Swine Manure Research Articles

Feasibility test and field application of biofoam spray to directly reduce ammonia emissions from a swine manure slurry pit

Bad-odor gases emitted from swine manure slurry are a global concern because of their detrimental effects on human health and animal welfare. We sprayed odor-removing microbe-loaded surfactant foam (biofoam) directly on the manure slurry surface to suppress NH3 (major odor component in slurry) emissions. Two subsequent experiments were conducted: a feasibility test in a tank and a field manure slurry pit test. The biofoam was sprayed directly onto the slurry once per day. The biofoam sprayed once on the slurry was stable for 20–24 h on the slurry. In the feasibility test tank, 99%–100% NH3 emissions were suppressed for 72 h, and a 61%–89% reduction in NH3 emissions was obtained for 72 h from the field manure slurry pit. The biofoam successfully blocked NH3 emissions. The NH3 reduction efficiency of the biofoam was consistently related to its stability on the surface of the manure slurry. The long-lasting surfactant foam is a good physical suppression cover for reducing NH3 release into the environment. After 72 h, NH3 slowly began to be emitted; nevertheless, the emission was much lower than that of the control. The tiny bubbles that formed after the foam broke still acted as an odor-suppression barrier. Moreover, NH3-reducing microbes loaded onto the surfactant foam degraded NH3 from the manure slurry, and a 34%-63% reduction in NH3 emission was attributed to biological effects after the foam was broken. Overall, NH3 emissions were reduced directly by the biofoam surface covering the manure slurries, the formation of a thin encapsulation layer on the slurry surface, and the activity of spontaneously added microbes. The developed method is a promising odor-reducing technique for swine manure.

Enhancing swine manure treatment: A full-scale techno-economic assessment of nitrogen recovery, pure oxygen aeration and effluent polishing

In regions with intensive livestock production, managing the environmental impact of manure is a critical challenge. This study, set in Flanders (Belgium), evaluates the effectiveness of integrating process intensification measures into the treatment of piggery manure to mitigate nitrogen (N) surplus issues. The research investigates the techno-economic benefits of implementing three key interventions: pure oxygen (PO) aeration, ammonia (NH3) stripping-scrubbing (SS) pretreatment, and tertiary treatment using constructed wetlands (CW), within the conventional nitrification-denitrification (NDN) process.Conducted at a full-scale pig manure treatment facility, our analysis employs steady-state mass balances for N and phosphorus (P) to assess the impact of these process intensification strategies. Findings indicate that the incorporation of advanced treatment steps significantly enhances the efficiency and cost-effectiveness of the manure management system. Specifically, the application of PO aeration is shown to reduce overall treatment costs by nearly 4%, while the addition of an NH3 SS unit further decreases expenses by 1–2%, depending on the counter acid utilized. Moreover, the implementation of a CW contributes an additional 4% in cost savings.Collectively, these measures offer substantial improvements in processing capacity, reduction of by-product disposal costs, and generation of additional revenue from high-quality fertilising products. The study highlights the potential of advanced treatment technologies to provide economically viable and environmentally sustainable solutions for manure management in livestock-dense regions, emphasizing the cumulative economic benefit of a holistic approach to process intensification (10%).

Thermogravimetric analysis and kinetic modeling of the pyrolysis of different biomass types by means of model-fitting, model-free and network modeling approaches

AbstractThis work aims at comparing the ability of 7 modeling approaches to simulate the pyrolysis kinetics of spruce wood, wheat straw, swine manure, miscanthus and switchgrass. Measurements were taken using a thermogravimetric analyzer (TGA) with 4 heating rates comprised between 5 and 30 K min−1. The obtained results were processed using 3 isoconversional methods (Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW) and Friedman), 1-step and 3-step Kissinger models, as well as an advanced fitting method recently proposed by Bondarchuk et al. [1] (Molecules 28:424, 2023, https://doi.org/10.3390/molecules28010424). Seventeen reaction models were considered to derive rate constant parameters, which were used to simulate the variation of the fuel conversion degree $$\alpha$$ α as a function of the temperature $$T$$ T . To complement this benchmarking analysis of the modeling approaches commonly used to simulate biomass pyrolysis, a network model, the bio-CPD (chemical percolation devolatilization), was additionally considered. The suitability of each model was assessed by computing the root-mean-square deviation between simulated and measured $$\alpha =f(T)$$ α = f ( T ) profiles. As highlights, the model-free methods were found to accurately reproduce experimental results. The agreement between simulated and measured data was found to be higher with the Friedman model, followed by the KAS, FWO, 3-step, and 1-step Kissinger models. As for the bio-CPD, it failed to predict measured data as well as the above-listed models. To conclude, although it was less efficient than the Friedman, KAS or OFW models, the fitting approach from Bondarchuk et al. [1] (Molecules 28:424, 2023, https://doi.org/10.3390/molecules28010424) still led to satisfactory results, while having the advantage of not requiring the selection of a reaction model a priori.

