Assessment of airborne bacteria and fungi in pig buildings in Korea

Posted in: Environment by admin on January 1, 2008 | No Comments

Inhalation of biological contaminants in a pig building can be detrimental to a farm worker’s health through effects such as infection, allergy or toxicosis. The principal aim of this field study was to determine the concentrations and emissions of biological contaminants, i.e. airborne bacteria and fungi, in the different types of pig buildings in Korea to allow an objective comparison with the other countries in terms of pig housing types. Pig buildings in this research were selected using three criteria such as manure removal system, ventilation mode and the growth stage of the pigs. Measurements of the concentration and emission of total airborne bacteria and fungi in the pig buildings were performed in 5 housing types and on 15 farms. The concentrations of total airborne bacteria and fungi in the pig buildings were averaged to 4.13 log(cfum-3) and 3.14 log (cfum-3), respectively, and ranged from 1.16 to 10.26 log(cfum-3) and from 0.48 to 6.86 log(cfum-3), respectively. The mean emissions of total airborne bacteria and fungi per pig (75 kg in terms of liveweight) and area (m2) from pig buildings were 0.98 log(cfu h-1 pig-1) and 0.73 log(cfu h-1 pig-1) and 1.32 log(cfu h-1 m-2)
and 0.96 log(cfu h-1 m-2), respectively. The pig buildings with a deep-litter bed system showed the highest emissions of total airborne bacteria and fungi (p<0.05). However, the emissions of total airborne bacteria and fungi from the other pig buildings were not significantly different. This study showed that the mean concentrations of total airborne bacteria and fungi in pig buildings situated in Korea were generally lower than those in other countries. The mean emissions of total airborne bacteria and fungi in the pig buildings showed little differences between Korea and other countries. It was concluded that the concentrations and emissions of total airborne bacteria and fungi were relatively higher in the pig buildings which are managed with deep-litter bed systems and those ventilated naturally than other pig housing types.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/15375110

The Impact of Swine Lagoon Seepage on Shallow Groundwater Quality: Groundwater Remediation through Lagoon Closure and Pumping

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An earlier study tested an unlined swine lagoon and detected elevated mineral nitrogen concentrations 38 m down gradient from the lagoon. The current study conducted hydrologic and water quality monitoring of the site from March 1999 to September 2004, a period during which the lagoon went from being semi-active to completely closed out. It was found that the average hydraulic gradient decreased from 0.0033 m m‐1, prior to the activation of a groundwater pumping system (Mar. 1999 to Jan. 2000) to 0.0010m m‐1 after pumping was initiated (Sept. 2000 to Sept. 2004). Also, the average hydraulic gradient was reduced by 70%. Since the installation of the pumping system, approximately 17,900 m3 of subsurface water has been pumped, removing 1200 kg of TN from the groundwater plume. TAN concentrations steadily declined from 120 mg L‐1 at the onset of pumping in September 2000 to less than 6 mg L‐1 by September 2004.

Sulphate and sulphide corrosion in livestock buildings, Part I: Concrete deterioration

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Reinforced concrete for the manure storage of a farm operation is often exposed to aggressive environmental conditions. Temporary storage of liquid manure underneath barn floors produces corrosive agents generated from aerobic and anaerobic fermentation, causing premature corrosion of reinforcement steel and degradation of the concrete. The rehabilitation of reinforced concrete structures due to corrosion of steel-reinforcing bars is quite expensive compared with the use of more resistant concrete at the time of construction, as it is generally accepted that the quality of the concrete cover that protects the reinforcement is critical in limiting corrosion damage. For Canadian climatic conditions, storage of manure for a period of 6 months, or even longer, is generally recommended, and in some provinces legislated, so that manure spreading can be avoided during winter. Before the manure can be removed from storage it usually has to be agitated, which causes the concentration of the various corrosive gases to increase drastically. Methane and carbon dioxide concentrations increased to a level 2–3 times higher than the level before mixing took place. Hydrogen sulphide concentration increased by a factor of 100–1000, whereas the NH3 concentration was 2–5 times lower. Of these, hydrogen sulphide is the most corrosive agent that leads to the rapid deterioration of concrete floors in barns. It is suspected that the relative humidity of the air, the concentration of various gases and vapours above liquid manure pits and the continuous wetting of concrete floor slats are all contributing factors (Svennerstedt et al., 1999). As a consequence of the concrete degradation, slatted floors have deteriorated, in some instances to the point of requiring replacement in less than 5 years. In order to improve the durability of concrete and the environmental protection under such severe agricultural aggressive conditions, some recent investigations have been carried out in an attempt to find ways to reduce the rate of deterioration by changing the concrete composition (Jiang, 2002; De Belie et al., 1997; Idriss, 2000). The overall objective of this study is to provide the technology to design and construct defences against reinforced concrete deterioration so that manure handling and storage structures will be able to withstand the corrosive environment created by the manure, and last a reasonable service life (25–30 years). In the present study 48 concrete cylindrical specimens, 100mmin diameter and 100mm in height, with a reinforcing steel bar in the centre were exposed to hydrogen sulphide gas and sulphate solution, some for more than 3 years. One half of the specimens was partially immersed in sodium sulphate (20,000ppm) and also subjected to hydrogen sulphide gas (1,000ppm). The second set was subjected to hydrogen sulphide gas only. Each set consisted of 8 different treatments including Portland cement (PC) concrete with 0.4 and 0.5W/CM ratios, PC concrete with 8% silica fume replacement, 25% fly ash and 35% slag of the total amount of cementing material and specimens made of PC concrete with combinations of silica fume and fly ash (6%, 25%), and silica fume and slag (6%, 25%). Finally one treatment was carried out with sulphate-resistant cement.

