Slurry Storage Research Articles

Research on Influence of Water‐Cement Ratio on Reinforcement Effect for Permeation Grouting in Sand Layer

In order to study permeation grouting reinforcement effect in the sand layer, a set of grouting test device is developed, which consists of a power device, a pressure‐bearing slurry tank, and several test frames. Compressive strength, deformation modulus, and permeability coefficient are selected to be the evaluation index of grouting reinforcement effect. Grouting reinforcement effect under different water‐cement ratio of cement slurry and curing time were measured. Eventually, under laboratory conditions, fitting formulas have been obtained which describe the quantitative relationship between reinforcement effect of permeation grouting and water‐cement ratio and curing time. Results show that water‐cement ratio of slurry has obvious effect on grouting reinforcement effect. Mechanical performance and impermeability of the grouted body are negative‐correlated with water‐cement ratio. There are two different destruction patterns for the grouted body in uniaxial compression process: global destruction pattern at low water‐cement ratio and local destruction pattern at high water‐cement ratio. If cement slurry at high water‐cement ratio is permeated into the sand layer, water bleeding phenomena will appear and lead to inhomogeneous performance of the grouted body, with lower performance in the upper part and higher performance in the lower part of the grouted body.

Partially defatted olive cake in finishing pig diets: implications on performance, faecal microbiota, carcass quality, slurry composition and gas emission

One of the key factors to improve swine production sustainability is the use of agro-industrial by-products in feeds, such as olive by-products. However, it is necessary to assess its effects on the overall production process, including the animal and the environment. With this aim, an experiment was conducted to determine the effects of including a partially defatted olive cake (PDOC) in pig diets on growth performance, faecal microbiota, carcass quality and gas emission from the slurry. Two finishing diets were formulated, a control (C) diet and a diet with PDOC included at 120 g/kg. Eighty finishing male pigs Duroc-Danbred × (Landrace × Large White) of 60.4 ± 7.00 kg BW were divided between these two treatments. During the finishing period (60 to 110 kg BW, 55 days) average daily gain, average daily feed intake and feed conversion ratio were recorded. Faecal samples from the rectum of 16 animals per treatment were incubated for bacteria enumeration. At the end of finishing period, backfat thickness and loin depth (LD) were measured. Animals were slaughtered to obtain carcass weight and carcass composition parameters, and subcutaneous fat was sampled to analyse the fatty acid (FA) profile. In addition greenhouse gas and ammonia emissions were measured during pig slurry storage using the methodology of dynamic flux chambers. An initial slurry characterisation and biochemical methane potential (B0) were also determined. No significant differences between treatments were found in performance, carcass quality and microbial counts with the exception of LD, which was lower in PDOC compared with C animals (45.5 v. 47.5 mm, SEM: 0.62; P = 0.020). The FA profile of the subcutaneous fat did not differ between treatments, but the monounsaturated FA (MUFA) concentration was higher and the polyunsaturated FA was lower in the animals fed PDOC (50.9 v. 48.3, SEM: 0.48, P < 0.001; 17.6 v. 19.3, SEM: 0.30, P < 0.001 in mg/100 g of Total FA, for PDOC and C animals, respectively). The initial pig slurry characterisation only showed differences in ADF concentration that was higher (P < 0.05) in the slurry from PDOC treatment. Regarding gas emission, slurries from both treatments emitted similar amounts of ammonia (NH3), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), as well as B0 values. The results obtained suggest that PDOC may be included in balanced pig diets at rates of up to 120 g/kg without negative effects on performance, carcass quality, gut microflora and slurry gas emission, while improving the MUFA concentration of subcutaneous fat.

