Manure Disposal Research Articles

MAY COMPOST LEAD TO INCREASED HORTICULTURAL PRODUCTION ON MIXED FARMS?

In Croatia small mixed farms (arable crop production and animal husbandry) with lack of horticultural production dominate. Besides that, producers have problems with manure disposal considering ecological requirements from EU and CAP. Mostly, farm manure is not disposed in a proper way and often farmers consider it as undesirable by-product. Moreover, production of compost from livestock manure almost does not exist in Croatia. Horticultural production is insufficient for domestic needs regardless convenient agro- ecological conditions. Compost production from stock manure could solve two problems on mixed farms (livestock combined to vegetable production): solving manure disposal problem while use of compost in horticulture could contribute to increased farm income (via compost selling, nursery production or horticultural production). The different models of mixed farms were analyzed from economic point of view: no manure management, only mineral fertilization of vegetables (NM), cattle manure combined with mineral fertilization of vegetables (MV), compost combined with mineral fertilization of vegetables (CV), farm produced compost sold on market, vegetables mineral fertilized (CM). The best economic results were obtained in CV and MV systems mostly due to positive impact of added organic fertilizers on yield what affects economic results as well.

The risk to human health related to disposal of animal wastes to soil — microbiological and parasitical aspects

Abstract The study was conducted to investigate the microbiological and parasitical risk related to the disposal of animal manure to soil by storage of raw pig slurry at temperatures 4 °C, 20 °C and 42 °C for 115 days. Plate counts of Salmonella typhimurium and number of devitalized non-embryonated model Ascaris suum eggs were determined on days 0, 7, 12, 22, 32, 40, 55, 90 and 115 of storage. At the same intervals level of selected physico-chemical parameters were determined. Microbiological examination showed that S. typhimurium survived in the slurry for less than 115 days at 4 °C and less than 90 days at 20 °C and 42 °C. Devitalization of A. suum eggs increased with temperature and time of storage, but complete devitalization was not achieved even after 115 days at 42 °C. Physico-chemical parameters showed changes related to decomposition processes, but did not allow us to draw definite conclusion regarding their influence on devitalization of pathogens. The results indicate potential risk to human food chain that can be prevented by strict observation of legislative provisions and appropriate treatment of animal manure.

Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands

Bork, E. W., Lambert, B. D., Banerjee, S. and Blonski, L. J. 2013. Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands. Can. J. Soil Sci. 93: 369–378. Expansion of intensive livestock operations into semiarid regions lacking cultivated lands requires consideration of perennial forages for the efficient and sustainable disposal of manure. Little information exists on the nutrient dynamics associated with the application of manure to these areas. We examined soil mineral nitrogen (N) responses in four sites of the mixed-grass prairie, including two native grasslands and two introduced pastures, following different seasons (fall vs. spring), methods (dribble broadcast vs. coulter injected) and rates of liquid hog manure application (9.4, 18.8, 37.5, 75 and 150 kg ha−1available N). Soil mineral N, including NO3-N, NH4-N and total mineral N, were assessed after application but prior to plant growth in April 1999, and again one growing season later in April 2000. Initial soil N did not vary with season of application. Soil mineral N predictably increased with application rate, but only in the upper soil profile (0–20 cm). Decreases in soil mineral N after one growing season in all treatments highlighted the ability of these perennial forage lands to immobilize large amounts of soil N, a significant portion of which was related to N uptake by vegetation. Compared with broadcast application, manure injection led to 35% greater soil mineral N (both NO3and NH4) prior to plant growth, a response that persisted 1 yr later (+12%), thus demonstrating the N conserved benefits of manure incorporation. Overall, increases in soil mineral N within these forage lands appeared to be relatively short-term in nature, largely depleting over the course of a single growing season, suggesting one-time liquid hog manure application at low to moderate rates may be sustainable in this region of the mixed-grass prairie.

