Slurry Storage Facilities Research Articles

Estimating methane emissions from manure: a suitable case for treatment?

Abstract Methane from livestock is a significant source of greenhouse gas emissions. Under the UN Framework Convention on Climate Change (UNFCCC), Annex I countries’ National Inventories report emissions from cattle as enteric or from manure management at ratios of between 3:1 and 9:1 depending on country and cattle type. Field research generally supports the inventories’ assumptions about enteric emissions, but these ratios have focused interest on enteric emissions and diverted attention away from those from manure management. Official calculations about manure management emissions factors are more varied than those for enteric emissions and evidence from field measurements suggests inventories may be underestimating manure management emissions especially in the dairy sector. This paper has three objectives. First, it reviews the science underpinning the international framework for estimating methane emissions from manure management. Second, it presents data from two dairy farms in south-west England where measured emissions of methane from slurry storage facilities are found to be four to five times greater than the assumptions in the UK’s inventory. If these measurements were representative of the UK, the implication is that total methane emissions from the UK dairy herd would be over 40% greater than the level reported to the UNFCCC and the proportion of total methane emissions from dairy cows arising from manure management would be almost a half rather than less than a quarter. Finally, the paper assesses the potential value if methane were captured from slurry storage facilities. Its value as a biogas is estimated to be £500 million per year for the UK dairy industry (at forecourt diesel prices). The paper concludes that the scale of emissions and the potential economic value of lost biogas are sufficient to warrant urgent research and action to reduce emissions from manure management with the beneficial prospect that a valuable new income stream for farm businesses could also be realised.

A novel approach to estimate the abatement of ammonia emissions from mitigation techniques at farm-scale slurry stores exemplified by a semifloating cover.

Ammonia (NH3 ) losses from livestock slurry stores substantially contribute to agricultural emissions to the atmosphere. Gas release from slurry storage facilities is driven by interactions between store operations and meteorological conditions. This study quantifies the abating effect of an impermeable semifloating cover as an emission mitigation technique at a farm-scale slurry storage tank. Emissions were measured over 1 yr and compared with the preceding 2 yr of measurements with the uncovered tank. In this novel approach, emission data were aggregated to categories within 1 h measuring intervals according to five key factors influencing emissions (time span after agitation and tank-filling level as surrogates for natural crust occurrence; the meteorological parameters precipitation, air temperature, and wind speed) for the two consecutive measurement campaigns with and without the cover. The emission abatement effect of the cover was determined by emission modeling of the entire measuring campaign based on measuring intervals of the uncovered and the covered tank where the aggregated categories of influencing factors were equal. The resulting average emission abatement was 48%. An average abatement of 37 and 54% was achieved during periods with and without a surface crust, respectively. The emission reduction was less with low tank filling level due to higher air exchange through openings of the cover. The presented approach is applicable to evaluate emission mitigation techniques for single farm-scale stores. With adequate measurement duration, it is appropriate to produce reliable emission data reflecting the complex interactions between emissions and influencing factors occurring at real-world storage facilities.

Composition for rock grouting based on insoluble calcium salts for groundwater protection

Importance to reduce permeability of rocks arises safety of mining operations and protecting the soil and underground water in the area of industrial waste storage with high contents of water-soluble salts. Disadvantage of the existing methods of grouting rocks by soluble salts is either their dissolution with changing of the composition or diluting of the contacting solution. The paper considers the composition of the grouting mixture for the deposition of insoluble calcium salts and its effectiveness in laboratory conditions. The eutonic solution of a four-component KCl–NaCl–CaCl2–H2O system was used as the initial solution, while saturated solutions of sodium sulfate and carbonate, and sulfuric acid were applied as the precipitators. Efficiency of rock grouting was estimated according to the water or solution filtration rate through the rock (sand, sylvinite, and halite) before and after calcium salt crystallization. Laboratory experiments showed that the precipitation of calcium sulfate responds to the challenge of plugging rocks. The paper proposes some recommendations of protective screens at the bed of the salt tailing piles and slurry storage facilities.

