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Development of Proficient Innovative Indoor Re-Circulating Aquaculture System and Re-Use Processes Necessary to Achieve Optimal Operating Efficiencies and Capacity to Support Value Added Diversified Multi-Tiered Polycultures

North Shore Fish Farms Ltd.

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Executive Summary

Given the direct market competition from the wild-caught commercial fishing industry and the relatively low margins attained on Yellow Perch being raised in North Shore Fish Farms (NSFF) existing indoor land based recirculating aquaculture system (RAS); sustainable production of Yellow Perch was not economically sound. As a result of AIMAP financially supporting our proposal, we achieved a sustainable production model that cost-effectively put NSFF in a better position by way of designing/advancing recirculating culture methods and technologies that successfully / substantially achieved energy and system efficiencies to reduce operating costs. In addition to achieving operation efficiencies, we also accomplished increased fish stocking and cohort distribution capabilities that will result in faster more proficient Yellow Perch development rates, yield potentials and revenues. Findings will also act as a template for the urban aquaculture industry across rural Canada for the sole purpose of Yellow Perch production.

The development and advancements undertaken and achieved during this claiming period was the first of a planned 3 phase expansion project for NSFF. Planned phases include:

  1. Expansion of existing Yellow Perch grow out RAS
  2. Addition of isolated Yellow Perch Nursery/Hatchery RAS
  3. Implementation of a Yellow Perch brood stock development program

As per our AIMAP agreement, we successfully developed and implemented capacity expansions onto our existing Yellow Perch indoor RAS production model that brought about industry efficiency and efficacy innovations in the form of carbon capture and removal, improved liquid oxygenation disbursement methods and energy efficient bio-filtration advancements that utilize unique downward low head pressure hydraulic load alternatives. System testing and preliminary rearing of fingerlings has demonstrated these innovations as being successful in achieving economically viable sustainable production of Yellow Perch.

With current technological limitations dictating production output, diversity and operating economics in urban aquaculture, we believe our accomplished RAS advancements will also help stimulate opportunity, attention and innovative alternatives to the Canadian urban aquaculture industry. We think these unique and economically sustainable RAS processes will also improve opportunities to surge growth and awareness within the Canadian marketplace that is currently dominated by foreign imported products.

Project Activity and Results Summary

AIMAP support funding has aided North Shore Fish Farms in being able to proficiently and successfully develop and implement innovative capacity expansions onto our existing Yellow Perch RAS production model that have helped us overcame specific challenges and weaknesses on identified system processes/technologies (oxygenation, degassing, biofiltration and solids removal/effluent control) to effectively achieve substantial operating efficiencies and production increases.

  • Energy savings of 22-30% per pound of fish
  • Oxygen savings of 31% per pound of fish
  • Estimated annual production yield increase of 43% for 2011