Fate of pirlimycin and antibiotic resistance genes in dairy manure slurries in response to temperature and pH adjustment

Quantifying the fate of antibiotics and antibiotic resistance genes (ARGs) in response to physicochemical factors during storage of manure slurries will aid in efforts to reduce the spread of resistance when manure is land-applied. The objectives of this study were to determine the effects of temperature (10, 35, and 55 °C) and initial pH (5, 7, 9, and 12) on the removal of pirlimycin and prevalence of ARGs during storage of dairy manure slurries. We collected and homogenized feces and urine from five lactating dairy cows treated with pirlimycin and prepared slurries by mixing manure and sterile water. Aliquots (200 mL) of slurry were transferred and incubated in 400 mL glass beakers under different temperatures (10, 35, and 55 °C) or initial pH (5, 7, 9, and 12). Pirlimycin concentration and abundances of 16S rRNA, mefA, tet(W), and cfxA as indicators of total bacteria and ARGs corresponding to macrolide, tetracycline, and β-lactam resistance, respectively, were analyzed during manure incubation. The thermophilic environment (55 °C) increased the deconjugation and removal of pirlimycin, while the acidic shock at pH 5 increased deconjugation but inhibited removal of pirlimycin, suggesting that the chemical stability of pirlimycin could be affected by temperature and pH. The thermophilic environment decreased mefA relative abundance on day 7 and 28 (P = 0.02 and 0.04), which indicates that the bacteria that encoded mefA gene were not thermotolerant. Although mefA relative abundance was greater at the pH 9 shock than the rest of pH treatments on day 7 (P = 0.04), no significant pH effect was observed on day 28. The tet(W) abundance under initial pH 12 shock was less than other pH shocks on day 28 (P = 0.01), while no temperature effect was observed on day 28. There was no significant temperature and initial pH effect on cfxA abundance at any time point during incubation, implying that the bacteria that carrying cfxA gene are relatively insensitive to these environmental factors. Overall, directly raising temperature and pH can facilitate pirlimycin removal and decrease mefA and tet(W) relative abundances during storage of manure slurries.

Assessing the impacts of uncertain future closure costs when evaluating strategies for tailings management

Abstract This paper reports on the economic evaluation of alternative strategies for managing a hypothetical gold tailings stream in Western Australia as a slurry, as a thickened, and as a filtered tailings. Suitable project designs were developed and the lifecycle cost was calculated for each project under two different scenarios; (i) baseline scenario in which a traditional accounting approach was adopted for assessing the options in terms of the total cost of the project, and (ii) an alternative scenario which considered higher rehabilitation costs compared to the costs envisaged in the baseline scenario, and a lower discount rate for discounting them. This was done to examine the extent to which uncertainties and potential sources of variability surrounding mine closure planning, accounting and provisioning impact the costs of tailings management. The results revealed that under the baseline scenario, managing thickened tailings is the option of lowest cost, but under the alternative scenario, managing slurry tailings resulted in the most economically feasible solution. However, the better cost performance of the slurry option should be viewed with caution given the difficulties associated with the closure of slurry tailings storage facilities and increasingly stringent regulations with regards to the rehabilitation of areas disturbed by mining operations. Although presenting the highest cost under both scenarios, filtered tailings has the lowest cost sensitivity to alternative input values and assumptions associated with mine closure. This is important information to be conveyed to decision-makers when a solution for tailings management is to be selected. Designing with closure in mind, and continued focus on developing leading practices for tailings management are essential to achieve optimal sustainability performance goals in mining.

Hydrodynamics of solid and liquid phases in a mixing tank containing high solid loading slurry of large particles via tomography and computational fluid dynamics

The main goal of this study was to assess the turbulent and hydrodynamics of the mixing of high solid loading slurries of large particles. To determine the state of homogeneity in the slurry tank, electrical resistance tomography was adopted. A computational fluid dynamics model was developed by employing the Eulerian-Eulerian multiphase model and the sliding mesh technique to explore the suspension of the large particles in the highly concentrated slurry tank. The influences of the solid loading, particle size, and impeller clearance on the homogeneity, just-suspended speed, power consumption, axial and radial velocities of the solid phase, and turbulent energy dissipation were assessed. It was found that the radial and axial velocities of the solid phase attained below the impeller plane at the just-suspended impeller speed were promoted by decreasing the particle size and increasing the solids loading while they were reduced with an increase in the impeller clearance.