Исследование фильтрационных свойств грунтов ограждающих сооружений шламохранилищ с учетом влияния эффекта пристенного скольжения

Установлена эмпирическая закономерность зависимости коэффициентов фильтрации песчаных грунтов от содержания в шламе полиакриламида в концентрации 0,17–0,90 мг/дм3 (эффект пристенного скольжения). Определен коэффициент фильтрации для грунтов ограждающих сооружений шламохранилищ Республики Беларусь с учетом присутствия в фильтрующемся шламе полиакриламида. Подтверждено результатами экспериментальных исследований и натурных наблюдений превышение скорости фильтрации шлама 0,045–0,047 см/с над скоростью фильтрации воды в 1,2–1,4 раза.

Прогнозирование возникновения чрезвычайных ситуаций на грунтовых подпорных сооружениях шламохранилищ

Проведен анализ материалов режимных наблюдений пьезометрического контроля в ограждающих сооружениях тестовых объектов шламохранилищ. В результате обработки данных исследований получены коэффициенты пропорциональности kпр для различных типов дамб, позволяющие при проведении фильтрационных расчетов учитывать наличие в жидкости поверхностно-активных веществ. Установлены причины развития возможных чрезвычайных ситуаций, разработана методика и проведена оценка вероятности возникновения гидродинамических аварий на сооружениях шламохранилищ Республики Беларусь.

Influence of Drainage with High Levels of Water-Soluble Salts on the Environment in the Verhnekamskoe Potash Deposit, Russia

Saline drainage from slurry storage facilities can deteriorate the properties of clay barriers in the beds of embankment dams and slurry ponds and cause saline drainage to infiltrate into groundwater. The chemistry of slurry material, drainage, springs, surface water, and soils was studied near the slurry storage facility of the Verhnekamskoe potash mine (Russia). Our study showed that the Na–Cl type mine drainage water, with high amounts of nitrogen compounds, increased the salinity of the groundwater and surface water, and the river valley ecosystems. As a result of ion exchange and leaching, the soil, groundwater, and surface water have elevated levels of \({\text{C}}{{\text{a}}^{2+}}\), \({\text{M}}{{\text{g}}^{2+}}\), \({\text{SO}}_{4}^{{2 - }},\) and \({\text{F}}{{\text{e}}_{{\text{total}}}}\), and extremely high \({\text{~N}}{{\text{a}}^+}\) and \({\text{C}}{{\text{l}}^ - }{\text{~}}\) values. Iron-rich precipitates and hydrogen sulfide tend to form down-gradient in the saline, water-logged seepage areas.

Dairy Manure Total Solid Levels Impact CH Flux and Abundance of Methanogenic Archaeal Communities.

Stored liquid dairy manures are methane (CH) emission hotspots because of the large amount of slurry volatile solids (VS) converted into CH by methanogens under anaerobic conditions. Our research has indicated that a reduction of total solids (TS) of slurries before storage can reduce CH emissions. In the current study, methanogen abundance was characterized in tanks with different CH emissions. Using mesoscale slurry storage facilities equipped for continuous gaseous emission monitoring, we stored dairy slurries having TS from 9.5 to 0.3% for up to 6 mo. Samples were taken after Day 30 and Day 120 of the storage (20 May-16 Nov. 2010) from the upper and bottom layers of the slurries. Methanogenic communities were studied by targeting the gene encoding the α subunit methyl-coenzyme M reductase (), which catalyzes the final step of methanogenesis. Interestingly, mean abundances of methanogens increased by ∼8 and 23% at the top and bottom sections, respectively, as slurry TS decreased from 9.5 to 0.3%. Cumulative CH emissions, however, decreased by ∼70% as slurry TS decreased from 9.5 to 0.3%. Nevertheless, compared with Day 30 of storage, mean abundances of methanogens were relatively higher at Day 120 (up to 19%), consistent with an increase in the cumulative CH emissions. Polymerase chain reaction denaturing gel electrophoresis analysis indicated a low methanogen diversity, with most bands sequenced closely related to the genus (>95% amino acid sequence similarity), the hydrogenotrophic methanogens. Results suggest that available carbon substrate and not methanogen abundance may be limiting cumulative CH emissions at reduced TS levels of dairy slurries.

