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Xinmin Zhan - One of the best experts on this subject based on the ideXlab platform.
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nutrient recovery from Pig Manure digestate using electrodialysis reversal membrane fouling and feasibility of long term operation
Journal of Membrane Science, 2019Co-Authors: Lin Shi, Xinmin Zhan, Sihuang Xie, Liam Morrison, Peter CrootAbstract:Abstract Membrane technologies are challenged by severe membrane fouling when treating animal Manure digestate due to high turbidity and high concentrations of organic and inorganic matter. In this study, a bench-scale electrodialysis reversal (EDR) was carried out to assess its feasibility for nutrient recovery from Pig Manure digestate. Pretreatment consisted of acidification for releasing phosphorus to the liquid phase and low-speed centrifugation for removing large particles. Results showed complete removal of NH4+ and removal of phosphate up to 84% from the feed solution, with their concentrations in the product reaching 4.2 and 0.7 g/L at a volumetric ratio of 6/2, respectively. During the semi-continuous operation, particle and chemical deposition were significantly mitigated. Despite periodical HCl cleaning, tyrosine-like and humic-like substances fouled anion-exchange membranes (AM) gradually. Nevertheless, this fouling ceased after treating the digestate at a capacity of 330 L/m2 membrane when the conductivity and ion-exchange capacity of AM decreased by 18.5% and 13.3% compared with the virgin membrane, respectively. Based on infrared spectra, these organic foulants existed in the fouling area around the membrane surface, rather than migrating deeper into the interior of the membrane. This study reveals a potential of long-term operation of EDR for treating Pig Manure digestate.
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inhibition of volatile fatty acids on methane production kinetics during dry co digestion of food waste and Pig Manure
Waste Management, 2018Co-Authors: Yan Jiang, Xinmin Zhan, Peadar G. Lawlor, Conor Dennehy, Matthew S Mccabe, Paul Cormican, Gillian E GardinerAbstract:Abstract Compared with wet digestion, dry digestion of organic wastes reduces reactor volume and requires less energy for heating, but it is easily inhibited by high volatile fatty acid (VFA) or ammonia concentration. The inhibition on methane production kinetics during dry co-digestion of food waste and Pig Manure is rarely reported. The aim of this study was to explore the inhibition mechanisms and the microbial interactions in food waste and Pig Manure dry co-digestion systems at different inoculum rates (25% and 50% based on volatile solids) and food waste/Pig Manure ratios (0:100, 25:75, 50:50, 75:25 and 100:0 based on volatile solids). The results showed that the preferable operation conditions were obtained at the inoculum rate of 50% and food waste/Pig Manure ratio of 50:50, with a specific methane yield of 263 mL/g VSadded. High VFA concentration was the main inhibition factor on methane production, and the threshold VFA inhibition concentrations ranged 16.5–18.0 g/L. Syntrophic oxidation with hydrogenotrophic methanogenesis might be the main methane production pathway in dry co-digestion systems due to the dominance of hydrogenotrophic methanogens in the archaeal community. In conclusion, dry co-digestion of food waste and Pig Manure is feasible for methane production without pH adjustment and can be operated stably by choosing proper operation conditions.
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recovery of nutrients and volatile fatty acids from Pig Manure hydrolysate using two stage bipolar membrane electrodialysis
Chemical Engineering Journal, 2018Co-Authors: Xinmin Zhan, Zhenhu Hu, Yuansheng Hu, Guangxue WuAbstract:Abstract Animal Manure should be regarded as a resource rather than a waste as it contains abundant nutrients (nitrogen and phosphorus) and organic matter. In this study, a laboratory-scale bipolar membrane electrodialysis (BMED) system was set up to assess the recovery of ammonium (NH4+), phosphate (PO43−) and volatile fatty acids (VFAs) from both synthetic and real Pig Manure hydrolysate for the first time. Synthetic hydrolysate was used as feed first to investigate the ionic migrations in the BMED system. After 5.5 h of operation, 52% of NH4+ migrated to the base compartment, and 98% of PO43− and 95% of VFAs migrated to the acid compartment. A BMED model was established to quantify the ion flux balance in the membrane stack. It substantiated that the low recovery efficiencies of NH4+ and the impurity of acid solution were primarily caused by the undesired diffusion of ions through bipolar membranes. Subsequently, a novel two-stage BMED operation based on the “inflection point” of voltage was developed to minimize the NH4+ loss and separate PO43− and VFAs from the acid compartment. Through this operation, the recovery efficiency of NH4+ increased to 78%, and 75% of PO43− and 87% of VFAs were separated from Cl− and SO42− in the acid compartment. Finally, real Pig Manure hydrolysate was tested and the variations of ions in the BMED were consistent as those using synthetic wastewater. This study demonstrates that it is feasible to recover valuable nutrients and VFAs from Pig Manure hydrolysate using two-stage BMED technology.