Microbial analysis of anaerobic digester reveals prevalence of manure microbiota

Anaerobic digestion of swine manure reduces farm greenhouse gases emissions and provides a renewable gas in the agricultural sector. The particular composition of manure, with high concentrations of ammoniacal nitrogen and volatile fatty acids, often threatens the stability of the process through inhibition of methanogens. In this work, continuous production of biogas was tested under relative short hydraulic retention time (15 days). Although a strong inhibition period was detected, adaptation of the microbiota and displacement of bacteria and archaea present in the inoculum by microorganisms present in the animal manure resulted in biogas production close to the values found in standardized batch tests in absence of inhibitions. These findings suggest that in anaerobic digestion of manure, it is not necessary to inoculate, as manure itself contains a large number of active fermentative microorganisms that can even resist long-term digestion inhibition.

Enzyme enhanced lactic acid fermentation of swine manure and apple waste: Insights from organic matter transformation and functional bacteria

Anaerobic co-fermentation is a favorable way to convert agricultural waste, such as swine manure (SM) and apple waste (AW), into lactic acid (LA) through microbial action. However, the limited hydrolysis of organic matter remains a main challenge in the anaerobic co-fermentation process. Therefore, this work aims to deeply understand the impact of cellulase (C) and protease (P) ratios on LA production during the anaerobic co-fermentation of SM with AW. Results showed that the combined use of cellulase and protease significantly improved the hydrolysis during the enzymatic pretreatment, thus enhancing the LA production in anaerobic acidification. The highest LA reached 41.02 ± 2.09 g/L within 12 days at the ratio of C/P = 1:3, which was approximately 1.26-fold of that in the control. After a C/P = 1:3 pretreatment, a significant SCOD release of 45.34 ± 2.87 g/L was achieved, which was 1.13 times the amount in the control. Moreover, improved LA production was also attributed to the release of large amounts of soluble carbohydrates and proteins with enzymatic pretreated SM and AW. The bacterial community analysis revealed that the hydrolytic bacteria Romboutsia and Clostridium_sensu_stricto_1 were enriched after enzyme pretreatment, and Lactobacillus was the dominant bacteria for LA production. This study provides an eco-friendly technology to enhance hydrolysis by enzymatic pretreatment and improve LA production during anaerobic fermentation.

Effects of Diet on the Gut Bacterial Community of Aldrichina grahami (Diptera: Calliphoridae) across Developmental Stages.

The blowfly, Aldrichina grahami (Diptera: Calliphoridae), is a well-known forensically important insect. Basic data related to A. grahami have been well documented; but despite the pivotal role of gut microbes in various facets of insect biology, little is known about its gut microbiome. To investigate the gut bacterial community of A. grahami and explore its stability, diet and developmental stage were selected as the two variables. Larvae were reared on bovine liver, swine manure, and chicken manure, and high-throughput sequencing of the 1st, 2nd, and 3rd instar larvae and the newly emerged adults was performed. According to our results, the alpha diversity of the gut bacterial community did not significantly vary among different diets and developmental stages. Principal coordinate analysis revealed that the gut microbiome of A. grahami clustered together among different diets and developmental stages. The main phyla in the gut microbial community of A. grahami were Firmicutes and Proteobacteria, and the dominant genera were Vagococcus, Providencia, Lactobacillus, and Morganella. These findings characterized the gut microbiome of A. grahami and demonstrated that the gut bacterial community is fairly stable. The dominant genera Vagococcus, Providencia, Lactobacillus, and Morganella have the potential to serve as core microbiomes within the gut microbial community of A. grahami.

