Slurry Storage Research Articles

A whole-farm assessment of the efficacy of slurry acidification in reducing ammonia emissions

Livestock slurry in animal houses, in manure stores and applied on fields is in Denmark the most important source of ammonia (NH 3) in the atmosphere. The emitted NH 3 is a source of NH 3 and ammonium (NH 4 +) deposition, which causes eutrophication of N-deficient ecosystems and may form NH 4 +-based particles in the air, which are a risk to health. This study examines the reductions in NH 3 emissions from pig houses, manure stores and manure applied in the field achieved by acidifying the slurry in-house. Sulphuric acid was used to acidify pig slurry to pH < 6 and the system was constructed is such a way as to prevent foaming in the animal house as well as during storage. Acidification of the pig slurry reduced the NH 3 emission from pig houses by 70% compared with standard techniques. Acidification reduced NH 3 emission from stored slurry to less than 10% of the emission from untreated slurry, and the NH 3 emission from applied slurry was reduced by 67%. The mineral fertilizer equivalent (MFE) of acidified slurry was 43% higher compared with the MFE of untreated slurry when applied to the soil. The odour emission from the slurry was not affected significantly by the treatment. The slurry acidification system is approved Best Available Technology (BAT) in Denmark.

Esterqueiras: avaliação físico-química e microbiológica do dejeto suíno armazenado

Este trabalho avaliou a eficácia do armazenamento de dejetos de suínos por 120 dias, em três esterqueiras de propriedades suinícolas localizadas na bacia do lajeado Suruvi, município de Concórdia, região oeste de Santa Catarina. Os parâmetros analisados foram: decomposição do material carbonáceo, transformação de compostos nitrogenados, adsorção do fósforo e viabilidade de microrganismos patogênicos. Os resultados revelaram que: a) as maiores remoções de material carbonáceo ocorrem entre 30 e 60 dias de armazenamento; b) o ambiente anaeróbio das esterqueiras impossibilitou as remoções de nitrogênio amoniacal por nitrificação/desnitrificação; c) embora as remoções de ortofosfato na fase líquida do dejeto tenham sido significativas, a estocagem por longo período parece favorecer a migração desse elemento para a fase sólida do resíduo, e d) ao longo dos 120 dias de armazenagem, não foi possível reduzir o NMP médio de coliformes (CF e CT), porém os valores remanescentes ainda são elevados, fato que dificulta a disposição do material.

Ammonia emissions from farmyard manure heaps and slurry stores—Effect of environmental conditions and measuring methods

Ammonia (NH3) emissions were measured from pig and cattle slurry storage by means of the funnel technique on the slurry surface and floating wind tunnels. Emissions from farmyard manure (FYM) heaps were quantified by the large open dynamic chamber technique. The trials on slurry stores were carried out in all four seasons whereas those on FYM heaps were carried out in cold temperature conditions only. Emissions from cattle slurry ranged from 1 to 1.6 g [NH3] m−2 day−1 with slurry temperatures of 4.7 and 24.3 °C, respectively, whereas emissions from pig slurry ranged from 0.8 to 2.5 g m−2 day−1 with slurry temperatures of 6.0 and 25.5 °C, respectively. FYM heaps showed average emissions of 3.4 g[NH3] m−2 day−1, with losses ranging from approximately 4.4% to 7.4% of the total Kjeldahl nitrogen (TKN) content. Emissions of ammonia from animal waste storage correlated with slurry temperature and were dependent on the measuring method used. Results obtained by the wind tunnel were considered to be the most representative of losses under real environmental conditions and could be used for an investigation of the national inventory.

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.

Persistence of Shiga toxin-producing Escherichia coli O26 in cow slurry

The main objective of this study was to evaluate the growth and survival of Shiga toxin-producing Escherichia coli (STEC) O26 in cow slurry; this serogroup is regarded as an important cause of STEC-associated diseases. Four STEC were examined by polymerase chain reaction (PCR) to determine whether they harbour key virulence determinants and also by pulsed-field gel electrophoresis (PFGE) to obtain overview fingerprints of their genomes. They were transformed with the pGFPuv plasmid and were separately inoculated at a level of 10(6) CFU ml(-1) in 15 l of cow slurry. All STEC O26 strains could be detected for at least 3 months in cow slurry without any genetic changes. The moisture content of the slurry decreased over time to reach a final value of 75% while the pH increased from 8.5 to 9.5 units during the last 50 days. STEC O26 strains were able to survive in cow slurry for an extended period. Long-term storage of waste slurry should be required to reduce the pathogen load and to limit environmental contamination by STEC O26.