Greenhouse gas emissions from swine operations: Evaluation of the Intergovernmental Panel on Climate Change approaches through meta-analysis1

The objective was to provide a systematic review of the literature on greenhouse gas (GHG) emissions from swine operations, with a meta-analysis that integrates results of independent studies. A total of 53 studies that measured GHG emissions from swine operations were included in the analyses. Results showed that the Intergovernmental Panel on Climate Change (IPCC) approaches were effective in estimating the overall CH4 and N2O emission levels from swine operations, but the variation of the measured emissions is not adequately captured. An overestimation by the IPCC approaches for CH4 emissions was observed for swine buildings with pit systems in European studies and the average percentage relative difference (PRD) between the measured and the IPCC values is -21.1%. The observed CH4 emissions from lagoons were lower than the IPCC estimated values and the average PRD is -33.9%. In North American studies the observed N2O emission factors for swine buildings with pit systems were significantly lower than the IPCC default values whereas in European studies they were significantly greater than the IPCC default values. The measured CH4 and N2O emissions were significantly affected by stage of production (P = 0.05 and <0.01, respectively) and geographic regions (P = 0.04 and 0.02, respectively). The IPCC approaches were effective in simulating the effect of temperature on CH4 emissions from outdoor slurry storage facilities whereas they could overestimate CH4 emissions from lagoons at low temperatures. The CH4 emissions from pits inside swine buildings were not significantly affected by average ambient temperatures. A positive relationship between diet CP content and CH4 emissions was confirmed in the meta-analysis. The obtained knowledge can be helpful in efforts to improve estimation of GHG emissions from swine operations.

Farmer perspectives and practices regarding water pollution control programmes in Scotland

Nitrate Vulnerable Zones (NVZ) were introduced in response to the Nitrates Directive (91/676/EEC) which states that all EU countries must reduce the nitrate in drinking water to a maximum of 50 mg/l. Farmers within a designated NVZ must adhere to strict rules over the timing and application of nitrogen from organic and inorganic sources. In Scotland, four NVZ regions were designated in 2003, covering around 14% of the land area and affecting over 12,000 farmers. This paper outlines the results of a recent study to understand farmer activities in response to and attitudes towards NVZ regulations in Scotland. A telephone survey was administered, obtaining a response of 184 farmers, supplemented by four workshops held in each NVZ region. This explored, both quantitatively and qualitatively, farmer behaviour and attitudes. The bulk of farmers have made little capital investment since the 2003 designation. Few farmers have invested in increased slurry storage facilities, nor begun to transport more slurry off-farm, claiming to have had enough storage capacity before designation to cover the imposed closed period. Farmer attitudes indicate a mostly negative view towards the perceived environmental benefits, water management and compliance. This can be explained by a number of concerns raised by farmers towards the scientific basis for designations. Furthermore, farmers viewed the restrictions placed on farming practices within NVZs as too inflexible. Given the mostly sceptical perceptions demonstrated by the farmers we call for a more integrated approach to water management at the catchment level. There is a role for policy-makers to provide clearer information over the science and purpose of the designations and also to invest in the transfer of technologies, in particular N-use software which is specifically tailored to NVZ regulations. Also, critical to this would be the development of transparent indicators of water quality. This may start to embed nitrogen pollution impacts within the farmer's cultural framework of decision-making.

Natural crusting of slurry storage as an abatement measure for ammonia emissions on dairy farms

Research on the incidence and effectiveness of natural crusting on slurry storage as a means of ammonia emission abatement was undertaken in studies at farm-scale, pilot-scale and on a small-scale. At the farm-scale, slurry crusting was found to be commonplace across a large proportion (ca 80%) of slurry storage facilities, despite the fact that regular store mixing and agitation was found to be carried out on 68% of farms. Observations provided information on the impact of a range of factors on the potential for crust formation. The most important factors were slurry solids content (crusting increasing with dry matter (DM) content), volume:surface area ratio of the storage (influencing nature of the crust and rate of formation), livestock diet (crusting more likely with grass silage), slurry management (agitation). Of particular importance, were weather conditions with evaporation increasing crusts and rainfall having the opposite effect. From measurements at farm- and pilot-scale (i.e. excluding small-scale comparative studies), mean ammonia emissions were 1.07 and 3.42 g m −2 d −1 NH 3 -N, for crusted and non-crusted slurry stores, respectively. Where direct comparisons between crusted and non-crusted slurry were possible, a reduction in NH 3 emission of about 60% was typical during the measurement period. Although the range in emission measurements was large, the results reported here have confirmed the potential for significant abatement under practical farm conditions. Assuming that natural crusting is as effective in reducing emissions as these results suggest, an objective assessment of crust integrity needs to be developed to assist with effective implementation of mitigation policy. A type of ‘crustometer’ could be developed, at least partly based on the falling weight technique described and tested briefly within the field studies. The work has also identified potential for a modelling approach for the prediction of crust development and, hence, likely emission abatement efficiency.

