Dry Swine Manure Research Articles

Evaluation of Properties of Pellets Made of Swine Manure

Abstract This paper deals with assessment of density, moisture content and mechanical properties of pellets made of dry swine manure utilizing pellet production line MGL 200. Pellets were subsequently subjected to compressive loading test. Furthermore, the values obtained were measured by means of device Andilog Stentor 1000 and compression diagrams were plotted. In terms of compressive strength, pellet type 1 showed value of 10.47 MPa; pellet type 2 showed value of 6.24 MPa. Considering the elasticity modulus, pellet type 1 showed value of 122.39 MPa; pellet type 2 showed value of 71.12 MPa. Other observed properties included force necessary for 10% compression strain; force in the first maximum of force-strain curve; force in the inflection point of the force-time curve. Results obtained from compressive loading test provide a basis for innovations in pellet production utilizing materials other than wood biomass.

Enhanced biogas production from swine manure anaerobic digestion via in-situ formed graphene in electromethanogenesis system

The aim of this work was to enhance methane production from swine manure anaerobic digestion (AD) with in-situ formed graphene in microbial electrolysis cell (AD-MEC). The AD-MEC for in-situ graphene exfoliation incorporated a carbon felt anode and a titanium mesh cathode with an applied voltage of 2.5 V. Atomic force microscopic and Raman analyses confirmed that the graphene was in-situ formed. Voltage stimulation (1 h per day) and graphene production enhanced AD efficiency by promoting direct interspecies electron transfer between AD microorganisms. The increased biomass owing to enrichment of AD microorganisms on the carbon felt could also enhance AD efficiency. The voltage-graphene group (VGG) greatly enhanced the biogas yield (356.49 m3/t dry swine manure) and methane yield (222.17 m3/t dry swine manure), which were 41.49% and 60.89% higher than that of the control group, respectively. Microbial community analysis identified the dominant methanogens in the VGG system as Methanosarcina and Methanobrevibacter, while only Methanosarcina was dominant in the control system. Network analysis showed that the VGG system established a narrower niche than the control system, and microorganisms trended to gather more in the module.

Effects of Pyrolysis Temperature and Holding Time on Physicochemical Properties of Swine-Manure-Derived Biochar

Biochars were slowly pyrolyzed from dried swine manure waste by slow pyrolysis at different temperatures (300–750 °C) and heating times (0–120 min). The influence of pyrolysis temperature and heating time on the physicochemical properties of the biochars were studied. It was found that the ash content, pH, mineral nutrients, total heavy metals (except Zn), and pore properties of all swine-manure-derived biochars increased with increasing temperature and time. The yield and N, O, and H contents decreased with increasing temperature and time. The manure-derived biochar was rich in soil macronutrients and micronutrients, such as N, P, K, Ca, Mg, Na, Fe, Mn, Cu, and Zn. Excessive pyrolysis temperature (i.e., 750 °C) significantly increased the electrical conductivities of the biochars, i.e., the amount of soluble salts, and was also associated with the risk of volatilization of heavy metals (e.g., Zn) with low melting point. Linear correlation analyses showed that there were significant correlations between physical and chemical characteristics of the biochars, and the P values of correlation coefficients were often < 0.001. The principal component analysis implied that the properties of the swine-manure-derived biochars were mainly affected by ash content. Furthermore, the chemical and pore properties were also consistent with the observations of the XRD and FTIR. The swine-manure-derived biochar at 450 °C after 60 min could be used as an excellent medium to soil environment because of relatively low soluble salts and heavy metals, abundant mesoporous pores, surface functional groups, and nutrients.

Effect of temperature on bacterial emissions in composting of swine manure

Swine manure was subjected to laboratory scale composting in order to quantify bioaerosols, i.e., airborne culturable bacteria and endotoxin, in the exhaust gas, which provided details on the effect of temperature on bacterial emissions. The concentration of airborne bacteria reached 31,250colony-forming units (CFU)/m3 during the thermophilic stage of composting, and positively correlated with the temperature profile of the compost pile. Initially, the endotoxin concentration was 1820endotoxin units (EU)/m3, but it decreased exponentially as the composting process proceeded. The temperature can be an excellent indicator of bacterial emissions during the composting process, indicating that the composting process requires a consistently high temperature to ensure sanitization of both compost and bacterial emissions. The cumulative emission data showed that emission factors was 11.2−13.5CFU/g dry swine manure and that of endotoxin was 0.5−0.9EU/g dry swine manure. The bacterial diversity in the bioaerosol was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis, revealing the presence of various gram-negative bacterial consortia.