Confirmation of mineral formation in slurry storage

Confirmation of mineral formation in slurry storage

Storage Stability of Ceramic Slurries for Gelcasting

In the industrialization of gelcasting, storage of ceramic slurry has been one of the key problems that must be solved. Except for sedimentation of ceramics particle, solidification properties of slurries were also affected after long-term storage. In this article, some factors in the process of slurry were discussed, and corresponding solution methods were put forward.

Methane and carbon dioxide emissions and nitrogen turnover during liquid manure storage

Animal slurry stored in-house and outside is a significant source of atmospheric methane (CH4). The CH4 source strength of stored slurry is greatly affected by temperature. To improve emission calculations on a global scale there is a need for knowledge about the relationship between production of CH4 in slurry and temperature. In this study, the filling of slurry channels was reproduced in the laboratory by gradually filling 1 m-high PVC vessels during 9 days followed by incubation for 100–200 days. A preliminary test showed that little CH4 was produced from animal slurry during 10 days of incubation at 20°C, if no inoculum (slurry incubated anaerobically at the test temperature for 1.5–2 months) was present. However, the addition of 7.6% inoculum supported an immediate production of CH4. Vessels amended with inoculum and gradually filled with cattle or pig slurry were then incubated at 10, 15 and 20°C. Methane production from stored pig and cattle slurry was not significant at temperatures below 15°C, where CO2 was the main product of decomposition processes. In contrast, the anaerobic production of CH4 was high and significant relative to the production of CO2 at 20°C. Peak emissions of CH4 averaging 0.012 and 0.02 g C h−1 kg−1 volatile solids (VS) were reached within about 10 days at 10 and 15°C, respectively. At 20°C, the emission of CH4 from pig slurry was about 0.01 g C h−1 kg−1 for 10 days, and thereafter emissions increased to about 0.10 g C h−1 kg−1 VS. For cattle slurry a peak emission of 0.08 g C h−1 kg−1 VS was measured after 180 days. Degradation of organic nitrogen (N) in cattle slurry was related to the reduction of organic material as reflected in CO2 and CH4 emission. The mineralization of organic N during storage represented 10–80% of organic N in cattle slurry, and 40–80% of the organic N in pig slurry.

The dissipation and transport of veterinary antibiotics in a sandy loam soil

The environmental fate of the antibiotics sulfachloropyridazine and oxytetracycline was investigated in a sandy loam soil. Liquid pig manure was fortified with the compounds and then applied to soil plots to investigate leaching, dissipation and surface run-off under field conditions. Additionally, as the macrolide antibiotic tylosin had been administered to the pigs from which the slurry had been sourced, this was also analysed for in the samples collected. Sulfachloropyridazine dissipated rapidly with DT 50 and DT 90 values of 3.5 and 18.9 days but oxytetracycline was more persistent with DT 50 and DT 90 values of 21.7 and 98.3 days. Both sulfachloropyridazine and oxytetracyline were detected in surface run-off samples at maximum concentrations of 25.9 and 0.9 μg/l respectively but only sulfachloropyridazine was detected in soil water samples at a maximum concentration of 0.78 μg/l at 40 cm depth 20 days after treatment. Tylosin was not detected in any soil or water samples. The results indicated that tylosin, when applied in slurry, posed very little risk of accumulating in soil or contaminating ground or surface water. However, tylosin may pose a risk if used to treat animals on pasture and risks arising from transformation products of tylosin, formed during slurry storage, cannot be ruled out. Oxytetracycline posed a very low risk of ground or surface water contamination but had the potential to persist in soils and sulfachloropyridazine posed a moderate risk of contaminating ground or surface water but had low potential to accumulate in soils. These findings were consistent with the sorption and persistence characteristics of the compounds and support a number of broad-scale monitoring studies that have measured these antibiotic classes in the environment.

