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In the event of a mass livestock mortality situation, disposal routes such as burial are commonly chosen. The impact of burial on the environment could be substantial, but the composition of the leachate arising from a burial site has not been well documented. This study was performed to determine the chemical composition of leachate arising from animal mortalities in a burial setting. Three species of livestock were used: bovine, swine, and poultry. Leachate collected from lined burial pits over two years of decomposition was analyzed for major and minor ions. Analysis indicated that livestock mortality leachate contains, on average, concentrations of 46,000 mg L-1 of alkalinity (as bicarbonate), 12,600 mg L-1 of ammonium-N, 2600 mg L-1 of chloride, 3600 mg L-1 of sulfate, 2300 mg L-1 of potassium, 1800 mg L-1 of sodium, and 1500 mg L-1 of phosphorus, along with lesser amounts of iron, calcium, and magnesium. Select samples had maximum concentrations of ammonium-N and bicarbonate up to 50% higher than these average values. In comparison to earthen swine manure storages and landfills, the ionic strength of the leachate was 2 to 4 times higher, and therefore its impact on water resources could be greater. Following the study of the chemical composition of livestock mortality leachate, the potential impacts of this leachate on the soil/water systems below a burial site were investigated. The ionic strength of the leachate presents its own set of challenges. Basic modeling of ion activity using the five most common activity coefficient equations (Debye-Hückel, extended Debye-Hückel, Truesdell-Jones, Davies, and Pitzer) were considered to assess the sensitivity of these methods for calculated ion activity as impacted by the ionic strength of the leachate. This was completed to further enhance the modeling and speciation efforts. Based on the results and the applicability of the Truesdell-Jones equation, PHREEQC was used to assess the chemical speciation of the leachate. The speciation of this leachate provides evidence of phosphate and sulfate compounds available for potential unattenuated transport. Understanding the geochemical implications of livestock mortality burial will give scientists and regulators more information for performing future risk analyses when considering mortality burial as a management option, either routinely or during a mass mortality event. [ABSTRACT FROM AUTHOR]

This study presents the first complete investigation using soil coring to evaluate the geochemical evolution of leachate plumes beneath existing livestock burial sites. The objective of the study was to broaden our understanding and provide evidence-based resources for minimizing the environmental impacts of mass-mortality carcass burial. Pre-existing livestock burial sites were selected for a detailed analysis of contaminant transport beneath and surrounding the sites in an attempt to determine the risk to soil and groundwater. This analysis entailed soil coring at the site along with specific ion and solution extraction analyses on the soil cores to provide detailed 2-D images of leachate movement around and below the burial sites. The first site, near Pierceland, Saskatchewan, was used in 2001 to bury euthanized elk potentially suffering from chronic wasting disease (CWD). The soil cores were taken seven years post-burial, and the extent of leachate transport, upon analysis of the soil cores, was 1 to 1.5 m of vertical transport of anions (Cl, alkalinity), as well as some cations arising from ion exchange reactions (Ca and Mg). Ammonium ions were attenuated near the bottom and in the first meter beneath the bottom of the trench. There was no indication of lateral movement of ions at this site. The second site, near McLean, Saskatchewan, was used in 1952 to bury carcasses of culled livestock during an emergency depopulation effort for disease control measures during Canada's only outbreak of foot and mouth disease. This site was cored nearly 60 years post-burial and demonstrated that vertical leachate movement was relatively slow over the 60 years, with movement of up to 1 to 2 m. Due to the presence of sand lenses in and around the burial pit, horizontal movement of up to 10 m of anions, such as Cl and bicarbonate, was discovered. Ammonium ions were indicated within the confines of the burial pit and in the soil immediately surrounding the pit. Both sites demonstrated plume characteristics consistent with previous geochemical models, and both showed little impact to the immediate surrounding environment. This would appear to indicate that the burial site selection characteristics were appropriately determined and that many parts of Saskatchewan are suitable for mass quantities of livestock carcass burial in the event of catastrophic events such as disease outbreaks or natural disasters. [ABSTRACT FROM AUTHOR]