BIOGAS PRODUCTION FROM PIG MANURE FED OPUNTIA ROBUSTA DIETS

This study was conducted with the aim to evaluated biogas production from swine manure of fattening pig fed 0, 5, 10 or 15% of Opuntia robusta (dry matter basis). Sun dried swine manure was stored in 20-L containers during 45 d. Biogas production was measured for 4 days in 1-L digesters at 32 °C, 48 digesters were used (12 by treatment), every day the material of the collector bags was extracted and was consider biogas if that was flammable. Volume of flammable gas, flame time and burning temperature were recorded daily. During the experimental periods gas production was different (P<0.001); 0% diet produced (963 ml day-1), 5% OR produced biogas (567 ml day-1); 10% OR diet produced (623 ml day-1) and 15% OR diet (170 ml day-1). Flame time showed similar trend with the volume with adjusted media of 19, 13, 17 and 4 seconds for 0, 5, 10 or 15% OR diets. Flame temperature was similar (P=0.64) 660°C when gas was flammable. The sun dried swine manure from Opuntia robusta diets reduces the biogas production, therefore OR’s manure could have less environmental impact than control diet manure for a faster degradation rate during the drying period.

Textural and chemical properties of swine-manure-derived biochar pertinent to its potential use as a soil amendment

Biochars have received increasing attention in recent years because of their properties pertaining to soil fertility and contaminant immobilization as well as serving as carbon sinks. In this work, a series of biochars were produced from dried swine manure waste by slow pyrolysis at different temperatures (i.e., 673–1073K). The characterization of the resulting biochars was examined for its relevance to its potential use as soil amendment. It was found that the pore properties, ash contents and pH values of all swine-manure-derived biochars basically increased as temperature increased, while the yield and nitrogen/oxygen contents decreased with increasing temperature as a result of pyrolytic volatilization during pyrolysis. From the organic and inorganic elements analyses, the manure-derived biochar was rich in soil nutrients such as N, P, Ca, Mg, and K. Furthermore, the pore, surface and chemical properties were also consistent with the observations of the SEM-EDS, XRD and FTIR. This result suggested that the mesoporous manure-derived biochar could be used as an excellent medium to soil environment.

Biochar from swine manure solids: influence on carbon sequestration and Olsen phosphorus and mineral nitrogen dynamics in soil with and without digestate incorporation

Interest in biochar (BC) has grown dramatically in recent years, due mainly to the fact that its incorporation into soil reportedly enhances carbon sequestration and fertility. Currently, BC types most under investigation are those obtained from organic matter (OM) of plant origin. As great amounts of manure solids are expected to become available in the near future, thanks to the development of technologies for the separation of the solid fraction of animal effluents, processing of manure solids for BC production seems an interesting possibility for the recycling of OM of high nutrient value. The aim of this study was to investigate carbon (C) sequestration and nutrient dynamics in soil amended with BC from dried swine manure solids. The experiment was carried out in laboratory microcosms on a silty clay soil. The effect on nutrient dynamics of interaction between BC and fresh digestate obtained from a biogas plant was also investigated to test the hypothesis that BC can retain nutrients. A comparison was made of the following treatments: soil amended with swine manure solids (LC), soil amended with charred swine manure solids (LT), soil amended with wood chip (CC), soil amended with charred wood chip (CT), soil with no amendment as control (Cs), each one of them with and without incorporation of digestate (D) for a total of 10 treatments. Biochar was obtained by treating OM (wood chip or swine manure) with moisture content of less than 10% at 420°C in anoxic conditions. The CO2-C release and organic C, available phosphorus (P) (Olsen P, POls) and inorganic (ammonium+nitrate) nitrogen (N) (Nmin) contents at the start and three months after the start of the experiment were measured in the amended and control soils. After three months of incubation at 30°C, the CO2-C emissions from soil with BC (CT and LT, ±D) were the same as those in the control soil (Cs) and were lower than those in the soils with untreated amendments (CC and LC, ±D). The organic C content decreased in CT and LT to a lesser extent than in CC and LC. In soils with D (+D), the CO2-C emissions were equal to or higher than those in soils without (-D). The Nmin content increased in all treatments; the POls content decreased in the +D treatments. The incorporation of BC into soil, by reducing CO2 emissions, actually contributes to C sequestration without modifying N availability for crops. For a given N content, the BC from swine manure solids supplies much more P than the non-treated OM and, therefore, represents an interesting source of P for crops.

