Search Results (22)

The temporal dynamics of nitrogen (N) fractions and ammonia (NH₃) volatilization were investigated over a 56-day storage period using a laboratory-scale pig slurry pit simulator. A detailed N mass balance, encompassing total N (TN), total ammonium N (TAN), organic N, and nitrate N (NO₃⁻-N) fractions, yielded a N mass recovery of 96.5%, despite uncertainties associated with discrete emission measurements, with a TN reduction of 28.3 g vessel⁻¹ closely matched by cumulative NH₃-N emissions of 27.3 g. The NH₃ emission profile exhibited a distinct two-phase pattern. During Phase I (days 1–28), emissions remained stable at 16.7–19.5 g m⁻² d⁻¹, accounting for approximately 58% of total cumulative NH₃-N loss (518.6 g m⁻²), consistent with zero-order kinetics. Phase II (days 29–56) was characterized by first-order exponential decay (k = 0.0293 d⁻¹, R² = 0.982), coinciding with progressive TAN depletion. Measured emission rates were strongly correlated with theoretical free ammonia N (FAN) concentrations derived from pH and temperature (R² = 0.74), confirming that theoretical FAN provides a useful upper bound for emission potential, although the actual gaseous flux is restricted by mass-transfer limitations at the slurry–air interface. These results demonstrate that continuous pH and temperature monitoring provides a practical basis for tracking emission dynamics and informing the timing of mitigation interventions, particularly during the high-flux initial storage phase. Full article

The large-scale use of compost in arable cropping systems is often limited by the large quantities required to meet the crop’s nutritional needs. Palletization can increase the nutrient density of organic fertilizers and improve their logistical feasibility by reducing storage, transport and application costs. This study evaluated the agronomic and environmental performance of compost pellets derived from pig slurry solids and olive pomace, using them as an alternative nitrogen source for wheat (Triticum aestivum L.) cultivated under Mediterranean conditions. A field experiment was conducted during the 2022–2023 growing season, with four treatments arranged in 24 m² replicated plots: an unfertilized control (C); pelletized compost (PSCOP); fresh pig slurry (PS); and mineral fertilization based on monoammonium phosphate and urea (IN). Excluding the control treatment, all fertilized plots received a uniform nitrogen rate of 150 kg N ha⁻¹. Soil chemical properties and nutrient availability (Pext, NH₄⁺-N and NO₃⁻-N) were evaluated at the beginning and end of the experiment, while wheat yield and grain quality were assessed at harvest. Greenhouse gas (GHG) emissions were monitored throughout the cropping season to evaluate environmental impacts. The results showed that the wheat yields achieved with PSCOP were comparable to those obtained with PS, although they remained lower than those achieved with mineral fertilization. Grain quality was not adversely affected by the application of PSCOP. Furthermore, PSCOP resulted in lower GHG emissions than mineral fertilization, with values closer to those observed in the unfertilized control. These findings suggest that pelletized organic fertilizers such as PSCOP may be a promising way to enhance nutrient circularity and reduce reliance on synthetic fertilizers and maintain crop productivity and limit environmental impact in Mediterranean agricultural systems. Full article

Anaerobic digestion (AD) is a proven and promising technology for recovering energy from biowastes, such as pig slurry (PS) from the fattening/finishing phase. The mechanisms of AD are widely studied, and nowadays, it is of the utmost importance to investigate strategies that give end-users the confidence to choose this technology and to adapt it to their reality, promoting the energy transition and circular economy. This study investigated how collection and storage period affect PS samples, and how hydraulic retention time (HRT) (15 versus 20 days) influences AD performance and stability. Seasonality was the primary factor influencing feedstock characteristics. Samples presented no significant differences during the storage period. A 20-day HRT led to higher digestate pH, total ammonia nitrogen (TAN), and free ammonia nitrogen (FAN) concentrations, which can cause process instability and methanogenesis inhibition. However, 20-day HRT led to a specific methane production that was 7% higher and to a methane quality (expressed in % v/v CH₄) that was 6% higher than 15-day HRT. Overall, methane quality, digestate pH, TAN, and FAN values may be considered key points that need to be monitored to prevent the AD system from being compromised. Nevertheless, these results provide the operational freedom to choose either HRT, allowing reduced reactor volume and investment. Full article

