2008 Annual Report
1a.Objectives (from AD-416)
This project plan uses a multi-disciplinary approach to develop and evaluate solutions for major challenges that delay expansion of controlled intensive aquaculture systems (CIAS). The objectives of this plan are:.
1)To develop and evaluate solutions that improve efficiencies of scale and reduce water quality constraints for sustainable production in controlled intensive aquaculture systems. Research includes overcoming obstacles associated with managing hydraulics and harvests within large (600 m3) tanks, and control of noise, dissolved organic compounds, micro-organisms, and dissolved carbon dioxide. .
2)To develop and evaluate sustainable waste management technologies that result in environmentally compatible controlled intensive aquaculture systems. This objective includes work on treatment processes for solids and nutrient removal from aquaculture effluents and mitigation of the impact of feed on water quality. .
3) Field test selected rainbow trout germplasm resources for performance in intensive recirculating aquaculture system.
1b.Approach (from AD-416)
To investigate approaches for enhancing economies of scale and to reduce water quality and other environmental constraints, the minimum bottom-center drain surface loading rate and the water inlet structure design required to produce rapid solids flushing and safe fish swimming speeds will be identified using a 600 m3 experimental tank. Studies will be conducted to determine if noise levels in the water produced by water pumping and treatment equipment affect hearing in fish and result in reduced growth. In addition, fish health will be assessed in conjunction with controlled ozone and UV treatment to determine treatment levels required to reduce bacterial load and organic carbon load; further, the utilization of bacteriophage to specifically mitigate pathogenic bacterial load in CIAS will be tested. Water quality control using new technology that facilitates carbon dioxide removal and enhances oxygen absorption will be tested and operating parameters defined. More sustainable waste management technologies for CIAS will be developed by testing several new and promising approaches to the capture and concentration of solid wastes and to their stabilization and denitrification. Further, new diets utilizing plant proteins as a substitute for fish meal proteins will be evaluated to determine if there is a differential impact on water quality of the wastes produced from feeding these diets in CIAS. Growth and survival data on selected rainbow trout germplasm cohorts or families provided by NCCCWA will be collected. Linkage with specific research objectives at the NCCCWA will be maintained.
Three controlled studies were completed with each comparing:.
1)rainbow trout health and performance;.
2)water quality; and.
3)unit process treatment efficiency, in re-circulating aquaculture systems (RAS). This work improved our understanding of inter-relations between production system design, loading, and water quality in addition to permitting the identification and amelioration of substances that accumulate within RAS and affect fish health. For instance, in addition to the quantification of off-flavor compounds in water, biofilm, and fillets of fish reared in RAS; several geosmin-producing bacteria species were isolated.
Effective management of aquaculture waste is critical to the success of re-circulating aquaculture systems. Nutrient removal across a membrane biological reactor system treating aquaculture wastewater was assessed. Results indicate that total nitrogen and total phosphorus removal was maintained even when the process was continuously fed an additional 100 mg/L of nitrate nitrogen and 3 mg/L of dissolved phosphorus, which are typical conditions encountered in commercial applications. Two of three research trials were completed on the evaluation of a novel aerated geotextile filter system that combines biological nutrient removal, sludge stabilization, and solids thickening in one membrane filter process. This research will determine the engineering criteria and performance expectations for solids and nutrient capture within a relatively simple and inexpensive membrane biological reactor system. Also, an experiment was completed that compared aluminum sulfate against aluminum chloride for phosphorus precipitation, biosolids capture and dewatering across an inclined belt filter. Results from this study will be used to develop design and management recommendations for fish farmers to simplify and improve waste capture, dewatering, and disposal.
A commercially produced fishmeal- and fish oil-based diet was compared to a commercially produced grain-based diet. Fish fed the fishmeal-based diet were significantly larger and had better feed conversion, but had higher mortality and worse fin condition than fish fed grain-based feed.
A novel technique was developed to herd fish in large culture tanks, and a custom sidewall drain box was developed to harvest fish. These discoveries will provide for more convenient, economical, and reduced labor fish harvest and transfer systems.
Process requirements to achieve full-flow disinfection of recycled water using ozonation followed by ultraviolet irradiation were determined. These findings have produced more biosecure aquatic production systems that sustain healthier and more growth-promoting environments.
National Program 106 , Component 7 Aquaculture Production Systems.
The ADODR monitors the project through regular phone discussions with the student and faculty member, and reciprocal site visits.