Odour emission from primary settling tanks after air-tightening

The purpose of the present article was to determine odour emission rate from primary settling tanks after hermetisation. The paper presents the results of the research on odour emission from four settling tanks, covered with self-supporting aluminium domes with a diameter of 52 meters, located on urban wastewater treatment plants, with the planned flow capacity equal to 200 000 m3/day. Altogether, the olfactometry analysis of 189 samples of polluted air pulled from the domes with the use of an air blower which has efficiency of 12 000 m3/h was conducted. The results of odour concentration measurements were in a range of approximately 10 800 to 763 600 ouE/m3. Average odour emission rate was equal to 102 ouE/(s · m2). The obtained value is much higher than the literature data, available for non-hermetised settlers only. This rate enables better estimation of the odour stream that has to be deodorised after sealing the settling tanks.

Coupling of mouse olfactory bulb projection neurons to fluctuating odour pulses

Odours are transported by turbulent air currents, creating complex temporal fluctuations in odour concentration. Recently, we have shown that mice can discriminate odour stimuli based on their temporal structure, indicating that information present in the temporal structure of odour plumes may be extracted by the mouse olfactory system. Here using in vivo electrophysiological recordings, we show that mitral and tufted cells (M/TCs), the projection neurons of the mouse olfactory bulb, can encode the dominant temporal frequencies present in odour stimuli up to frequencies of at least 20 Hz. We show that M/TCs couple their membrane potential to odour concentration fluctuations; coupling was variable between M/TCs but independent of the odour presented and with TCs displaying slightly elevated coupling compared to MCs in particular for higher frequency stimulation (20Hz). Pharmacologically blocking the inhibitory circuitry strongly modulated frequency coupling. Together this suggests that both cellular and circuit properties contribute to the encoding of temporal odour features in the mouse olfactory bulb.

Fundamentals of Odour Assessment in Slovenia

From a sociological and economic perspective, odour pollution is one of the most complex problems in the field of air quality. Therefore, various approaches and odour impact criteria are particularly relevant when assessing odour exposure in the areas of different land use. The number of odour assessment methods is limited, and the lack of analytical techniques to determine odour concentration makes odour assessment even more complex. It is essential to analyse the spatial and temporal distribution of odour concentrations in order to assess odour nuisance in the ambient air. Since sampling of odorous air in the field for subsequent determination of odour concentrations in a laboratory by dynamic olfactometry is time-consuming, two approaches are used to assess odour concentrations in ambient air: estimating odour concentration by field inspection and calculation of odour concentrations using atmospheric dispersion models. The latter is the most commonly used technique. Our study aimed to provide fundamentals for an odour regulatory framework in Slovenia. While a multitude of approaches is presently applied to establish odour regulation framework, a broader approach remains lacking. Various odour emission sources were identified to evaluate available methods and techniques to assess odour impact. The impact area was selected to analyse and compare the impact of different odour sources in terms of odour concentration, odour frequency, odour offensiveness, land use, and receptor location. Finally, odour impact criteria were set according to odour offensiveness and concentration, percentile compliance level and land use.From a sociological and economic perspective, odour pollution is one of the most complex problems in the field of air quality. Therefore, various approaches and odour impact criteria are particularly relevant when assessing odour exposure in the areas of different land use. The number of odour assessment methods is limited, and the lack of analytical techniques to determine odour concentration makes odour assessment even more complex. It is essential to analyse the spatial and temporal distribution of odour concentrations in order to assess odour nuisance in the ambient air. Since sampling of odorous air in the field for subsequent determination of odour concentrations in a laboratory by dynamic olfactometry is time-consuming, two approaches are used to assess odour concentrations in ambient air: estimating odour concentration by field inspection and calculation of odour concentrations using atmospheric dispersion models. The latter is the most commonly used technique. Our study aimed to provide fundamentals for an odour regulatory framework in Slovenia. While a multitude of approaches is presently applied to establish odour regulation framework, a broader approach remains lacking. Various odour emission sources were identified to evaluate available methods and techniques to assess odour impact. The impact area was selected to analyse and compare the impact of different odour sources in terms of odour concentration, odour frequency, odour offensiveness, land use, and receptor location. Finally, odour impact criteria were set according to odour offensiveness and concentration, percentile compliance level and land use.

