Evaluating the toxicity of woodchip bioreactor outflows
The denitrifying woodchip bioreactor remediates nitrate-rich effluents produced in RAS. However, it is currently unknown if this nitrate treatment process may inadvertently leach wood-bound contaminants at harmful concentrations. Bioreactor outflow reuse within RAS would offer considerable water savings and valuable alkalinity recuperation, provided outflow leachate concentrations are safe for fish production. Bioreactor outflow concentrations of dissolved metals and compounds will be discussed within the context of The Environmental Protection Agency’s Freshwater Water Quality Criteria and generally recommended guidelines for salmonid safety. Toxicity to Ceriodaphnia dubia from combined outflow toxicants will also be examined.