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greenhouse gas emissions from different Pig Manure management techniques a critical analysis
Frontiers of Environmental Science & Engineering in China, 2017Co-Authors: Conor Dennehy, Sihuang Xie, Peadar G. Lawlor, Yan Jiang, Gillian E Gardiner, Long D Nghiem, Xinmin ZhanAbstract:Manure management is the primary source of greenhouse gas (GHG) emissions from Pig farming, which in turn accounts for 18% of the total global GHG emissions from the livestock industry. In this review, GHG emissions (N2O and CH4 emissions in particular) from individual Pig Manure (PGM) management practices (European practises in particular) are systematically analyzed and discussed. These Manure management practices include Manure storage, land application, solid/liquid separation, anaerobic digestion, composting and aerobic wastewater treatment. The potential reduction in net GHG emissions by changing and optimising these techniques is assessed. This review also identifies key research gaps in the literature including the effect of straw covering of liquid PGM storages, the effect of solid/liquid separation, and the effect of dry anaerobic digestion on net GHG emissions from PGM management. In addition to identifying these research gaps, several recommendations including the need to standardize units used to report GHG emissions, to account for indirect N2O emissions, and to include a broader research scope by conducting detailed life cycle assessment are also discussed. Overall, anaerobic digestion and compositing to liquid and solid fractions are best PGM management practices with respect to their high GHG mitigation potential.
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effect of Pig Manure to grass silage ratio on methane production in batch anaerobic co digestion of concentrated Pig Manure and grass silage
Bioresource Technology, 2011Co-Authors: Sihuang Xie, J P Frost, Zhenhu Hu, Peadar G. Lawlor, Xinmin ZhanAbstract:Anaerobic co-digestion of concentrated Pig Manure (PM) with grass silage (GS) at five different PM to GS volatile solid (VS) ratios of 1:0, 3:1, 1:1, 1:3 and 0:1 was evaluated by examining operation stability and methane (CH4) production potentials. The highest specific CH4 yields were 304.2 and 302.8ml CH4/g VS at PM to GS ratios of 3:1 and 1:1, respectively. The digestion systems failed at the ratio of 0:1. The lag phase lasted 29.5, 28.1, 24.6 and 21.3days at the ratios of 1:0, 3:1, 1:1 and 1:3, respectively. The daily methane yield was linearly correlated with the acetic acid concentration, indicating methane production was probably associated with acetoclastic methanogenesis. The hydrolysis constant linearly decreased with increasing the fraction of GS in the feedstock. This study recommends applying the PM to GS ratio of 1:1 in practice due to a high specific methane yield and a short lag phase.
Johann Bauer - One of the best experts on this subject based on the ideXlab platform.
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heavy metals in liquid Pig Manure in light of bacterial antimicrobial resistance
Environmental Research, 2012Co-Authors: Christina S Holzel, Karin Schwaiger, Katrin S Harms, Christa Muller, Sabine Mikolajewski, Stefanie Schafer, Johann BauerAbstract:Heavy metals are regularly found in liquid Pig Manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 Pig Manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08-5.30 mg cadmium, 1.1-32.0 mg chrome, 22.4-3387.6 mg copper, <2.0-26.7 mg lead, <0.01-0.11 mg mercury, 3.1-97.3 mg nickel and 93.0-8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against β-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against β-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.
