Nutrient Removal from Recirculating Aquaculture System Water

Recirculating aquaculture systems (RAS), where only approximately 10% of the total system water is exchanged per day, have grown in popularity in recent years due to their potential to provide a high-quality protein source in a contained environment. With increased production comes the need for RAS water treatment to mitigate recirculation and discharge of nutrients produced by fish; mainly phosphorus and nitrogen. When discharged, nutrients can contribute to eutrophication in surrounding water bodies, harming the fish and other aquatic life. Therefore, RAS effluent should be treated before discharge. One method of phosphorus removal is adsorption, a surface phenomenon that is often used to bind dissolved pollutants to a solid-phase medium and remove them from water. Nitrogen is present in RAS as ammonia, which is toxic to fish even at concentrations as low as 0.05 mg L-1. Therefore, the ammonia is transformed to nitrogen’s non-toxic form, nitrate, before recirculation or discharge, by a process called nitrification. Both adsorption and nitrification can be affected by RAS process parameters such as salinity. Many anadromous fish such as Atlantic salmon require a change in salinity over their lifetimes; therefore, both of these processes should be investigated for their response to salinity changes. An adsorption study was performed on an aluminum oxide-based material, RhizoSorb®, to assess its response to different RAS variables. It was found that both film diffusion and intraparticle diffusion are rate-controlling steps in the adsorption process, and the removal efficiencies in batch tests were affected by time, salinity, and phosphate concentration. The Freundlich isotherm fit the equilibrium data better than the Langmuir isotherm, showing that adsorption is a multi-layer process and that the adsorbent is highly heterogeneous. The Clark model was better suited than the Thomas model for predicting the performance of the RhizoSorb® in a flow-through system. The results of this study showed that RhizoSorb® and other alumina-based sorbents have high potential towards application to the RAS water treatment process to remove and recover phosphorus. A second study was performed to assess the effects of salinity changes on nitrifying biofilters. Acclimation to a small amount of salinity before transition to a higher salinity may help biofilters recover from the larger shift; therefore, a series of experiments was performed on both freshwater and brackish (3 parts per thousand (ppt)) biofilters to assess their respective levels of recovery after an abrupt change in salinity (3, 20, and 33 ppt). Tests were run for a two-week period in which the nitrification rates were monitored. The freshwater biofilters quickly recovered from a shift to 3 ppt, but did not recover from a shift to 20 or 33 ppt. The brackish filters started to recover at the end of the two-week test, but did not recover from a shift to 33 ppt. DNA sequencing of the variable V4 region of the 16s rRNA gene showed that the heterotrophic communities in the biofilm were lysed at a greater proportion than the nitrifiers, though the nitrifiers were inactivated in higher salinities. A longer series of tests could fully characterize the effects of acclimation to salinity with the effects of ammonia concentration and organic matter, which could help to fully understand the microbial community dynamics

Automatic translation among spoken languages

The Machine Aided Voice Translation (MAVT) system was developed in response to the shortage of experienced military field interrogators with both foreign language proficiency and interrogation skills. Combining speech recognition, machine translation, and speech generation technologies, the MAVT accepts an interrogator's spoken English question and translates it into spoken Spanish. The spoken Spanish response of the potential informant can then be translated into spoken English. Potential military and civilian applications for automatic spoken language translation technology are discussed in this paper

The Partial Replacement of Perennial Ryegrass Silage with Ensiled Biorefined Perennial Ryegrass Press Cake, and its Impact on Productivity of Late Lactation Dairy Cows

Although necessary to maintain milk production in late lactation when grass is scarce, dependency on imported concentrate has negative environmental credentials; diversifying native feeds i.e., perennial ryegrass, using biorefinery, to produce high quality by-products may be a solution (Sanders et al., 2020). To validate these suggestions, a study was undertaken on dairy cows during the winter period; 60% of a perennial ryegrass silage diet was replaced with perennial ryegrass (PRG) press cake in treatment cows (GSPC; n=20), while a perennial ryegrass silage diet was offered to control cows (GS; n=20). Cows substituted with press cake produced 9.1 and 10.5 % more milk solids (kg), and fat and protein corrected milk (kg), respectively, compared to their GS herd mates (P \u3c 0.05). The GSPC cows also produced 6.5% more methane than GS cows (P\u3c0.05). This was primarily driven by a higher group average dry matter intake in GSPC cows (15.6 kg) compared with GS cows (15.1 kg). Although cows offered press cake had a higher group average dry matter intake, they were not significantly heavier than cows offered a silage based diet, and they tended (P=0.05) to have a lower body condition score (BCS). Cows substituted with press cake produced 3.8% more methane per kg dry matter intake and 13.0% more methane per kg body weight (P=0.01), respectively. Feeding PRG press cake to late lactation dairy cows did not improve environmental credentials, as there was a greater methane output compared to cows offered a grass silage based diet. Although PRG press cake significantly improved milk solids yield, when methane was expressed per kg milk solids output was similar for treatment and control cows

