PowerPoint Presentation

Tank Optimization For Improved Hydrodynamics In Aquaculture and aquaponicsMichael Galloway1 and Shaun M. Gill21UNE Aquaculture and Aquarium Sciences 15, Pratt & Whitney Marine Fellow in Aquaculture Engineering2Marine Science Center, University of New England

BackgroundThe aquaculture industry is a dynamic field which is growing at a rapid rate. This growth is driven by a combination of static or declining catches from most traditional fisheries, declines in stocks of many commercially caught fish species, and the increased need for marine protein as a result of global population growth. Consequently, aquaculture engineering is being turned to for solutions that allow this growth to be possible. Aquaculture engineering requires great knowledge breadth, covering traditional general engineering specialties such as mechanical, environmental, materials technology, but also solid understandings of biology, chemistry, and ecology. Understanding how these specialties interact and complements each other allows one to engineer solutions that efficiently utilize resources, such as water, land, feed, broodstock and seed, to their fullest potential. Balancing engineering and biological interactions ensures quality aquaculture systems with hearty products required for our expanding society. This project focuses on engineering designs that drive aquaculture and aquaponics tank hydrodynamics in order to maximize a tanks self cleaning capabilities. Effective self cleaning is desirable because quickly collecting and removing settable solids improves water quality, system function, and overall economy. In the case of aquaponics the solids are further processed via additional system engineering to provide valuable plant nutrition.

Trout Room InternshipPratt & Whitney FellowshipIntroduction The University of New England is enthralled in new and groundbreaking opportunities in sustainability and human food systems. A pivotal place for new growth and development has been the Marine Science Center (MSC), where students can be immersed in new hands-on learning initiatives and allowed to explore their passions. Through collaborations between the Marine Sciences and Biology departments, one project that was made possible was the repurposing of a 10,000 gallon pool for the growout of Kamloops variety of Rainbow Trout (Oncorhynchus mykiss) obtained from Shy Beaver Trout Hatchery in Hollis, Maine. In the Spring of 2015, I held a UNE CAS internship focused on managing the Trout project, inheriting a quickly changing system that taught me the intricacies of managing new and evolving system processes.Design Lessons LearnedUndersized filtration and high stocking densities lead to high waste production creating immediate and significant challenges for managing water quality and operating the system efficiently. Upgrading filtration components is a logical and simple solution, but expensive. But even the best filtration, is only as good as the systems ability to concentrate and collect settleable solids. Hence, identifying improvements and creating prototypes for improving system hydrodynamics were the immediate steps towards resolving the tank's self cleaning challenges. Challenges The trout were housed in a recirculating system initially designed for holding sea turtles. As a repurposed system, the trouts high stocking density overwhelmed the systems capabilities and forcing new solutions to be identified. The system was run as both a recirculating and flow through to control parameters such as temperature shifts, open-environment interactions, and water quality. When operated as a closed-looped, recirculating aquaculture system (RAS) additional challenges arose due to shifts in dissolved oxygen (D.O), pH, and Ammonia (Nitrate and Nitrite).

AcknowledgmentsI would like to give a special thank you to Pratt & Whitney for funding my fellowship in Aquaculture Engineering; as well as The University of New England College of Arts and Science and CAS Internship office for allowing me to work alongside a group of amazing people; Asahi- America, Inc. for donating parts; and my mentors and advisors Shaun Gill, Jeri Fox, Adam St. Gelais, Timothy Arienti, and Troy Thibeau for all of their help across two different internships and throughout this fellowship.

New ProspectsThrough the generous support of Pratt & Whitney, I was awarded the 2015 Pratt and Whitney Marine Fellowship in Aquaculture Engineering. My fellowship focused on evaluating and decommissioning the initial trout system along with doing research to identify and prototype engineered solutions for improving aquaculture and aquaponics tank hydrodynamics. This summers work entailed reverse engineering and tested vertical manifolds to increase flow velocities in the Oncorhynchus mykiss holding tank. The goal is to provide a successful proof of concept that will provide grounds for future investments in system infrastructure.