Treatment of anaerobically digested swine manure using Chlorella vulgaris and bacteria in scaled-up systems

In previous studies, an integrated process (flocculation, struvite precipitation, Chlorella vulgaris and bacteria co-treatment) was shown to be a potentially effective treatment for anaerobically digested swine manure (ADSM). To assess the feasibility of engineering application, the biological treatment (Chlorella vulgaris and bacteria) of this integrated process was scaled up and implemented in an open vertical runway treatment system in this study. With continuous analysis and improvement of natural conditions, equipment and environmental factors, the effect of biomass accumulation and pollutant removal were significantly improved in the second 100 L batch. After 7 days of treatment, the biomass accumulation reached 2.06 ± 0.11 g/L, and the removal rates of chemical oxygen demands (COD), NH4+-N, TN and TP reached 75.7 %, 99.3 %, 79.7 % and 76.9 %, respectively, in the second 100 L batch. Results showed that the integrated treatment process could become a reliable way in treating ADSM by optimizing operation conditions in scale-up system.

Persistent effects of swine manure biochar and biogas slurry application on soil nitrogen content and quality of lotus root.

Using swine manure biochar and biogas slurry in agriculture proves to be an effective strategy for soil improvement and fertilization. In this study, a pot trial on the growth of lotus root was conducted to investigate the persistent effects of applying 350°C swine manure biochar (1% and 2%) and biogas slurry (50% and 100%) on soil nitrogen nutrient and lotus root quality. The results showed that compared to chemical fertilizer alone (A0B0), swine manure biochar significantly increased soil nitrogen content after one year of application. The contents of total nitrogen (TN), alkali-hydrolyzed nitrogen (AHN), ammonium nitrogen (NH4 +-N), and nitrate nitrogen () increased by 17.96% to 20.73%, 14.05% to 64.71%, 17.76% to 48.68% and 2.22% to 8.47%, respectively, during the rooting period. When swine manure biochar was present, the application of biogas slurry further elevated soil nitrogen content. The co-application of swine manure biochar and biogas slurry significantly increased soil nitrogen content, and the 100% nitrogen replacement with biogas slurry combined with 2% swine manure biochar (A2B2) treatment exhibited the most significant enhancement effect during whole plant growth periods. Soil enzyme activities, including soil protease (NPT), leucine aminopeptidase (LAP), b-glucosidase (β-GC) and dehydrogenase (DHA), showed a tendency to increase and then decrease with the prolongation of lotus root fertility period, reaching the maximum value during the rooting period. Compared to A0B0, the treatment with 2% swine manure biochar had the most significant effect on enzyme activities and increased the lotus root's protein, soluble sugar, and starch contents. Nitrate content decreased with the application of 2% swine manure biochar as the amount of biogas slurry increased. In conclusion, swine manure biochar effectively improved soil nitrogen content, enzyme activity, and lotus root quality. Even after one year of application, 2% swine manure biochar had the best enhancement effect.

Heated scallop-shell powder and lime nitrogen effectively decrease the abundance of antimicrobial-resistant bacteria in aerobic compost

The emergence and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are global public health concerns. Hence, measures should be implemented to reduce the abundance of ARB and prevent the spread of ARGs from livestock to the environment. In this study, to clarify the potential of reducing ARB abundance in livestock waste during aerobic composting, the effects of adding heated scallop-shell powder (HSSP) and lime nitrogen (LN) to manure compost on the abundance of several bacterial species were investigated. Several bacterial species (Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus aureus, and Enterococcus faecalis), spores of Clostridioides difficile, and various concentrations of HSSP/LN were added to livestock manure. After 24 h, the tested bacteria and spores were eliminated using 2% (w/w) and 4% (w/w) HSSP/LN, respectively. Subsequently, field trials were conducted on a pig farm to investigate the effect of adding HSSP/LN to manure composts. Swine manure and rice husk were mixed with or without 4% (w/w) HSSP/LN, and aerobic composting was continued for 13 days. The results showed that all the tested bacteria were eliminated after adding HSSP/LN, but the abundance of antibiotic resistance genes was not significantly altered. Adding HSSP/LN significantly affected the bacterial diversity in the compost. In conclusion, using HSSP/LN as an additive in aerobic composting effectively reduced the abundance of ARB, including spore-forming bacteria.

