Biological Removal of VFA from Animal Wastes (Volatil Fatty Acids)

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The use of a bioscrubber and compost as treatment for VFA on a laboratory scale has been very effective. However even if the VFA play an important role in odour emissions, no information has been given on the possible odour reduction.

Pig building dustiness as affected by canola oil in the feed.

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Experiments were performed in a pig grower-finisher room to determine the effect of canola (rapeseed) oil treatment of feed on several indices of dustiness. The effectiveness of the oil treatment was assessed over 18 weeks by measuring the respirable dust particle counts (RPC), airborne dust inhalable mass concentration (IMC), and dust sedimentation rate (DSR). The dry feed contained 0% and 2% canola oil on alternate weeks. The pen floors were partially slatted during the first 8 weeks and were totally slatted during the last 10 weeks. The mean RPC was 45% higher for the oil treatment compared to the no-oil treatment. The mean IMC was 31% lower for the oil treatment compared to the no-oil treatment. The mean DSR within the room was 7% lower and within the recirculation duct was 9% lower for the oil treatment compared to the no-oil treatment. None of these differences were statistically significant (P>0.1).

Deodorization of Swine Sewage by Addition of Photorophic Bacterium, Rhodopseudomonas capsulata

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Swine feces generate substances with an offensive odor composed of volatile fatty acid and hydrogen sulfide. A phototrophic bacterium, rhodopseudomonas capsulata, plays an important role in preserving water in its natural habitat. Rhodopseudomonas capsulata, a bacteria isolated from pond-bottom ponds, has been used in wastewater treatment. It has been suggested that the bacteria plays a role in the utilization of volatil fatty acids (VFA) that contribute to offensive odour. Laboratory testing has been done to verify if the bacteria could lower the VFAs emissions when mixed to swine sewage. Under controlled conditions, gas sampling was taken from the headspace of swine sewage incubated with the bacteria. The results obtained showed that the amounts of VFAs can be reduced.
The tests were done under controlled conditions in laboratory with sinthetic sewage manure. Further testing on swine production facilities should be done to verify if such treatment is efficient on production scale.

Removal of airborne dust from swine housing by electrostatic precipitation.

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An electrostatic precipitator in conjuction with a recirculation duct was developed to remove airborne swine dust from an environmental chamber at the University of Alberta. The collection efficiency of the electrostatic precipitator was evaluated at varying applied voltage and airspeed levels. The three applied voltage levels were: -10.3, -11.0 and -12.1 kVDC. The three airspeed levels were 0.55, 0.76 and 0.95 m/s. The overall collection efficiency of the precipitator ranged from 18.5% at an applied voltage of -10.2 kVDC to 96.4% at an applied voltage of -12.0 kVDC. Applied voltage had a significant effect (P<0.05) on collection efficiency. Airspeed did not have a significant effect (P<0.05) on collection efficiency. The optimal airspeed was 0.76 m/s for all applied voltages. Collection efficiency increased by approximately 5% when the precipitator length was increased by 50%. Inter-electrode spacing had little effect on collection efficiency. An applied voltage of -12.1 kVDC produced ozone level of 0.21 ppm which exceeded the recommended TLV of 0.1 ppm.

Olfaktometrie – Bestimmung der Geruchsintensitat – Olfactometry – Determination of Odour Intensity

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This guideline was developed to describe an olfactometric method to investigate odorant samples whose concentrations are above the odour threshold (suprathreshold) and relate them to sensation intensity induced in human. While evaluating many samples whose concentrations vary and exceed odour threshold, intensity variation can be assess. The use of olfactometers and this method allow the evaluation of degree of odorant concentration reduction that could be obtained from different emission treatments or from dilution (such as samplings taken at different distances from the source). Information is given on the procedures that have to be done to realize the tests (sampling procedures from VDI3881, panel selection of at least 8 persons, olfactometer, presentation of the different odorant concentrations, exposure and response to stimuli associated with an intensity level scale from 0 – not perceptible to 6 – extremely strong). The evaluation of the results is also explained with the presentation of the test results, the mathematical evaluation and the graphical presentation to clearly represent the intensity variations of a specific odorant gases or air mixes at their different concentrations. A relationship is established between the odorant concentration and the odour intensity thus giving the suprathreshold intensity variation. However to establish nuisance, the hedonic odour response, the frequency and exposure time have also to be considered.

