Process studies of odour emissions from effluent ponds using machine-based odour measurement

Replicable experimental studies using a novel experimental facility and a machine-based odour quantification technique were conducted to demonstrate the relationship between odour emission rates and pond loading rates. The odour quantification technique consisted of an electronic nose, AromaScan A32S, and an artificial neural network. Odour concentrations determined by olfactometry were used along with the AromaScan responses to train the artificial neural network. The trained network was able to predict the odour emission rates for the test data with a correlation coefficient of 0.98. Time averaged odour emission rates predicted by the machine-based odour quantification technique, were strongly correlated with volatile solids loading rate, demonstrating the increased magnitude of emissions from a heavily loaded effluent pond. However, it was not possible to obtain the same relationship between volatile solids loading rates and odour emission rates from the individual data. It is concluded that taking a limited number of odour samples over a short period is unlikely to provide a representative rate of odour emissions from an effluent pond. A continuous odour monitoring instrument will be required for that more demanding task

Continuous odour measurement from fattening pig units

peer reviewedA study in experimental slatted-system fattening pig units was conducted with the aim of estimating the odour emission factor (in ou/s.pig), which can subsequently be used in dispersion models to assess the odour annoyance zone. Dynamic olfactometry measurements carried out at different development stages of pigs showed a logical trend of the mean predicted odour emission factor with the pig weight. However, the variation within the same weight class was much larger than variation between classes. Possible causes of such variation were identified as the evolution of ventilation rate during the day and the circadian rhythm of pig. To be able to monitor continuously the daily variation of the odour, an electronic nose was used with suitable regression model calibrated against olfactometric measurements. After appropriate validation check, the electronic nose proved to be convenient, as a complementary tool to dynamic olfactometry, to record the daily variation of the odour emission factor in the pig barn. It was demonstrated that, in the controlled conditions of the experimental pens, the daily variation of the odour emission rate could be mainly attributed to the sole influence of the circadian rhythm of pig. As a consequence, determining a representative odour emission factor in a real case cannot be based on a snapshot odour sampling

Investigation of mechanisms governing emission of odorants

The literature identifies several models that describe inter-phase mass transfer, key to the emission process. While the emission process is complex and these models may be more or less successful at predicting mass transfer rates, they identify three key variables for a system involving a liquid and an air phase in contact with it: • A concentration (or partial pressure) gradient driving force; • The fluid dynamic characteristics within the liquid and air phases, and • The chemical properties of the individual components within the system. In three applied research projects conducted prior to this study, samples collected with two well-known sampling devices resulted in very different odour emission rates. It was not possible to adequately explain the differences observed. It appeared likely, however, that the sample collection device might have artefact effects on the emission of odorants, i.e. the sampling device appeared to have altered the mass transfer process. This raised the obvious question: Where two different emission rates are reported for a single source (differing only in the selection of sampling device), and a credible explanation for the difference in emission rate cannot be provided, which emission rate is correct? This research project aimed to identify the factors that determine odour emission rates, the impact that the characteristics of a sampling device may exert on the key mass transfer variables, and ultimately, the impact of the sampling device on the emission rate itself. To meet these objectives, a series of targeted reviews, and laboratory and field investigations, were conducted. Two widely-used, representative devices were chosen to investigate the influence of various parameters on the emission process. These investigations provided insight into the odour emission process generally, and the influence of the sampling device specifically

Air Treatment Techniques for Abatement of Emissions from Intensive Livestock Production

Intensive livestock production is connected with a number of environmental effects, including emissions of ammonia (NH3), greenhouse gases (CH4 and N2O), odour, and particulate matter (PM10 and PM2.5). Possible strategies for emission reduction include feed management, adaptation of housing design, and, in case of mechanically ventilated animal houses, the application of end-of-pipe air treatment, viz acid scrubbers and bioscrubbers. Air treatment techniques can achieve very high emission reductions (up to 100% ammonia removal for acid scrubbers). Furthermore, air treatment offers the possibility to achieve removal of not just one compound but of a combined removal of a variety of pollutants (ammonia, odour and particulate matter) at the same time. The successful application of scrubbers is of increasing importance as intensive livestock operations have to comply with ever stricter regulations and emission limits. Research is needed to address topics such as reduction of costs (both investment and operational costs), improvement of process control to guarantee stable removal efficiencies, decrease of N2O production in bioscrubbers, and increase of odour removal efficienc

A software application for mapping livestock waste odour dispersion

In developed Countries, coexistence of livestock production and urban settlements is a source of problematic interactions that are regulated by specific legislation, often requiring the evaluation of the potential environmental impact of livestock odour emissions. For this purpose, dispersion models are powerful tools that can be classified as dynamic (Eulerian and Lagrangian) or static (Gaussian). The latter, while presenting some limitations in condition of wind calm and complex orography, are widely adopted for their ease of use. OdiGauss is a free multilingual software application allowing to estimate odour dispersion from multiple point sources and to generate the related maps. Dispersion is calculated according to a Gaussian approach, as a function of wind speed and direction, precipitation, temperature, and solar radiation. OdiGauss incorporates a model of odour emissions from poultry farms (EmiFarm) which makes predictions based on manure production and management. Two case studies of software application on real poultry and swine farms are presented

Free range chicken farms - odour emissions and nutrient management

This report focuses on odour emissions and nutrient management from free range meat chicken farms. Specifically – odour emissions from the sheds and free range area as well as potential nitrogen and phosphorus loss from the range areas in the soil and in runoff. There is currently a lack of information relating to free range meat chicken farms when it comes to odour emissions and nutrient loss. Improved understanding of the emissions from free range farms will support the continued growth of the free range sector in Australia

A systematic study on the VOCs characterization and odour emissions in a full-scale sewage sludge composting plant

Sewage sludge management is known to cause odour impact over the environment. However, an information gap exists about odour emissions quantification from different treatment strategies. In the present work, odorous emissions generated in a full-scale sewage sludge composting plant were characterized, aiming at providing specific odour emission factors (OEF) and to determine their variability depending on the composting time. Additionally, characterization of VOCs emitted during the process was conducted through TD-GC/MS analyses. Odour emission and VOCs characterization considered both (1) a first stage where a raw sludge and vegetal fraction mixture were actively composted in dynamic windrows and (2) a second curing stage in static piles. After increasing the composting time, a reduction of 40% of the maximum odour concentration referred to the dynamic windrow stage was estimated, whereas a reduction of 89% of the maximum odour concentration was achieved after turning of curing piles. However, global OEF increased from 4.42E + 06 to 5.97E + 06 ou·Mg−1 RS - VF when the composting time increased. Finally, different VOCs such as isovaleraldehyde, indole, skatole, butyric acid, dimethyl sulphide and dimethyl disulphide were identified as main potential odour contributors. Results obtained are a valuable resource for plant management to choose an appropriate sewage sludge composting strategy to mitigate odour emissions

Summarised findings from Australian poultry odour research (2005–2018)

D&E related to odour is integral to addressing community concerns, reducing the potential for odour impacts and supporting sustainable growth of the chicken meat industry. By necessity, the industry is typically established on the urban fringe, which increases the potential for amenity impacts. Odour RD&E has involved several research teams, including government agencies, universities, and consultancy businesses. The industry must now undertake the important tasks of broadly reviewing the overall knowledge that has been developed to date, taking stock of the achievements and challenges, and planning the path forward to address emerging and unresolved issues. This project summarises the odour-related RD&E that has been supported by the Australian chicken meat industry (through AgriFutures Australia or the Poultry CRC) since 2005. It was funded by industry revenue, the Australian Government, and the Queensland Government Department of Agriculture and Fisheries