The potential to reduce poultry nitrogen emissions with specific uricase egg yolk feed grade antibodies

One of the environmental challenges that the poultry industry has faced is manure utilisation and/or disposal. Poultry manure and its nitrogenous compounds can be a potential pollutant causing eutrophication, nitrate or nitrite contamination of water, ammonia volatilisation, and acid deposition in the air. Therefore, reducing nitrogen excretion and emissions in poultry manure is important to maintain a clean environment. Proper nutrition is an important first step to optimise performance and growth in animals as well as to reduce the negative impacts on the environment. Amino acids are components of protein nutrition that greatly influence animal growth. However, excess or insufficient amino acid supplementation in diets increases nitrogen excretion and emissions. One way to reduce this is to prevent uricase activity in the microflora in poultry manure. Egg yolk antibodies are economic alternatives for administering in feed to poultry. Supplementation of feed grade antibodies into poultry diets can be a potential approach to minimise bacterial uricase activity and reduce ammonia emissions from poultry manure. In order to use this dietary strategy effectively, a well-balanced feed formulation and a more practical way of delivering the antibodies in feeds remains to be developed.

DRYING POULTRY MANURE FOR POLLUTION POTENTIAL REDUCTION AND PRODUCTION OF ORGANIC FERTILIZER

Disposal and storage of raw poultry manure has become an environmental problem because of the associated air, water and soil pollution. Poultry manure begins to decompose immediately after excretion giving off ammonia which, in high concentrations, can have adverse eff ects on the health and productivity of birds as wel l as the health of the farm workers. Application to land is the most common way for utilizing poultry manure as a viable source of major plant nutrients and soil conditione r to improve soil tilth and reduce the problems ass ociated with soil compaction. The aim of this study was to inves tigate the effects of drying depth and temperature on the nutritional profile of dried poultry manure and its suitability as a plant fertilizer. Drying temperat ure and manure depth had no significant effects on manure pH, but the loss of ammonia during the drying process decre ased the pH (from 8.4 to 6.4-6.7). Greater nitrogen losses ( 44-55 %) were observed at the deeper manure layer (3 cm) and the higher temperature (60°C) which resulted in a r eduction of N:P:K (from 4.58:1.29:1 to 2.07:1.30:12.57:1.28:1). Drying of poultry manure helped reduc e the presence and offensiveness of odor by 65.3 an d 69.3%, respectively. Drying of poultry manure also achieve d significant reductions in bacteria (65.6-99.8%), yeast and mold (74.1-99.6%) and E. coli (99.97 %). Dried poultry manure can be used as a fertilizer source for p lants because of its high nitrogen, phosphorus and potass ium contents which are essential for plant growth. Other elements (such as calcium, magnesium, sulfur, boron, copper, iron, manganese, molybdenum, cobalt and zinc) which are lacking in commercial fertilizer are also present in manure in significant amounts.

Development of an avian influenza virus inactivation evaluation method using dialysis cassette in animal manure and mortality disposal systems

This study was conducted to evaluate the performance of dialysis cassettes (DCs) as a virus containment vessel during avian influenza (AI) inactivation research in animal mortality disposal systems. During such work viruses must be contained while simultaneously being exposed to process-specific environmental stressors such as pH change, toxic gases, and heat. Although DCs contain porous membranes that permit diffusion of chemicals, virus retention tests showed that DCs retain AI viruses safely inside. Test data also showed very good exchange of hydrogen ions, CH4, and CO2 through the membrane. In the case of hydrogen ion exchange, it took only 24 h to reach equilibrium within DCs and the surrounding buffer solution. In addition, gas concentrations inside all DCs reached values similar to those in the environment surround the DCs after 24 h. Based on these results, DCs are effective tools for evaluating virus inactivation within animal manure and mortality disposal systems.