This guideline is interesting and give the frame for odour intensity determination. However, the information given is general and the results obtained could be difficult to reproduce (different laboratory with different apparatus).

Ausbreitung von Luftverunreinigungen in der Atmosphare – Dispersion of pollutants in the atmosphere – Gaussian dispersion model for air quality management

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Emissions dispersion is evaluated using a mathematical Gaussian model. The use of the model and the limits of application are presented. The model needs input data on the emission source (coordinate of the source, volume and strength of the source, and other characteristics of the emission) and also meteorological input such as the frequency distribution of wind direction and velocity, dispersion categories, mixing layer height and precipitation if any. The Gaussian model has certain advantage over more complex models because the dispersion parameters have been derived from dispersion investigation experiments and running the model needs relatively short computing time.

The Gaussian model is well presented in the publication and is widely used for emissions dispersion evaluation. However this model doesn’t consider eddies and meandering and is thus limited in the exact representation of the dispersion pattern. This model can be used for odours as well as gas emissions.

Waste Management – Odor Control in Liquid Hog Manure by Added Amendments and Aeration

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Laboratory studies were done to evaluate the capacity of different amendments and aeration added to liquid hog manure(LHM) to reduce the emission of malodorous gases. The amendments, sphagnum peat moss (80% dry matter) in proportion of 1%, 4% and 8%, monocalcium phosphate monohydrate (reagent grade) (4% addition), H2SO4 (1.5 M), H3PO4 (1.7M), CaCO3 (2% and 2% + sphagnum peat moss 1%), CaO (2%) and elemental S (4%), were surface applied to manure and mixed by intermittent brief aeration. Aeration and nonaeration were also define as treatments for the 1 kg LHM samples placed in 2.7 L jars which incubated for 720 h at 23 C. Gas samples were taken from the jars at 2, 4, 24, 96 and 720 h after the beginning of the experiments and presented to volunteer untrained panelists for sensory evaluation rating the odour presence and offensiveness on a numerical scale of 0 to 10. Gas samples were also taken for gas chromatography and mass spectroscopy analysis. The results showed that aeration markedly reduced the odor. As this process is expensive, considerations should be made on treatments under nonaerated conditions. The effectiveness of these treatments still have to be evaluated on scale applications however some combination of sphagnum peat moss and CaCO3 should be further investigated in field applications as these are the treatment giving the most interesting results.

Important differences could be obtained in a large scale application. This experiments leave unanswered questions has to the apparatus necessary to achieve those treatments in a large scale and particularly the economics of such treatments. The method uses to evaluate the odor only qualify the odor intensity and cannot be compared to the olfactometric method more commonly used.

Loss of Nitrogenous Compounds During Composting of Animal Wastes

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Composting is a process causing important nitrogen losses (from 46,8% to 77,4% of the initial total N). Losses also occur under the form of NOx to the air (<5%) and also as leachates (9,6 to 19,6% of the initial total N). Composting of animal wastes is not an efficient process if we consider it under a fertilizer source and also if we consider the environmental impact resulting from it (emissions, leaching).

Resolving Land Use Conflicts

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The increase in urban sprawl is resulting in greater instantances of nuisance related complaints respective to intensive livestock operations. The poultry industry in California has taken a proactive approach in dealing with concerns that have arisen with intensive poultry operations. They have recognized the importance of community wide representation: need for industry members, unbiased public representation and a regulatory body (usually the health department). Coordinating these focus groups in establishing siting (seperation) standards and operating guidelines will reduce the conflicts which arise between intensive livestock operations and the public.

Odor Issues with Wastes

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Methods of measuring odours from livestock production systems are described. The odour emissions in pig production systems can be separtated into those arising from buildings, storage and land application. The best methods of odour reduction for these sources are considered and areas for future research are proposed.