Intensive pig production generates significant emissions of ammonia (NH₃) and methane (CH₄), gases with both environmental and health impacts, primarily originating from slurry storage lagoons and their management. This study monitored a maternity pig farm over a 360 day period, using sensors located next to the slurry storage lagoon (Sensor 4) and in the immediate external surroundings of the facility, while simultaneously recording environmental variables (temperature, relative humidity, wind, and precipitation). The results showed that concentrations at the lagoon were thousands to tens of thousands of times higher than those measured in the surrounding area, with temperature and relative humidity emerging as key factors that increase volatilization and microbial generation, especially in summer under medium humidity conditions. Precipitation and wind modulate concentrations through resuspension and dispersion processes. Overall, the slurry storage lagoon constitutes the primary hotspot of emissions, and proper sensor placement is essential to accurately estimate its real impact, while integrating climatic and spatial conditions is crucial for designing and implementing effective mitigation strategies in intensive pig production systems. Full article

This study evaluated a simplified precision feeding (PF) strategy on pig fattening farms to assess its effects on economic performance and pollutant emissions. PF in pig production can reduce nitrogen (N) intake, excretion, and slurry-related environmental impacts, yet its implementation is difficult due to the need for daily diet adjustments to match pigs’ changing requirements. This work tested a simplified PF approach: two commercial feeds, a nutrient-rich pre-grower and a nutrient-poor finisher, were blended weekly based on the lysine needs of two groups of pigs, defined by initial body weight. During the fattening period, blend feeding (BF) sustained growth and feed intake at levels comparable to those with conventional three-phase feeding, but heavy pigs under BF showed reduced feed efficiency. Nitrogen excretion and slurry ammonia (NH₃) emissions did not differ significantly, but BF increased methane and carbon dioxide emissions in the slurry from heavy pigs. The results show that simplified PF can provide economic benefits without compromising performance, but BF formulation should also address potential NH₃ and greenhouse gas emissions during slurry storage. The integration of artificial intelligence-driven tools for real-time diet adjustments at the farm level would be of great interest to enhance sustainability and efficiency, because the economic benefits of PF application were evident. Full article

Spain has been the largest pork producer in the EU in recent years, leading to significant pig slurry (PS) production that requires proper management to prevent environmental impacts. The objectives of this study were to quantify greenhouse gas (GHG) and ammonia emissions and to characterize the PS in storage pond systems. A straw cover pond (SP) and addition of effective microorganisms (EMs) in a biological pond (BP) were used to treat the slurries. During two periods (autumn and spring), PS was characterized and GHG (CO₂, CH₄, N₂O) and NH₃ emissions were measured with a dynamic chamber. After 5 weeks of storage, BP achieved a reduction of 96% for CO₂, 98% for CH₄ and 59% for NH₃ compared to the control pond (CP) in spring, while SP presented a 74% reduction for CO₂ in autumn, and 60% and 97% reductions for CH₄ and NH₃, respectively, in spring. Additionally, the PS samples showed a decreasing trend for EC, dry matter, COD, BOD₅, total N, NH₄⁺-N, Org.-N, NO₃⁻-N, and PO₄³⁻ during both seasons. This preliminary study shows promise in reducing GHG/NH₃ emissions and improving PS properties, but further replication is recommended. Varying straw cover thickness, optimizing EM dose, and a pH reduction may enhance outcomes. Full article

This study delves into the innovative application of a novel bacterial and enzyme mixture alone or combined with aeration in mitigating emissions from pig slurry storage and explores their impacts on the methane (CH₄), carbon dioxide (CO₂), and ammonia (NH₃) emissions from stored pig slurry. A dynamic chamber was used in this research to assess the efficacy of the treatments. Biological additives (HIPO-PURÍN) of specific microbial strains were tested (a mixture ofof Bacillus subtilis, Bacillus megaterium, Bacillus licheniformis, Bacillus amyloliquefacien, and Bacillus thuringiensis) alone and combined with an aeration system (OXI-FUCH). Controlled experiments simulated storage conditions, where emissions of ammonia, methane, and carbon dioxide were measured. By analyzing the results statistically, the treatment with HIPO-PURÍN demonstrated a significant reduction in CH₄ emissions by 67% and CO₂ emissions by 60% with the use of biological additives, which was increased to 99% and 87%, respectively, when combined with OXI-FUCH aeration, compared to untreated slurry. Ammonia emissions were substantially reduced by 90% with biological additives alone and by 76% when combined with aeration. The study was driven by the need to develop sustainable solutions for livestock waste management, particularly in reducing emissions from pig slurry. It introduces techniques that significantly lower greenhouse gases, aligning with circular economy goals and setting a new standard for sustainable agriculture. Furthermore, there is a need to validate that farmers can independently manage pig slurry using simple and effective treatments techniques with profound environmental benefits, encouraging broader adoption of climate-conscious practices. Full article