Nutrient retention after crop harvest in a typic hapludults amended with biochar types under no-tillage system

The utilization of biochar’s as soil amendments for enhancing nutrient retention in subsoils present potential limitations. To address this issue, we conducted a greenhouse experiment to assess the effects of various biochar’s derived from animal manures (swine manure, poultry litter, cattle manure) and plant residues (rice straw, soybean straw, corn straw) when applied to surface of an acidic soil. Our study focused on wheat crops under a no-tillage system, with a subsequent evaluation of the residual impacts on soybeans. The experimental design involved the application of biochar’s at different rates i.e. 10 and 20 Mg ha−1, followed by the assessment of their influence on NPK levels, pH, and exchangeable Al in stratified soil layers (0–5, 5–10, 10–15, and 15–25 cm). Furthermore, we investigated the interplay between biochar doses and the application of nitrogen (N) in the top 5 cm of soil, specifically examining NO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{NO}}_{{3}}^{ - }$$\\end{document}, NH4+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{NH}}_{{4}}^{ + }$$\\end{document}, P and K levels. Our findings revealed that in the top 5 cm of soil, biochar doses and N application significantly affected NO3-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{NO}}_{{3}}^{ - }$$\\end{document}, NH4+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{NH}}_{{4}}^{ + }$$\\end{document}, P and K concentrations. However, in deeper soil layers, no significant differences were observed among biochar doses with or without N application. Interestingly, K levels were impacted throughout all soil depths, regardless of the presence or absence of N application. Moreover, biochar application up to a 5 cm depth induced favorable changes in soil pH and reduced exchangeable Al. In contrast, deeper layers experienced a decrease in soil pH and an increase in exchangeable Al following biochar treatment. In conclusion, our study demonstrates that biochar’s can effectively retain NPK nutrients, enhance soil pH, and decrease exchangeable Al, independent of the type and dosage of application under a no-tillage system. Nonetheless, the efficacy of biochar amendments may vary with soil depth and type of nutrient, warranting careful consideration for maximizing their benefits in sustainable agricultural practices.

Tracking contaminants in the aqueous effluent during supercritical water gasification and oxidation of swine manure in the flow mode

Biomass waste processing is an area of great interest due to its potential for reducing environmental impact and recovering resources. The present work investigates for the first time the composition of products resulting from supercritical water (SCW) gasification and oxidation of swine manure (SM) continuously fed into a tubular reactor at a temperature gradient along its vertical axis of 390–600 °C and a pressure of 25 MPa. Special attention is paid to how the operating parameters, including SM flow rate (6.5–10.7 g/min), oxidation ratio (OR ≤ 1.78), and the presence of NaOH additive (1 wt%) influenced the composition and concentration of contaminants (phenols, N-bearing aromatics, polyaromatic hydrocarbons (PAHs), and ammonia) in the effluent collected at the reactor outlet. The results of gas chromatography-mass spectrometry indicate that water-soluble products comprise predominantly of phenols, pyridines, pyrroles, indoles, pyrazines, anilines, and quinolines. Increasing the reagent’s residence time during SCW gasification was observed to lower the amount of phenols in the effluent. In addition, the introduction of NaOH increases the yields of syngas and NH3 while lowering the concentration of N-bearing aromatics and PAHs. SCW oxidation of SM not only reduces contaminant levels in the effluent by several orders of magnitude, but also partially compensates for thermal inputs needed for the process implementation. Among N-bearing compounds, ammonia, pyridines, indoles, and quinolines display the highest resistance to oxidation. The paper explores the resource-saving and ecological benefits of SCW gasification and oxidation of SM.

Control of odorants in swine manure and food waste co-composting via zero-valent iron /H2O2 System