Mitigation of ammonia and greenhouse gas emissions from stored cattle slurry using acidifiers and chemical amendments

Cattle and cow slurry storage is a significant source of agricultural greenhouse gas (GHG) and ammonia (NH3) emissions. While acidification has been demonstrated to significantly reduce these emissions, a knowledge gap exists to identify a range of chemical amendments that are safe, suitable and cost effective to mitigate both GHG and NH 3 gases simultaneously. The current study showed that ferric chloride, sulphuric acid, alum and acetic acid were extremely effective at abating emissions, with NH 3 reduced by 96%, 85%, 82% and 73%, respectively. In terms of methane (CH 4 ), ferric chloride, alum, sulphuric acid and acetic acid reduced emissions by 98%, 96%, 95% and 94%, respectively. Previous studies have found that the reduction of >pH 6 can inhibit the release of these gases; however, the effectiveness can vary depending on each amendment's composition. The cost benefit analysis, assessed the amendments in terms of both gaseous emissions reduction and net cost. Sulphuric acid, acetic acid, ferric chloride and alum ranked best, respectively. Currently, the cost of implementing these amendments is, at best, cost neutral. Therefore, incentivising chemical amendments for the abatement of GHG and NH 3 gases from slurry storage is needed. This incubation experiment is an effective means of pre-screening amendments before they are explored at pilot or full scale with subsequent field application. Future research should consider the assessment of cheaper on- and off-farm alternative waste streams as slurry amendment. • Acidification of cattle and dairy slurry was investigated. • Target pH of 5.5 resulted in a 96% reduction in NH 3 and 98% reduction in CH 4 . • Ferric chloride reductions were independent of pH value. • Cost analysis revealed financial incentives are needed for scaled implementation.

Biogenic factors of geochemical uranium anomalies formation in subsurface waters near to Novosibirsk chemical concentrates plant slurry storage

This article presents data on the possible impact of aerobic and anaerobic microbiological processes in the upper aquifers to uranium migration t sulfate and nitrate polluted waters near to Novosibirsk chemical concentrate plant. Uranium immobilization is possible in local areas, with high content of organic substances and the most important microbiological process is the redox potential reduction due to aerobic respiration. After that in anaerobicс conditions redox-dependent uranium reduction can be expected. Moreover, in the presence of sulfate ions, further anaerobic processes of microbial sulfate reduction and iron reduction lead to the formation of iron sulphide, which plays the significant role of an antioxidant buffer in the case of oxygen migration.

The Possibility of Contamination of Water-Soil Environment as a Result of the Use of Pig Slurry

AbstractPig slurry is a heterogeneous mixture of faeces, urine, undigested remains of feed items and water used for flushing of animal excrement and to maintain the proper hygiene of livestock housing. It is formed on farms which use the non-bedding system of pig breeding i.e. animals are kept on the partially or fully slatted floors. According to the Polish law pig slurry is defined as a liquid natural fertilizer intended for agricultural use. The storage and application of pig slurry on arable land affect the surroundings and may create a number of serious risks related to, among others, the pollution of water-soil environment with biogenic elements, heavy metals, pathogens and pharmaceuticals. The article presents the reasons for the occurrence of excessive amounts of nitrogen, phosphorus, copper, zinc and antibiotics in pig slurry. The possibility of microbial and pharmaceutical contamination of water, soil and plants as well as their pollution with biogens and heavy metals as a result of improper storage and excessive spreading of pig slurry have been characterized. Moreover, methods of preventing the above-mentioned threats with reference to Polish and EU legal acts have been discussed.