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sewage sludge and liquid Pig Manure as possible sources of antibiotic resistant bacteria
Environmental Research, 2010Co-Authors: Christina S Holzel, Karin Schwaiger, Katrin S Harms, Helmut Kuchenhoff, Anne Kunz, Karsten Meyer, Christa Muller, Johann BauerAbstract:Within the last decades, the environmental spread of antibiotic resistant bacteria has become a topic of concern. In this study, liquid Pig Manure (n=305) and sewage sludge (n=111) - used as agricultural fertilizers between 2002 and 2005 - were investigated for the presence of Escherichia coli, Enterococcus faecalis and Enterococcus faecium. Bacteria were tested for their resistance against 40 chemotherapeutics including several "reserve drugs". E. coli (n=613) from Pig Manure were at a significantly higher degree resistant to streptomycin, doxycycline, spectinomycin, cotrimoxazole, and chloramphenicol than E. coli (n=116) from sewage sludge. Enterococci (Ent. faecalis, n=387, and Ent. faecium, n=183) from Pig Manure were significantly more often resistant to high levels of doxycycline, rifampicin, erythromycin, and streptomycin than Ent. faecalis (n=44) and Ent. faecium (n=125) from sewage sludge. Significant differences in enterococcal resistance were also seen for tylosin, chloramphenicol, gentamicin high level, fosfomycin, clindamicin, enrofloxacin, moxifloxacin, nitrofurantoin, and quinupristin/dalfopristin. By contrast, aminopenicillins were more effective in enterococci from Pig Manure, and mean MIC-values of piperacillin+tazobactam and third generation cefalosporines were significantly lower in E. coli from Pig Manure than in E. coli from sewage sludge. 13.4% (E. coli) to 25.3% (Ent. faecium) of Pig Manure isolates were high-level multiresistant to substances from more than three different classes of antimicrobial agents. In sewage sludge, high-level-multiresistance reached from 0% (Ent. faecalis) to 16% (Ent. faecium). High rates of (multi-) resistant bacteria in Pig Manure emphasize the need for a prudent - cautious - use of antibiotics in farm animals.
Clive A Edwards - One of the best experts on this subject based on the ideXlab platform.
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the influence of earthworm processed Pig Manure on the growth and productivity of marigolds
Bioresource Technology, 2002Co-Authors: Rola M Atiyeh, Clive A Edwards, Norman Q Arancon, James D MetzgerAbstract:The effects of additions of earthworm-processed Pig Manure (vermicompost) on the growth and productivity of French marigold (Tagetes patula) plants were evaluated under glasshouse conditions. Marigolds were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) Pig Manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were supplied regularly with a complete mineral nutrient solution for 121 days. The greatest vegetative growth resulted from substitution of Metro-Mix 360 with 30% and 40% Pig Manure vermicompost, and the lowest growth was in the potting mixtures containing 90% and 100% vermicompost. Most flower buds occurred in the potting mixtures containing 40% Pig Manure vermicompost (19.4 buds), and fewest in the potting mixtures containing 100% vermicompost. Marigolds grown in Metro-Mix 360 substituted with 90% and 100% Pig Manure vermicompost had the fewest and smallest flowers. After substitution of Metro-Mix 360 with 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% vermicompost, the marigold roots were larger than those of plants grown in the Metro-Mix 360 controls. Substitution of Metro-Mix 360 with any concentration of Pig Manure vermicompost, with all needed nutrients provided, increased the overall nitrate-nitrogen concentrations of the marigold leaf tissues at flowering stage. Some of the marigold growth and productivity enhancement, resulting from substitution of Metro-Mix 360 with Pig Manure vermicompost, may be explained by nutritional factors; However, other, factors, such as plant-growth regulators and humates, might have also been involved since all plants were supplied regularly with all required nutrients.
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Pig Manure vermicompost as a component of a horticultural bedding plant medium effects on physicochemical properties and plant growth
Bioresource Technology, 2001Co-Authors: Rola M Atiyeh, Clive A Edwards, Scott Subler, James D MetzgerAbstract:This experiment was designed to characterize the physical, chemical and microbial properties of a standard commercial horticultural, greenhouse container, bedding plant medium (Metro-Mix 360), that had been substituted with a range of increasing concentrations (0%, 5%, 10%, 25%, 50% and 100% by volume) of Pig Manure vermicompost and to relate these properties to plant growth responses. The growth trials used tomatoes (Lycopersicon esculentum Mill.), grown in the substituted media for 31 days under glasshouse conditions, with seedling growth recorded in 20 pots for each treatment. Half of the tomato seedlings (10 pots per treatment) were watered daily with liquid inorganic fertilizer while the other half received water only. The percentage total porosity, percentage air space, pH and ammonium concentrations of the container medium all decreased significantly, after substitution of Metro-Mix 360 with equivalent amounts of Pig Manure vermicompost; whereas bulk density, container capacity, electrical conductivity, overall microbial activity and nitrate concentrations, all increased with increasing substitutions of vermicompost. The growth of tomato seedlings in the potting mixtures containing 100% Pig Manure vermicompost was reduced, possibly as a result of high soluble salt concentrations in the vermicompost and poorer porosity and aeration. The growth of tomato seedlings was greatest after substitution of Metro-Mix 360 with between 25% and 50% Pig Manure vermicompost, with more growth occurring in combinations of Pig Manure vermicompost treated regularly with a liquid fertilizer solution than in those with no fertilizer applied. Some of the growth enhancement in these mixtures seemed to be related to the combined effects of improved porosity, aeration and water retention in the medium and the high nitrate content of the substrate, which produced an increased uptake of nitrogen by the plant tissues, resulting in increased plant growth. When the tomato seedlings were watered daily with liquid inorganic fertilizer, substitution of Metro-Mix 360 with a very small amount (5%) of Pig Manure vermicompost resulted in a significant increase in the growth of tomato seedlings. Such effects could not be attributed solely to the nutritional or physical properties of the Pig Manure vermicompost. Therefore, it seems likely that the Pig Manure vermicompost provided other biological inputs, such as plant growth regulators into the container medium, that still need to be identified fully.
