Dust control strategies for livestock buildings- a review.

Posted in: Environment by admin on January 1, 1995 | No Comments

Dust in animal buildings should be controlled to levels that affect health only minimally. Dust control strategies include reducing the rate of emission (source control), effective ventilation (ventilation control), and air cleaning (removal control). Source control strategies include use of feed additives, cleaning dusty surfaces and spraying water or oil over dusty surfaces. Ventilation control includes purge ventilation and effective room air distribution. Air cleaning strategies involve filtration, electrostatic precipitation, or wet scrubbing. Promising techniques for livestock buildings include the use of feed additives, oil or water spraying, purge ventilation, and effective room air distribution. Technical and economic constraints have prevented these methods from being widely practiced. Effective and economically feasible dust control methods should be developed and systematically tested under both controlled laboratory needs include: (1) characterization of dust particles, dust sources and sinks; and (2) development of sensors and control devices that incorporate the dust control technology into the environmental control system.

Le lecteur d'azote AGROS: evaluation d'une methode rapide de determination in situ de l'azote ammoniacal des lisiers et des fumiers

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The manure managed and spread correctly allow for optimal used of the fertilizer elements without any harm to the environment. Part of this management is the evaluation of the nitrogen content of the manure in order to determine the optimal application rate. Laboratory testing can be realized in advance, however even if the manure is well mixed the homogeneity of the nutrients content can differ from one load to subsequent ones. The determination of the nitrogen content just before spreading would improve the nutrient management and optimize the fertilizing value of the manure and would also improve the confidence producers have in the valorization of manure they spread on their lands. The soil hygrometer has been used to estimate different constituent in manure. However this method gives poor estimates for ammoniacal nitrogen (NH4). A nitrogen measurer AGROS has been developed in Sweden. AGROS has been tested on site and compared with the soil hygrometer and standard laboratory testing. For swine manure, AGROS has been very reliable in evaluating the NH4 content, as good as laboratory testing and superior to the hygrometer technique. A relationship established with laboratory tests can be made to estimate the total nitrogen content of the manure. The cost of an analysis with this measurer is evaluated at $2,00 to $4,50 compared to $25,00 for laboratory testing. No calibration is necessary and the reading of the NH4 content is direct.

Direct measures of the nitrogen content in the manure could help adjust the application rate when spreading or in case the nitrogen is not the limiting nutrients in the manure, this result would help in the determination of the mineral nitrogen needed to assure an optimal fertilization.

Evaluation d'un systeme de separation feces-urines en levage porcin.

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A continuous net placed under the slatted floor filtrate the feces from the urine. Different testing have realized in order to determine the optimum operations parameter such as the net mesh size (optimum size 800 microns), the correct location for the net under the slatted floor and its dimension (depending on the position of the equipment and production pattern). The solid phase removed using this system is of 26% of dry matter and the liquid part is of 2%. The solid part can be composted (and disposed later) and the liquid can be spread on grass or land as a fertilizer. No information on the economics of such system is not given. Such system could be considered if a lot of manure hauling has to be done on long distances. The liquids could be spread close to the storage facility and the solids of smaller volume and more concentrated per volume could be transported and used as a fertilizer further from the farm. The lower cost in transportation could compensate for the cost of such separation system.

Zeolite as feed additive to control swine manure odours and to improve animal growth performance

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Zeolite was used as a feed additive (addition of 5% zeolite) and its effect was verified on swine manure odours and hogs growth performances improvements in an experiment realized on 54 grower hogs. Zeolite is a tektosilicate and was obtained from southern Alberta. This compound is found in volcanic deposits and exhibits a cation retention capacity (CEC) of 400 meq /100g. The group of 54 weaners (average 18.6 kg) was separated equally in two and placed in different rooms, with a control group fed a 16% crude protein pelleted standard feed and the other group fed the same diet supplemented with 5% zeolite. The animals’ weight was measured regularly and the given feed was weighed daily. NH3, CO2 and H2S levels were measured regularly in both rooms and manure samples were taken for nitrogen content analysis. The results are given for the first 4 weeks for the hogs performances: the hogs fed the zeolite diet didn’t significantly grow at a faster rate but showed a significant improvement in the feed conversion compared to the control group (2.2 kg feed/ kg body weight vs. 2.75 kg/kg). In both rooms, the H2S concentrations were not high enough to be measured. The NH3 levels measured were lower in the room were the zeolite fed hogs were for the 5 first weeks of experiment. This experiment was continued until hogs had reach market weight.