Assessment of the Odour Impact Range of a Selected Agricultural Processing Plant

Within the research, on the premises of an agricultural plant, the odour concentration was measured, and the odour emission was determined. The obtained values allowed us to analyse the odour distribution using the Polish reference mathematical model for four different scenarios, including (1) all identified emission sources, i.e., point and surface: scenarios 1 and 2, and (2) only point sources, scenario 3 and 4. The values of the comparative level and the frequency of exceedances in scenarios 1 and 3 were based on the Polish draft act on counteracting odour nuisance, while the Dutch guidelines were used for scenarios 2 and 4. Model calculations showed the potential impact of the tested structure on adjacent residential areas, i.e., in scenarios 1 and 2, the permissible value of the frequency of exceedances was exceeded at all points representing residential buildings. The exceedances for scenario 3 and 4 took place in seven out of eight and two out of eight points, respectively. The results indicated that to accurately and reliably assess the odour impact and to determine the measures to prevent and reduce odour emissions, it is necessary to consider all types of emission sources in the facilities potentially causing odour nuisance.

Livestock odour dispersion and its implications for rural tourism: case study of Valencian Community (Spain)

Aim of study: To study the relationship between the problem odours caused by livestock farms and the evolution of rural tourism.Area of study: A coastal region in Spain, the Valencian Community.Material and methods: The odour emission rates of 4,984 farms have been calculated, and the ambient odour concentration was determined to assess the odour nuisance. The odour concentration was modelled by applying the Gaussian model based on emission data and the most unfavourable meteorological conditions of the 45 climatic stations distributed throughout the analysis area. The dispersion model was implemented in a geographic information system, deducing the municipalities affected using the odour concentration thresholds. Furthermore, the evolution of rural tourism in municipalities was studied during the period of 2006-2017. The relationship between the evolution of rural tourism and the effects of odours is studied by means of a bivariate spatial correlation analysis.Main results: Pigs are the predominant species in areas with the greatest odour emission problems; ~ 29% of farms can result in annoyances among the population with odour concentrations greater than 5 OU/m3, and 46% of municipalities can be affected by odour problems. These odour nuisances had negative consequences in the municipality where measures were carried out to favour rural development, such as rural tourism. Municipalities were detected in which the problem of odours can be a deterrent to rural tourism, whereas in other municipalities it was observed that minimizing livestock activity can be a method to promote rural tourism.Research highlights: This study provides a methodology that allows modeling the odour dispersion of livestock and relates its implications to rural tourism. Municipalities have been identified where livestock odours can cause a stagnation of the rural tourism income.

Synthesis and application of natural sorbents with silver nanoparticles in reducing the emission of odours

The paper concerns the applicability of silver nanoparticles for reducing the emission of odours. Silver nanoparticles were successfully adsorbed on three different dolomitic limestone samples. In the next stage, wastewater from the meat industry was mixed with sorbents modified with a variable content of silver nanoparticles. After 4 days and 7 days, the concentration of ammonia was examined spectrophotometrically. Also, the degree of reduction of total odour concentration by olfactometric method was carried out. Depending on the concentration of the silver nanoparticles on the sorbents, the concentration of ammonia was 15-42 μg/cm3 for nAg content equal to 0.08%, while for sorbents containing approximately 36% of nAg the concentration of ammonia was 0.09-16 μg/cm3. A leaching test of nanosilver from sorbents confirmed that the particles were bound with the sorbents by strong bonds. The percentage of eluted silver increased from 0.67% to 11%, with increased initial concentrations of nAg on the sorbents from 0.18% to 0.37%.