Experimental study on thermal storage and heat transfer performance of microencapsulated phase-change material slurry

Microencapsulated phase change material (MPCM) slurry has received attention due to their higher thermal storage density, was introduced as a storage medium in latent thermal energy storage (LTES) system. Based on this background, this article presented the experimental results of the thermal storage and heat transfer characteristics of MPCM slurry during cooling discharging process, a series of experiments were carried out by controlling variable. Hexadecane (C16H34) and urea-formaldehyde was used as the core and shell of PCM to form MPCM with core–shell ratio of 7:3 by weight. The temperature evolutions of the MPCM slurry were obtained during the experiment, and the volumetric thermal storage capacity, cooling discharging rate were calculated under different stirring rates and heat transfer fluid (HTF) initial inlet temperatures. From the experimental results, it is estimated that the thermal storage and heat transfer performance of MPCM slurry both were enhanced remarkably by phase change. In addition, accelerating the stirring rate of stirrer can enhance the thermal storage capacity. At 300 rpm, the volumetric thermal storage capacity and mean discharging rate are about 1.28 times higher than that of MPCM slurry without stirring. At the same stirring rate, the mean discharging rate of 20 °C is 1.24 times higher than that of 10 °C.

Исследование фильтрационных свойств грунтов ограждающих сооружений шламохранилищ с учетом влияния эффекта пристенного скольжения

Установлена эмпирическая закономерность зависимости коэффициентов фильтрации песчаных грунтов от содержания в шламе полиакриламида в концентрации 0,17–0,90 мг/дм3 (эффект пристенного скольжения). Определен коэффициент фильтрации для грунтов ограждающих сооружений шламохранилищ Республики Беларусь с учетом присутствия в фильтрующемся шламе полиакриламида. Подтверждено результатами экспериментальных исследований и натурных наблюдений превышение скорости фильтрации шлама 0,045–0,047 см/с над скоростью фильтрации воды в 1,2–1,4 раза.

ELEMENTAL COMPOSITION OF TISSUES AND TOXICOKINETICS OF ARSENIC AND ANTIMONY ON INTAKE IN MALE WHITE RATS OF THE WISTAR LINE WITH DRINKING WATER

The biogeochemical province of antimony and arsenic created in the area of massive sulphide deposits forms a level of their exchange in the biosphere that is different from the usual conditions. These elements along with a number of common properties of the semi-metals have significant features of biological action. The aim of the study was to assess the variability of the elemental composition of the liver tissues of white rats with oral intake of wastewater from the tailings of Komsomolsk gold mine (Kemerovo region) with a high content of antimony and arsenic. The objects of the study were wastewater from the slurry pits of Komsomolsk gold mine (Kemerovo region); liver tissue of white rats of the Wistar line, whole blood, urine, excrements. The contents of sulfur, chlorine, potassium, calcium, titanium, manganese, chromium, iron, nickel, copper, zinc, selenium, bromine, rubidium, strontium, molybdenum, arsenic, mercury, lead, antimony in the tissues of the liver, blood, urine, excrements before priming, after 3 weeks of priming and after 1, 2 and 4 weeks during the recovery period after priming have been determined. It has been established that combined oral 3 weeks intake of arsenic in a dose of 10,0-15,1 µg / kg / day and antimony in a dose of 4,2-6,1 µg / kg / day in male white rats of the Wistar line is accompanied by their accumulation in the liver and blood and the excretion with urine and excrements, the parameters of the toxicokinetics of arsenic indicate its absorption and elimination from the blood about the same rate, whereas in liver, the rate of elimination of arsenic is somewhat higher than the rate of absorption (t 1/2 - 38 and 49 days and constants of elimination and absorption - 0.018 and 0.014, respectively). The predominance of elimination processes over absorption for antimony in the blood (t 1/2 - 12 and 22 days, constants of elimination and absorption – 0.058 and 0.032, respectively) has been established.