The efficient management of slurry, which is a by-product rich in nutrients derived from feces, urine, cleaning water, and animal waste that stands out for its high concentration of nutrients such as nitrogen, phosphorus, and potassium, is of vital importance, highlighting the importance of slurry management in storage ponds, which. The Murcia–Spain region has an important number of pig farms. Hence, infrastructures dedicated to managing by-products are necessary to prevent environmental pollution and eutrophication of groundwater. The aim of a recent study was to evaluate the relationship between electrical values and geochemical parameters of pig slurry stored in a pond using ERT and geochemical analysis. In addition, the study was designed to monitor the pond to determine the geochemical characteristics of the slurry and to assess the risk of lateral contamination. The study results indicate a noticeable decrease in electrical resistivity values at 0.4 and 1.6 m depth in surveys 1 and 2. The reduction ranges from 50 to 100 percent. This paper presents a new method for monitoring slurry ponds using electrical resistivity tomography. This non-invasive method provides detailed information on the distribution and characteristics of the fluids, as well as a clear picture of the electrical resistivity of the subsurface. Full article

This study addresses the challenge of mitigating ammonia and greenhouse gas (GHG) emissions from stored pig slurry using chemical and biological additives. The research employs dynamic chambers to evaluate the effectiveness of these additives. Chemical agents (sulfuric acid) and biological additives (DAB bacteria) containing specific microbial strains are tested (a mixture of Rhodopseudomonas palustris, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, Nitrosomona europea, Nictobacter winogradaskyi, and nutritional substrate). Controlled experiments simulate storage conditions and measure emissions of ammonia, methane, and carbon dioxide. Through statistical analysis of the results, this study evaluates the additives’ impact on emission reduction. Sulfuric acid demonstrated a reduction of 92% in CH₄, 99% in CO₂, and 99% in NH₃ emissions. In contrast, the biological additives showed a lesser impact on CH₄, with an 8% reduction, but more substantial reductions of 71% for CO₂ and 77% for NH₃.These results shed light on the feasibility of employing these additives to mitigate environmental impacts in pig slurry management and contribute to sustainable livestock practices by proposing strategies to reduce the ecological consequences of intensive animal farming. Full article

The present study investigated the impact of peat moss as a feed additive on the emission of methane (CH₄) and carbon dioxide (CO₂) from piggery slurry stored in slurry pits. There is no well-known study on the relationship between pig manure generated after feeding peat moss as a feed additive and CH₄ and CO₂ released during the storage period. A lab-scale experiment was conducted for two months using a slurry pit simulator composed of six vessels—three for pig slurry collected after feeding 3.0% peat moss as a feed additive (PFS) and three for pig slurry without feeding peat moss (CTL). PFS reduced CO₂ and CH₄ emissions (p < 0.05) from stored pig slurry by approximately 23% and 44%, respectively. PFS exhibits substantially elevated concentrations of humic substance (HS) such as humic acid, fulvic acid, and humin compared with CTL, with fold differences of 2.3, 1.8, and 1.1, respectively. Elevated HS levels in the PFS seemed to limit hydrolysis, resulting in lower total volatile fatty acid concentrations compared with CTL. A dominance of CH₄ in total carbon emissions was observed (p < 0.05), with CH₄ accounting for approximately 93% and 95% of total carbon emissions in PFS and CTL, respectively. PFS had a roughly 43% lower impact on cumulative carbon emissions than CTL, primarily due to decreased CH₄ emissions. These findings suggest that PFS may be a promising approach for mitigating carbon emissions and potentially impacting environmental sustainability and climate change mitigation efforts. Full article

Assessing the phosphorus (P) balance in agricultural soils is crucial for optimizing its use and reducing contamination risks. The objective of this study was to evaluate the impact of different animal wastes on the distribution of P in soil profiles subjected to 12 years of successive applications of animal wastes and mineral phosphate fertilizer, within a crop rotation system under no-till system. The study was conducted from 2004 to 2016 in the southern region of Brazil. The treatments were the applications of pig slurry (PS), cattle slurry (CS), pig deep-litter (PD), mineral fertilizer (MF), and a control treatment without application. The highest accumulation of P and its movement was observed in the 0–40 cm layer, in the soil submitted to applications of all P sources. The inputs of P via MF, CS, PS, and PD promoted the accumulation of 18, 42, 48, and 100 kg P ha⁻¹ year⁻¹. The P mass balance showed that between 77 and 98% of the P added by animal manure and MF was accounted for in grain exports (17–34%), soil storage (41–72%), and post-harvest residues (<1%), with the remaining 2–33%, unaccounted for, which was attributed, especially, to P transfer at the soil surface. Full article

