Submitted to: Aquacultural Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2007
Publication Date: 1/1/2008
Citation: Masters, A.L., Vinci, B.J., Brazil, B., Creaser, D.A., Summerfelt, S.T. 2008. Performance Characterization of Influent and Effluent Treatment Systems: A Case Study at Craig Brook National Fish Hatchery. Aquacultural Engineering. 38:66-76. Interpretive Summary: Fish raised in intensive and semi-intensive culture environments are more susceptible to disease outbreaks when exposed to opportunistic or obligate pathogens. Aeromonas salmonicida is present in the Craig Brook National Fish Hatchery (NFH) watershed area and there are concerns of transferring the bacteria to the hatchery; consequently, surface water supplies are disinfected at the hatchery prior to use. The influent disinfection system at Craig Brook NFH consists of sand filtration followed by UV irradiation. Although not as common as disinfecting influent water supplies, several facilities such as the Western Fisheries Research Center(Seattle,WA), National Fish Health Research Lab (Leetown, WV), and National Cold Water Marine Aquaculture Center(Franklin,ME) operate effluent disinfection systems to minimize risks of pathogen transmission to surrounding waters. An effluent disinfection system was installed in the wild fish-receiving building at Craig Brook NFH in 2002. Construction of the disinfection system was primarily the result of USFWS concern over the potential impact of infectious salmon anemia (ISA) virus on the endangered Atlantic salmon restoration activities at the hatchery. The ISA virus was detected in commercial salmon net pen operations in Cobscook Bay,Maine, an area through which wild Atlantic salmon broodstock returning to spawn in their native rivers pass. Horizontal and vertical transmission of various diseases including ISA is possible, and young wild Atlantic salmon are captured in the rivers and brought to the wild fish receiving building at Craig Brook NFH to be used for future broodstock. The USFWS installed the effluent disinfection system to prevent the spread of fish pathogens that may have been transported to the facility with the young salmon captured from the wild. Disinfection of receiving building effluent protects the Service's restoration goals by protecting the Lower Penobscot watershed area and prevents disease transmission from the hatchery to Alamoosook Lake and potentially from Alamoosook Lake back into the hatchery. Effluent disinfection consists of microscreen filtration for gross particle exclusion followed by UV irradiation. The sand filtration and UV irradiation equipment in the influent treatment building and the microscreen filter and UV irradiation equipment in the effluent treatment building were evaluated and found to remove particulate matter, total coliforms, and heterotrophic bacteria.
Technical Abstract: This study characterizes the performance of influent and effluent disinfection systems at Craig Brook National Fish Hatchery, a U.S. Fish and Wildlife Service (USFWS) Atlantic salmon (Salmo salar) restoration facility in East Orland, ME. Influent treatment of the hatchery’s water supply limits fish exposure to pathogens and protects the hatchery’s goal to recover endangered Atlantic salmon. Disinfection treatment of effluent from the hatchery’s wild fish receiving building ensures containment of pathogens that could be transferred to the facility with young fish captured from native rivers and protects the downstream hatchery watershed area. Evaluation of the influent treatment system consisted of assessing the effectiveness of the sand filtration and ultraviolet (UV) disinfection equipment, which are used to treat the water supply for the entire hatchery. Evaluation of the effluent treatment system examined the effectiveness of microscreen filtration and UV equipment that are used to disinfect effluent from the hatchery’s wild fish-receiving building. Water samples were collected every 2 weeks for a 6-month period. The evaluation of both treatment systems indicates effective solids removal and total heterotrophic bacteria inactivation (2–4 log10 reductions). No disease issues attributable to the hatchery’s water supply have occurred during operation of its influent disinfection system, enabling the USFWS continued success with its restoration programs.