Impact of Biochar on Manure Carbon Stabilization and Greenhouse Gas Emissions

Previous studies indicate that biochar additions sometimes increase soil respiration and CO2 emissions which could partially offset C credits associated with soil biochar applications. Little is known, however, about the impact of biochar on the mineralization of manure in soil systems and how interactions between biochar and manure impact C sequestration and greenhouse gas (GHG) emissions from soils. We studied the effect of biochar and dried swine manure additions on changes in soil bulk density (Db), total soil organic carbon (SOC), and emissions of N2O and CO2 during a 500-d soil column incubation study. The addition of biochar to the soil increased SOC content measured after the 500-d incubation by 17.6 to 68.8%, depending on the treatment. Biochar additions reduced N2O emissions measured once near the end of the incubation. The N2O emissions were weakly correlated with Db, suggesting that enhanced soil aeration contributed to the reductions in N2O emissions. Biochar additions consistently increased CO2 emissions (measured 13 times during the incubation) relative to no-biochar controls with cumulative CO2–C emissions equivalent to 17 to 23% of biochar C applied. However, a distinct biochar-by-manure interaction for CO2 flux indicated that biochar either helped stabilize manure C or the presence of manure reduced the effect of biochar on the mineralization of SOC. For the studied system, we conclude that biochar additions sequestered large amounts of highly stable C, reduced N2O emissions, increased CO2 emissions from the soils, and reduced rates of CO2 emissions following a manure addition.

Biochar impact on nutrient leaching from a Midwestern agricultural soil

Application of biochar to highly weathered tropical soils has been shown to enhance soil quality and decrease leaching of nutrients. Little, however, is known about the effects of biochar applications on temperate region soils. Our objective was to quantify the impact of biochar on leaching of plant nutrients following application of swine manure to a typical Midwestern agricultural soil. Repacked soil columns containing 0, 5, 10, and 20 g-biochar kg − 1 -soil, with and without 5 g kg − 1 of dried swine manure were leached weekly for 45 weeks. Measurements showed a significant decrease in the total amount of N, P, Mg, and Si that leached from the manure-amended columns as biochar rates increased, even though the biochar itself added substantial amounts of these nutrients to the columns. Among columns receiving manure, the 20 g kg − 1 biochar treatments reduced total N and total dissolved P leaching by 11% and 69%, respectively. By-pass flow, indicated by spikes in nutrient leaching, occurred during the first leaching event after manure application for 3 of 6 columns receiving manure with no biochar, but was not observed for any of the biochar amended columns. These laboratory results indicate that addition of biochar to a typical Midwestern agricultural soil substantially reduced nutrient leaching, and suggest that soil–biochar additions could be an effective management option for reducing nutrient leaching in production agriculture.

Industrial Application of Animal Manure Filled Thermoplastics

Animal agriculture is under increasing pressure to produce more and more meat, milk and eggs giving rise to an increasing amount of manures. In the past, manures have been viewed as a waste byproduct used mainly as a fertilizer that has a value of 2 to 4 cents per dry pound. We need to change our view of manures from waste to asset. Destroying manures by burning or lagooning may solve the environmental problem but it does nothing to add to animal income. One of the alternatives is to use animal manures in industrial products. Based on past research at the Forest Products Laboratory in the area of wood and agricultural flours and fibers as fillers in thermoplastics, this research program uses swine and cow manures as reinforcing fillers in HDPE and HDPP. This is a win-win situation as it increases the value of the animal manures, decreases the cost and improves mechanical properties of the thermoplastic composites. A 40% blend of dry swine manure with HDPE and 2% MAPE gives a composite with MOE in bending of 1.31 GPa and MOR of 34.7 MPa as compared to unfilled HDPE MOE of 0.75 GPa and MOR of 15.1 MPa. A 40% blend of dry dairy manure with HDPE and 2% MAPE gives a composite gives MOE in bending of 2.18 GPa and MOR 21.9 MPa as compared to 40% pine flour with 2% MAPE MOE 2.98 and MOR 33.4 MPa.