Slurry storage is a significant source of NH₃ and greenhouse gas (GHG) emissions. The aim of this laboratory study was to assess the effects of different chemical additives and biochars on the emissions of NH₃, N₂O, CO₂, and CH₄ during the short-term storage of pig slurry. The experiment was performed using Kilner jars filled with raw slurry as control and six treatment additives (5% w/w): acidified slurry, alkalinized slurry, neutralized slurry, agroforestry biochar, cardoon biochar, and elderberry biochar. The gas emissions were measured for 30 days, and the composition of the slurries was determined. During short-term storage, the results of this laboratory study indicated that the NH₃ emissions were reduced by 58% by acidification and by 20% by the biochars (Agroforestry, Cardoon, and Elderberry treatments), while neutralization reduced this loss by only 12%. Nitrous oxide emissions were not reduced by the chemical additives (Acidified, Alkalinized, and Neutralized treatments), while this loss was increased by 12% by the biochars. Carbon dioxide, CH₄, and global warming potential emissions were not affected by the chemical additives and biochars. Furthermore, the absence of differences between the biochars may be related to their similar composition. Regarding the influence of the studied additives on NH₃ losses, it can be concluded that acidification was the best mitigation measure and the biochars were quite similar due to their composition. Furthermore, neutralization had the advantage of sanitizing the slurry, but only had a mild impact on NH₃ preservation. Full article

Livestock production contributes to releasing methane into the atmosphere. Liquid manure management offers significant opportunities to reduce these emissions. A better understanding of the factors controlling methane emissions from manure is necessary to select effective mitigation strategies. Our study aimed to identify the influence of storage temperature and the associated change in chemical composition on methane emissions from dairy and fattening pig manure. Storage temperature affects microbial activity and induces changes in chemical composition that are key influences in methane emissions. Dairy and fattening pig manure samples were stored at five different temperatures (5–25 °C) for 90 days in a laboratory-scale experiment to measure the methane production. The chemical composition of the slurry samples was analyzed, and the biochemical methane potential (BMP) tests were performed before and after storage. For pig manure stored at 25 °C and 20 °C, methane emissions accounted for 69.3% and 50.3% of the BMP, respectively. Maximum methane emissions for dairy slurry were observed at 25 °C but remained at a low level. Analyses of the accumulation of volatile fatty acids (VFAs) during storage are presented in few studies, this work revealed a potential inhibition of methane production, where the accumulation of VFAs was most elevated in samples stored at 20 °C and 25 °C. This partly counteracted the increase in methane emissions expected from the higher temperatures. The degree of VFA and dissociated fatty acids accumulation in dairy cattle slurry should be assessed for more accurate estimations of methane emissions from slurry stores. Full article

In Spain, livestock farming is a significant activity area that generates substantial revenues and essential jobs. However, the actual impact that this intensive activity might have on the environment is not entirely understood. Moreover, coastal aquifers are subjected to a significant environmental pressure due to nearby growing population, intensive agriculture, and livestock farming. In this work, three representative pig slurry ponds, under semiarid conditions, were studied using different techniques to evaluate the subsurface conditions in terms of pH, electrical conductivity, salts, and nitrate content. The electrical resistivity tomography (ERT) technique was employed in this study, which provides electrical resistivity values from the subsurface materials and fluids. These electrical resistivity values were compared to data obtained from geochemical analyses to derive their relationships and establish the pig slurry-affected subsurface area. Thus, ERT-based lower electrical resistivity values were associated with higher salts concentrations and nitrate content. ERT values indicated a near-surface affected by slurry infiltration that coincided with the increase of geochemical values obtained from sample analyses. Additionally, Spearman’s correlation was used to evaluate the correlation between electrical resistivity data and the physical-chemical properties of soil. The most important pollutant accumulation mainly occurs in the two-meter depth. Therefore, the risk of slurry ponds affecting deep aquifers is limited in the studied area. Finally, this study proves a complete, affordable, and scalable methodology application to livestock residue storage facilities. Full article

The pig farm sector has been developing rapidly over recent decades, leading to an increase in the production of slurry and associated environmental impacts. Breeding farms require the maintenance of adequate indoor thermal environments, resulting in high energy demands that are frequently met by fossil fuels and electricity. Farm heating systems and the storage of slurry constitute considerable sources of polluting gases. There is thus a need to highlight the advantages that new green heating solutions can offer to reduce the global environmental impact of pig farming. This research presents an overview of alternative pig farm slurry technology, using geothermal heat pumps, which reduces the harmful effects of slurry and improves the energy behavior of farms. The results reflect the environmental benefits of this solution in terms of reducing carbon and hydric footprints. Reducing the temperature of slurry with the geothermal heat pump of the system also reduces the annual amount of greenhouse gases and ammonia emissions, and, via the heat pump, slurry heat is used for installation heating. Annual emissions of CO₂e could be reduced by more than half, and ammonia emissions could also experience a significant reduction if the slurry technology is installed. Additional advantages confirm the positive impact that the expansion of this renewable technology could have on the global pig farm sector. Full article