A review of the environmental pollution originating from the piggery industry and of the available mitigation technologies: towards the simultaneous biofiltration of swine slurry and methaneThis article is one of a selection of papers published in this Special Issue on Biological Air Treatment.

In Canada, the piggery industry is an essential part of the agricultural sector, but the main waste product of this industry, swine slurry, is particularly harmful to the environment. The anaerobic storage conditions and the excessive use of slurry for agricultural fertilization contribute, respectively, to the emission of greenhouse gases and to aquatic pollution. This paper provides a review of these environmental concerns and of the existing mitigation technologies. Water pollution from swine slurry is associated with the nutrients it contains, such as nitrogen and phosphorous, while the main greenhouse gases produced by the piggery industry are methane and nitrous oxide. Available technologies can valorize the slurry through agricultural fertilization, reduce greenhouse gas emissions, by limiting nutrient availability for example, or treat the effluents using solid – liquid separation, flaring or biological processes. Specific attention is paid to biofiltration due to its potential to simultaneously treat these two types of pollution.

BACKGROUND: The piggery industry is important both worldwide and in Canada, but localized production of large quantities of swine slurry causes severe environmental problems such as aquatic pollution and greenhouse gas emissions. The main objective of this study was to determine whether it is possible to simultaneously treat methane (CH4) and swine slurry using an inorganic biofilter.RESULTS: A novel biofilter was designed to overcome the inhibition of CH4 biodegradation by swine slurry. The CH4 elimination capacity increased with the inlet load and a maximum value of 18.8 ± 1.0 g m−3 h−1 was obtained at an inlet load of 46.7 ± 0.9 g m−3 h−1 and a CH4 concentration of 3.3 g m−3. Four pure strains of fungi were used in an attempt to improve the removal of CH4, but no significant effect was observed. Between 0.35 and 3.4 g m−3, the CH4 concentration had no effect on swine slurry treatment with removal efficiencies of 67 ± 10% for organic carbon and 70 ± 7% for ammonium. The influence of the slurry supply was analyzed and the best results were obtained with a supply method of six doses of 50 mL per day.CONCLUSION: Even though the results were lower than those obtained for the biofiltration of CH4 alone, this study demonstrated the feasibility of treating CH4 and swine slurry with the same biofilter using a novel design. Copyright © 2012 Society of Chemical Industry

Anaerobic digestion, solid-liquid separation, and drying of dairy manure: Measuring constituents and modeling emission

Swine production in temperate and tropical environments: W.G. Pond and J.H. Maner. Freeman, San Francisco, Calif., 1974, 646 pp., US $ 17.50

Simple SummaryMinimizing the effects of climate change by reducing GHG emissions is crucial and can be accomplished by truly understanding the carbon footprint phenomenon. This study aims to improve the understanding of carbon footprint alteration due to agricultural management and fertility practices. It provides a detailed review of carbon footprint management under the impacts of environmental factors, land use, and agricultural practices. The results show that healthy soils have numerous benefits for the general public and especially farmers. These benefits include being stable and resilient, resistant to erosion, easily workable in cultivated systems, good habitat for soil micro-organisms, fertile and good structure, large carbon sinks, and hence lower carbon footprint. Intensive tillage is harmful to soil structure by oxidizing carbon and causing GHG emissions. If possible, no-till; if not, minimum tillage frequency and depth of tillage, and optimum moisture are recommended. The soil should be at an appropriate level of moisture when tillage takes place. Diverse cropping systems are better for the soil than monocultures. Minimizing machinery operations can help to avoid soil compaction. Building soil organic carbon in the most stable form is the most efficient practice of sustainable crop production.Global attention to climate change issues, especially air temperature changes, has drastically increased over the last half-century. Along with population growth, greater surface temperature, and higher greenhouse gas (GHG) emissions, there are growing concerns for ecosystem sustainability and other human existence on earth. The contribution of agriculture to GHG emissions indicates a level of 18% of total GHGs, mainly from carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Thus, minimizing the effects of climate change by reducing GHG emissions is crucial and can be accomplished by truly understanding the carbon footprint (CF) phenomenon. Therefore, the purposes of this study were to improve understanding of CF alteration due to agricultural management and fertility practices. CF is a popular concept in agro-environmental sciences due to its role in the environmental impact assessments related to alternative solutions and global climate change. Soil moisture content, soil temperature, porosity, and water-filled pore space are some of the soil properties directly related to GHG emissions. These properties raise the role of soil structure and soil health in the CF approach. These properties and GHG emissions are also affected by different land-use changes, soil types, and agricultural management practices. Soil management practices globally have the potential to alter atmospheric GHG emissions. Therefore, the relations between photosynthesis and GHG emissions as impacted by agricultural management practices, especially focusing on soil and related systems, must be considered. We conclude that environmental factors, land use, and agricultural practices should be considered in the management of CF when maximizing crop productivity.