Phosphorus transformations in acid light-textured soils treated with dry swine manure

Organic matter can sorb P in acid soils through metal-organic matter-phosphate complexes. The pyrophosphate extractable Al and Fe and soil C contents were hypothetized to influence P partitioning in Ferro-Humic Podzols. Reaction of added P may be mitigated by adding lime or organic matter as dry swine manure (DSM) together with mineral P fertilizers. Three soils had 40 to 50 g kg-1 of soil organic matter (SOM) content, and 76 to 140 mmol (Al + Fe)pyro kg-1. A peaty soil phase had 200 g SOM kg-1, and 58 mmol (Al + Fe)pyro kg-1. Rates of monoammonium phosphate were 0, 27, 69, and 144 kg P ha-1 in a simulated fertilizer band. Rates of DSM and lime were 800 and 185–369 mg per 35 mL of soil, respectively. After 6 wk of incubation, soil P was fractionated sequentially into aluminium bound P (Al-P), iron bound P (Fe-P), and loosely bound P. Total P, desorbed P and organic P were determined in separate subsamples. A proportion of 79–92% of added P was recovered as Al-P and Fe-P in the three low SOM soils, compared to 51–61% in the high SOM soil. The DSM increased loosely bound P from 25 to 34% in the high SOM soil and from 4.8 to 5.9% in low SOM soils. With DSM, the proportion of desorbed P was much higher in the high (70%) than in low SOM (22%) soils. Compared to the non-amended treatment, lime showed no significant effect on any P fraction but desorbed P. The DSM increased P availability in the fertilizer band considerably more in the soil having the lowest (Al + Fe)pyro/C ratio. Key words: P fractionation, organic ligand, P sorption, fertilizer band

PRODUÇÃO E COMPOSIÇÃO MINERAL DE CENOURA ADUBADA COM RESÍDUOS ORGÂNICOS

Este trabalho objetivou avaliar o estado nutricional, a produção e a qualidade de raízes de cenoura, cultivar Brasília, influenciados pelos seguintes tratamentos: sete tipos de compostos orgânicos produzidos com dejeto de suínos na forma líquida e material palhoso (bagaço de cana-de-açúcar, capim-napier e palha de café), com o bagaço de cana-de-açúcar contendo ou não gesso ou superfosfato triplo; um tratamento com dejeto seco de suínos; um com adubação mineral e uma testemunha, sem adubação. O experimento foi realizado em 3 de maio a 23 de agosto de 1994, em condições de campo, no delineamento de blocos casualizados com quatro repetições, na Fazenda Experimental da EPAMIG, em Ponte Nova (MG). De modo geral, a maior altura de planta e a produção de parte aérea foram obtidas nos tratamentos com compostos orgânicos e dejeto seco de suínos. Os tratamentos com compostos produzidos com palha de café mais dejeto líquido, bagaço de cana-de-açúcar mais dejeto líquido mais superfosfato triplo e capim-napier mais palha de café mais dejeto líquido proporcionaram produções totais de raízes superiores a 50 t.ha-1. O composto produzido com palha de café e dejeto líquido proporcionou a maior produção de raízes total e comerciável. O enriquecimento do composto, bagaço de cana-de-açúcar mais dejeto líquido, com gesso ou superfosfato triplo, não alterou a produção de raízes nem os teores de Ca e P nas folhas e raízes. As raízes de cenoura, cujos tratamentos receberam adubação orgânica ou mineral, apresentaram teores de P e K superiores e Ca semelhante aos teores considerados padrões para elaboração de dietas para o ser humano.