Dietary and Manure Management Practices on Equine Farms in Two New Jersey Watersheds

Equine farms are increasing in number in Northeast and Mid-Atlantic states. These farms may influence environmental quality owing to manure collection, storage, spreading, and disposal practices. A manure management survey was mailed to 700 New Jersey equine farms during the winter of 2009-2010 (these farms were located in two watersheds). Two hundred forty-two surveys were returned; 10% were training or performance farms, whereas the remainder (90%) were breeding, boarding, or pleasure farms. There were differences between the two watersheds in turnout time, pasture acreage, use of drag harrows, and income. Respondents answered questions about diet and environmental management on farms. Seventy-eight percent had bunk management plans. Forty-seven percent disposed of waste feed in a manure pile, 35% left it on fields or paddocks, and 18% put it in a dumpster. Twenty-six percent engage a professional for feeding advice (21% veterinarians, 2% extension, 3% nutrition consultants). Most respondents did not have a regular feed management plan. Sixty-two percent of all farms spread manure on-farm. Of those who spread, 29% have >8.09 hectares (20 acres) for spreading. Ninety-six percent of respondents stored manure >100 ft from water or wetlands. Comparison of cross-tabulations indicates a strong relationship (P < .01) between rotational grazing and the use of a sacrifice or exercise area. Eighty-eight percent of respondents using sacrifice areas also rotationally graze. Results indicate future outreach programs should focus on feed management, manure storage location, rotational grazing, and the use of sacrifice areas as part of a pasture management program.

Man vs. manure: Examining the effects of residential demand on dairy farming in rural America

Spatial concerns are growing in many rural regions in the United States. Exurban sprawl and residential development can often surge past urban boundaries and encroach on historically rural areas. These emerging “co-existence” problems affect both farms and non-farming rural residents. One area of particular concern has been zoning and land use regulation laws associated with livestock waste handling. In this research, we develop an agent based simulation/case example of a representative county in rural Vermont to illustrate how the proximity of non-farm rural residents (NFRRs) to existing dairy farms in the region can curtail potential farm expansion, primarily through laws governing livestock waste disposal and pit location. The disposal problem is further exacerbated by certain physical land features as many NFRR homes are located on escarpments, as well as other physical features which tend to run diagonally, the latter situation being one that further complicates field manure disposal traffic patterns. Thus, the co-existence issue in dairy farming in much of rural America has an important spatial dimension.

Energy from Agricultural and Animal Farming Residues: Potential at a Local Scale

Animal wastes from high-density farming have severe impacts on the nitrogen cycle. According to current regulations, the disposal of manure on cropland is constrained by nitrogen content in the agricultural soils. On the contrary, anaerobic digestion (AD) of these wastes can produce energy and a digestate, which is easier to handle than manure and can be applied for agronomic uses. When herbaceous crops are co-digested with manure to increase the efficiency of biogas production, the nitrogen content in the digestate further increases, unless these larger plants are equipped with nitrogen stripping technologies. We propose a model to compare larger (cooperative) and smaller (single parcel) AD conversion plants. The whole process is modeled: from the collection of manures, to the cultivation of energy crops, to the disposal of the digestate. The model maximizes the energy produced on the basis of available biomass, road network, local heat demand and local availability of land for digestate disposal. Results are the optimal size and location of the plants, their technology and collection basins. The environmental performances of such plants are also evaluated. The study has been applied to the province of Forlì-Cesena, an Italian district where animal farming is particularly relevant.

Environmental and health impacts of poultry manure disposal methods: a case study of Lagelu and Egbeda local government areas in Oyo State, Nigeria

Indiscriminate disposal of poultry manure has been identified as a major source of environmental degradation in production areas through air and water pollution associated with nitrogen and phosphorus emissions and losses from manure. Methods of disposing of poultry manure which might have negative consequences on the environment and the farmers were investigated in two Local Government Areas of Oyo State, Nigeria. Data collected using structured questionnaires as well as direct field observations from a random sample of 100 farming households showed that the commonly used methods of manure disposal are burning (87 households) and application on crops (9 households). Almost all of the farmers (99) had no proper manure management facilities. Ammonia is the major air pollutant perceived by 71 farmers in the study area. Farmers suffered from discomforts ranging from various combinations of sneezing (65%), eye irritation (38%), coughing (34%), headache (20%), stomach ache (13%) and diarrhoea (6%). The awareness of farmers and authorities needs to be raised regarding the management of poultry manure and the need for protective equipment during its disposal: 99 farmers had no formal training in safe handling and disposal of poultry manure. There should be stricter enforcement of existing environmental regulations and enactment of new legislation to minimize the threats that the farmers’ current practices pose to their health and to the environment.

