2008 Annual Report
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.