Design of an Emergency Aeration System for Intensive Aquaculture Raceway Systems

Over the past hundred years, agriculture productivity in the United States has reached record levels through mechanization, intensification, and automation. The short history of aquaculture has also seen a similar trend of increasing production levels in both open pond systems and indoors intensive recirculation systems. Improved monitoring and control of these production systems will yield a reduction in the risk of catastrophic losses and stress, in effluents and their potential environmental impact, in cost of production by maximizing yield per dollar of capital, and most importantly an overall improvement in product quality. Low concentration of dissolved oxygen is the major variable limiting production in intensive aquaculture systems. With production densities approaching one pound of fish per gallon of water, supplemental oxygen is required to maintain optimal growing conditions. The high cost of on-site generation or transportation and storage of liquid oxygen makes it critical, for economic reasons, that pure oxygen be used in the most efficient manner possible. The ability to adjust oxygen concentration to meet constantly changing oxygen demand should have a significant impact on the overall economics of pure oxygen use. An improved understanding and control of dissolved oxygen in intensive systems will yield: 1) real time control of oxygen levels in the production tank, 2) elimination of high and low oxygen levels following feeding and other disturbances, thus reducing opportunities for stress induced diseases, 3) a quicker response to the faster changes in water quality as systems are pushed closer to their carrying capacity limits, and 4) automation of a critical process to reduce labor requirements and management responsibility. This is one aspect of an overall research program to apply modern control system analysis to intensive aquaculture recirculating system, design and develop control algorithms and systems for optimizing water quality parameters and automate routine functions. This project developed a negative feedback control system for dissolved oxygen in intensive recirculating aquaculture systems. Control algorithms were developed and computer simulated for maintaining the dissolved oxygen levels in the