The title suggest that this experiment evaluated the odours to compared the air in the rooms of the hogs fed zeolite supplemented feed and the control group fed standard diet. However, testing were done on only 3 gases and 2 of them being odours components therefore comments can be made on the difference on those gases concentrations but not on the odour. The results presented only the 4 and 5 first week which give and idea on the zeolite possibilities but could not be considered for the whole growing and finishing periods as the hogs’ nutritional needs change.

REDUCING NITROUS OXIDE GAS EMISSIONS FROM FILL-AND-DRAW TYPE ACTIVATED SLUDGE PROCESS

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Air pollution from livestock building

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Long-term measurements are made to produce an inventory of different gaseous emissions from livestock building in UK. This inventory is made to in order to further know the present emissions and be able adjust and meet the greenhouse gas emissions reduction at 1990 levels by 2000 (from the Earth Summit in Rio).
Short terms measurements are also made as part of a European project. With the Netherlands, Denmark, and Germany intensive monitoring is done in the summer and the winter for 24 hours periods on UK livestock buildings of 12 different types. The ammonia, methane and nitrous gases concentrations are measured as well as the inspirable and respirable dust. This sampling are done at 3 locations at the animal level and 3 locations at the workers levels in the building and also one sampling is done outside to evaluate a background level. Comparable techniques and equipments are used in each country of the four countries. The emissions rates of the contaminants are evaluated from the data measured and the estimated ventilation rates obtained via a carbon dioxide balance.

SWAMP : Sustainable Waste Application Management Project

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As the nutrient content in the manure is not always easy to determined, farmers tend to consider manure more as a waste to dispose. SWAMP aims at the development of new technologies to improve manure utilization by nutrient determination, spreading accuracy and pollution prevention. A computer program is being developed in order integrate the estimated nutrients in manure to a pollution risk assessment and decision support for spreading and ultimately control the application rate according to the spreading recommendations and the field conditions by acting on the tanker control system. This program would also maintain detailed records.

Le recyclage du lisier de porc par lagunage.

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The system presented in this publication is an integrated nutrient recycling chain: manure – micro-algae – micro-shellfish – fish. The system developed is meant to be simple of operation in order to be easily integrated on the same site than the production buildings and to the farm operations. The biotreatment rely on normal bio-climatic conditions that nature provides without important human intervention. As a result, the biological activity in temperate climate will slow considerably during the cold season. Different techniques could be used to keep the biological activity however they are considered expensive and have not yet been studied. Another criteria retained is that the biomass produced have to be easily integrated in the agro-food economics and ideally directly at the farm level. Considering the algae-micro-shellfish chain, the biomass produced can be used for different purposes including as feed component for aquatic and terrestrial animals. The publication gives information on the biological and biochemical processes involved in the recycling chain, the valorization of the biomass, the economical and sanitary aspects of such recycling and the conception and management of such systems. Succinct information is also given on other treatment processes.
This recycling chain is interesting as the manure is reused in a longer chain than only manure concentration, treatment and reintroduction directly in the feed. However such lagoon system for biomass production doesn’t work when the weather too cold. Such system would be efficient only few months a year when the cold season is long.

A Study on the Air Flow and Odor Emission Rate from a Simplied Open Manure Storage Tank

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To represent the odor dispersion with the use of mathematical models, the odor emission rate should be defined as it is an input parameter of the model. Odor emission rates from open manure tanks are difficult to evaluate and a study was realized to develop a numerical evaluation of air flow and odor emission rate. The tank dimensions, the odor concentration at the manure surface, the manure surface area and the wind speed were input parameters for the mathematical model developed using the SIMPLER algorithm from Patankar and a 2-layer turbulence model to realize numerical simulation with a 152 x 139 grid. Experimental verifications were performed to validate the model for air flow pattern and velocity profile and the emission rate results obtained agreed with field measurements obtained in the literature.

Dispersion models can be effective tool to evaluate the odor dispersion pattern of an odorant source and the area affected. As mentioned, another numerical model was needed to evaluate the odor emission rate of open manure tanks and those odor emissions rate are costly to evaluate with field measurements.

Diffusion of rural biogas technology: survey of experience

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