Summary of "In Pond Raceway System: An Intensive Fish Production System - Dr. Jesse Chappell"
Summary of Scientific Concepts and Technology in the In-Pond Raceway System (IPRS)
Overview:
- The In-Pond Raceway System (IPRS) is an advanced aquaculture technology designed to intensify fish production within earthen ponds.
- It contrasts with traditional pond culture by using a flowing water principle rather than static water.
- The system integrates raceway cells inside large ponds, with continuous water circulation driven by specialized aeration units called white water units (WWUs).
Key Scientific and Technical Concepts:
- System Design and Requirements:
- Minimum pond size: 10,000 cubic meters per raceway cell (220 m³ per raceway).
- Typically, 2-3 raceways per pond (20,000 to 30,000 m³ pond volume) for economic viability.
- Raceway dimensions: 22 m long, 5 m wide, 2 m water depth.
- Continuous electrical power required, with automatic backup generators to prevent system failure.
- Only high-quality floating feed is used; no sinking feed or agricultural by-products.
- The system is principle-driven; strict adherence to design and management is critical for success.
- Water Management:
- Water is continuously circulated around and through raceways to maintain oxygen levels and remove waste.
- white water units (floating aerators with regenerative blowers) create a robust, circular water flow.
- Baffles are installed to lengthen water flow path and prevent short-circuiting of water flow.
- Water exchange in raceways occurs every 5-7 minutes, exchanging the entire raceway volume 8-9 times per hour.
- Flow velocity targeted around 8 cm/s to ensure fish comfort and effective waste transport.
- Aeration and Circulation Equipment:
- white water units are floating, with no moving parts except the blower underneath a protective shroud.
- Diffuser tubes (aerotube brand recommended) produce fine bubbles for efficient aeration and water movement.
- Each raceway requires:
- One blower for the raceway white water unit.
- One blower for an associated open pond white water unit.
- One supplementary blower for additional aeration when biomass reaches ~60%.
- One spare blower for backup.
- For ponds deeper than 3 meters, vertical mixing chimneys or additional white water units are used to maintain oxygen homogeneity.
- Fish Management and Production:
- Fish are confined within raceways by upstream and downstream confinement gates made of metal frames and PVC-coated mesh.
- Gates allow water flow but prevent fish escape and exclude wild fish from the quiescent zone.
- The quiescent zone (6 m long) at the downstream end of the raceway allows settling of waste solids.
- Target production per 10,000 m³ pond volume:
- 33 tons of fed species per cycle.
- 7.5 tons of non-fed "service" or filtering species in open pond water.
- Staggered stocking and harvesting of multiple raceways allows continuous production.
- Waste Management:
- The pond acts as a biological filter, maintaining aerobic conditions through thorough mixing.
- Waste solids settle in the quiescent zone and are removed mechanically 3-4 times daily using oscillating vacuum heads.
- Waste removal systems use semi-solid pumps and a cable-driven carriage to efficiently collect and pump solids to shore-based settling tanks.
- The system is designed as zero discharge; removed solids are used as fertilizer for crops.
- Proper pond bottom preparation (removal of vegetation, shaping) is critical to avoid oxygen depletion and ensure efficient water flow.
- Construction and Operation:
- Raceway walls constructed from brick, concrete, and reinforced steel bars.
- Floors are thin concrete slabs supported by footers.
- Working walkways are installed for feeding and maintenance, avoiding obstruction of gates and white water units.
- Electrical installations must follow strict safety protocols due to proximity to water.
- backup generators should be tested regularly under load, and staff trained with fire drills for power outage scenarios.
- Key Principles for Success:
- Follow design parameters strictly (pond volume per raceway, flow rates, equipment specifications).
- Use only recommended equipment (e.g., aerotube diffusers, Gast regenerative blowers).
- Maintain continuous operation of water circulation and aeration.
- Properly manage stocking density and harvest timing to avoid exceeding peak biomass.
- Efficiently remove waste solids to reduce oxygen demand and maintain water quality.
- Ensure reliable electrical power with automatic backup systems.
- Maintain and clean equipment regularly (e.g., blower filters, diffuser racks).
Methodology / Setup Outline:
- Pond Preparation:
- Ensure pond volume ≥ 10,000 m³ per raceway.
- Remove organic vegetation and shape pond bottom.
- Combine smaller ponds if possible for economic efficiency.
Category
Science and Nature
