Odorous Air Research Articles

Photooxidation in Combination with Nanotechnologies - Principles, Developments and R&D Approaches of an Advanced Technology for Water and Air Treatment - Uviblox®

AbstractMany organic and oxidizable inorganic substances are main targets for oxidation and destruction during treatment, purification and disinfection of contaminated ground water, waste water, air, soil and waste gas and odor. Uviblox® technology uses the effects of photooxidation and photocatalytical processes by middle and low pressure UV lamps for technical systems. There are many possibilities for combination and optimisation of photooxidation with other technologies like nanotechnologies. Degradation processes can be enforced by nano structures of photocatalysts significantly. Different approaches are strongly pursued in research & development projects like NanoAqua, Fe-NANOSIT and nanoblox. These projects search for different ways of applying and handling the photocatalytical nano particles like TiO

Multiple-Chamber Instrumentation Development for Comparing Gas Fluxes from Biological Materials

The complex and often confounding factors that influence gas emission from biological materials require a measurement procedure that is precise, accurate, repeatable, and reliable. A multiple-chamber instrumentation system was developed to rapidly and precisely measure gas emission potential from multiple sources, such as manure and biosolids, to compare gas emission reduction potential of various treatments. Up to eight steady-state flux chambers, a photoacoustic multi-gas monitor, and a hydrogen sulfide pulsed fluorescence analyzer were coupled through a multiplexer relay to measure concentrations of ammonia and hydrogen sulfide, respectively. Depending on the number of chambers used, gas concentration in the chambers was measured on 20- to 72-min intervals over a nominal 24-h period via fully-automated data collection software. Built-in quality controls allowed potential cross-contamination to be quickly identified in order to maintain the precision of the instrument. Air flow rate in each chamber was maintained at 0.5 air changes per minute using calibrated flow meters. The performance of the multiple chamber system in evaluating ammonia gas flux was tested using ammonia calibration gas (accuracy; 97.3% recovery through the system) and freestall barn-floor manure sub-samples (precision 8% for biologically heterogeneous material; standard error of 2% of mean). Using separately-collected dairy cow urine and feces the instrument system was used to evaluate impact of source depth showing an apparent slight reduction of ammonia release with increasing depth but findings were within the expected precision range of the instrument for this type of material. An example demonstrating the multiple-chamber system use in evaluating ammonia flux processes evaluated urine and feces mixed to five ratios ranging from 10:90 to 90:10. The 50:50 ratio had the highest cumulative emission over 23 h. Removing ammonia with a scrubber and moisture via condensation trap significantly improved the accuracy of hydrogen sulfide concentration measurements when analyzing dairy manure slurry. Odorous air samples were easily collected from each chamber headspace and evaluated using triangular forced-choice dynamic olfactometry and odor-quality assessments for simultaneous gas emission and odor evaluation. This instrumentation system offers repeatable, concurrent monitoring of gas and odor emission from biological sources and provides a powerful tool for gas emission research and evaluation of management practices directed at reducing gas release.

Ozonation of Odorous Air in Wastewater Treatment Plants

This study was conducted to evaluate the effects of gas scrubbing techniques for the elimination of odorous compounds in wastewater treatment plants. A pilot plant was installed and operated at Tuzla Wastewater Treatment Plant in Istanbul, Turkey for this purpose. Gas scrubbing experiments conducted using water, ozonated water, caustic and ozone injected caustic revealed different removal efficiencies. The highest and reliable hydrogen sulfide removal efficiencies were obtained in the ozone oxidation experiments.

Interaction Between Visual and Olfactory Cues During Host Finding in the Tomato Fruit Fly Neoceratitis cyanescens

Herbivorous insects searching for a host plant need to integrate a sequence of multimodal sensory inputs. We conducted a series of no-choice experiments in a laboratory wind tunnel to examine the behavioral response of the specialist fruit fly, Neoceratitis cyanescens (Diptera: Tephritidae), to host visual and olfactory stimuli presented singly or in combination (e.g., colored fruit model with or without host fruit odor). We also studied the influence of wind flow, age, and sex on the response of flies. In two-choice experiments, we evaluated the ability of mature females to discriminate between two fruit models emitting host vs. non-host fruit odor or clean air. Neoceratitis cyanescens mature females can use independently or interactively olfactory and visual stimuli to locate their host, whereas immature females and males respond primarily to host fruit odor. In the absence of wind, mature females mainly use visual information to locate the host fruit. In wind, host fruit odor significantly increases the probability and speed of locating the host fruit. In a two-choice situation between two bright orange spheres, flies accurately detected the sphere emitting host fruit odor vs. non-host fruit odor or odorless air. Nevertheless, they preferred to land on the bright orange sphere when the sphere emitting host fruit odor was blue. Furthermore, when odor source and fruit model were spatially decoupled (90 or 180 degrees ), >50% flies that landed on the fruit model initially performed an oriented flight toward the odor source, then turned back to the fruit model while in flight or after one landing, thus suggesting visual information to be the ultimate indicator of host fruit.

