Doaktown, New Brunswick
Municipal Wastewater Treatment
Completion Date: 2011
640 m3/day (0.14 MGD)
Effluent Quality Requirements:
10 mg/L cBOD5
10 mg/L TSS
1 mg/L Total Ammonia (Summer)
7 mg/L Total Ammonia (Winter)
Project Background & Challenges
The Village of Doaktown is located in Northumberland County, New Brunswick and discharges its wastewater to the Miramichi River. The Miramichi River once supported one of the largest Atlantic salmon populations in North America and today continues to support a large fishery. The river attracts recreational fly fisherman from all over the world. The New Brunswick Department of Natural Resources has implemented rules and regulations for fishing, as well as the wastewater effluent that is discharged into the river, in order to protect the salmon population.
The Nexom Answer
Doaktown chose Nexom's optAER wastewater treatment system to both increase the capacity and improve effluent quality of their lagoon system. The upgrades included:
- Constructing a new aerated lagoon cell
- Implementing partial mix optAER aeration in lagoon cells 1 and 2.
- Implement an post-lagoon SAGR for final cBOD5 removal and partial nitrification after cell 2. (While this case study focuses on the optAER aerated lagoons, you can refer to the SAGR treatment process page, as well as the Long Plain First Nation, Manitoba, Glencoe, Ontario, or Mentone, Indiana cases for a in-depth look at the SAGR.)
Upgraded System Performance
With the lagoon upgrades in place, Doaktown has been able to get its cBOD5 and TSS numbers down averages of 7.4 and 12.6 mg/L respectively, even before the water hits the SAGR that has itself been shown to remove 90%+ of both.
Although this case study places the focus on the optAER-enhanced lagoon performance, the treatment objectives set targets for the effluent from the entire system, including the post-lagoon SAGR. To that end, the system has been achieving remarkable results.
During the summer months, when the system targets 1 mg/L, samples have average 0.2 mg/L. But perhaps even more impressivley, in the cold of winter, when targets imposed on the system are 7 mg/L, effluent samples have averaged less than 0.9 mg/L.