Embracing Sustainability through Control Technology

Sustainable Blue, a Nova Scotia-based inland salmon farm, faced a fundamental tension in land-based aquaculture: scaling production volume while maintaining the closed environmental controls that define premium, sustainable fish. Conventional inland farms rely on continuous exchange with open water sources for discharge and replenishment, which introduces uncontrolled temperature variation, disease risk, and geosmin contamination — the compound responsible for the earthy taste consumers reject. With six farms housing live fish across thousands of tonnes of water, the cost of system failure was severe: fish would not survive more than ten minutes without continuous water circulation, with potential losses running into the millions of dollars.

Working with system integrator Fairfield Control Systems and technology partner BlueTech Systems, Sustainable Blue implemented a fully closed-loop Recirculation Aquaculture System (RAS) built on Rockwell Automation hardware. The control architecture centers on CompactLogix 1769 programmable controllers with POINT I/O 1734 distributed I/O modules, supported by PowerFlex 525 and 755 AC drives, Stratix 5700 and 8300 managed Ethernet switches, and E1 Plus and E300 electronic overload relays for motor protection. The system processes 5,000 tonnes of water per hour across the facility, maintaining closed-loop control over temperature, pH, dissolved oxygen, and water pressure — with no dependency on external water supply. Historical data logging and alarm management are integrated throughout. Deployment began with the RBR 3 farm in 2016 and expanded across all six Red Bank Road sites.

The control system enabled Sustainable Blue to scale from an initial 80 tonnes of salmon to more than 1,000 tonnes across six farms — a 12x capacity increase — while maintaining product quality without antibiotics or growth hormones. Key outcomes include:

• Production time halved by holding tank temperatures within tight optimal bands
• Complete water purity control with 100% recirculation, eliminating geosmin contamination and disease risk from open-water exchange
• System availability sufficient to protect against failure events where fish survival window is under 10 minutes
• End-to-end traceability from water chemistry to harvest, supporting premium market positioning with major supermarkets and restaurants

Sustainable Blue is now expanding the model to new sites, with a transition to 100% renewable energy underway.

• Design for the cost of failure first: when a system outage has a 10-minute survival window and million-dollar downside, availability engineering must drive every architecture decision.
• Closed-loop control unlocks scalability: eliminating external dependencies — water, temperature, discharge — is what made 12x capacity growth feasible without quality trade-offs.
• Established integrator relationships reduce deployment risk: Fairfield Control Systems' 30+ year history with Rockwell Automation meant the team arrived with proven patterns, not experimentation.
• Automation replaces human inconsistency in high-repetition processes: continuous modulation of RAS variables is a task where manual control fails at scale; automation is not optional.
• Sustainability as a control system output, not just a value statement: measurable water purity and traceability data directly supported market differentiation and customer acquisition.