Nitrogen dynamics in soils cultivated with maize and fertilized with pig slurry

The proper disposal of pig manure is of great importance because, when mishandled, it can contaminate water resources. This study aimed to evaluate the nitrogen dynamics in a Cerrado Oxisol and its absorption, over time, by a maize crop managed with pig slurry associated with mineral fertilization (N P K). The study was conducted at a private farm, in the region of Sete Lagoas, Minas Gerais, Brazil. The maize crop was able to recover 62% of the mineral nitrogen that entered the soil-plant system, while 9% leached as nitrate and, to a lesser amount, as ammonium. The maximum average content of nitrate and ammonium of 92 kg ha -1 and 43 kg ha -1 , respectively, was observed in the 0 to 0.3 m soil layer during the early crop development stage. A minimum content of 5.8 kg ha -1 of nitrate and 9.0 kg ha -1 of ammonium, respectively, was measured at the end of the cycle. In addition, the nitrate content at that soil layer, at the end of the maize cycle, remained below the values measured at the native Cerrado, indicating that the agricultural use of the land poses no additional risk to the nitrate accumulation and leaching into the soil profile.

DRYING OF POULTRY MANURE FOR USE AS ANIMAL FEED

The poultry industry is one of the largest and fastest growing sectors of livestock production in the world. The estimated 2010 world flock was over 18 billion birds with a yearly manure output of 22 million tonnes. Storage and disposal of raw poultry manure have become an environmental problem because of the associated air, water and soil pollution. Environmental and health problems such as odor and pathogens that may arise during and after land application of raw manure can be eliminated by drying. Dried manure can be utilized as a feed for ruminants because of its high nitrogen content. The aim of this study was to investigate the effects of drying temperature and depth, as well as the nutritional profile of dried manure and its suitability as an animal feed. Dried poultry manure contained sufficient levels of digestible energy, crude fiber, crude protein, crude fat, cobalt and iodine. Although dried poultry manure did not meet the dietary requirements for calcium, chloride, magnesium, phosphorus, potassium, sodium, copper, iron, manganese, selenium, sulfur or zinc it could be used as a feed stuff for ruminants after supplementation with the required nutrients. Heated air drying was most efficient at 60°C and at a depth of 3 cm. During drying poultry manure decreased in pH (8.4-6.9), protein content (43 to 39-43%) and amino acid content. The greatest reductions in microbial population occurred at the highest temperature (60°C) and the lowest manure depth (1cm). Reductions in the number of bacteria, mold/yeast and E. coli were 65-99, 74-99 and 99.97% respectively, Salmonellae was not detected in the dried product. Dried poultry manure was found to have a non-offensive odor. Odor intensity and offensiveness were reduced by 65 and 69% respectively during drying. Thin layer heated air drying of poultry manure between 40 and 60°C created a safe and nutritionally appropriate feed for ruminants.

