New Emerging Trends in RAS
Steven Summerfelt
3rd RAS Conference Sunndalsora, Norway
OUTLINE
• Trends – Biosecurity – Increased production scale – Water Quality Limits – Increased oxygenation and CO2 removal – Land-based salmon growout – Capture, dewater, & dry biosolids – Conclusions
Cultured Fish, Eggs
Water Supply
Equipment
Personnel
Feed
Aerosol
Birds
Mink, otter
Fish
Aerosol
Trend: Biosecurity Focus in RAS
• Exclude obligate pathogens – healthier fish ̶ Reduce mortality & improve health and performance ̶ Reduce or eliminate vaccine, antibiotic, & pesticide use ̶ Avoid losses and costs of mitigating:
• sea lice, viruses (ISA, PD), amoeba, obligate bacteria, toxic algae • storms, marine mammals, • super chill
Wild fish & foods
Parasites
Biosecurity Focus in RAS
ü Implementation: o Farms are shifting away from surface water sources
• RAS are used to minimize water flushing • sophisticated filtration & UV irradiation to disinfect
makeup water o Farms introduce only pathogen-free eggs (when possible)
• avoid introducing fish carrying disease
Trend: Increasing Production Scale
• Scale of land-based projects is increasing –1,000 to 6,000 ton/yr under one roof – smolt/post-smolt – food-size fish
Increasing Production Scale
• Example: 1,000 MT/yr of salmonid production – 11,000 to 16,000 m3/hr RAS flow for water quality
• < 80 m3/hr of makeup water (about 99.5% flow reuse)
– 4-5 MT/day feeding – 6,000-10,000 m3 growout volume
• approximation with many variables
Photo credit: Bell Aquaculture
Increasing Production Scale
• Capital cost for 1000 MT/yr farm ranges from about $10 to $17 million – Potential to reduce capital costs
Trend: Economies of Scale
• Economies of scale – Reduce fixed-capital costs and operating costs – Savings in capital per ton production
• Smaller building footprint • Fewer culture tanks, pumps, filters, biofilters, gas balancing units • Fewer water quality monitoring points, SCADA, feeders, pipe runs, etc. • Centralized grading & vaccination
– Cheaper to build one giant RAS than multiple small RAS • Compromises & tradeoffs
Trend: Water Quality Limits
• Regulations & performance criteria govern water quality limits for healthy fish culture
Dissolved O2 100% sat.
Total Gas Pr. ≤ 100% sat.
CO2 < 15-25 mg/L
NH3 < 0.01-0.02 mg/L
NO2-N < 0.2 mg/L
NO3-N < 80 mg/L Example of guidelines used at Freshwater Institute for trout & salmon
Trend: Increase Available Oxygen
• Increasing available O2 without creating total gas super-saturation = increased production – Be careful of high-pressure side-stream units – Be careful of aerating deeper than 1-2m (MBBR)
– Treat full-flow at low pressures using vented oxygen transfer technology • create O2 super-saturation while venting N2 off-gas
to the atmosphere • reduces the opportunity for total gas pressure
super-saturation.
Increase Available Oxygen
• Low Head Oxygenation (LHO) Units – Treat entire RAS flow – Low head/energy (0.5-1 m total dynamic head) – Efficiently produces 150-200% O2 saturation – Near 100% O3 transfer – Vents N2 & avoids TGP – Scales to high flows
PRAqua
(REDUCE ENERGY USED IN
OXYGENATION)
Aerator Pump
Trend: Increase CO2 Removal
• Locate adjacent to the culture tank – improve energy efficiency & reduce fixed costs of CO2 stripping
Airlift Pump Cascade Column and
Axial Flow Pump
(BE SMART, BUT EXECT TO USE ENERGY TO REMOVE CO2)
Airlift Pumps & Cascades Aeration Outside Large Circular Culture Tanks
Airlift Pumps INSIDE TANKS
Airlift Pumps OUTSIDE
TANKS
Air Lift Pumps INSIDE SQUARE TANKS
Cascade Exiting Tank Side-Drain
Culture Tank CO2 Depends on Daily Feed Load and Fan Speed
0 5
10 15 20 25 30 35 40 45
0,0 100,0 200,0 300,0 400,0
Dis
solv
ed C
O2,
mg/
L
Daily Feed Rate in a Culture Tank, kg/d
50 hz 30 hz 20 hz
Forced ventilation Cascade Column
Trend: Land-Based Salmon Growout
• Producing salmon in RAS is biologically and technically viable
• Industry is testing whether producing salmon in RAS is economically viable
• Location, location, location • Permits can be obtained • No site-license system to
stop the farm
Trend: Land-Based Salmon Growout
1. KUTERRA (Canada)
2. Golden Eagle Aqua (Canada)
3. Spring Salmon (USA)
4. Bell Aqua (USA)
5. Freshwater Institute (USA)
6. Sustainable Blue (Canada)
7. BDV (France) 8. Langsand Laks (Denmark)
9. Danish Salmon (Denmark)
10. Jurrasic Salmon (Poland)
11. Xinjiang Ehe (China)
