1. Recirculating Aquaculture Systems

2. Recirculating Aquaculture Systems
Recirculating aquaculture systems (RAS) are systems in which aquatic organisms are cultured in water which is serially reconditioned and reused.

3. Why recirculate? Conserves water
Permits high density culture in locations where space and or water are limiting
Minimizes volume of effluent, facilitating waste recovery
Allows for increased control over the culture environment, especially indoors
Improved biosecurity
Environmentally sustainable

4. Water Reuse Rates Open or Flow-through System Semi-Closed System0%
25%
50%
75%
100%

5. Characteristics of Culture Tank Effluent
High concentrations of suspended
and dissolved solids
High ammonia levels
High concentration of CO2
Low levels of dissolved oxygen

6. Recirculating System Applications
Broodstock maturation
Larval rearing systems
Nursery systems
Nutrition and health research systems
Short-term holding systems
Ornamental and display tanks
High density growout of food fish

7. Scientific Hatcheries Huntington Beach, California

8. Scientific Hatcheries Huntington Beach, California

9. Seagreen Tilapia Palm Springs, California

10. Seagreen Tilapia Palm Springs, California

11. Kent SeaTech Southern California

12. Kent SeaTech Palm Springs, California

13. Southern Farm Tilapia Raleigh, North Carolina

14. Southern Farm Tilapia Raleigh, North Carolina

15. Mote Marine Lab Sarasota, FL

16. Mote Marine Lab Sarasota, FL

17. Harbor Branch Shrimp Fort Pierce, Florida

18. Harbor Branch Shrimp Fort Pierce, Florida

19. Classification of Culture Systems
Trophic Level
Temperature
Salinity

20. Classification of Culture Systems
Examples
Tropical Rainforest
Tropical Display & Breeding
Warmwater growout
Hardy warmwater
Salmonid spawning
Coldwater growout
Null
Marine reef
Marine growout
Coldwater aquaria
Oligotrophic
Warmwater
Mesotrophic
Eutrophic
Freshwater
Oligotrophic
Coldwater
Mesotrophic
Eutrophic
Recirculating Systems
Oligotrophic
Warmwater
Mesotrophic
Eutrophic
Marine
Oligotrophic
Coldwater
Mesotrophic
Eutrophic

21. Major effect on the oxygen saturation level
Salinity
Major effect on the oxygen saturation level
Freshwater
Less than 10 ppt
Marine
Greater than 10 ppt

22. Temperature
Impacts the rates of chemical and biological process at the most fundamental level
Affects: bacterial growth, respiration, nitrification efficiency
Cool-water species: below 20º C
Warm-water species: above 20º C

23. Distinguishes the level of nutrient enrichment
Trophic Level
Distinguishes the level of nutrient enrichment
Oligotrophic
Mesotrophic
Eutrophic

24. Oligotrophic Excellent water quality Very Clear
Used in display aquaria
Most frequently used for breeding purposes
Some species are kept in these conditions all of their lives, while others for a period of time

25. Mesotrophic
Describes the bulk of high-density production systems where risk and economics must be carefully balanced to achieve profitability
Some deterioration in aesthetics
Water quality at safe levels
Dissolved Oxygen- above 5 mg/L
TAN & Nitrite – less than 1mg-N/L
Total suspended solids – less than 15 mg/L

26. Eutrophic
Exist for the grow out of the most tolerant species that show vigorous growth under moderately deteriorated water quality conditions
Dissolved oxygen levels- economic optimum level
Ammonia & Nitrite – less than 2mg-N/L
Water quality – marginal
Species evolved under similar natural conditions prosper in these conditions

27. Integrated Treatment
An assembly of components that creates an artificial environment suitable for production, breeding or display of aquatic animals
Must be reliable
Must be cost effective
Must be compatible with the intended user group

28. Disinfection & Sterilization Aeration & Oxygenation
System Components
Disinfection & Sterilization
Aeration & Oxygenation
CO2 Removal
System
Control
Biofiltration
& Nitrification
Water Quality, Loading, Culture Units, Species
Fine & Dissolved
Solids Removal
Solids
Capture
Waste Mgmt
Hydraulics

29. System Design & Construction Monitoring & System Control
Management Decisions
Economics
System Design & Construction
Nutrition
Monitoring & System Control
Biosecurity

30. Water Quality, Loading, Culture Units, Species
System Components
Water Quality, Loading, Culture Units, Species

31. Circular Tank Flow Pattern

32. Alternative Drainage Strategies
Two Drains

33. Dual Drains Cornell Dual-Drain Design Tank depth - 1.0 m
Tank diameter m
Tank volume m3

34. Commercial Dual Drains
Aqua Optimas
Aquatic EcoSystems

35. Raceway - Plug Flow

36. Racetrack Configuration

37. Water Quality, Loading, Culture Units, Species
System Components
Water Quality, Loading, Culture Units, Species
Fine & Dissolved
Solids Removal
Solids
Capture
Waste Mgmt

38. P R E T R E A T M E N T M A I N T R E A T M E N T P O L I S H I N G TC o u r s e S c r e e n S e d i m e n t a t i o n T u b e S e t t l e r M i c r o s c r e e n s G r a n u l a r F i l t e r D E o r C a r t r i d g e F i l t e r F o a m F r a c t i o n a t i o n 1 7 5 5 3 1 P a r t i c l e S i z e i n a n I n t e n s i v e A q u a c u l t u r e S y s t e m ( A f t e r C h e n
& M a l o n e , 1 9 9 1 )

39. Tube Settler Settling Media OUTFLOW INFLOW Sludge Removal Sludge

40. Tube Settler