Science into policy: preparing for pandemic influenza

Authoratative government pandemic preparedness requires an evidence-based approach. The scientific advisory process that has informed the current UK pandemic preparedness plans is described. The final endorsed scientific papers are now publicly available

How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation

Citation: Fencl, J. S., Mather, M. E., Costigan, K. H., & Daniels, M. D. (2015). How Big of an Effect Do Small Dams Have? Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation. Plos One, 10(11), 22. doi:10.1371/journal.pone.0141210Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0-15.3 km) or 287 wetted widths (136437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic approach that has been applied to larger dams

Dexterity Test Data Contribute To Reduction in Leaded Glovebox Glove Use -9055

ABSTRACT Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (TA-55) involve working with various amounts of plutonium and other highly toxic, alpha-emitting materials. The spread of radiological contamination on surfaces, airborne contamination, and excursions of contaminants into the operator&apos;s breathing zone are prevented through the use of a variety of gloveboxes. Using an integrated approach, controls have been developed and implemented through an efficient Glovebox Glove Integrity Program. A key element of this program is to consider measures that lower the overall risk of glovebox operations. Line management who own glovebox processes through this program make decisions on which type of glovebox gloves (hereafter referred to as gloves), the weakest component of this safety-significant system, would perform best in these aggressive environments. As Low as Reasonably Achievable considerations must be balanced with glove durability and worker dexterity, both of which affect the final overall risk of the operation. In the past, lead-loaded (leaded) gloves made from Hypalon ® were the primary glove for programmatic operations at TA-55. Replacing leaded gloves with unleaded gloves for certain operations would lower the overall risk as well as reduce the amount of mixed transuranic waste. This effort contributes to the Los Alamos National Laboratory Continuous Improvement Program by improving the efficiency, cost-effectiveness, and formality of glovebox operations. In this report, the pros and cons of wearing leaded gloves, the effect of leaded gloves versus unleaded gloves on task performance using standard dexterity tests, the justification for switching from leaded to unleaded gloves, and the pollution prevention benefits of this dramatic change in the glovebox system are presented

Dexterity test data contribute to reduction in leaded glovebox gloves use

Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (T A-55) involve working with various amounts of plutonium and other highly toxic, alpha-emitting materials. The spread of radiological contamination on surfaces, airborne contamination, and excursions of contaminants into the operator's breathing zone are prevented through the use of a variety of gloveboxes. Using an integrated approach, controls have been developed and implemented through an efficient Glovebox Glove Integrity Program. A key element of this program is to consider measures that lower the overall risk of glovebox operations. Line management who own glovebox processes through this program make decisions on which type of glovebox gloves (hereafter referred to as gloves), the weakest component of this safety-significant system, would perform best in these aggressive environments. As Low as Reasonably Achievable considerations must be balanced with glove durability and worker dexterity, both of which affect the final overall risk of the operation. In the past, lead-loaded (leaded) gloves made from Hypalon(reg.) were the primary glove for programmatic operations at TA55. Replacing leaded gloves with unleaded gloves for certain operations would lower the overall risk as well as reduce the amount of mixed transuranic waste. This effort contributes to the Los Alamos National Laboratory Continuous Improvement Program by improving the efficiency, cost-effectiveness, and formality of glovebox operations. In this report, the pros and cons of wearing leaded gloves, the effect of leaded gloves versus unleaded gloves on task performance using standard dexterity tests, the justification for switching from leaded to unleaded gloves, and the pollution prevention benefits of this dramatic change in the glovebox system are presented

Pollutant transfer through air and water pathways in an urban environment

The authors are attempting to simulate the transport and fate of pollutants through air and water pathways in an urban environment. This cross-disciplinary study involves linking together models of mesoscale meteorology, air pollution chemistry and deposition, urban runoff and stormwater transport, water quality, and wetland chemistry and biology. The authors are focusing on the transport and fate of nitrogen species because (1) they track through both air and water pathways, (2) the physics, chemistry, and biology of the complete cycle is not well understood, and (3) they have important health, local ecosystem, and global climate implications. The authors will apply their linked modeling system to the Los Angeles basin, following the fate of nitrates from their beginning as nitrate-precursors produced by auto emissions and industrial processes, tracking their dispersion and chemistry as they are transported by regional winds and eventually wet or dry deposit on the ground, tracing their path as they are entrained into surface water runoff during rain events and carried into the stormwater system, and then evaluating their impact on receiving water bodies such as wetlands where biologically-mediated chemical reactions take place. In this paper, the authors wish to give an overview of the project and at the conference show preliminary results