The Impact of Microclimate Parameters on Odour Emissions from Pig Production in Spring

The aim of this study was to examine the impact of inside temperature and relative humidity, ventilation rate and gas concentrations (NH3, N2O, CO2) on odour emissions from deep-litter piggery. The studied facility had temperature-controlled mechanical ventilation. The measurements were conducted from March to June 2014. During the research, selected microclimate parameters, as well as number and mass of animals were monitored and air samples were collected (two samples of air in each series of measurements). Temperature and relative humidity were measured using Testo 435-4 multifunctional measuring instrument. To measurements of gas concentrations was used the photo-acoustic spectrometer Multi Gas Monitor Model 1312. The concentration of odours in the air samples was determined by dynamic olfactometry with the TO 8 olfactometer, according to PN-EN 13725:2007. The odour concentration ranged from 450 to 2004 ouE · m–3 (mean 1048 ouE · m–3) and the mean odour emission factor was from 5.76 to 46.79 ouE · (s · pig)−1 (mean 20.93 ouE· (s · pig)−1.The statistical analysis showed that the inside temperature explained most of the variability of the odour concentration and the relationship was described by equation: cod = 5634 – 197 Tinside (R2 = 0.82, p ≤ 0.05). For odour emission factor, two parameters: the inside temperature and ventilation rate, explained most of the variability, according to the equation: EFod = 108 + 1939 VR – 5.5 Tinside (R2 = 0.81, p ≤ 0.05).

ODOUR POLLUTION ASSESSMENT THROUGH INDIRECT METHODS BASED ON THE MONITORING OF TECHNOLOGICAL PARAMETERS - CASE STUDY

The odours in the ambient air, through the discomfort that they induce, represent an actual problem for the communities located nearby companies with technological processes that emit in the air different strong and unpleasant odorous substances. The standard method for odour assessment involves measuring the concentration through dynamic olfactometry according with SR EN 13725:2003, a very complex method that requires specialized working staff and expensive equipment. The paper presents an indirect method for odour assessment in the ambient air, based on monitoring the process and meteorological data - Predictive Emission Monitoring Systems (PEMS) and it is applied to a livestock farm. Using the multiple regression analysis of the monitoring data for the most important specific technological and meteorological parameters it can be developed a mathematical model that could be used for the calculation of odour concentration in air, without the necessity of direct measurement, after the initial step. For the case study presented in the paper, the distance between the slurry lagoon was identified as a significant statistical parameter that can determine in a proportion of 72% the concentration of odour in the ambient air nearby the farm; the margin of error for odour concentration assessment, according to the model validation tests, is ± 8%, acceptable value for an estimation method by mathematical modelling.

Evaluation of Health Hazard Due to Emission of Volatile Organic Compounds from Various Processing Units of Wastewater Treatment Plant

The paper describes an attempt at health risk assessment and odour concentration determination in the most important units of a wastewater treatment plant. The cancer risk (CR) and hazard index (HI) parameters in selected measurement locations were calculated based on the results of chromatographic analyses (GCxGC-TOF-MS) and the United States Environmental Protection Agency (US EPA) guidelines. No exceedance of the CR and HI acceptable levels was observed for identified and quantitatively determined compounds from the VOCs group. The acceptable level was exceeded for the summary HI parameter. Following a classification of the International Agency for Research on Cancer (IARC), it was noticed that the highest hazard was connected to the presence of formaldehyde belonging to group 1—the compounds regarded as carcinogenic. Based on the olfactometric analyses, it was estimated that the highest odour concentration, 37.2 ou/m3, occurred at the solid waste composting piles. It was also revealed that an increase in odour concentration corresponded to a higher health risk for employees of the wastewater treatment plant, due to exposure to volatile odorous compounds. Accordingly, this method of odour measurement can be a fast indicator describing health risk level.