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influence of earthworm processed Pig Manure on the growth and yield of greenhouse tomatoes
Bioresource Technology, 2000Co-Authors: Rola M Atiyeh, Clive A Edwards, Norman Q Arancon, James D MetzgerAbstract:The eAects of earthworm-processed Pig Manure (vermicompost) on germination, growth, and yields of tomato (Lycopersicon esculentum Mill.) plants were evaluated under glasshouse conditions. Tomatoes were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) Pig Manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were grown for 158 days and were frequently supplied with a complete mineral nutrient solution. The germination rates of tomato seeds increased significantly upon substitution of Metro-Mix 360 with 20%, 30%, and 40% vermicompost. Seedlings grown in 100% Pig Manure vermicompost were significantly shorter, had fewer leaves, and weighed less than those in Metro-Mix 360 controls. Incorporation of 10% or 50% vermicompost into Metro-Mix 360 increased the dry weights of tomato seedlings significantly compared to those grown in the Metro-Mix 360 controls. The largest marketable yield was in the substitution of Metro-Mix 360 with 20% vermicompost (5.1 kg/plant). The average weight of a tomato fruit in substitution of Metro-Mix 360 with 20% vermicompost was 12.4% greater than that in the Metro-Mix 360 control. Substitution of Metro-Mix 360 with 10%, 20%, and 40% vermicompost reduced the proportions of fruits that were non-marketable, and produced more large size (diameter > 6:4 cm) than small size (diameter < 5:8 cm) tomato fruits. There was no significant diAerence in overall tomato yields between Metro-Mix 360 and 100% Pig Manure vermicompost. Some of the growth and yield enhancement resulting from substitution of Metro-Mix 360 with Pig Manure vermicompost could be attributed to the high mineral N concentration of the Pig Manure vermicompost. However, other factors might have also been involved since all plants were frequently supplied with all required nutrients. These factors need to be investigated in future studies. ” 2000 Elsevier Science Ltd. All rights reserved.
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effects of stocking rate and moisture content on the growth and maturation of eisenia andrei oligochaeta in Pig Manure
Soil Biology & Biochemistry, 1997Co-Authors: Jorge Dominguez, Clive A EdwardsAbstract:Abstract The effect of stocking rate and moisture content on the growth and maturation of Eisenia andrei (Bouche, 1972) in Pig Manure was studied in laboratory trials at 20°C. Six moisture contents (65, 70, 75, 80, 85 or 90%) and five stocking rates (1, 2, 4, 8 or 16 worms, each per the same volume of substrate) were tested. Growth and maturation of earthworms were monitored over 44 days. The 85% moisture content was found to be most favourable for earthworm growth. The 80 and 90% moisture contents were found to be adequate. Eight earthworms per 43.61 g (dry wt) was found to be the most favourable inoculation density.
James D Metzger - One of the best experts on this subject based on the ideXlab platform.