Characterization of urease derived from Citrullus lanatus (watermelon) seeds to estimate total Kjeldahl nitrogen in human urine

ABSTRACTA urease extract prepared by decanting liquid from a suspension of finely ground Citrullus lanatus (watermelon) seeds was characterized and applied to dilute urine samples to demonstrate a low-cost field method to estimate total Kjeldahl nitrogen (TKN) concentrations in human urine. The extract exhibited a Michaelis-Menten constant, Km, of 3.00 mM urea and a specific activity of up to 12.2 U/mg protein at an optimum pH of 8.1. A statistical F-test on 54 samples demonstrated that TKN can be estimated as the total ammonium-nitrogen recovered upon addition of urease in dilute fresh and stale urine samples. The total ammonium-nitrogen in urine samples determined after treatment with watermelon seed urease was consistent with that determined using traditional acid digestion techniques. The extract retained 85% of its initial capacity after three months of refrigeration. The effectiveness of this method to assay nitrogen in unbuffered urine samples will be useful in nitrogen analyses in nutrient recovery and urine or slurry storage contexts. Accordingly, this study is useful in understanding the kinetics of a plant-derived urease acting in dilute urine.

Give them credit‐the greenhouse gas performance of regional biogas systems

AbstractAnaerobic digestion to produce biogas is an important decentralised renewable energy technology. Production varies extensively between different countries and within countries, as biogas production is heavily dependent on local and regional feedstocks. In Germany, distinct regional differences can be observed. Therefore, understanding the kinds of biogas systems operating within a region is crucial to determine their greenhouse gas (GHG) mitigation potential and carbon neutrality. This is the first study to conduct an integrated life cycle assessment of biogas configurations in the landscape (biogas plants and their biomass catchments) for an entire region. RELCA a ‘REgional Life Cycle inventory Assessment’ approach was used to model the GHG mitigation potential of 425 biogas plants in the region of Central Germany (CG), aggregated to nine biogas clusters, based on feedstock mix (e.g. animal manures and energy crops) and installed capacity. GHG emission profiles were generated to compare and to identify the role of GHG credits and size of installed capacity on the mitigation performance of the regional biogas clusters. We found that smaller scaled slurry dominant clusters had significantly better GHG mitigation performance (−0.1 to −0.2 kg CO2eq kWhel−1), than larger energy crop dominant (ECdom) clusters (0.04–0.16 kg CO2eq kWhel−1), due to lower cultivation emissions and larger credits for avoided slurry storage. Thus, for the CG region larger ECdom clusters should be targeted first, to support GHG mitigation improvements to the overall future electricity supplied by the regional biogas systems. With the addition of GHG credits, the CG region is producing biogas with GHG savings (−0.15 kg CO2eq kWhel−1, interquartile range: 0.095 kg CO2eq kWhel−1). This infers that biogas production, as a waste management strategy for animal manures, could have important ramifications for future policy setting and national inventory accounting.

Impact of different treatments on Escherichia coli during storage of cattle slurry

There are different types of effluents from farming operations including untreated slurry (a mixture of manure, urine, split feed, and water), and treated slurry that normally is filtered to separate the solid fraction from the liquid fraction. With the amount of slurry applied on the soils as fertiliser every year, there are necessary to measure the leaching of microbial capable of transmitting infective agents that can be normally on slurry, because slurry can be a potential biohazard capable of transmitting infective agents. The aim of this study was to investigate the presence and survival of Escherichia coli (E. coli) on liquid fraction of dairy slurry, with the addition of different treatments during storage, such as addition of Biochar, beneficial microorganisms, sulphuric acid and the combinations of them. All the applied treatments to slurry show statistically significant differences (P < 0.001), according to the different sampling dates. Results showed that there are conditions and treatments that benefit the survival probability of E. coli, the treatments that include the acidification of slurry have the highest averages of CFU/ml (243288.3 at 37 °C; 136584 at 44 °C). These results can contribute to the improvement of the quality of slurry applied on soils, beneficiating agriculture but also public health.