Livestock operations deploy increasingly complex facilities and technologies in manure management to reduce negative environmental impacts and to improve the agronomic value of manures. To capture and quantify processes of degradation, conversion and emission of manure constituents in these complex systems, this study presented a newly developed modular manure management (FarmM3) model. Using this model, we simulated flows and losses of manure organic matter (OM), carbon (C), nitrogen (N), phosphorus (P) and potassium (K) from manure management chains (MMCs) with deep litter, anaerobic lagoon, solid-liquid separation (SLS), anaerobic digestion (AD), and combinations of SLS and AD. The sensitivity of degradation and losses of manure constituents to changes in the configuration and parameters of MMCs was assessed. Results showed the MMCs with deep litter and AD led to higher OM degradation, C losses and greenhouse gas (GHG) emissions due to the substantial amounts of straw added to bedding and the digester. A trade-off between GHG and ammonia emissions was identified in the MMCs with deep litter. Application of SLS could reduce GHG emissions by 40% to 60% due to reduced methane and nitrous oxide emissions from separated liquid fraction storage. A stronger reduction of ammonia emission was observed when applying SLS to digested slurry than to raw slurry. Sensitivity analysis showed that the N loss was most sensitive to N transformation in the MMC with deep litter, and was most affected by the loss coefficients of ammonia during liquid manure storage and application in MMCs with SLS and AD. Losses of P and K from MMCs with SLS were influenced by separation efficiencies from SLS and loss coefficients from solid fraction storage. The impact of model input parameters on GHG emissions highly depended on the selected manure management facilities. This study shows that manure management facilities have a strong influence on the fate of manure constituents. The FarmM3 model can be used to quantify the degradation and losses of different manure constituents in complex MMCs and the effects of manure treatment facilities, and to identify the most important parameters determining these losses.

Towards greenhouse gases mitigation for liquid pig slurry management with solid-liquid separation technologies.

Identifying novel flocculants to improve the separation efficiency of dairy slurries is important to facilitate slurry recycling with a low carbon footprint. Two microcosm experiments were conducted to differentiate ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) emissions from liquid and solid fractions obtained using conventional (mechanical separator) and enhanced (flocculant + mechanical separator) solid–liquid separation (SLS) methods during the storage and soil application phases. Tannic acid (TA) was investigated as a potential flocculant in order to explore its effectiveness in reducing greenhouse gas (GHG) emissions during the storage and soil phases. Compared to the conventional SLS method, the employment of the enhanced SLS method reduced GHG emissions during the storage and soil application phases by 53.64% and 31.63%, respectively, thereby leading to an integrative mitigation of GHG emissions across the storage and soil application chain; however, it strongly increased NH3 emissions by 70.96% during the soil application phase, demonstrating a higher risk of gaseous N loss. Meanwhile, large trade-offs in N2O, CH4, and NH3 emissions between the solid and liquid fractions during the storage phase were observed, and the reduced CH4 and NH3 emissions during the storage phase were also partly offset by increased emissions during the soil application phase. In conclusion, enhanced separation technology using tannic acid as a flocculant can reduce GHG emissions from the management chain, with synergistic mitigation of CH4 and N2O, but the risk of increased NH3 emissions requires further attention. This study may be helpful in mitigating GHG emissions and recycling plant-derived tannic acid in the circular agriculture context.