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the influence of earthworm processed Pig Manure on the growth and productivity of marigolds
Bioresource Technology, 2002Co-Authors: Rola M Atiyeh, Clive A Edwards, Norman Q Arancon, James D MetzgerAbstract:The effects of additions of earthworm-processed Pig Manure (vermicompost) on the growth and productivity of French marigold (Tagetes patula) plants were evaluated under glasshouse conditions. Marigolds were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) Pig Manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were supplied regularly with a complete mineral nutrient solution for 121 days. The greatest vegetative growth resulted from substitution of Metro-Mix 360 with 30% and 40% Pig Manure vermicompost, and the lowest growth was in the potting mixtures containing 90% and 100% vermicompost. Most flower buds occurred in the potting mixtures containing 40% Pig Manure vermicompost (19.4 buds), and fewest in the potting mixtures containing 100% vermicompost. Marigolds grown in Metro-Mix 360 substituted with 90% and 100% Pig Manure vermicompost had the fewest and smallest flowers. After substitution of Metro-Mix 360 with 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% vermicompost, the marigold roots were larger than those of plants grown in the Metro-Mix 360 controls. Substitution of Metro-Mix 360 with any concentration of Pig Manure vermicompost, with all needed nutrients provided, increased the overall nitrate-nitrogen concentrations of the marigold leaf tissues at flowering stage. Some of the marigold growth and productivity enhancement, resulting from substitution of Metro-Mix 360 with Pig Manure vermicompost, may be explained by nutritional factors; However, other, factors, such as plant-growth regulators and humates, might have also been involved since all plants were supplied regularly with all required nutrients.
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Pig Manure vermicompost as a component of a horticultural bedding plant medium effects on physicochemical properties and plant growth
Bioresource Technology, 2001Co-Authors: Rola M Atiyeh, Clive A Edwards, Scott Subler, James D MetzgerAbstract:This experiment was designed to characterize the physical, chemical and microbial properties of a standard commercial horticultural, greenhouse container, bedding plant medium (Metro-Mix 360), that had been substituted with a range of increasing concentrations (0%, 5%, 10%, 25%, 50% and 100% by volume) of Pig Manure vermicompost and to relate these properties to plant growth responses. The growth trials used tomatoes (Lycopersicon esculentum Mill.), grown in the substituted media for 31 days under glasshouse conditions, with seedling growth recorded in 20 pots for each treatment. Half of the tomato seedlings (10 pots per treatment) were watered daily with liquid inorganic fertilizer while the other half received water only. The percentage total porosity, percentage air space, pH and ammonium concentrations of the container medium all decreased significantly, after substitution of Metro-Mix 360 with equivalent amounts of Pig Manure vermicompost; whereas bulk density, container capacity, electrical conductivity, overall microbial activity and nitrate concentrations, all increased with increasing substitutions of vermicompost. The growth of tomato seedlings in the potting mixtures containing 100% Pig Manure vermicompost was reduced, possibly as a result of high soluble salt concentrations in the vermicompost and poorer porosity and aeration. The growth of tomato seedlings was greatest after substitution of Metro-Mix 360 with between 25% and 50% Pig Manure vermicompost, with more growth occurring in combinations of Pig Manure vermicompost treated regularly with a liquid fertilizer solution than in those with no fertilizer applied. Some of the growth enhancement in these mixtures seemed to be related to the combined effects of improved porosity, aeration and water retention in the medium and the high nitrate content of the substrate, which produced an increased uptake of nitrogen by the plant tissues, resulting in increased plant growth. When the tomato seedlings were watered daily with liquid inorganic fertilizer, substitution of Metro-Mix 360 with a very small amount (5%) of Pig Manure vermicompost resulted in a significant increase in the growth of tomato seedlings. Such effects could not be attributed solely to the nutritional or physical properties of the Pig Manure vermicompost. Therefore, it seems likely that the Pig Manure vermicompost provided other biological inputs, such as plant growth regulators into the container medium, that still need to be identified fully.
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influence of earthworm processed Pig Manure on the growth and yield of greenhouse tomatoes
Bioresource Technology, 2000Co-Authors: Rola M Atiyeh, Clive A Edwards, Norman Q Arancon, James D MetzgerAbstract:The eAects of earthworm-processed Pig Manure (vermicompost) on germination, growth, and yields of tomato (Lycopersicon esculentum Mill.) plants were evaluated under glasshouse conditions. Tomatoes were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) Pig Manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were grown for 158 days and were frequently supplied with a complete mineral nutrient solution. The germination rates of tomato seeds increased significantly upon substitution of Metro-Mix 360 with 20%, 30%, and 40% vermicompost. Seedlings grown in 100% Pig Manure vermicompost were significantly shorter, had fewer leaves, and weighed less than those in Metro-Mix 360 controls. Incorporation of 10% or 50% vermicompost into Metro-Mix 360 increased the dry weights of tomato seedlings significantly compared to those grown in the Metro-Mix 360 controls. The largest marketable yield was in the substitution of Metro-Mix 360 with 20% vermicompost (5.1 kg/plant). The average weight of a tomato fruit in substitution of Metro-Mix 360 with 20% vermicompost was 12.4% greater than that in the Metro-Mix 360 control. Substitution of Metro-Mix 360 with 10%, 20%, and 40% vermicompost reduced the proportions of fruits that were non-marketable, and produced more large size (diameter > 6:4 cm) than small size (diameter < 5:8 cm) tomato fruits. There was no significant diAerence in overall tomato yields between Metro-Mix 360 and 100% Pig Manure vermicompost. Some of the growth and yield enhancement resulting from substitution of Metro-Mix 360 with Pig Manure vermicompost could be attributed to the high mineral N concentration of the Pig Manure vermicompost. However, other factors might have also been involved since all plants were frequently supplied with all required nutrients. These factors need to be investigated in future studies. ” 2000 Elsevier Science Ltd. All rights reserved.