An Innovative Farm Scale Biogas/Composting Facility for a Sustainable Medium Size Dairy Farm

Approach: The amount of energy related costs as a portion of the total farm operating cost can be as high as 29% and the continuing increase of the real cost of energy related farm input has been one of the major factors impacting the cost of agricultural production. However, agricultural has the potential of replacing some of the purchased energy in the form of fossil fuels, commercial fertilizer and field production of animal feed with bioenergy and organic fertilizer from onsite renewable biomass such as animal manure in order to economically and environmentally sustain it. The aim of this study was to develop an innovative energy efficient pilot scale anaerobic digester composting facility. Methodology: A solid/liquid manure separator farm scale anaerobic digester and composting facility for a medium sized dairy farm were designed, constructed and tested. In order to make the anaerobic digestion economically viable under Canadian climatic conditions, the design, installation and operation of the system were based on advantages gained from the digester as a component of the total farm management system. In addition to the biogas production, benefits related to manure handling and storage, environmental quality improvement through odor control and water pollution reduction, fertilizer recovery and water recycling, were considered. Results: The layout of the farm was modified to provide solutions for four environmental problems related to: disposal of milkhouse wastes and overflow from the manure storage facility into the fire pond. The system possesses high energy conversion efficiency at relatively low capital cost and reduced labour requirement and has indirect energy ramifications through the production of organic fertilizer (compost) to replace expensive and energy consuming commercial fertilizer as well as the production of bioenergy (biogas) which will reduce the demand for energy. The overflow from the system (purified water) can be recycled for cleaning the barn, thereby reducing the costs of water use and manure storage facilities on one hand and eliminating pollution problems associated with manure storage and disposal on the other hand. Conclusion: The use of dairy waste as a source of energy and fertilizer resulted in a saving of 6289 kg of fertilizer at a cost of $17 925 annually and additional saving of $20 547 on energy use.

KINETICS OF THIN LAYER DRYING OF POULTRY MANURE

The poultry industry is one of the largest and fastest growing sectors of livestock production in the world. The estimated 2010 world flock was over 18 billion birds with a yearly manure output of 22 million tonnes. Storage and disposal of raw poultry manure has become an environmental problem because of the associated air, water and soil pollution. Environmental and health problems such as odor and pathogens that may arise during and after land application of raw manure can be eliminated by drying. Dried manure can be utilized as a soil conditioner to improve soil tilth and reduce the problems associated with soil compaction and as a feed for ruminants because of its high nitrogen content. The aim of this study was to investigate the kinetics of thin layer drying of poultry manure and evaluate the effects of drying with heated air on the chemical and biological properties of manure. The effects of temperature and depth of manure layer were evaluated. The profile of the moisture content of poultry manure followed an exponential decay curve. The moisture decay constant was affected by the drying temperature and the depth of the manure layer. At the three temperature levels studied, the time required to dry poultry manure in 1 cm-deep layer was the least, followed by 2 and 3 cm-deep layers, respectively. The diffusion coefficient increased with both temperature and depth of drying layer, but did not show a linear increase with either variable. The optimum depth for drying manure (at which the highest drying effectiveness occurred) was 3 cm. Drying manure at 40-60°C resulted in the loss of 44-55% of the total Kjeldahl nitrogen, with losses increasing with both the temperature and depth of manure. The pH of the manure decreased from the initial value of 8.4 before drying to about 6.6 after drying. The odor analysis indicated that dried poultry manure did not have an offensive odor. Drying achieved 65.3 and 69.3% reductions in odor intensity and offensiveness, respectively. Reductions in the number of bacteria, mold/yeast and E.coli were 65-99, 74-99 and 99.97% respectively. The greatest reductions in microbial population occurred at the highest temperatures (60°C) and the thinest manure depths (1 cm). Heated air drying of poultry manure at temperatures between 40 and 60°C was effective in killing pathogens and removing odor.

The role of riparian buffer management in reducing off-site impacts from grazed dairy systems