Odors have posed challenges to the advancement of aerobic composting. This work aims to identify the primary components responsible for odors and assess the effectiveness and mechanisms of the zero-valent iron/H2O2 system controlling various odorants in aerobic composting. Swine manure and food waste were used as composting materials, with the addition of zero-valent iron and hydrogen peroxide to mitigate odor emissions. Results revealed that odorants included ammonia, hydrogen sulfide, and 22 types of volatile organic compounds (VOCs), with ethyl acetate, heptane, and dimethyl disulfide being predominant. Among the odorants emitted, ammonia accounted for 75.43%, hydrogen sulfide for 0.09%, and identified VOCs for 24.48%. The ZVI/H2O2 system showed a significant reduction in ammonia and VOCs emission, with the reduction of 51% (ammonia) and 41.3% (VOCs) respectively, primarily observed during the thermophilic period. The occurrence of Fenton-like reactions and changes in key microbial populations were the main mechanisms accounting for odor control. The occurrence of Fenton-like reaction was confirmed by X-ray photoelectron spectroscopy and reactive oxygen detection, showing the oxidation of zero-valent iron by H2O2 to higher valence elemental iron, and the simultaneous production of ·OH. Microbial analysis indicated that an enrichment of specific microorganisms with Bacillus contributed to feammonx and Bacillaceae contributed to organic biodegradation. Redundancy analysis highlighted the role of key microbial species (Bacillaceae, Bacillus, and Ureibacillus) in effectively reducing the level of ammonia and volatile organic compounds. These novelty findings illustrated that the potential of this system is promising for controlling the emission of odorants and aerobic composting reinforcement.

Effects of Fe-modified digestate hydrochar at different hydrothermal temperatures on anaerobic digestion of swine manure

Hydrothermal carbonization temperature is a key factor in controlling the physico-chemical properties of hydrochar and affecting its function. In this study, effects of hydrochar and Fe-modified hydrochar (Fe-HC) prepared at 180 °C (180C-Fe), 220 °C (220C-Fe) and 260 °C (260C-Fe) on anaerobic digestion (AD) performance of swine manure was investigated. Among the three Fe-HCs, 220C-Fe had the highest amount of Fe and Fe2+ on the surface. The relative methane production of control reached 174 %-189 % in the 180C-Fe and 220C-Fe treatments between days 11 and 12. The degradation efficiency of swine manure was highest in the 220C-Fe treatment (61.3 %), which was 14.8 % higher than in the control. Fe-HC could act as an electron shuttle, stimulate the coenzyme F420 formation, increase the relative abundance of Methanosarcina and promote electron transport for acetotrophic methanogenesis in the AD. These findings are helpful for designing an efficient process for treating swine manure and utilizing digestate.

Microbial resistance and resilience to drought and rewetting modulate soil N2O emissions with different fertilizers

Future climate models indicate an enhanced severity of regional drought and frequent rewetting events, which may cause cascading impacts on soil nitrogen cycle and nitrous oxide (N2O) emissions, but the underlying microbial mechanism remains largely unknown. Here we report an incubation study that examined the impacts of soil moisture status and nitrification inhibitor (DCD) on the N2O-producers and N2O-reducers following the application of urea and composted swine manure in an acid soil. The soil moisture treatments included 100 % water-holding capacity (WHC) (wetting, 35.3 % gravimetric soil water content), 40 % WHC (drought, 7 % gravimetric soil water content), and 40 % to 100 % WHC (rewetting). The results showed that N2O emissions were significantly decreased under drought conditions and were significantly increased after rewetting. The resistance of ammonia-oxidizing bacteria and nosZII, which was inhibited by urea or manure application, modulated N2O emissions under drought conditions. The resilience of the functional guilds modulated their dominant role in N2O emissions with rewetting. Ammonia-oxidizing bacteria, nirS-type denitrifying bacteria and nosZI showed significant resilience in response to rewetting. Significant negative relationships were observed between N2O emissions and nosZII clade under wetting condition and between N2O emissions and nosZI clade after rewetting. Our results highlighted the importance of microbial resistance and resilience in modulating N2O emissions, which help to better understand the dominant way of N2O emissions, and consequently make efficient mitigation strategies under the global climate change.

Influence of zero-valent iron nanoparticles on anaerobic digestion of swine manure: effects on methane yield

ABSTRACT This study evaluated the effect of zero-valent iron nanoparticles (NZVI) on the anaerobic digestion of swine manure. A wide range of doses of NZVI was evaluated (5, 10, 15, 20, 25, 50, and 100 mgFe°/gVS). The maximum methane yield of 0.4506 L/gVSremoved was obtained with the concentration of 10 mgFe°/gVS representing an increase of 58.99% than the control system with 0.2834 L/gVSremoved, indicating that Fe° improves the methanogenic activity. However, when using doses greater than 20 mgFe°/gVS, there were decreases in the methane yield of 34.4–47.98%. Also, to observe the effect of NZVI in anaerobes was evaluated the activity in the electron transport system (ETS), where the control reactor showed an activity of 31.91 μg INTred/gVS•h, while in reactors with NZVI showed values of 39.48 μg INTred/gVS•h (10 Fe°mg/gVS), observing a stimulation of Fe° in microbial activity. However, the dose of 100 mgFe°/gVS showed the greatest decrease in methane yield (0.1474 L/gVSremoved) and a reduction in ETS was observed by 8.5% compared to the control. The effect on the composition of the volatile fatty acids was observed, where the control system obtained a maximum production of acetic acid of 639 mg/L, which was exceeded with the dose of 10 mg Fe°/gVS by 215% and a decrease of 41.15% with the inhibitory concentration of 100 mg Fe°/gVS. As a result, higher doses of NZVI affect the metabolic activity of anaerobes as well as the acetoclastic pathway causing a decrease in the methane production.