Oxygenation Advancements

Existing Oxygenation Technology
  • Centralized oxygenation system utilizing two liquid oxygen saturators provides nourishment to all culture tanks
  • Liquid oxygen is injected through a venturi nozzle to create a fine bubble suspension in the pressurized saturators
  • One central liquid oxygenation source for distribution to all tanks (unable to adjust levels per individual tanks) requires high head pressure
  • Approximately 3000 m3 of liquid oxygen is required to produced 20,000 lbs of Yellow Perch annually
Deficiencies with Existing Oxygenation Technology
  • Single distribution hub prohibits adequate/essential saturation levels for independent culture tanks, resulting in:
  • Impeded fish performance/stress and reduced eating habits in lower saturated tanks (loss yield potential)
  • Wasted oxygen in supersaturated tanks (economics)
  • Inability to utilize tank sizes to their full capacity (loss yield potential)
  • High energy consumption design
Work carried out to overcome oxygenation deficiencies
  • We designed and installed a low head oxygenation delivery system (adaptable to high flow with minimal hydraulic head) that employs an individual side contactor for each independent culture tank that feeds up to 60% of its specific oxygen requirements using only a 1/4hp pump (7 tanks in total - demand variance between tanks is relative to stocking density and cohort groupings). Remainder (baseline level) of oxygen demand is accomplished with centralized oxygenation delivery system (advanced from feeding 3 to 7 culture tanks)
Oxygenation performance measures achieved
  • On demand control of independent culture tank oxygenation consumption and saturation levels that can sustain optimal growing conditions while mitigating excess oxygen loss/consumption
  • Reduced stress
  • Advanced sizing rate (faster to market)
  • Reduce labour (less monitoring will be required after optimum parameters for each general sizing/density class are identified)
  • Yellow Perch production increases as a result of efficient saturation levels
  • Can effectively target 105% saturation levels at all times for all tanks
  • Estimating 35,000 lbs annual production with liquid oxygen consumption of approximately 4000 m3      
  • Increased feed rates in excess of 100% (from less than 100 lbs cumulative for system, now exceeding 200 lbs)
  • Increased independent culture tank stocking density capabilities, increased yield/fish production for same volume of water
  • Low head downward flow accomplished increased gas transfer rates in vertical setting
Oxygenation measurements included and identified
  • Daily saturation monitoring at several points
  • Fish behavior patterns during feedings
  • Monthly oxygenation consumption
  • Cost of O2/ lbs of fish production
  • Rate of fish growth
  • Water quality performance
  • Oxygen consumption/culture tank at various stocking densities and feeding rates

Degassing Advancements

Existing Degassing Technology
  • Open packed high pressure water column for carbon dioxide removal through gas transfer. High energy consuming centrifugal pump (5 hp) propels water up to top of vertical tower. Water flows downward though plastic packing and breaks up creating a large gas-liquid interface area for gas transfer. Large surface of media required for off gassing high head pressure, minimal degassing occurs in bio-sumps
Deficiencies with Existing Degassing Technology
  • Gas transfer creates release of atmosphere carbon dioxide into our indoor environment, creating potential for re-absorption back into process. Indoor design inhibits ability to contain and remove the released atmospheric carbon dioxide.      
  • CO2 presence in water impedes fish performance and creates stress
  • 20 ppm of liquid CO2 = 1000 ppm of atmospheric CO2. A maximum of 25 ppm is tolerable by Yellow Perch (80 lbs of feed generates maximum levels) because CO2 reduces capacity of blood to transport oxygen, as CO2 in water increases, so does blood CO2 level
  • Energy deficiencies as a result of high head pressure pumping system
Work carried out to overcome degassing deficiencies
  • We designed and integrated a captive degassing chamber for nitrifying and de-nitrifying stages that uses passive outdoor ventilation to prevent build up and re-absorption of carbon dioxide and other gases back into the process or indoor environment. The self-contained bio-filtration units were manufactured onsite, using custom ventilation accessories. Design employed 4 low head energy efficient 1/4hp pumps for hydraulic control and a high volume 1/4 hp blower to accomplish large volumes of air flow required for sufficient CO2 removal. Hydraulic network took advantage of enclosed bio-sumps with attached ventilation to prevent build up within the production facility and a bypass circuit to circumvent existing system and reduce energy demands during lower level feeding periods.
Degassing performance measures achieved
  • Energy efficiencies, along with environmental upgrades:
  • Reduced daily atmospheric and liquid carbon dioxide levels (immediate)
  • Energy efficient low hydraulic head using, using a 1/4hp fan, and four 1/4hp low head pressure pumps (1-1/4 total) for 7 culture tanks
  • Flexibility of bypassing existing systems when feed rates are lower for energy conservation
  • Increased daily feeding capacity (upwards of 120 lbs of feed/day) with manageable CO2 increases (permits increased stocking densities)
  • Augmented availability of dissolved oxygen by reducing the blood CO2 levels
  • Accomplished a beneficial reuse/recapture model
Degassing measurements included and identified
  • Daily liquid CO2 concentrations reductions
  • Fish health and overall performance
  • Water quality on a daily basis
  • Carbonate cycle response and oxygen transfer improvements
  • Daily feed increases and restrictions