Microbial communities were characterized through a depth of 10 m in and near an eight-year-old burial site that was implemented as a control measure for cases of chronic wasting disease among wild elk. Quantitative PCR based on the 16S rRNA-encoding gene showed that the burial trench had significantly (2 to 5 orders of magnitude) more bacterial 16S rRNA-encoding genes g-I soil within and up to 2 m below the burial site compared to a nonburial control core sample at the same depths. Topsoil and depths below the burial site (>6 m) showed similar quantities of 16S rRNA genes for both cores. Furthermore, when microbial communities were examined by cpn60 universal target amplification and pyrosequencing, 5825 operational taxonomic units (OTU) were found at a variety of abundances in all of the 13 core samples that were analyzed. Taxonomic analysis indicated that the overall community composition changed considerably with increasing depth, and that the burial core community was distinct from that of the control core at all depths. Organisms associated with phosphate accumulation, nitrogen fixation, and ammonium oxidation were found in highest abundance near the surface of the burial core (up to 2.5 m), while organisms associated with ammonification were found at the burial depth, consistent with an increase in ammonium concentration in pore water. Sequences from organisms associated with dissimilatory metal reduction were concentrated just below the burial depth (4.5 to 5.5 m). Anaerobic microorganisms dominated the microbial community at the burial site (3.75 m). The approaches described in this study provided distinct sequences that can be used to develop molecular assays for organism tracking and overall fingerprinting of microbes associated with burial sites. These data can be helpful in site evaluation and may help in the selection of future burial sites. [ABSTRACT FROM AUTHOR]

Sequential chemical extraction and synchrotron-based XANES spectroscopy techniques were used to identify P species in two ashes before and after addition to a prairie soil. The used ashes were: meat and bone meal ash (MBMA) and dried distillers grains ash (DDGA) plus mineral P fertilizer (MP) for comparison. Soil treated with MP contained higher content of resin-Pi and NaHCO 3 -Pi followed by DDGA and MBMA. The MBMA amended soil had the highest (47%) proportion of the soil P contained in recalcitrant HCl extractable fraction, reflecting more Ca-bound P present and being formed in soil after application. Analysis of both ashes with XANES spectroscopy before application to soil revealed that MBMA had strong spectral features consistent with hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)). DDGA exhibited spectral features consistent with a mixture of several Mg and K phosphate salts rather than a single mineral species. The distinctive features in the XANES spectra of both ashes largely disappeared after amendment to the soil, suggesting transformation to different P forms in the soil after application. It is also possible that the added amount of P to the studied soil via DDGS or MBMA was small enough so that P speciation is not different from the background P level.

Biochemical methane potential (BMP) assays were conducted on byproducts from dry-grind wheat-based ethanol plants amended with feedlot manure at two input ratios. Whole stillage (WST), thin stillage (TST) and wet cake (WCK) were tested alone and with 1:1 and 2:1 ratios (VS basis) of byproduct:feedlot manure in bench-scale batch reactors. The addition of manure increased both the rate and consistency of methane production in triplicate reactors. In addition, digesters co-digesting thin stillage and cattle manure at 1:1 and 2:1 stillage:manure produced 125% and 119% expected methane based on the biomethane potential of each substrate digested individually. Bacterial community analysis using universal target amplification and pyrosequencing indicated there was a numerically dominant core of 42 bacteria that was universally present in the reactors regardless of input material. A smaller-scale analysis of the archaeal community showed that both hydrogenotrophic and acetoclastic methanogens were present in significant quantities., (Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.)

A biomass fuel feeding system has been designed, constructed and evaluated for a fluidized bed gasifier (FBG) pilot plant at the University of Saskatchewan (Saskatoon, SK, Canada). The system was designed for meat and bone meal (MBM) to be injected into the gasifier at a mass flow-rate range of 1-5 g/s. The designed system consists of two stages of screw conveyors, including a metering stage which controlled the flow-rate of fuel, a rotary airlock and an injection conveyor stage, which delivered that fuel at a consistent rate to the FBG. The rotary airlock which was placed between these conveyors, proved unable to maintain a pressure seal, thus the entire conveying system was sealed and pressurized. A pneumatic injection nozzle was also fabricated, tested and fitted to the end of the injection conveyor for direct injection and dispersal into the fluidized bed. The 150 mm metering screw conveyor was shown to effectively control the mass output rate of the system, across a fuel output range of 1-25 g/s, while the addition of the 50mm injection screw conveyor reduced the irregularity (error) of the system output rate from 47% to 15%. Although material plugging was found to be an issue in the inlet hopper to the injection conveyor, the addition of air sparging ports and a system to pulse air into those ports was found to successfully eliminate this issue. The addition of the pneumatic injection nozzle reduced the output irregularity further to 13%, with an air supply of 50 slpm as the minimum air supply to drive this injector. After commissioning of this final system to the FBG reactor, the injection nozzle was found to plug with char however, and was subsequently removed from the system. Final operation of the reactor continues satisfactorily with the two screw conveyors operating at matching pressure with the fluidized bed, with the output rate of the system estimated based on system characteristic equations, and confirmed by static weight measurements made before and after testing. The error rate by this method is reported to be approximately 10%, which is slightly better than the estimated error rate of 15% for the conveyor system. The reliability of this measurement prediction method relies upon the relative consistency of the physical properties of MBM with respect to its bulk density and feeding characteristics., (Copyright © 2012 Elsevier Ltd. All rights reserved.)