AbstractAgriculture in general and intensive animal production in particular can degrade the environment, especially as a consequence of the overuse of nutrients. Intensively grazed dairy systems, defined by the presence of foraging animals in the landscape, are often considered a more benign approach to dairy production with perceived smaller impacts due to the reduced requirement for manure disposal. However, grazing dairy cows contribute nutrients and pathogens in excreta, and sediment through landscape deformation. These impacts can dramatically increase in parts of the farm such as feeding, watering and sacrifice areas, laneways and night paddocks where animals are concentrated and spend a disproportionate amount of time. Other practices such as the disposal of dairy shed or dairy factory effluent and cultivation of fodder crops can also pollute the environment. A common approach to reduce nutrient, pathogen and sediment losses from dairy farms is to establish buffer zones in riparian areas that act as an interface between upland land use and waterways. This is generally done by fencing riparian areas to exclude stock and revegetating with understory and overstory species, with the aim of increasing infiltration, trapping sediment and decreasing contaminant losses from upland pastures. However, poorly designed and managed riparian areas may themselves contribute to further environmental degradation. Rarely is an integrated approach, including factors such as animal behavior and dairy farm management practices, as well as an analysis of landscape and riparian hydrology used in developing riparian management recommendations for individual farms. This paper reviews the threats posed by intensively grazed dairy systems, approaches to improve riparian zone management and recommends future research needs.

Efficiency of RO/NF membranes at the removal of veterinary antibiotics

The production of pharmaceuticals has increased rapidly during the last several decades as they have been used for the health of both humans and animals. Routes of environmental exposure include the release of treated wastewater, the land disposal of livestock manures and municipal biosolids (i.e. sewage sludge), as well as the use of medicated aquaculture feed. This study deals with application of reverse osmosis (RO) and nanofiltration (NF) membranes for removing of antibiotic residues (sulfamethoxazole, trimethoprim, ciprofloxacin, dexamethasone and febantel) and their mixture. According to the results obtained in this work the use of RO (LFC-1 and XLE) and the tight NF (NF90) membranes are recommended to achieve a high level of retention (>95%) of all selected veterinary antibiotics (VAs). Nanofiltration NF270, NF and HL membranes showed a lower rejection of individual components, but much higher in a mixture solution, due to the synergistic effect.

Short-term native grassland compositional responses following liquid hog manure application

Bork, E. W. and Blonski, L. J. 2012. Short-term native grassland compositional responses following liquid hog manure application. Can. J. Plant Sci. 92: 55–65. Intensive livestock operations (ILOs) are becoming more common in remote regions of the Canadian prairies in an effort to reduce conflict with other land uses. This has led to ILOs situated where the typical sink for manure application, cultivated land, is not available, leading to growing interest in using native grasslands for manure disposal. Significant opposition exists to this practice, in part due to limited information available on the impact of manure application to native grassland diversity and species composition. We examined plant species composition changes over two growing seasons following varying rates (∼9.5, 19, 38, 75 and 150 kg ha−1 available N), methods (surface broadcast vs. coulter injected) and timing (fall vs. spring) of one-time liquid hog manure (LHM) application. Our results revealed divergent responses between study sites, with metrics of plant diversity declining in mixed prairie but increasing in fescue grassland with increases in manure application rate. Both communities also demonstrated minor changes in plant species composition, primarily in response to LHM rate and manure application method. Responsive plant species included a mix of native grasses and dicots, some of which may be regarded as undesirable (e.g., Artemisia frigida): however, most vegetation responses were temporary and disappeared by the second year. Although invasion of non-native plant species was not observed, suggesting these communities are tolerant of LHM application, changes in the reproductive effort of dominant grasses (negative in Hesperostipa curtiseta; positive in Pascopyrum smithii and Festuca hallii) suggest LHM application could alter long-term grassland composition. Thus, despite exhibiting resilience to one-time LHM application, future use of native grasslands for manure disposal should be done cautiously.