From the results it can be concluded that high-quality concrete with a low W/CM ratio and sulphate-resistant binder-like type 50 Portland cement (SR) is a simple and cost effective method to produce durable reinforced concrete for livestock buildings.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/15375110

Modelling of biological nitrogen removal from the liquid fraction of pig slurry in a sequencing batch reactor

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Biological nitrogen removal through nitrification–denitrification is a treatment alternative that can be considered for scenarios in which there is a nitrogen surplus linked to pig manure management. Studies found in the literature referring to the treatment of the liquid fraction of pig slurry using sequencing batch reactors (SBRs) were reviewed and typified. Mathematical modelling of this treatment was carried out considering: nitrite and pH as state variables; nitrification and denitrification as two-step processes; surface limited kinetics for hydrolysis and dependence for the heterotrophic biomass yield, as well as for the anoxic maximum growth rate, on the electron acceptor. Sensitivity analysis permitted identification of the parameters that had the greatest influence on the response of the model under specific test conditions. These were subsequently assessed, principally using respirometry. Finally, model-based predictions were contrasted with results obtained in a lab-scale SBR following two different operational strategies. The availability
of biodegradable organic substrates for complete denitrification was identified as one of the main limiting factors of the treatment, even when treating raw waste. Low aeration intensity during oxic periods made it possible to mainly conduct the process along the nitrite route and to thereby reduce the organic and oxygen requirements of the process.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/15375110

Geotextile Filtration Performance For Lagoon Sludges and Liquid Animal Manures Dewatering

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A geotextile filtration testing method termed a hanging‐bag test was used to treat dairy lagoon sludge, swine lagoon sludge, liquid dairy manure, and liquid swine manure. Hanging‐bag performance was evaluated by: (1) determining solids and plant nutrient mass retention efficiencies, (2) quantifying the overall volume reduction, and (3) characterizing the dewatered manure or liquid dairy manure, geotextile filtration reduced the total influent volume to less than 1%, concentrated the solids and nutrients in the dewatered material 16 to 21 times greater than the influent, and retained 38.4% of total solids, 25.8% of total ammoniacal nitrogen, and 45.0% of total phosphorous, making this an effective liquid‐solid separation technique.

Emissions of ammonia, methane and nitrous oxide from pig houses and slurry: Effects of rooting material, animal activity and ventilation flow

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Animal houses are an important source of ammonia (NH3), methane (CH4) and nitrous oxide (N2O) gases that can have negative consequences for people, animals and environment. These gases are produced inside the buildings by direct emission from the digestive system of the animals or from the decomposition of the animal wastes. The produced gases are subsequently volatilized, and emitted to the outdoor environment by the ventilation. Many different factors can influence gas formation and volatilization and so, gaseous concentrations and emissions from animal houses. These factors are mainly related to: animals (e.g. genetics, diet, number and weight, animal activity, and behaviour), wastes (e.g. handling, treatment, pH, temperature, and surface area), environment (e.g. indoor and outdoor temperature, ventilation flow, and air velocity over the manure surface) and other site-specific factors. Regarding these site-specific factors, the presence of certain materials inside of pig barns, used either as bedding material or for any other purpose, can have an effect on the emission of gases (Monteny et al., 2006; Sommer et al., 2006). This effect is partly due to the fact that during storage most organic solid materials (including the rooting materials that fall through the slats to the slurry pit in slatted houses) float to the surface of the slurry forming a crust layer. This crust layer can decrease the wind speed over the slurry, resulting in reduced transport by convection, higher levels of gases above the free surface of the slurry, and lower gas escape. It can also contribute to a reduction in pH in the surface of the slurry. Therefore, the objectives of this work were to evaluate the influence of animal activity, indoor, outdoor and slurry temperature, ventilation flow, number of heat production units (hpu, where 1 hpu is equal to 1000 Wof total heat produced by the animals at 20 8C) and time of day (day or night) on NH3, CH4 and N2O emissions, measured in a pig building for fatteners over 37 days. Another objective was to study the effects of the type of rooting material provided to the animals on gaseous emissions, from data collected in two experiments: the 37 days field experiment in the pig building, and a laboratory test carried out with different types of rooting materials added to slurry in enclosed flux chambers, simulating the conditions during storage of slurry. It was concluded that in the pig building, the three parameters that explained most of the variability of ammonia and methane emissions were type of rooting material, animal activity, and ventilation flow. The diurnal variations of ammonia and methane emissions were highly correlated with the diurnal variation of animal activity and ventilation flow, respectively. The change of the rooting material, from maize silage to straw, caused an increase in the averaged ammonia emission from 1.68 to 2.22 g hˉ¹ hpuˉ¹, and a decrease in the averaged methane emission from 3.05 to 1.70 g hˉ¹ hpuˉ¹,. In the laboratory test, ammonia emissions were significantly higher from pig slurry added maize silage (43 mg hˉ¹ mˉ²) than from pig slurry added straw (3.5 mg hˉ¹ mˉ²), while no significant differences were found concerning methane emissions. This work revealed that the use of rooting materials as environmental enrichment for improving the welfare of growing finishing pigs has an effect on ammonia and methane emissions from pig houses. The evaluation of this effect has to be done under normal housing conditions including presence of animals in the barn.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/01678809