Impact of valence and age on olfactory induced brain activation in healthy women.

The aim of the present study was to assess the effect of age on cerebral correlates of olfactory induced negative emotions. We investigated 15 healthy women (aged 21-47) in a functional MRI (fMRI) study during passive smelling of one negative odor (rotten yeast) and two control conditions presenting a neutral odor (vanilla) and odorless ambient air. Besides odor-specific differences in ratings of valence (yeast less pleasant than vanilla and air), intensity (yeast more intense than vanilla and air), and arousal (yeast more arousing than vanilla and air), self-ratings verified the intended mood induction effect: subjects experienced more disgust during yeast stimulation compared to ambient air and vanilla. Along with the superior temporal cortex, medial, and lateral orbitofrontal activations were found to discriminate between negative and neutral olfactory stimulation (yeast and vanilla) directly. Activations of the dorsolateral prefrontal cortex and the caudate were correlated with age and showed stronger valence-related responses (yeast vs. vanilla) in younger compared to older women. Stronger BOLD signals within the anterior cingulate gyrus, insula and motor areas were found during negative compared to neutral stimulation and are considered to represent an attempt to down-regulate the strong emotional experience and the organisms' preparation for withdrawal, respectively. Our results stress the role of orbitofrontal and superior temporal brain regions in odor-related valence coding and stress the necessity to consider age as a modulating factor for further studies, even in relatively young samples.

Denver Metro's Solids Processing Buildings Ionized Air Odor Control Systems Eliminate Odor with Ninety-Eight Percent Less Power and Carbon Emissions than Traditional Capture and Treat Technologies

Denver Metro's Solids Processing Buildings Ionized Air Odor Control Systems Eliminate Odor with Ninety-Eight Percent Less Power and Carbon Emissions than Traditional Capture and Treat Technologies

Odour and VOC impact assessment and air quality monitoring program at a municipal solid waste landfill

The scope of this paper is to present and compare the results of (1) an extensive odour, VOC and H2S impact assessment, and (2) a complete odour, VOC and H2S air quality monitoring program at a municipal solid waste landfill (MSWL). This study was conducted over a year, with an unprecedented amount of cross-assessment techniques and data points on a 1.3 million tonnes per year MSWL. All potential landfill emission sources were characterized for odours, VOCs, CH4 and H2S using a set of over 150,000 onsite samplings & measurements. An air quality monitoring program included continuous odour, CH4 and H2S monitoring, a 12-day-frequency VOC sampling campaign, and a 24h/7d odour survey at the nearest receptors. This paper will present the standardized methodologies used and comparative results from each independent assessment program.

Adsorption of Nitrogen Oxides, Water Vapour and Ozone onto Activated Carbon

Noxious gases and odours in cabin air are reduced by activated carbon filters. However, the adsorption process involved in cabin air filtration is very complex because of the large number of influencing parameters. Some important parameters are changes in the input concentrations and surrounding conditions. Furthermore, the presence of different substances leads to their mutual influence on the respective adsorption processes. The separation of nitrogen oxides is an especial focus of discussion in Germany at present because of decreasing ambient exposure limits. One part of the study presented herein deals with the binary adsorption of nitrogen dioxide in humid air at varying NO2 input concentrations, relative humidity and temperature. In order to obtain more information about this process, after initial validation of the test procedure employed, breakthrough curves of NO2 have been undertaken in the present study. In the second part of the study, the influence of a third adsorptive (ozone) on the adsorpt...

Evolutionary lability of odour‐mediated host preference by the malaria vector Anopheles gambiae

