitrite availability for anaerobic ammonium oxidizing bacteria (anammox) in mainstream systems. Shortcut N removal systems developed based on the partial denitrification (PdN) route rather than the NOB (nitrite oxidizing bacteria) out-selection route, will likely provide more reliable nitrite production and could accelerate full-scale implementation of shortcut N technologies. Partial denitrification/anammox (PdNA) technologies span a range of readiness levels. The attached growth polishing PdNA concepts that will be explored further in this project have already been partially validated in pilot testing and full-scale treatment plants. HRSD transitioned their York River Treatment Plant post-dentification filters to PdNA almost two years ago, the first real full-scale example of mainstream anammox oxidizing a relevant amount of the influent ammonia load. Based on the successful outcome of piloting PdNA in a polishing moving bed biofilm reactor (MBBR) process, the pending full-scale nutrient upgrade for the HRSD James River plant will include this technology. This project will address remaining unknowns with designing and operating polishing PdNA processes. Integrated PdNA applications, whereby anammox are incorporated into the main plant BNR process pre- or post-anoxic zones, have been validated conceptually in laboratory and pilot studies at DC Water and Columbia University, and this project will move these concepts rapidly to full-scale application. This project will also evaluate the integration of biological P removal with PdNA shortcut N removal.