Effect of Liquid Swine Manure Rate, Incorporation, and Timing of Rainfall on Phosphorus Loss with Surface Runoff

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This study assessed total runoff P (phosphorus), bioavailable P, and dissolved reactive P concentrations and loads in surface runoff after liquid swine manure application with or without incorporation into soil and different timing of rainfall. It was found that incorporating swine manure when the probability of immediate rainfall is high reduces the risk of P loss in surface runoff ; however, this benefit sharply decreases with time.

For more information the full article can be found at https://www.agronomy.org/publications/jeq

Fecal Indicator Bacteria in Subsurface Drain Water Following Swine Manure Application

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This study focused on the movement of bacteria to receiving tile drains following swine manure application. Specifically, the impacts of different manure application regimes on fecal coliform (FC), Enterococcus (EN), and Escherichia coli (EC) densities in subsurface tile drain water were examined for three years. Results of this study suggest that manure broadcast onto frozen ground may lead to significantly elevated EN and EC levels in tile water in similar environments, especially when applied in excess of crop nutrient requirements.

Solids and nutrients removals from the liquid fraction of swine slurry through screening and flocculation treatment and influence of these processes on anaerobic biodegradability

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Concentrated animals feeding operations (CAFOs) are the objective of many studies since they pose an important environmental risk. The most common practice in farms involves manure flushing and consecutive collection in anaerobic lagoons. The final effluent is usually applied to cropland as fertilizers. However, this practice is becoming a problem because nutrients are spread out constantly in the same area, with the subsequent soil saturation. Some of the negative effects that hog manure causes are gas emissions (which affects animals and humans health), accumulation of heavy metals on soils, groundwater pollution due to leaching as well as contamination of surface water. Therefore an effluent treatment must be implemented before swine waste dischargement. Many techniques used nowadays for treating manure are developed in order to reduce nutrients (biological systems), to generate energy (anaerobic digestion), or to use the manure as solid fertilizer (compostage). In this context, a correct pre-treatment involving the separation of solids from liquid and treating each matrix separately is crucial for the success of the above-mentioned techniques. Mechanical separation and addition of chemicals (coagulants and flocculants) are the common techniques used for the separation of matrices. The inconvenience that mechanical separation exhibits is the impossibility to retain the fine suspended matter that contains the organic nutrients (nitrogen and phosphorus) in swine wastewater (Vanotti and Hunt, 1999). Therefore, many chemicals like ferric chloride and aluminium sulphate (Zhang and Lei, 1998) as inorganic coagulants and polyacrylamides and chitosan as organic polymers have been tested for separation enhancement. Among the organic polymers, polyacrylamides (PAM) have been widely studied during the last years in swine wastes by different authors. The objective of this study was to evaluate the optimal PAM dosage in two different livestock matrices, namely the mixture of hog manure from feeder-to-finish and nursery and from feeder-to finish alone. In order to determine and enhancement on methane productivity, biodegradability assays were carried out using the liquid and solid fraction separately obtained by two different processes; sieving and flocculation followed by sieving. A range of 80–200 ppm of polyacrylamide (PAM) followed by screening was employed in the case of flocculation treatment. The best results were observed when using the highest PAM dose in the matrix correspondent to the mixture of slurries. The removal rates in the liquid fraction were 73% for total solids, 87% for volatile solids, 98% for suspended total and volatile solids, 71% for chemical oxygen demand, 40% for total Kjeldahl nitrogen, and 34% for soluble phosphorus. Once the best PAM dose (120 ppm) was chosen, an anaerobic biodegradability study was performed in order to check the increase of methane production in the separated fractions by using the flocculant and the screen. The assay determined that the solid fractions biodegradability was constant at 79%. Meanwhile for the liquid fractions, an increase of 9% points was achieved with PAM-amendment when compared with 82% reached for the liquid fraction obtained by screening.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/09608524

The Fate of Sulfate in Acidified Pig Slurry during Storage and Following Application to Cropped Soil

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Acidification of slurry with sulfuric acid is a recent agricultural practice that may serve a double purpose: reducing ammonia emission and ensuring crop sulfur sufficiency. In this study they investigated sulfur transformations in untreated and acidified pig slurry stored for up to 11 mo at 2, 10, or 20°C. Furthermore, the fertilizer efficiency of sulfuric acid in acidified slurry was also  investigated.

For more information the full article can be found at https://www.agronomy.org/publications/jeq