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Recirculation Aquaculture

Recirculation Aquaculture

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Recirculation Aquaculture

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  1. Recirculation Aquaculture

  2. Why Recirculation • Water use • Climate • Quality • Predation • Environmental impact • Land • Disease • Exotic species (or control thereof…

  3. Cost of Labor : $7/day Solids Siphon Near Ensenada, Mexico; 2002

  4. Near Ensenada, Mexico; 2002

  5. Near Ensenada, Mexico; 2002

  6. Raise a lot of fish with Little Labor

  7. Definitions Recirculating System: A production system that reconditions water to extend it’s reuse A technique that increases the value of a limited resource An artificial well that never ceases to flow A stable platform forming a reliable base for commercial production

  8. Five Major Processes 1) Circulation 2) Clarification (Solids capture) 3) Biofiltration (BOD reduction/nitrification) 4) Aeration (Oxygen replacement) 5) Degasification (CO2 stripping)

  9. Five Major Treatment Objectives The Five Major Processes in a Recirculating System Feeding Circulation Aeration Fish Tank Degasification Biofiltration Solids Capture

  10. Return to Tank Double Drain at Center of Tank

  11. Inlet Outlet Sludge outlet From Under-drain

  12. Over-Drain Flow

  13. Captured Solids

  14. Microscreen Cleaning Jets

  15. From Microscreen Micro-Bead Filter

  16. 1 mm Styrene Beads

  17. Centrifugal Pumps

  18. Pressure line from Centrifugal Pumps Oxygen Bubbles 02 Flow Meter Pressure Gauge Water Return to Tanks

  19. Solids Capture Feeding Circulation Aeration Fish Tank Degasification Biofiltration Solids Capture

  20. Solids Capture Impact of Solids on Recirculating Systems • Increased BOD load (organic solids) causes problems with Biofilters • Increased system turbidity (fine particles) • Gill damage in fish (fine particles)

  21. Solids Capture Particle Size Distribution (microns) Settleable 10-4 10-3 10-2 10-1 1 10 100 Dissolved Colloidal Suspended

  22. Tilapia No Fine Solids Capture

  23. Coarse Screens Cartridge Filter Plain Sedimentation Tube Settler Microscreen Granular Filter Foam Fractionation 100 30 75 10 Particle Size, microns SOLIDS REMOVAL PROCESSES AND PARTICLE SIZES

  24. Solids Capture SEDIMENTATION Vh OUTFLOW Vs Settling Zone Inlet Zone INFLOW Outlet Zone (Vs> Overflow Rate to settle) Sludge Zone

  25. Solids Capture Solid Removal Technologies • Effective for selected particle size • Differ in headloss…energy $$$ • Differ in labor for upkeep • Sensitive to organic loading

  26. Floor Plan

  27. “BYPASS” FILTRATION TANKS Pump Liquid O2 Bead Filter Packed Column Fluidized Bed Packed Column Lime Addition

  28. “IN-LINE” FILTRATION TANKS Shrimp Maturation in South America Pump Bead Filter Fluidized Bed Packed Column

  29. Feeding Circulation Aeration Fish Tank Degasification Biofiltration Solids Capture

  30. Biofiltration Types of Biofilters

  31. Biofiltration

  32. Biofiltration

  33. Biofiltration

  34. 0.45 kg/m3 USDA - SBIR/AST, 97

  35. Production Units

  36. Propellor-washed Floating Bead Filters

  37. Broodstock Return Anti-siphon valve Bypass Sludge View Port Pressure Gauge Sludge Intake

  38. ADM Tilapia System

  39. Gas Exchange Feeding Circulation Aeration Fish Tank Degasification Biofiltration Solids Capture

  40. Oxygen 21% of air Saturation 10 mg/l Poorly soluble Transfer H20 limited Carbon Dioxide 0.035% of air Saturation 0.5 mg/l Highly soluble 50 mg/l + Transfer gas limited Gas Exchange Different Behavior Oxygen goes in easier than CO2 comes out

  41. Gas Exchange No CO2 Removal Enrichment Devices • Commonly used for large scale applications • Self-generates pressure (150-200 psi) • 1 m3 liquid860 m3 gas • Dependent on local source of liquid oxygen • Not impacted by power failure • 15-35cents/kg typical Liquid Oxygen Timmons and Lorsordo (1994) pg. 188

  42. Gas Exchange • Air stones • Paddle wheels • Surface Agitators • Spray nozzles • Packed columns Ambient Air –Oxygen Addition and Carbon Dioxide removal are balanced

  43. Gas Exchange Ambient Air Options

  44. Circulation Feeding Aeration Circulation Fish Tank Biofiltration Degasification Solids Capture