Many species of disease-vector mosquitoes display vertebrate host specificity. Despite considerable progress in recent years in understanding the proximate and ultimate factors related to non-random host selection at the interspecific level, the basis of this selection remains only partially understood. Anopheles gambiae sensu stricto, the main malaria vector in Africa, is considered a highly anthropophilic mosquito, and host odours have been shown to play a major role in the host-seeking process of this species. Studies on host preference of An. gambiae have been either conducted in controlled conditions using laboratory reared mosquitoes and worn stockings as host-related stimuli, or have been done in the field with methods that do not account for internal (e.g. age of sampled mosquitoes) and/or environmental effects. We explored differential behavioural responses to host odours between two populations of the same sibling species, An. gambiae in semi-field conditions in Burkina Faso. The behavioural responses (i.e. degree of activation and strength of anemotaxis) were investigated using a Y-olfactometer designed to accommodate whole hosts as a source of odour stimuli. Two strains of An. gambiae (3 to 4-day-old female) from laboratory Kisumu strain, and from field-collected individuals were confronted to combinations of stimuli comprising calf odour, human odour and outdoor air. In dual-choice tests, field mosquitoes chose human odour over calf odour, outdoor air over calf odour and responded equally to human and outdoor air, while laboratory mosquitoes responded equally to human and calf odour, human odour over outdoor air and calf odour over outdoor air. Overall, no effect of CO(2) exhaled by humans and calves neither on the proportion of activated mosquitoes nor on the relative attractiveness to odour stimuli was found. We report for the first time an intraspecific variation in host-odour responses. This study clearly suggests that there may be genetic polymorphism underlying host preference and emphasizes that the highly anthropophilic label given to An. gambiae s.s. must be carefully interpreted and refer to populations rather than the whole sibling species.

Odour and ammonia emission from pig manure as affected by dietary crude protein level

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, odour hedonic tone, ammonia and greenhouse gaseous emission from pig manure, and on fresh faeces and manure characteristics. An experiment was conducted with finishing pigs ( n = 12) in a randomized complete block arrangement with 2 treatments of 12 and 15% dietary CP in six blocks. The 2 diets were supplemented with essential AA up to the level of the animal's requirement. Pigs with an initial body weight (BW) of 57.7 ± 0.7 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 3rd week of the collection period, fresh faeces were collected for identifying fresh faeces characteristics and for assessing dry matter, organic matter, nitrogen (N), fat and non-starch polysaccharides digestibility using Cr 2O 3 as a marker. In the 6th week of the collection period, air samples were collected directly from each manure pit: one for odour, one for ammonia concentration and one for greenhouse gases. Afterwards the manure was mixed and a representative sample was taken for manure characteristic analysis. Odour samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indolic, phenolic, sulphurous compounds, ammonium and total N concentrations and pH. Reducing dietary CP level from 15 to 12% did not affect odour emission, odour intensity and odour hedonic tone and greenhouse gaseous concentration (CH 4, CO 2 and N 2O) ( P > 0.05) of odorous air above the manure pit. Reduced dietary CP level decreased manure pH ( P < 0.001), total N ( P < 0.001) and ammonium ( P < 0.001) concentrations and ammonia emission from pig manure ( P = 0.03). In addition, total VFA, acetic, propionic, iso-butanoic and iso-pentanoic acids, phenol, 4-ethyl phenol and carbon disulfide concentrations in manure were decreased by reducing dietary CP level ( P < 0.05). We conclude that reducing dietary CP from 15 to 12% did not reduce odour emission and greenhouse gaseous concentration; however, ammonia emission was significantly reduced.

Comparison of odour emission rates measured from various sources using two sampling devices

Two commonly used sampling devices (a wind tunnel and the US EPA dynamic emission chamber), were used to collect paired samples of odorous air from a number of agricultural odour sources. The odour samples were assessed using triangular, forced-choice dynamic olfactometry. The odour concentration data was combined with the flushing rate data to calculate odour emission rates for both devices on all sources. Odour concentrations were consistently higher in samples collected with a flux chamber (ratio ranging from 10:7 to 5:1, relative to wind tunnel samples), whereas odour emission rates were consistently larger when derived from wind tunnels (ratio ranging from 60:1 to 240:1, relative to flux chamber values). A complex relationship existed between emission rate estimates derived from each device, apparently influenced by the nature of the emitting surface. These results have great significance for users of odour dispersion models, for which an odour emission rate is a key input parameter.

Denver Metro's Solids Processing Buildings Ionized Air Odor Control Systems Successfully Eliminate Odor with Ninety-Eight Percent Less Power than Capture and Treat Systems

Denver Metro's Solids Processing Buildings Ionized Air Odor Control Systems Successfully Eliminate Odor with Ninety-Eight Percent Less Power than Capture and Treat SystemsPolarized air ionizing hardware that produces positively and negatively charged oxygen molecules, or ions, but no ozone. will be discussed. This European technology has been successfully applied at wastewater facilities in Europe for over twenty years. Operating systems in the US now have a successful track record of over six years. The ionized air effectively oxidizes hydrogen sulfide, ammonia,...Author(s)Dennis TulenkoMichael CarverSourceProceedings of the Water Environment FederationSubjectSession 69: Management of Odors and Air EmissionsDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:11L.5350;1-DOI10.2175/193864708788804595Volume / Issue2008 / 11Content sourceWEFTECFirst / last page(s)5350 - 5358Copyright2008Word count276