Evaluation of Three Storage Systems Used for Chilling and Holding Swordfish

ABSTRACT Swordfish are kept chilled, not frozen, for up to 15 days before being unloaded at Australian ports. Swordfish landed alive, and to a lesser extent prerigor, have better quality when unloaded. Warmer fishing waters did not lead to poorer quality at unloading. There was a serious loss of quality during long fishing trips. Sex had no influence on swordfish quality. Three methods of chilling were evaluated: refrigerated seawater (RSW) chilling for up to 2 days followed by storage under ice, refrigerated brine (seawater with extra salt added) for up to 2 days followed by storage in a freshwater ice slurry, and ice slurry (freshwater ice mixed with seawater) for up to 2 days followed by storage under ice only. Two fishing trips were monitored for each method. The freshness indicator K value was used to determine which method produced the best quality swordfish when unloaded at the factory. Storage method played a larger role in quality loss than capture conditions. Refrigerated brine produced the best quality swordfish when the machinery functioned properly closely followed by RSW. Ice slurry chilling of large fish such as swordfish exhibited initial delays in the reduction of core temperature which led to lower quality. This method could be improved with the addition of mechanical circulation. Mechanical problems, which resulted in minor increases of temperature during brine storage, led to a much larger loss of quality than would be expected.

Potential Ammonia Emissions from Straw Bedding, Slurry Pit and Concrete Floors in a Group-housing System for Sows

To assess the contribution of straw bedding, concrete floors, slats, and slurry in the pits to ammonia emission in a straw-bedded group-housing system for sows, the ammonia volatilisation response of urination on the potential emitting surfaces from a sow house was studied under laboratory conditions. Ammonia is mainly produced by hydrolysis of the urea in the urine: a process that depends on the characteristics of the surface of the emitting area. For the study, substrate samples were obtained from the surfaces of a concrete floor in the walking alley (A), slurry pits under the drinking area and the waiting area (D and W) and from the straw bedding (S1, S2, S3). The latter represented straw with respectively a small (S1), an average (S2) and a high (S3) content of slurry dropped by the sows. The controls were a sample of slurry from a reference conventional housing system with sows kept individually on partly slatted floors (R), and a sample of unsoiled fresh straw from the farm depot (S0). After sprinkling 150 ml of urine on each sample, the ammonia volatilisation (E in mg), maximum volatilisation rate (rmax in mg/h) and time of occurrence of the maximum volatilisation rate (tmax in h) were measured during 7 days. Paired comparisons of the predicted means were based on standard error of differences (SEDs, probability P 0·05) and most from the slurry from the reference system (1686 mg, P 0·05). The highest volatilisation rate occurred from the concrete floor in the walking alley (17·5 mg/h, P>0·05). The volatilisation rate peaked soonest with heavily soiled straw, slurry in the pit under the waiting and drinking area, concrete floor and slurry from the reference system, and latest from unsoiled straw (P>0·05). The results reveal that in a sow house with straw bedding, the largest source of ammonia emission is a urine puddle on the concrete floor in the walking alley, and the smallest is a urination on straw, irrespective of the slurry content of the straw. Only at high slurry contents in the straw bedding does the rate at which ammonia is produced from urea increase. The implication is that straw bedding in a group-housing system for sows decreases the ammonia emission per m2 after a urination; however, its effect on other gaseous emissions remains to be clarified.

Influence of different methods of covering slurry stores on greenhouse gas and ammonia emissions

Slurry storage contributes considerably to NH 3 and GHG emissions. Different methods of covering slurry stores may influence NH 3 and GHG emissions. Emissions were analysed for five scenarios: storage of untreated dairy cattle slurry (1) with and (2) without a wooden cover; anaerobically digested dairy cattle slurry (3) without any cover, (4) with a layer of chopped straw, and (5) with a layer of chopped straw and a wooden cover. Experiments were carried out under cold winter and warm summer conditions. Anaerobic digestion was found to be an effective mitigation option for GHG emissions from slurry stores. A wooden lid placed on the slurry tank reduced CH 4 and NH 3 emissions, whereas NH 3 emissions from uncovered anaerobically digested slurry were high. A layer of chopped straw was less effective in reducing NH 3 emissions and has the potential to increase GHG emissions. It is recommended that slurry tanks, particularly those used for storage of slurry treated in biogas plants, be equipped with a solid cover.