Farmyard Manure Integrated with Triple Superphosphate for Improved Soil Conditions and Yield of Bio-Fortified Common Beans

Increasing prices of fertilizers and low nutrient concentration in organic manure are highly contributing to poor soil conditions and increased yield gap of bio-fortified common beans. A field study was carried out to assess the effect of farmyard manure integrated with triple superphosphate on soil conditions and yield of bio-fortified common bean Genotypes in central Uganda. The experiments were set in a Randomized Complete Block Design (RCBD) conducted at Mukono Zonal Agricultural Research Institute (MUZARDI) in two rainfall seasons. Treatments included; Cattle manure + TSP, Swine manure + TSP, Chicken manure + TSP, TSP alone and control replicated five times. Bio-fortified common bean genotypes studied were: Naro bean 1, Naro bean 3 and NABE16 a local check. Data was collected on; organic matter, soil pH, nitrogen, potassium and phosphorus content, harvest index, number of pods, pod length, number of seeds per pod, weight of 100 seeds, and grain yield of bio-fortified common beans. Data was subjected to statistical test and analysis of variance using GenStat statistical package (15th edition). Results showed that amending field plots with Swine manure + TSP significantly increased Organic matter by; 1.51% and potassium 1.22% than Chicken manure + TSP, Cattle + TSP, TSP alone and a control respectively. Chicken manure + TSP increased soil pH and Nitrogen by 1.80 and 2.20% while, TSP alone improved Phosphorus by 5.2 PPM than other treatments. Yield parameters were not significantly (P>0.05) affected by treatments except weight of 100 seeds. However, bean genotypes grown in Swine manure + TSP recorded maximum yield of 14 pods, 4 seeds per pod, 32.93 g weight of 100seeds, grain yield was (1843 kgha-1) and lowest (1253 to 650 kg/ha) in TSP+ cattle manure and control. It was therefore, concluded that swine manure + TSP significantly improved soil conditions and yield of bio-fortified common beans. Therefore, basing on these findings, farmers should adopt amendment of swine manure with TSP for improved soil conditions and yields of Naro bean 1

Wheat straw biochar as an additive in swine manure Composting: An in-depth analysis of mixed material particle characteristics and interface interactions

In recent research, biochar has been proven to reduce the greenhouse gases and promote organic matter during the composting. However, gas degradation may be related to the microstructure of compost. To investigate the mechanism of biochar additive, composting was performed using swine manure, wheat straw and biochar and representative solid compost samples were analyzed to characterize the mixed biochar and compost particles. We focused on the microscale, such as the particle size distributions, surface morphologies, aerobic layer thicknesses and the functional groups. The biochar and compost particle agglomerations gradually became weaker and the predominant particle size in the experiment group was < 200 μm. The aerobic layer thickness (Lp) was determined by infrared spectroscopy using the wavenumbers 2856 and 1568 cm−1, which was 0–50 μm increased as composting proceeded in both groups. The biochar increased Lp and facilitated oxygen penetrating the compost particle cores. Besides, in the biochar-swine manure particle interface, the aliphatic compound in the organic components degraded and the content of aromaticity increased with the composting process, which was indicated by the absorption intensity at 2856 cm−1 decreasing trend and the absorption intensity at 1568 cm−1 increasing trend. In summary, biochar performed well in the microscale of compost pile.