Drivers of Farmers' Investments in Nutrient Abatement Technologies in Five Baltic Sea Countries

Adoption of new manure and fertiliser technology is considered an effective tool to reduce diffuse nutrient pollution from agriculture, and policy instruments to encourage technology uptake are therefore widespread. But policy makers need to understand farmers' reasons for adoption of such technologies to design policies that actually work. Using data from a survey with responses from 2439 farmers in five countries around the Baltic Sea, we identify the drivers of technology adoption for three different abatement technologies: manure spreading equipment, slurry tanks, and precision technology for fertiliser application. We compare drivers for technology investments across technologies with a particular focus on the role of the scale of farm operations, neighbour relations, environmental concerns and innovation readiness. The results show that the scale of farm operation is important for the uptake of all three technologies, while we find no evidence that neighbour relations are important for technology investments. Environmental concerns for soil quality and other on-farm environmental qualities do drive investment; however, the impact of environmental concerns differs across technologies. Innovation readiness is a driver of investments in relation to some technologies, suggesting that the novelty or sophistication of the technology matters to the investing farmers.

The operation control and application of CFB boiler unit with high blending ratio of coal slurry

In China, a large amount of coal slurry is produced every year as the by-product of coal washing. If all these slurry were utilized, it could not only bring huge economic benefits but also solve the environmental pollution caused by coal slurry storage. As one of the most important devices to burn the coal slurry, circulating fluidized bed (CFB) boilers needs to improve the control level to consume more slurry. In this paper, the characteristics of CFB boiler with large blending ratio of coal slurry are investigated from both the operation and control aspects. The energy fluctuation caused by long-term coal slurry combustion in CFB boiler is analyzed, which would influence the operating stability of the unit and restrict the blending ratio of coal slurry. Based on the analysis and boiler energy storage theory, a novel control strategy is proposed to improve energy conversion and stabilize energy fluctuation caused by co-combustion of coal slurry. Finally, the control strategy is applied to an actual 300 MW CFB boiler unit. The long-term operation shows that the improved control system can reduce the energy fluctuations, raise the control stability and increase the coal slurry blending ratio, bringing huge economic benefits to power plant.

Critical review of different aspects of liquid-solid mixing operations

Abstract Mechanically stirred slurry tanks are utilized in several industries to perform various unit operations such as crystallization, adsorption, ion-exchange, suspensions polymerization, dispersion of solid particles, leaching and dissolution, and activated sludge processes. The major goal of this review paper is to critically and thoroughly analyse the different aspects of previous research works reported in the literature in the field of liquid-solid mixing. This paper sheds light on the advantages and limitations of various particle concentration measurement methods employed to assess the suspension quality and the extent of solid suspensions in slurry reactors. Attempts are being made to identify and compare various mathematical models and methods to quantify particle dispersion and distribution in slurry reactors. It has been shown that various factors such as geometric configurations, agitation conditions, and physical characteristics of liquid and solid have pronounced influence on local suspension quality and power consumption. Computational fluid dynamics (CFD) modeling can be extremely useful in assessing the suspension of solid particles in slurry tanks. A critical review of different scale-up procedures employed for solid suspension and distribution in liquid-solid systems is presented as well. The findings of this review paper can be useful for future research works in liquid-solid mixing.

Effect of Chloride Ions on the Chemical Mechanical Planarization Efficiency of Sapphire Substrate

Sapphire is widely used in solid lasers, semiconductor chip substrates, light emitting diodes substrates and other high-tech fields for its excellent mechanical and optical properties. At the same time, the chemical mechanical polishing(CMP) performance and quality need to be improved for different crystal plane sapphire substrate. In this paper, in order to improve the removal rate NaCl was used as an additive in sapphire slurry. From the CMP experiment results of a- and c-plane sapphire, it was found that higher material removal rate (MRR) and lower surface roughness (Sq) were obtained by adding NaCl with the concentration of 0.2wt% in sapphire slurry. In order to reveal the action mechanism of NaCl, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) measure methods were used. From the SEM measure results it can be seen that there were microscopic corrosion pits on substrate surface, which indicates that chemical reaction took place between NaCl and substrate material. From XPS measure results it was verified that sodium tetrachloroaluminate (NaAlCl4) was formed during CMP. However, during the experiment, it was found there was a very small amount of silica sol crystalline particles after NaCl was added to the slurry. After analyzing the formation mechanism of crystalline particles, KCl was selected to replace NaCl. The same polishing effect was obtained and there were no crystalline particles found in the slurry tank. From the results it is found chloride ions played an important role in improving the removal rate and surface roughness of sapphire substrate.