A low cost solution for ammonia emission abatement from slurry storage

A Leca® balls layer was evaluated for its ability to reduce losses of ammonia from the liquid surface of stored swine manure. An uncovered slurry tank partly embedded in the ground was divided into two halves by a plastic sheet. A 10 cm thick Leca® balls layer was applied to the surface of one half of the slurry tank. Ammonia emission was measured by means of the funnel technique floating on the slurry surface. Ammonia emitted from the Leca® balls covered and uncovered slurry, respectively, was measured simultaneously over time periods of 24 h for 6 consecutive days. Measurements were repeated in each of the four seasons during 1 year. Ammonia emission from the uncovered slurry ranged between 0.98 and 2.68 gNH 3/m 2, whereas from the surface covered with Leca® between 0.25 and 0.35 gNH 3/m 2 were emitted. Results pointed out a significant reduction of ammonia emission (up to 87%) due to the Leca® balls layer, what showed the persistency of this strategy for the whole time period of the trial. A first economic evaluation showed that Leca® results in an increase in slurry management costs of up to 4 Eurocent/m 2.

Gaseous emissions (NH 3, N 2O, CH 4, CO 2) during pig slurry biological aerobic treatment and treatment by-product storages

Field measurements of ammonia (NH 3), nitrous oxide (N 2O), methane (CH 4) and carbon dioxide (CO 2) were made from raw pig slurry storage, from different biological aerobic treatments and from stores holding the treated products. Biological treatments consisted of intermittent aeration by (i) submerged ejector aerator, (ii) surface aerator and (iii) fine-bubble diffuser. Emissions were measured from the solid separated fraction of raw slurry and from whole-aerated slurry and from supernatant and sludge following sedimentation. Measurements of gaseous emissions were made under field conditions using the dynamic chamber technique for all liquids (raw slurry, reactors and treatment by-products) and by enclosing the heap of solid separated fraction in a large polytunnel with air drawn up by a fan. The results showed that the emissions of CH 4, CO 2 and NH 3 were greater for the non-aerated effluents (raw slurry and separated solid fraction) which have a higher ammonium and organic matter level than for treatment by-products. N 2O was only detected above the biological reactor and the concentration was low (< 1% of the total nitrogen entering the treatment plant).

Greenhouse gas mitigation by covers on livestock slurry tanks and lagoons?

Liquid manure (slurry) storage facilities are important point sources of atmospheric pollution. Being point sources, containment of gaseous emissions via improved storage conditions may be possible, and permeable surface covers (natural crusts and artificial covers) are increasingly recognized for their capacity to reduce various gaseous emissions. Microbial transformations in permeable surface covers include bacterial methane oxidation, but this interface between nitrogen-rich slurry and the atmosphere is also an environment with intense nitrogen turnover than can lead to nitrous oxide emissions. Both methane and nitrous oxide are greenhouse gases, and strategies to reduce environmental impact of slurry stores must consider the total greenhouse gas balance. In this paper, greenhouse gas mitigation options for manure storages are discussed with reference mainly to practical storage conditions in Europe and North America.

Salmonella enterica level in French pig farms effluents: Experimental and field data

Abstract The study aimed to (1) validate the mini-MSRV-MPN method to quantify Salmonella enterica in pig slurry, (2) estimate the effect and interaction on temperature, time and initial Salmonella load on the survival of the 2 strains of Salmonella typhimurium (PF 1690 and DT104 100/706/037) during slurry storage and (3) identify Salmonella contaminated finishing pig batches and assess the level of contamination of their slurry. The mini-MSRV-MPN method was compared to direct isolations on brilliant green agar supplemented with rifampicin to quantify Salmonella in pig slurry. Doelhert uniform shell design was used to study the effect of different parameters on the survival of the 2 strains of Salmonella in pig slurry. Environmental samples of faecal material and a sample of the slurry of 50 batches of finishing pigs were analysed by bacteriological classical method to identify Salmonella. Quantification was performed on pools of faeces and in slurry using the mini-MSRV-MPN technique. This method proved to be suited to quantify Salmonella in pig slurry. Temperature, time of slurry storage and their interaction influenced Salmonella decrease. 12 batches of pigs tested Salmonella positive. Quantification was possible in 5 batches of faecal samples (2.4–350 MPN g− 1 of Salmonella). Quantification was achieved in 2 out of 6 positive samples of slurry (1.6 and 110 MPN mL− 1 of Salmonella).

