North & South Durham Wastewater Reclamation Facility Improvements

Project Facts

The City of Durham owns and operates two water reclamation facilities (WRFs) - North Durham WRF along East Club Boulevard, and South Durham WRF along Farrington Road. In 2011, master plans for each WRF were finalized, detailing the projects required to meet the City’s wastewater treatment needs through the year 2031. These master plans considered the City’s build-out flow projections and new, more stringent regulatory discharge limits for Falls Lake and Jordan Lake. They also took into account process upgrades and replacements for obsolete or aging equipment. In 2014, City Council awarded a professional services contract to Hazen and Sawyer to design Phase 1 of the North and South Durham Water Reclamation Facilities Process Improvements Project. These improvements were recommended in the 2011 master plans.

Phase 1

The Department of Water Management (DWM) opened bids on August 16, 2017 for construction of Phase 1 improvements. Crowder Construction Company was the low bidder, with a total project cost of $65,429,412.00. Construction began in January 2018, and is on schedule to date.

North Durham WRF

1. New influent screenings facility
2. New secondary clarifiers
3. Aeration basin improvements
4. Odor control improvements*
5. New polymer feed systems
6. Stormwater improvements
7. Floodwall improvements

South Durham WRF

1. New influent screenings facility
2. New secondary clarifier
3. Aeration basin improvements
4. Odor control improvements*
5. New polymer feed systems
6. Grit removal equipment
7. New equalization basin
8. Tertiary filter improvements
9. New UV disinfection system

*Odor control improvements under Phase 1 will include covering and scrubbing the new influent screening/grit removal facilities.

Phase 2

Design of Phase 2 improvements is now 90% complete. Construction of Phase 2 will occur upon completion of Phase 1. DWM expects Phase 2 to bid around late 2020.

Phase 2 design includes:

• New odor control facilities and primary settling tank improvements at both WRFs.
• A new Camden Road lift station, equalization basin improvements, tertiary filter upgrades, digester rehabilitation, and sidestream treatment at the North Durham WRF.
• New solids dewatering equipment at the South Durham WRF. Preliminary estimate of construction cost for Phase 2 Improvements is $25 million.

Odor Control

In October 2015, the City decided to upgrade odor control measures at South Durham WRF as generally outlined in the attached Technical Memorandum. Aging chemical scrubbers, originally installed in the early 1990s, are no longer usable due to deteriorated condition of equipment. Recommendations contained within this Technical Memorandum were developed during the preliminary study portion of the project. Changes to the odor control plan that were made during the detailed design process include the following:

• In Phase 1 of the project, a biofilter with a carbon polishing step will be used in place of a bio-trickling filter for the new Preliminary Treatment Facility. This was based on the capabilities of the selected biofilter manufacturer as well as estimated hydrogen sulfide concentrations in the new facility.
• In Phase 2 of the project, some additional areas will be scrubbed including the anoxic tank weir area. Although the preliminary study indicated low hydrogen sulfide in this area, the City has elected to address the minimal odor that was detected.