Microbial load in bio-slurry from different biogas plants in Bangladesh.

Objective:The study was aimed to isolate, identify, and characterize common indicator bacteria, including Escherichia coli, Salmonella spp., and Staphylococcus spp. in manure and bio-slurry samples of different livestock farms and biogas plants of Bangladesh.Materials and Methods:A total of 114 samples of manure and bio-slurry were collected from different livestock farms and biogas plants in Bangladesh. The total viable count (TVC), E. coli, Salmonella spp., and Staphylococcus spp. counts were determined by the spread plate technique method. Isolation and identification were performed by colony characteristics, staining, biochemical tests, and, finally, by using PCR. Antibiotic susceptibility test of the isolated bacteria was tested against commonly used antibiotics by using the disk diffusion method.Results:The mean TVC, E. coli, Salmonella spp., and Staphylococcus spp. counts were ranged from 8.19–10.75, 5.2–6.96, 5.81–6.87, 5.68–7.68 in manure samples and 7.26–8.65, 3.82–5.2, 4–5.54, 3.14–5.9 log cfu/gm in bio-slurry, respectively. In anaerobic digester after 30 days digestion, the presence of E. coli, Salmonella spp., and Staphylococcus spp. varied from 0–5.11, 0–4.84, and 0–5.59 log cfu/gm at 25°C, 27°C, 29°C, and 45°C temperature. Above-mentioned bacteria were absent in bio-slurry collected from anaerobic digester after 60 days digestion at environmental temperature. Bacterial counts were reduced significantly in both household slurry pits and experimental anaerobic digester. Antibiotic susceptibility results revealed that multidrug-resistant indicator bacteria were present in the bio-slurry samples.Conclusion:Our findings conclude that the microbial load after treatment of animal manure via anaerobic digestion (Biogas plant) was grossly reduced and the reduction of bacterial pathogen depends on the duration and temperature of digestion.

Removal of copper from cattle footbath wastewater with layered double hydroxide adsorbents as a route to antimicrobial resistance mitigation on dairy farms

Copper and zinc are routinely used in livestock antimicrobial footbaths in commercial farming. The footbath mix is a cost to farmers, and the disposal of spent footbath into slurry tanks leads to soil contamination, as well as the potential for antimicrobial metal resistance and co-selection. This study assesses the potential to mitigate a source of antimicrobial metal resistance in slurry tanks while recovering copper and zinc from spent cattle footbaths. This is the first study in literature to investigate the potential of recovering copper from cattle footbath solutions via any method. The sorbent, Ca2Al-EDTA Layered Double Hydroxides (LDH), were used to remove Cu2+ from a Cu2SO4·5H20 solution at different temperatures. The maximum Cu2+ uptake from the Cu2SO4·5H20 solution was 568 ± 88 mg g−1. Faster and higher equilibrium uptake was achieved by increasing the temperature of the solution. The sorbent was found to be effective in removing copper and zinc from a commercially available cattle footbath solution (filtered footbath solution Cu2+ uptake 283 ± 11.05 mg g−1, Zn2+ uptake 60 ± 0.05 mg g−1). Thus, this study demonstrates the opportunity for a completely novel and potentially economically beneficial method of mitigating antimicrobial resistance in agriculture and the environment, while also providing a new valuable copper and zinc waste stream for secondary metal production.