Pathways to sustainable transitions in a complex agricultural system: a case study of swine waste management in North Carolina

North Carolina has a high density of swine farms with nearly half of the commercial operations located in two eastern counties. Lagoon and sprayfield (LS) is the dominant method of swine manure management despite pressure to transition to environmentally superior technologies. LS is an efficient and cost-effective method of waste management but has negatively impacted the environment and local communities from both discreet events (breeches, flooding) and ongoing issues (odor, disease vectors). The Multilevel Perspective Theory (MLP) is a frame for understanding the relationships between a sociotechnical regime, its surrounding landscape, and emerging niches for sustainable technology development to help align these different levels of perspective and support transitioning toward more sustainable practices. Here, a farm level is added to represent the user perspective of regime technology in complex agriculture systems (MLP + F). We demonstrate how change may influence the North Carolina swine waste management (NC SWM) system through alternative scenarios applied to a conceptual model developed with the MLP + F frame in a methodology for analyzing complex agricultural systems with input from a diverse panel of experts. This case study demonstrates how the methodology can be applied through two NC SWM model scenarios analyzed with fuzzy cognitive mapping techniques. The first scenario explores whether panel recommended changes generate a shift toward sustainable manure management. Inference results suggest that experts have a broad understanding of how these goals may be achieved, but strategies are needed to enhance the specificity of proposed changes. Testing scenarios with more targeted interventions within specific subsystems could provide greater guidance with regard to policy, economic factors, farm practices, or societal demands. The second scenario considers the systemic effect of introducing a manure dewatering process on swine operations, with and without landscape support. Results from this scenario indicate that the more landscape support is engaged, the greater the impact on desirable outcomes. However, contradictions emerged between different versions of this scenario such as increased negative public perceptions despite positive community outcomes. This may require further investigation to tease out potential misalignment between perceptions of a complex system and actual system behaviors.

Waste Sludge: Entirely Waste or a Sustainable Source of Biocrude? A Review.

Biomass-derived biocrude is gaining greater recognition from people in general as an alternative fuel source to traditional fossil fuels. Worldwide, a great deal of research is being done to develop fuels made from sustainable biomass in order to replace the current conventional energy sources. Waste sludge has been thought of as a viable raw biomass source because of its accessibility, affordability, high lignin content, and higher heating value. Additionally, considering sludge contains a high proportion of moisture and water acts as a catalyst during the hydrothermal liquefaction (HTL) process, it is the best choice for thermochemical conversion. From the ultimate component value ranges obtained from elemental analysis, it can be demonstrated that the C, H, and higher heating value (HHV) of petrocrude are approximately 8.78%, 23.5%, and 10.66% higher than those of biofuel. According to the overall analysis, co-liquefaction of waste vegetable oil and swine manure can result in 87.97% bio-oil at 340°C. The temperature, retention period, inclusion of catalysts, and use of solvents, however, can all affect this proportion. To support this illustration, it has been assessed from the study that municipal wet sewage sludge can produce an HHV of 28.52MJ/kg when water is used as the solvent. However, 34.14MJ/kg, or 16.5% more than the previous one, can be produced for the same amount of biomass, when the mixture of water and methanol serves as the solvents. This review article highlights an array of waste sludge categories, their chemical properties, and their conversion through the HTL process. It also features a Van Krevlen diagram with a graphical representation of essential operating parameters. This review research illustrates one of the best strategies for producing biofuel in which waste sludge can be used as raw material through the HTL conversion process, considering the prospective mass commercial production of biocrude oil.

Chemical looping with oxygen uncoupling of swine manure for energy production with reduction of greenhouse gas emissions

The thermochemical conversion of swine manure using chemical looping processes is an alternative for obtaining bioenergy with CO2 capture and solving environmental problems related to excess nutrients and greenhouse gas emissions. In this study, the combustion of swine manure was performed in a chemical looping with oxygen uncoupling (CLOU) unit at the 0.5 kWth scale with copper-based oxygen carrier particles supported on magnetic MnFe spinel. The effects of the fluidisation agent (CO2 or steam), air excess (7%–23%), and temperature (800–950 °C) on different parameters, namely the CO2 capture rate, combustion efficiency, and nitrogenous compound emissions, were analysed. High combustion efficiencies (95%–98%) were achieved, and tar compounds were not detected in the flue gases. Similarly, elevated CO2 capture efficiency values (82%–99%) were also achieved, which increased by increasing the temperature. Most nitrogen (ca. 93%–96%) is converted into innocuous N2. The NO concentration increased with temperature, whereas N2O and NH3 concentrations decreased.