12. Shandong Oriental OT(China)
1,2
4 6 8,9
10 3 5 7 11
12
(Facilities harvesting fish or at least with eggs stocked)
Land-Based Salmon Growout
• One of ten Norwegian “Dark-green licenses” – Senja Akvakultursenter AS – To produce harvest size salmon, on-land
• Norwegian government to decide if land-based farms should be connected to the sea license-system and pay license fee
• Large land-based farms in planning stage: – Norway, Sweden, France, Scotland, USA, Canada, China – No requirement to pay sea license fee outside Norway
Land-Based Salmon Growout
Male Harvests
Premium Harvests
0
1000
2000
3000
4000
5000
6000
0 200 400 600 800 1000 1200
Mea
n Si
ze (g
)
Age (Days)
1208 Gaspe Bay
111 Cascades
109 St. John River
110 St. John River
1208 Gaspe Bay-109 St. John River Mixed Cohort Net Pen STJR
212AS Cascades
1212AS SB
Average Harvest Weight
23-25 months post hatch to 4.5 kg
(16-18 months post-smolt)
Data from Atlantic Salmon growout trials at Freshwater Institute
Land-Based Salmon Growout
Trial #2 Trial #3 Trial #4 Trial #5 Strain St John River Cascade Cascade SalmoBreed
Density 36 kg/m3 100 kg/m3 118 kg/m3 tbd
• Maximum Growout Density in freshwater
(Mean CO2 = 14 mg/L; Max CO2 < 20 mg/L at highest density)
Atlantic Salmon Growout Trials
• Early Maturing Males Trial #2 Trial #3 Trial #4 Trial #5
St John River Cascade Cascade SalmoBreed Grilse harvest size, kg
2.7 & 3.7 2.6 2.1 2.2
Prevalence, % 36.6 38.5 17.1 18.0 Post-harvest use
Hot smoked Cold smoked
Fresh fillets & smoked
Fresh fillets
High maturation: Post-smolt initially comingled with previous cohort that
were maturing
Land-Based Salmon Growout
• Trial #1: – All females Gaspe strain, – 1 to 2% sexually mature
0
400
800
1200
1600
2000
2400
2800
3200
3600
4000
4400
247 277 308 338 369 400 428 459 489 520 550 581 612 642 673 703 734 765 793
Wei
ght (
g)
Days Post-hatch
Gaspe (Continuous Light + S0 Winter)
Gaspe (Continous Light)
St. John's (Continuous Light + S0 Winter)
St. John's (Continuous Light)
24 months
post-hatch
Land-Based Salmon Growout
• No major fish health events were noted – A little fungus, mostly during incubation & fry culture
• Tested sixty fish from each cohort – No sea lice or kudoa – No ISAV, IPNV, VHSV, OMV, SVCV, A. salmonicida,
R. salmoninarum, Y. ruckeri, M. cerebralis, C. Shasta, or K. thyrsites
• No vaccination, antibiotics, formalin, or pesticides used at any time in over a decade
• No escapees
Data from Atlantic Salmon growout trials at Freshwater Institute
Trend: Capture & Dewater Biosolids
• Gravity thickening settling units – Lower fixed & variable costs – No coagulant / flocculants required to 5-10% solids
– Low maintenance – Farmer friendly
Trend: Dewater & Dry Biosolids
• Dry biosolids to avoid storage lagoons (odor), reduce transport volume, & prepare for composting
30-40% CAKE
ROLLERPRESS
35% dry weight
Trend: Reclaim Nutrients
• Nutrients in biosolids & effluent can be reclaimed – Agronomic application of
biosolids to crops – Compost – Aquaponics
Trend: Remove Nitrogen
Woodchip Bioreactor Membrane Biological
Reactor
Conclusions
• Seafood production must increase • Closed-containment systems can increase seafood
production in the face of: – water resource limitations, – pollution restrictions, – siting restrictions, and – mounting disease challenges
• MORE RESEARCH
Acknowledgements
ØResearch support
Use native, freshwater snails to clean RAS surfaces and mitigate off-flavor in RAS
Bioremediation
Ø Total solids (biofilm) per area
• Snails - 0.03 ø 0.02 mg/cm2 • No Snails – 1.16 ø 0.16 mg/cm2
Ø Off flavor results still pending
Ø 100 snails, Physa gyrina, completely grazed the submerged surfaces of 50 gallon tanks within replicated reuse systems (left)
Ø Systems without snails had substantial
biofilm accumulation (below)
Snail Treated RAS
No Snail Control RAS
Bioremediation
ØSnails control biofilm accumulation on surfaces ØRapid snail reproduction & distribution ØWaiting for data on geosmin & MIB accumulation ØMore research necessary
Bioremediation
Ø Disinfect between cohorts Ø Use no water aeration media in
depuration systems because it provides surface area for biofilm attachment and is difficult to clean and disinfect
Ø Use simple partial-reuse or flow-through
systems and avoid treatment processes with difficult to clean areas
SOP’s for Depurating Salmon
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