Sensory and Analytical Evaluations of Paints With and Without Texanol

Perception of odor can figure prominently in complaints about indoor air,yet identification of the responsible compound(s) is often difficult. For example, paint emissions contain a variety of odorous volatile organic compounds (VOCs) which maytrigger reports of irritation and upper respiratory health effects. Texanol ester alcohol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate), a paint coalescing agent, is frequently associated with the "persistent, characteristic odor" of water-based paint. To evaluate the sensory impact of Texanol, naive (unfamiliar with paint constituents) and experienced (familiar with paint constituents) subjects evaluated the odor properties of paints with and without Texanol. VOC emissions from neat paint and paint applied to gypsum wallboard were collected via solid-phase microextraction and analyzed by gas chromatography/ mass spectrometry and gas chromatography/olfactometry. Regardless of subjects' prior experience, aromatic hydrocarbons and oxygenated compounds, introduced from other paint additives and not Texanol, were most commonly associated with paint odor. However, quantitative sensory techniques demonstrated that addition of Texanol to paints led to an overall increase in the perceived intensity of the coating. The combined use of these techniques proved to be an effective methodology for analyzing the structure of paint volatiles and their sensory properties and holds promise for solving many odorous indoor air problems.

Identification of Odor Causing Compounds in a Commercial Dairy Farm

The odorous air emissions from confined animal feeding operations (CAFOs), such as swine, poultry and dairy farms, are increasingly raising community complaints. Odorous emissions can result in health damages, psychological discomforts and adverse aesthetic effects in the community. However, these emissions are not well characterized up to now due to the lack of legislation, the limitations in sampling and instrumentation techniques, and the complexity of the emissions themselves. This study is aimed at the development of a high volume sampler and sorbent assembly to identify the odor causing compounds from a diary CAFO. The sorbent was custom designed to target the potential compounds that may exist in a dairy farm and was validated in laboratory with a synthetic odor from the swine manure. The actual samples at the diary farm were collected in spring and summer of 2005. The sorbents were solvent extracted and individual odor compounds were identified using GC–MS (gas chromatography–mass spectroscopy). The data obtained indicated that high volume sampling can shorten the sampling time from days to within 4 h. Both volatile organic compounds (VOCs) and volatile fatty acids (VFAs) have been identified from the dairy farm, such as phenol, methylphenol, 4-ethyl phenol, indole, methyl indole, benzyl alcohol, hexanoic acid, valeric acid and iso-valeric acid, together with some nitrogen containing compounds that have not been reported before.

Development of an integrated sensor to measure odors

Odorous air samples collected from several sources were presented to an olfactometer, an electronic nose, a hydrogen sulfide (H(2)S) detector and an ammonia (NH(3)) detector. The olfactometry measurements were used as the expected values while measurements from the other instrumentation values became input variables. Five hypotheses were established to relate the input variables and the expected values. Both linear regression and artificial neural network analyses were used to test the hypotheses. Principal component analysis was utilized to reduce the dimensionality of the electronic nose measurements from 33 to 3 without significant loss of information. The electronic nose or the H(2)S detector can individually predict odor concentration measurements with similar accuracy (R(2) = 0.46 and 0.50, respectively). Although the NH(3) detector alone has a very poor relationship with odor concentration measurements, combining the H(2)S and NH(3) detectors can predict odor concentrations more accurately (R(2) = 0.58) than either individual instrument. Data from the integration of the electronic nose, H(2)S, and NH(3) detectors produce the best prediction of odor concentrations (R(2) = 0.75). With this accuracy, odor concentration measurements can be confidently represented by integrating an electronic nose, and H(2)S and NH(3) detectors.

Analysing livestock farm odour using an adaptive neuro-fuzzy approach

In livestock farming, odour measurement and reduction are necessary for a cleaner environment, lower health risks to humans, and higher quality of livestock production. There have been many studies on modelling of livestock farm odour by analysing the chemical components in odorous air. It is suggested that the component analysis approaches should be extended to factors such as temperature, relative humidity, and airflow speed. In this paper, a neuro-fuzzy-based method for analysing odour generation factors to the perception of livestock farm odour was proposed. The proposed approach incorporates neuro-adaptive learning techniques into fuzzy logic method. Rather than choosing the parameters associated with a given membership function by trail and error, these parameters could be tuned automatically in a systematic manner so as to adjust the membership functions of the input/output variables for optimal system performance. A multi-factor livestock farm odour model was developed, and both numeric factors and linguistic factors were considered. The proposed approach was tested with a livestock farm odour database. The results demonstrated the effectiveness of the proposed approach in comparison to a typical neural network model.