Identifying Host Sources of Fecal Pollution: Diversity of Escherichia coli in Confined Dairy and Swine Production Systems

Repetitive extragenic palindromic PCR fingerprinting of Escherichia coli is one microbial source tracking approach for identifying the host source origin of fecal pollution in aquatic systems. The construction of robust known-source libraries is expensive and requires an informed sampling strategy. In many types of farming systems, waste is stored for several months before being released into the environment. In this study we analyzed, by means of repetitive extragenic palindromic PCR using the enterobacterial repetitive intergenic consensus primers and comparative analysis using the Bionumerics software, collections of E. coli obtained from a dairy farm and from a swine farm, both of which stored their waste as a slurry in holding tanks. In all fecal samples, obtained from either barns or holding tanks, the diversity of the E. coli populations was underrepresented by collections of 500 isolates. In both the dairy and the swine farms, the diversity of the E. coli community was greater in the manure holding tank than in the barn, when they were sampled on the same date. In both farms, a comparison of stored manure samples collected several months apart suggested that the community composition changed substantially in terms of the detected number, absolute identity, and relative abundance of genotypes. Comparison of E. coli populations obtained from 10 different locations in either holding tank suggested that spatial variability in the E. coli community should be accounted for when sampling. Overall, the diversity in E. coli populations in manure slurry storage facilities is significant and likely is problematic with respect to library construction for microbial source tracking applications.

Slurry Covers to reduce Ammonia Emission and Odour Nuisance

Covering of liquid manure storage facilities causes additional costs. Furthermore, the building of rigid covers such as tent roofs over large slurry lagoons is prohibitively expensive. Therefore, emission reducing effects and floating behaviour of low-cost covers were investigated. Such alternative cover materials are granules, chopped straw and rape oil.Tests took place both in the laboratory and in the field. On-farm studies served to determine emissions from liquid manure surfaces in large slurry storage facilities. Laboratory tests were carried out in transparent Perspex containers on a 65 l scale. The floating behaviour of the covers and the sedimentation of slurry during storage and after homogenization were observed. The ammonia emission was also measured here and sampling for odour measurements and chemical analysis was carried out.Cover materials showed very different behaviour. The granules made a closed cover within a few hours after homogenization, while rape oil rose to the surface only during a period of several days. Chopped straw made a solid floating layer infiltrated with slurry.Laboratory scale and on-farm studies with granules and straw as covers reduced odour emission by about 83–91%. Ammonia emission decreased by about 80–91%. The emission reduction of 85% for a 6 mm rape oil layer was similar to the other covers, but the 3 mm oil layer showed an insufficient effect.

Risk of damage to crops in the direct neighbourhood of ammonia sources

In the Netherlands ammonia is emitted from several thousand sources (animal buildings, manured pastures, slurry storage facilities, etc.). Obviously, the ammonia concentrations are higher close to the source, but at this short distance vegetation has no special value in terms of nature conservation, as it mostly consists of ammonia-resistant agricultural crops. However, three crop categories include relatively sensitive species (fruity culture, glasshouse crops and arboriculture). This paper presents an estimation of the risk of ammonia damage to sensitive crops as related to the distance to the source, based on the mean and variation in emission, dispersion, regional background concentration, landscape characteristics and plant sensitivity. Some attention is paid to damage of natural vegetation and to risk-reducing measures (elevation of emission point, wind fence around the source). The goal is to provide information for regional and local officials and farmers who are dealing with risk evaluation, claims for damages, and environmental policy matters like stable reallocations etc.