Christina S Holzel - One of the best experts on this subject based on the ideXlab platform.
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heavy metals in liquid Pig Manure in light of bacterial antimicrobial resistance
Environmental Research, 2012Co-Authors: Christina S Holzel, Karin Schwaiger, Katrin S Harms, Christa Muller, Sabine Mikolajewski, Stefanie Schafer, Johann BauerAbstract:Heavy metals are regularly found in liquid Pig Manure, and might interact with bacterial antimicrobial resistance. Concentrations of heavy metals were determined by atomic spectroscopic methods in 305 Pig Manure samples and were connected to the phenotypic resistance of Escherichia coli (n=613) against 29 antimicrobial drugs. Concentrations of heavy metals (/kg dry matter) were 0.08-5.30 mg cadmium, 1.1-32.0 mg chrome, 22.4-3387.6 mg copper, <2.0-26.7 mg lead, <0.01-0.11 mg mercury, 3.1-97.3 mg nickel and 93.0-8239.0 mg zinc. Associated with the detection of copper and zinc, resistance rates against β-lactams were significantly elevated. By contrast, the presence of mercury was significantly associated with low antimicrobial resistance rates of Escherichia coli against β-lactams, aminoglycosides and other antibiotics. Effects of subinhibitory concentrations of mercury on bacterial resistance against penicillins, cephalosporins, aminoglycosides and doxycycline were also demonstrated in a laboratory trial. Antimicrobial resistance in the porcine microflora might be increased by copper and zinc. By contrast, the occurrence of mercury in the environment might, due to co-toxicity, act counter-selective against antimicrobial resistant strains.
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sewage sludge and liquid Pig Manure as possible sources of antibiotic resistant bacteria
Environmental Research, 2010Co-Authors: Christina S Holzel, Karin Schwaiger, Katrin S Harms, Helmut Kuchenhoff, Anne Kunz, Karsten Meyer, Christa Muller, Johann BauerAbstract:Within the last decades, the environmental spread of antibiotic resistant bacteria has become a topic of concern. In this study, liquid Pig Manure (n=305) and sewage sludge (n=111) - used as agricultural fertilizers between 2002 and 2005 - were investigated for the presence of Escherichia coli, Enterococcus faecalis and Enterococcus faecium. Bacteria were tested for their resistance against 40 chemotherapeutics including several "reserve drugs". E. coli (n=613) from Pig Manure were at a significantly higher degree resistant to streptomycin, doxycycline, spectinomycin, cotrimoxazole, and chloramphenicol than E. coli (n=116) from sewage sludge. Enterococci (Ent. faecalis, n=387, and Ent. faecium, n=183) from Pig Manure were significantly more often resistant to high levels of doxycycline, rifampicin, erythromycin, and streptomycin than Ent. faecalis (n=44) and Ent. faecium (n=125) from sewage sludge. Significant differences in enterococcal resistance were also seen for tylosin, chloramphenicol, gentamicin high level, fosfomycin, clindamicin, enrofloxacin, moxifloxacin, nitrofurantoin, and quinupristin/dalfopristin. By contrast, aminopenicillins were more effective in enterococci from Pig Manure, and mean MIC-values of piperacillin+tazobactam and third generation cefalosporines were significantly lower in E. coli from Pig Manure than in E. coli from sewage sludge. 13.4% (E. coli) to 25.3% (Ent. faecium) of Pig Manure isolates were high-level multiresistant to substances from more than three different classes of antimicrobial agents. In sewage sludge, high-level-multiresistance reached from 0% (Ent. faecalis) to 16% (Ent. faecium). High rates of (multi-) resistant bacteria in Pig Manure emphasize the need for a prudent - cautious - use of antibiotics in farm animals.