Livestock Odour Dispersion as Affected by Natural Windbreaks

Natural windbreaks have been planted around livestock shelters to improve odour dispersion without substantial knowledge of their best implementation practices. Using three groups of four trained panellists and an odour generator, the objective of the present research was to measure and compare the length of odour plumes (LOP) produced in the field in the absence of, and in the presence of four natural windbreaks exposed to various climatic conditions. During 39 mornings in August, September and December 2003, panellists observed the resulting odour plumes using hedonic tone (HT) as scale and in the afternoon, evaluated the odour concentration (OC) of the odorous air sampled at the generator. By correlating HT with to their corresponding OC, filed HT values were converted into OC units, and 2 OU m−3 contours were used to establish LOP. A multiple factor analysis verified the effect significance on LOP of the presence of a windbreak, of windbreak properties and of climatic conditions. While being diluted, OC decreased exponentially with HT as observed by panellists (P < 0.05). Secondly, the windbreaks significantly reduced LOP by 22% as compared to the site without a windbreak. Thirdly, the denser windbreaks had a greater impact on reducing LOP. The LOP of windbreaks with an optical porosity of 0.55 was not significantly different compared to that created in the absence of a windbreak. The wind speed, direction and ambient temperature had a strong influence on LOP while atmospheric stability, windbreak position downwind from the odour source within 60 m and odour emission rate had little impact, based on the analysis of 36 field tests in the presence of a windbreak.

‘Infotaxis’ as a strategy for searching without gradients

Chemotactic bacteria rely on local concentration gradients to guide them towards the source of a nutrient. Such local cues pointing towards the location of the source are not always available at macroscopic scales because mixing in a flowing medium breaks up regions of high concentration into random and disconnected patches. Thus, animals sensing odours in air or water detect them only intermittently as patches sweep by on the wind or currents. A macroscopic searcher must devise a strategy of movement based on sporadic cues and partial information. Here we propose a search algorithm, which we call 'infotaxis', designed to work under such conditions. Any search process can be thought of as acquisition of information on source location; for infotaxis, information plays a role similar to concentration in chemotaxis. The infotaxis strategy locally maximizes the expected rate of information gain. We demonstrate its efficiency using a computational model of odour plume propagation and experimental data on mixing flows. Infotactic trajectories feature 'zigzagging' and 'casting' paths similar to those observed in the flight of moths. The proposed search algorithm is relevant to the design of olfactory robots, but the general idea of infotaxis can be applied more broadly in the context of searching with sparse information.

Chemical characterization of odors due to some industrial and urban facilities in Izmir, Turkey

The relationship between odor concentrations (olfactometry) and chemical concentrations (gas chromatography-mass spectrometry, GC-MS) was studied for the odorous air compositions of a rendering plant, a sanitary landfill and an industrial area with large petroleum and petrochemical industries. Samples taken from the university campus located in a non-industrial and non-urban area were also studied for several organic components for comparison. Ambient air samples were taken into special bags by using an odor sampling device designed for field sampling of odors. In the laboratory odorous chemicals in the samples were transferred into adsorbent tubes and analyzed using a combination of thermal desorption and GC-MS. Results point to different characteristics of the odorous gases and air in and around the urban and industrial sources. Among the 64 specific compounds studied, 49 volatile organic compounds (VOCs) were detected in rendering plant, 53 VOCs were detected in sanitary landfill and 44 VOCs were detected in petroleum and petrochemical industries. The compounds measured in the odorous gas composition are the alkanes, alkenes, carbonyls, arenes, chlorinated and other halogenated compounds and organic chlorides as well as the volatile fatty acids.

Assessment of Control Strategies for Reducing Volatile Organic Compound Emissions from the Polyvinyl Chloride Wallpaper Production Industry in Taiwan

This study attempts to assess the effectiveness of control strategies for reducing volatile organic compound (VOC) emission from the polyvinyl chloride (PVC) wallpaper production industry. In Taiwan, methyl ethyl ketone, TOL, and cyclohexanone have comprised the major content of solvents, accounting for ∼113,000 t/yr to avoid excessive viscosity of plasticizer dioctyl phthalate (DOP) and to increase facility in working. Emissions of these VOCs from solvents have caused serious odor and worse air quality problems. In this study, 80 stacks in five factories were tested to evaluate emission characteristics at each VOC source. After examining the VOC concentrations in the flue gases and contents, the VOC emission rate before treatment and from fugitive sources was 93,000 and 800 t/yr, respectively. In this study, the semiwet electrostatic precipitator is recommended for use as cost-effective control equipment.