Understanding the Cornell Dual-Drain SystemResearchers at Cornell University dedicated to creating sustainable agricultural and food production processes developed a world-renowned aquaculture and aquaculture engineering design called the Cornell dual-drain self cleaning system. They determined that creating uniform flow in a round tank via vertical manifolds allowed them to collect settleable solids at a centralized point (i.e. a modified center drain). In addition, the incorporation of a second side drain would be able to skim off the remaining solids that float to create better water quality and more efficient use of resources.

Design ChallengesFully adopting the Cornell design specifications was a challenge as the MSC pools are made of concrete and rectangular in shape. Due to limited information availability on manifold and center drain design the vertical manifold prototypes were reverse engineered based upon literature findings and limited photographs and opted for a modular design to promote trial and error. The manifolds are constructed with threaded fittings that can be interchanged for experimentation and easily swapped out in the event of part failure. True-Union Balls valves donated by Ashai-America allowed for fully customizable water flow and direction adjustments. Manifold testing is currently underway to determine proper nozzle orifice size and number for achieving rotational velocities that promote self cleaning.

Application to AquaponicsA Balancing ActWhen simultaneously growing fish and plants in the same system, finding a balance between feed additions, nutrient conversion and overall water quality is crucial, each relying heavily on proper system engineering and hydrodynamics. Below, preliminary data from the MSC system shows how a properly functioning system maintains at or near-zero ammonia levels (red) , which is toxic to fish, even as feed levels (light blue) are increased, causing subsequent and desirable increases in nitrate levels (purple) for improved plant nutrition. As part of the sustainable and Edible Campus initiatives at the University of New England, a student-centered aquaponics system was developed. Aquaponics is the fusion of two sustainable practices, hydroponics and aquaculture, in which the waste of one organism is beneficial to another. Hydroponics is a soilless method of growing plants in soil-alternative media or fully immersed in water. In comparison to aquaculture which prioritizes fish as end products, aquaponics prioritizes plants nourished by strategically collected and re-purposed fish waste. Despite different end products, all three practices rely upon efficient hydrodynamics and system engineering for concentrating, collecting, and moving waste. In the case of aquaculture, the waste is simply collected and removed. Aquaponics, on the other hand, takes the collected waste and through the process of biological filtration converts the normally toxic fish waste into bioavailable nutrition for plants. Future DirectionsIn the future we hope to see this whole room function as a research and educational centerpiece. There is much to be learned about rearing fish for open ocean stocking, and the biology and chemistry of such a complex system. As a living system we hope to teach students how to interchange components and understand system operation and appreciate design.Design specifications call for a 140 gpm of flow through the manifolds. The modular nature of this design allows all system components the ability to rotate and swing in a 360 motion, allowing for almost infinite flow adjustments. Experiments employing a rubber ball to measure surface currents are helping to determine rotational velocities. Furthermore, the seawater being used unfiltered and contains particulate solids. Upon shutting the system down, the shape and concentration of the solids deposited on the tank bottom are used are used as a proxy for assessing hydrodynamic efficacy.

Rainbow Trout (Oncorhynchus mykiss)The 10,000 gallon trout holding poolThe making s of a new and improved biofilterWith the help of Pentair Aquatic Ecosystems engineering team we designed a new recirculating system that capitalizes on the new vertical manifolds. Not only will the entire system better collect and capture solids, it disposes of them faster, yielding better water quality, maximizing resources, increasing our biomass and ensures greater quality and welfare of our fish.

Hydrodynamic and Infrastructure Improvements:

The newly proposed Pentair trout system with vertical manifolds (arrows) as integral design components.A vertical manifold prototypeAdjusting manifold directionVertical manifold construction

The new student-centered aquaponics pilot system housed in the Marine Science Center.