Emissions of Ammonia, Hydrogen Sulfide, and Odor before, during, and after Slurry Removal from a Deep-Pit Swine Finisher

It is a common practice in the midwestern United States to raise swine in buildings with under-floor slurry storage systems designed to store manure for up to one year. These so-called “deep-pit” systems are a concentrated source for the emissions of ammonia (NH3), hydrogen sulfide (H2S), and odors. As part of a larger six-state research effort (U.S. Department of Agriculture-Initiative for Future Agriculture and Food Systems Project, “Aerial Pollutant Emissions from Confined Animal Buildings”), real-time NH3 and H2S with incremental odor emission data were collected for two annual slurry removal events. For this study, two 1000-head deep-pit swine finishing facilities in central Iowa were monitored with one-year storage of slurry maintained in a 2.4 m-deep concrete pit (or holding tank) below the animal-occupied zone. Results show that the H2S emission, measured during four independent slurry removal events over two years, increased by an average of 61.9 times relative to the before-removal H2S emission levels. This increase persisted during the agitation process of the slurry that on average occurred over an 8-hr time period. At the conclusion of slurry agitation, the H2S emission decreased by an average of 10.4 times the before-removal emission level. NH3 emission during agitation increased by an average of 4.6 times the before-removal emission level and increased by an average of 1.5 times the before-removal emission level after slurry removal was completed. Odor emission increased by a factor of 3.4 times the before-removal odor emission level and decreased after the slurry-removal event by a factor of 5.6 times the before-removal emission level. The results indicate that maintaining an adequate barn ventilation rate regardless of animal comfort demand is essential to keeping gas levels inside the barn below hazardous levels.

Dynamics of a Pig Slurry Microbial Community during Anaerobic Storage and Management

The microbial community of a pig slurry on a farm was monitored for 6 months using both molecular and cultural approaches. Sampling was carried out at all the different stages of effluent handling, from the rearing build-up to slurry spreading. Total DNA of each sample was extracted and analyzed by PCR-single-strand conformation polymorphism (SSCP) analysis using primers targeting the 16S rRNA genes from the archaeal and bacterial domains and also the Eubacterium-Clostridium, Bacillus-Streptococcus-Lactobacillus, and Bacteroides-Prevotella groups. A comparison of the SSCP profiles showed that there were rapid changes in the dominant bacterial community during the first 2 weeks of anaerobic storage and that the community was relatively stable thereafter. Several bacterial populations, identified as populations closely related to uncultured Clostridium and Porphyromonas and to Lactobacillus and Streptococcus cultured species commonly isolated from pig feces, remained present and dominant from the rearing build-up to the time of spreading. Enumeration of fecal indicators (enterococci and Escherichia coli) performed in parallel using cultural methods revealed the same trends. On the other hand, the archaeal community adapted slowly during pig slurry storage, and its diversity increased. A shift between two hydrogenotrophic methanogenic Methanobrevibacter populations from the storage pit to the pond was observed. Microorganisms present in pig slurry at the time of spreading could not be detected in soil after spreading by either molecular or cultural techniques, probably because of the detection limit inherent in the two techniques.

Dichtheitskontrollen mit Augenmaß

Existing regulations for constructing slurry storage and manure removal facilities strive to reflect state of the art methods of preventing environmental damage and realising them in newly built facilities. What should be done with containers and collecting units, which were built in former times, before current construction standards were set?

Microbial pollution of soil around slurry storage lagoons at a pig-farm

Hygienic evaluation of the microbial pollution of the soil in a pig-farm at distances of 1.0 m and 30.0 m around the slurry storage lagoons, based on the number of cultivable microorganisms (NCM—log CFU/g slurry/soil) and the number of Escherichia coli (NEc—log CFU/g slurry/soil) was performed in the present study. The results from the investigation demonstrated: - NCM and NEc varied widely, with clear differences between the various elements of the “fresh slurry–stored slurry–soil at 1.0 m from the lagoons and soil at 30.0 m from the lagoon” chain; - NCM in stored slurry was higher than that in fresh slurry. Further, it significantly decreased in soil at a distance of 1.0 m and further decreased in soil 30.0 m from the lagoons when compared to the NCM of the previous element in the chain; - NCM in stored pig slurry and in soil around lagoons correlated very well with air temperature and rainfalls, which allowed developing of regression equations for estimation of the microbial activity. Temperature was the factor with the higher impact in regulation of microbial contamination compared to rainfalls. - NEc in soil at 30.0 m from lagoons decreased 32.4 times over fresh slurry, 11.7 times over stored slurry and 3.0 times over soil at 1.0 m from lagoons, i.e. increasing of the distance from lagoons, led to reducing the NEc in the soil. - The slurry obtained from clinically healthy pigs and stored in lagoons was a potential source of soil pollution with saprophytic microorganisms and coliform bacteria, subject to sanitary control.