Bio-Filtration Advancements

Existing Bio-Filtration Technology
  • Moving bed fluidized bio-filters using sinking Kaldnes media for nitrification and de-nitrification surface areas. This sinking b-celled media required a 5 hp blower to properly agitate all bio-sumps (each contactor container) and high head centrifugal pumps (3@5hp) to complete hydraulic loading rate
  • System used 6 various sized moving bed bio-sumps (10,000gal) and 259 ft2 of Kaldnes media surface area with capacity limitations of 0.6 lbs fish/gal water
  • Ammonia removal capacity of biological filter is largely dependent upon the total surface area available for biological growth of the nitrifying strain.
Deficiencies with Existing Bio-Filtration Technology
  • High energy consumption and high head loss across sumps
  •  3 pumps and 1 blower at 5hp each = 20hp  (+ costly plumbing schematic)
  • Media density changes over time with bio-film accumulation
  • Maximum of 80 lbs of daily feed consumed before water quality deterioration
  • Limitation on fish capacity is a system deficiency
  • Total Ammonia Nitrogen (TAN), CO2, NH2
Work carried out to overcome bio-filtration deficiencies
  • We designed and integrated low head bio-filtration sumps (side contactors) for each individual culture tank, using floating media with a larger surface area (355 ft2) and downward water pressure to accomplish fluid transfer overtop of media.  This design combination minimized use of floor space required for nitrification and further increased culture tank fish carrying capacities
  • Design of low head pressure system used only six ¼ hp pumps (for all 7 culture tanks) to move fluid across media (2hp total at 355 ft2 of media vs. existing 20hp total at 259ft2 of media)
  • Raw filter media selected for contactors has very high specific surface are at low cost, which allows for expansion and load fluctuations
Bio-filtration performance measures achieved
  • Reduction in capital investment (using lower hp pumps/blowers and smaller bio sumps) that accomplished energy savings of up to 30%/lb of fish produced
  • Increased daily feeding capacity (upwards of 120 lbs of feed/day) without deteriorating water quality (manageable levels of total ammonia nitrogen on a daily basis) supports higher density stocking capabilities
  • Hydraulic design of contactor tanks improved self cleaning of culture tanks
  • Increased biological activity created more heat to offset heating costs
  • More efficient process layout combined in independent sumps (biofiltration, degassing and oxygenation)
Bio-Filtration measurements included and identified
  • Rates of nitrification and denitrification: daily monitoring and response time during high ammonia periods
  • Rates of nitrification and denitrification at specific stocking densities
  • Media loading rates compared to specific feeding rates
  • Media loading rates at specific pump settings (load head Super Falls )

Solids Removal / Effluent Control

Existing Solids Removal/Effluent Control Technology
  • Drum filter using 60 micron paneling for solids removal
Deficiencies with Existing Solids Removal/Effluent Control Technology
  • Fecal matter/waste quickly obstructs flow of water/heat/oxygen through 60 micron filter paneling for reuse
  • Frequent mechanical filter and panel maintenance required
Work carried out to overcome Solids Removal/Effluent Control deficiencies
  • Developed and established nutritional related strategies to enhance fecal matter coagulation
  • Advancement from 60 micron to 90 micron paneling in solids removal filter
Solids Removal/Effluent Control performance measures achieved
  • Nutritional advancements enhanced fecal matter binding properties and allowed for a more open mechanical filter panel (90 micron). Combined, these advancements improved water flow, heat and oxygen transfer to effectively accommodate 3 additional 6000 gallon culture tanks and 700 gallons of vertical bio-contactor tanks.
  • Reduced mechanical filter maintenance and panel maintenance
  • Reduction in daily effluent water loss (5% down to 3%)
Solids Removal/Effluent Control measurements included and identified
  • Drum Filter cycle time at specific feeding rates
  • Drum Filter cycle time during heavier feeding times
  • Required Drum Filter maintenance
  • Increased flow rates with a larger paneling
Date Modified: 2012-06-18

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