Fate of steroid hormones and endocrine activities in swine manure disposal and treatment facilities

Manure may contain high concern endocrine-disrupting compounds (EDCs) such as steroid hormones, naturally produced by pigs, which are present at μg L −1 levels. Manure may also contain other EDCs such as nonylphenols (NP), polycyclic aromatic hydrocarbons (PAHs) and dioxins. Thus, once manure is applied to the land as soil fertilizer these compounds may reach aquifers and consequently living organisms, inducing abnormal endocrine responses. In France, manure is generally stored in anaerobic tanks prior spreading on land; when nitrogen removal is requested, manure is treated by aerobic processes before spreading. However, little is known about the fate of hormones and multiple endocrine-disrupting activities in such manure disposal and treatment systems. Here, we determined the fate of hormones and diverse endocrine activities during manure storage and treatment by combining chemical analysis and in vitro quantification of estrogen (ER), aryl hydrocarbon (AhR), androgen (AR), pregnane-X (PXR) and peroxysome proliferator-activated γ (PPARγ) receptor-mediated activities. Our results show that manure contains large quantities of hormones and activates ER and AhR, two of the nuclear receptors studied. Most of these endocrine activities were found in the solid fraction of manure and appeared to be induced mainly by hormones and other unidentified pollutants. Hormones, ER and AhR activities found in manure were poorly removed during manure storage but were efficiently removed by aerobic treatment of manure.

Green Electricity from Biomass, Part II: Environmental Impacts Considering Avoided Burdens from Replacing the Conventional Provision of Additional Functions

Environmental impacts of the introduction of electricity generation from biomass are investigated on the basis of data from plants operated in Austria. Different conversion technologies (anaerobic digestion, combustion, gasification) are considered and environmental impacts are analyzed according to ISO 14040 for Life Cycle Assessment. For the impact assessment the CML 2001 base line approach covering 11 impact categories is used. The paper presents the calculation of the avoided environmental burdens from replacing the conventional provision of functions by the additional functions of the biomass system. These additional functions are the provision of heat, nutrients and waste disposal. The conventional provision of heat and the disposal of manure and organic residues show the highest influence on total results. After the consideration of avoided burdens emission-savings are calculated in the impact categories GWP, ADP, ODP, AP and EP, while emissions remain in the impact categories POCP, LUC, HTP, TAETP, FAETP and MAETP for most of the plant types. In comparison with the UCTE-electricity-production-mix total emissions are lower for almost all plant types and impact categories. A ranking of the total results based on the unweighed aggregation of all impact category results is lead by anaerobic digestion of mainly organic residues followed by gasification of wood chips, the anaerobic digestion in small plants and combustion of wood chips. These results show that it is essential to consider both direct and indirect environmental impacts.

Exposure to (1 → 3)-β-D-glucans in swine farms

The aim of this study was to assess the exposure to organic dust and (1 → 3)-β-D-glucans in the buildings where an intensive breeding of swine is going on and evaluation of the impact of the breeding technical conditions on the observed levels of bioaerosols. The study was carried out in 30 swine farms differentiated by the size of the herd and technical conditions of breeding. In 35 randomly selected buildings, air samples were collected by stationary measurements to determine the concentrations of organic dust and (1 → 3)-β-D-glucans in inhalable and respirable fractions. Furthermore, each of the investigated buildings was precisely characterized by means of a questionnaire for technical conditions and type of breeding. In each of the points, the microclimate parameters were measured, i.e., temperature, relative humidity, CO2 concentration and air velocity. The analyzed levels of organic dust and (1 → 3)-β-D-glucans were characterized by a wide range of concentrations. For inhalable fraction, they reached respectively: organic dust (0.43–11.8 mg/m3), (1 → 3)-β-D-glucans (14–3,594 ng/m3). For respirable fraction, the results were as follows: organic dust (0.01–4.69 mg/m3), (1 → 3)-β-D-glucans (1–703 ng/m3). The concentrations of (1 → 3)-β-D-glucans were positively correlated with organic dust (r = 0.68; p < 0.001). The most significant factor increasing the concentrations of organic dust and (1 → 3)-β-D-glucans was the use of bedding in the form of cut straw. Additionally, the levels of (1 → 3)-β-D-glucans were affected by manual forage feeding, mechanical manure disposal and the lack of the liquid manure container in breeding buildings. In view of the hazardous effects of biological agents on the health of swine-breeding workers, the swine management systems without beddings should be used, along with automated dosing techniques.