#36915 D37 – the green footprint of regional anesthesia

Parameterization, calibration and validation of the DNDC model for carbon dioxide, nitrous oxide and maize crop performance estimation in East Africa

Agricultural practices such as repeated fertilization impact carbon (C), nitrogen (N) and phosphorus (P) cycling and their relationships in the plant–soil continuum, which could have important implications for the magnitude of greenhouse gas emissions. However, little is known about the effect of C and N additions under contrasting soil P availability status on nitrous oxide (N2O) and carbon dioxide (CO2) emissions. In this study, we conducted a field-based experiment that investigated the impact of long-term (23 years) P management (no (P0, 0 kg P ha−1), low (P15, 15 kg P ha−1) and high (P45, 45 kg P ha−1) P inputs) on N2O and CO2 emissions following two C + N application events in two managed grassland ecosystems with loam and sandy loam soils. The magnitude of fluxes varied between the soil P availability levels. Cumulative N2O emission was significantly higher in P0 soils (1.08 ± 0.09 g N2O-N m−2) than P45 soils (0.63 ± 0.03 g N2O-N m−2), with the loam soil (1.04 ± 0.04 g N2O-N m−2) producing significantly higher emissions than the sandy loam soil (0.88 ± 0.05 g N2O-N m−2). We conclude that P-limitation stimulates N2O emissions, whereas P-enrichment promotes soil respiration in these temperate grassland sites. Our findings inform effective nutrient management strategies underpinning optimized use of N and P inputs to agricultural soils as mitigation measures for both food security and reducing greenhouse gas emissions.

Climate Change and Health: Strengthening the Evidence Base for Policy

The contribution of agriculture to the emission of the main greenhouse gases, CO2, N2O, and CH4, is estimated to be between 25 and more than 50% of the total emissions worldwide. These data indicate that in developed, industrialized countries, severe policies might be successful in strongly reducing greenhouse gas emissions by focusing on agriculture. However, despite its central importance, agriculture is not at the center of political debate or meaningful emission-reducing policies. In this scientific review, current knowledge of the factors affecting the emission of greenhouse gases, including carbon dioxide, nitrous oxide, and methane, from agriculture is critically discussed. The pathways through which the reduction in greenhouse gas emissions from agriculture can be achieved are evaluated. For this purpose, we list the main factors contributing to the emission of greenhouse gases from agriculture and evaluate the roles of agricultural intensification, industrialization, and organic farming in greenhouse gas emissions. If the present trajectory of agricultural development continues, industrialized, intensive conventional agriculture will become an increasing source of greenhouse gas emissions worldwide. Also, the increasing quantitative relevance of energy plants in agriculture will contribute to increasing greenhouse gas emissions. Organic agriculture may offer an alternative means to reduce greenhouse gas emissions by applying the following central boundary conditions: a. the omission of mineral nitrogen fertilizers produced by the Haber–Bosch process, b. the combination of crop and livestock production, and c. the application of nutrient recycling at a regional level. This kind of organic agriculture may combine relatively high and sustainable crop yields with low emissions of greenhouse gases. Industrialized agriculture, whether in its conventional or even its industrialized organic form, is an important source of greenhouse gases with increasing emissions worldwide. Under conditions of agricultural industrialization, industrialized organic agriculture will also contribute to increasing greenhouse gas emissions. At present, there are no political attempts in the countries of the industrialized Western hemisphere to address agriculture-related contributions to greenhouse gas emissions.

How do greenhouse gas emissions vary with biofertilizer type and soil temperature and moisture in a tropical grassland?

Better information on greenhouse gas (GHG) emissions and mitigation potential in the agricultural sector is necessary to manage these emissions and identify responses that are consistent with the food security and economic development priorities of countries. Critical activity data (what crops or livestock are managed in what way) are poor or lacking for many agricultural systems, especially in developing countries. In addition, the currently available methods for quantifying emissions and mitigation are often too expensive or complex or not sufficiently user friendly for widespread use.The purpose of this focus issue is to capture the state of the art in quantifying greenhouse gases from agricultural systems, with the goal of better understanding our current capabilities and near-term potential for improvement, with particular attention to quantification issues relevant to smallholders in developing countries. This work is timely in light of international discussions and negotiations around how agriculture should be included in efforts to reduce and adapt to climate change impacts, and considering that significant climate financing to developing countries in post-2012 agreements may be linked to their increased ability to identify and report GHG emissions (Murphy et al 2010, CCAFS 2011, FAO 2011).