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United States Department of Agriculture

Agricultural Research Service

2010 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)Develop and evaluate solutions that improve efficiencies of scale and reduce water quality constraints for sustainable production. .
2)Develop and evaluate sustainable waste management technologies that result in environmentally compatible controlled intensive aquaculture systems. .
3)Field test selected rainbow trout germplasm resources for performance in intensive recirculating aquaculture systems.

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.

3.Progress 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.

Last Modified: 7/5/2015
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