ECOLOGICAL AND RESOURCE RECOVERY APPROACHES TO REDUCE THE ENVIRONMENTAL IMPACT OF AQUACULTURE PRODUCTION

Authors: Adler, Paul

Submitted to: Ecological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2000
Publication Date: 8/1/2000
Citation: Adler, P.R. 2000. Ecological and resource recovery approaches to reduce the environmental impact of aquaculture production. Ecological Society of America Proceedings. August 6-10, 2000, Snowbird, Utah.

Interpretive Summary:

Technical Abstract: Agricultural production has become regionally specialized leading to the spatial separation of animal and feed production. This spatial separation has led to nutrient imbalances in watersheds and increases in nonpoint source runoff losses of nutrients to the water environment. When animal manure is viewed as a waste, storage in lagoons is a common management and treatment alternative. Anaerobic storage of manure in lagoons, however, degrades its value by increasing offensive odors and air pollutants and reducing organic matter and nutrient content. As a resource, value-added processes are used to maximize its value, thereby opening up more market options. In contrast to technological solutions, ecological approaches are less capital intensive and by using ecosystem services, have reduced operating costs. Two nutrient streams from the production of rainbow trout [solids (~10% dw) and overflow water from off-line settling basins for aquaculture solids] were the focus of this study. Solids were mixed with range of carbon sources from switchgrass and barley straw to hybrid poplar, willow, pine, and oak over a C:N ratio gradient. Course mesh bags filled with the mixture were placed on the soil surface and changes in mass and nutrient content were measured over time. Sequestration increased with C:N ratio, but P sequestration was N limited. Overflow water was passed through a carbon biofilter in which microorganisms utilized the carbon source and nutrients from the water for their growth. The rate that N and P were removed from the overflow water increased with concentration; 15-50g N and 2.5-10g P/m3 carbon/d have been achieved.