Project Scale:
Two pilot water treatment systems of less than 300 gpm.

Where:
Fort Richardson & Fairbanks, Alaska, USA

When:
Fort Richardson pilot system: supplied in 2002; Fairbanks pilot system: supplied in 2005.

Project Description:
The State has conducted an in-depth, multi-year exploration of Recirculation Aquaculture Systems (RAS) as a way of meeting their fish production goals.  As part of this exercise the pilots were obtained for proof-of-concept and familiarization purposes. The water treatment system at Fort Richardson is a 300 gpm RAS system; at Fairbanks there is a 120 gpm RAS system installed side-by-side with an equivalent-sized, less intensive “partial re-use” system.  The Fairbanks system will provide the opportunity to compare recirculation and partial reuse technology in the context of the State’s specific rearing requirements.

Services Provided:
PR Aqua designed and supplied the three water treatment systems, to be installed and operated by State staff.  PR Aqua subsequently provided install support and continues to provide operational support and assessments.

Project Features:
Each of the treatment systems incorporate many of the same elements as the commercial scale facilities designed by PR Aqua but at a pilot scale and serving only a single culture tank each.  The main components of the RAS at Fort Richardson are a dual drain circular tank, a drum filter, a pump station, a fluidized sand bed biofilter, and an OxyTower™ for gas balancing/oxygenation.  At Fairbanks, the RAS incorporates these basics, but also includes a swirl separator to treat the tank bottom drain water, an immersion chiller in the pump sump, a UV reactor for pathogen control, and an oxygen cone (replacing the LHO). The partial reuse system at Fairbanks is identical to the RAS system except the fluidized sand bed biofilter, immersion chiller, and UV reactor are excluded and a higher rate of water exchange is used.

Challenges and Solutions:
The pilot treatment systems were devised to facilitate operational training and to allow the State of Alaska to become comfortable with the risks, and realize the benefits of recirculation and partial reuse technologies. PR Aqua’s commitment to the successful achievement of these goals is demonstrated by the comprehensive equipment support and operational assistance and advice that have been provided to these projects.  The same level of support and service is provided with all PR Aqua projects and is key to our success and the success of our clients.

Both pilot systems were constructed in existing buildings with very tight spatial constraints.  PR Aqua worked closely with on-site personnel to develop designs that maximized the use of available space while maintaining operational and maintenance access requirements.

Results:
Based on the success of the pilot projects, the State of Alaska is embracing the use of recirculation and partial reuse technology in meeting their fish-production objectives.  For more information regarding PR Aqua’s continuing involvement with the State’s Sport Fish production programs, see our news release at >>> News