2010 Annual Report
The overall goal of this project has been to develop and improve technologies that enhance the sustainability and reduce the environmental impacts of the modern fish farming industry. Progress was made in several areas.
Research on rainbow trout performance, health, and welfare, and water quality, was carried out in WRAS operated at close to zero water exchange, with or without ozone. This work has provided valuable insight into water quality parameters that accumulate (with or without ozone) in near-zero exchange WRAS, and has stimulated hypotheses regarding, among other things, nitrate levels that will be explored in controlled research in the next 5-year cycle.
The cost and effectiveness of three solids thickening processes, i.e., gravity thickening cone, geotextile filter, and belt filter, were determined and published in the refereed journal Bioresource Technologies. This research will provide design and management recommendations that can be used by fish farmers to improve waste capture, dewatering, and disposal, which will reduce the risk of potentially adverse interactions between aquaculture operations and the surrounding aquatic environment.
Performance of a novel aerated geotextile filter system that combines biological nutrient removal, sludge stabilization, and solids thickening in one membrane filter process was determined. This research has determined the engineering criteria and performance expectations for solids and nutrient capture within a relatively primitive but inexpensive membrane biological reactor system.
Data collection was concluded in a study that determined the capacity of a membrane biological reactor to provide nitrification, denitrification, and enhanced biological phosphorus removal of a high-strength aquaculture backwash flow (control condition), or the same flow amended with 100 mg/L of NO3–N and 3 mg/L of dissolved P (test condition) using only endogenous carbon. A paper summarizing these findings was written and published in the journal Bioresource Technologies. Our findings suggest that permeate flow could be reclaimed to recycle alkalinity, salts, and heat for fish culture and that the waste activated sludge does not produce metals concentrations that would prevent its land application (reclaiming phosphorus) or prevent its use as a protein source in animal feeds.
Two year class of select rainbow trout germplasm that were provided by the NCCCWA were reared at the Freshwater Institute during this reporting period. These fish serve as a back-up repository for NCCCWA rainbow trout broodfish.
A select strain of rainbow trout developed by Troutlodge was reared in two water reuse systems at the Freshwater Institute to provide fish performance and survival data to this key industry stakeholder.
The ADODR is in frequent contact with the cooperator through phone calls, email, and site visits in addition to receipt of written reports.