Deammonification System in North Carolina

Client: City of Durham
Location: Durham, NC

Hazen and Sawyer has designed a deammonification system for the 20 mgd South Durham Water Reclamation Facility in Durham, North Carolina. This was the first Anitamox® process to be designed in the United States, beginning in 2011, and went operational in the summer of 2015. This process was installed following a detailed economic and process evaluation that determined removing one pound of nitrogen in the sidestream using deammonification is about one-third the cost of removing a pound of nitrogen in the mainstream process. The process is guaranteed to remove 70 percent of ammonia and 60 percent of total nitrogen, but is expected to perform better, removing approximately 90 percent of ammonia and 80 percent of total nitrogen.

The Anitamox process in Durham features an equalization basin capable of holding approximately 3-days of centrate.

The process also features two sidestream deammonification reactors with media, seen being installed here.

Hazen led the sampling effort during startup of the Anitamox system at South Durham, the first system designed and the second system started up in the United States.

The reactors were designed to utilize the main plant blowers.

Project Outcomes and Benefits

  • Process features an equalization basin capable of holding approximately 3-days of centrate, and two sidestream deammonification reactors with media.
  • Waste heat loop installed in the equalization basin for start-up and reliability enhancement.
  • Passive overflow in the equalization basin to ensure protection of the process and fail-safe operation.
  • Reactors designed to utilize the main plant blowers, and an additional program was written to provide a fail-safe for the DO probes if the actual airflow differs significantly from the theoretical air required based on influent ammonia load.

For more information on this project, or to discuss a similar project in your area, contact Katya Bilyk at kbilyk@hazenandsawyer.com