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 CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 54, 2016 

A publication of 

 
The Italian Association 

of Chemical Engineering 
Online at www.aidic.it/cet 

Guest Editors: Selena Sironi, Laura Capelli 
Copyright © 2016, AIDIC Servizi S.r.l., 
ISBN 978-88-95608-45-7; ISSN 2283-9216 

Assessment of Range of Olfactory Impact of Plant to 
Mechanical-Biological Treatment of Municipal Waste 

Andrzej Kulig*, Mirosław Szyłak-Szydłowski 

Faculty of Building Services, Hydro and Environmental Engineering, Warsaw University of Technology, 20 Nowowiejska 
Street, PL-00653 Warsaw, Poland 
Andrzej.Kulig@is.pw.edu.pl 

Plants (installations) to mechanical-biological treatment (MBT) of municipal solid waste belong to the object 
group being potential sources of odorants emission. One of the most important parameters of their 
characteristic is the range of the real olfactory impact. It depends on many factors, such as: the type of emitter 
(point or surficial) and its characteristics (among other things, height and surface, polluted air stream 
temperature), emission value and its variability in time, and also topography and land management method 
and local climatological and meteorological conditions. Assessment of range of olfactory impact of plants is 
the issue, which may be the subject of theoretical considerations. The search for answers for practical 
purposes is associated among other things with spatial planning (land use), decision-making on location and 
land management (improvement of the territory) around the MBT installation and resolving complaints and 
disputes arising from their nuisance for residents (inhabitants). In Poland, the range of onerous impact of 
waste management facilities has been, in the past, assessed mainly by the indicator method (based on the 
widths of the so-called protection zone), and currently is determined using mathematical modelling (especially 
for of planned undertakings) and direct olfactometric measurements (in the case of existing facilities). 
In the paper is presented a general outline of the methodology of assessment of a range of olfactory impact of 
fugitive emission from surficial sources. Theoretical considerations are illustrated on the example of the results 
of the examinations of large plant (installation) of the mechanical-biological treatment of waste. During the 
examinations, apart from usual odour emission and dispersion processes, the effect of the convective vertical 
flow of the odorant-polluted air effect was observed. 
The research program includes twelve series of direct olfactometric measurements (with field olfactometers) 
and odorimetric observations in measurement-observation (receptor) points, deployed in and around the MBT 
installation. In each series has been tagged the background of air polluted with odorants (on the windward 
side of MBT installation). The olfactometric examinations were carried out by method of identification and with 
characterizing the trail of the odour emitted from the explored source. The receptor points were determined 
mainly in the area, in which the odours were uniquely identifiable as to their origin. In addition, has been made 
one “intervention” series of odorimetric observations. During field examinations, olfactometric measurements 
were carried out with control of the current meteorological situation – measurements and observations of the 
weather conditions (wind, temperature and relative humidity of the air, the degree of cloudiness). 

1. Introduction 

The importance of the olfactory impact issues in environmental engineering is shaped considerably through 
the sensitivity of local communities for the presence of emission sources of odorants in the vicinity of 
residence areas. It is the result of an interest in the quality of environmental conditions, ie. inter alia purity of 
air, water and soil, but also a derivative of rational location decisions and more widely, to meet other basic 
social needs. Socioeconomic changes in Poland, in the period of 25 years, resulted in an increased interest 
and activity of the residents in the field of environmental protection, in this mainly in ambient air quality and in 
environmental noise quality, because they are parameters, which can be not only closely monitored, but also 
checked organoleptically. 

                               
 
 

 

 
   

                                                  
DOI: 10.3303/CET1654042

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Please cite this article as: Kulig A., Szydlowski M., 2016, Assessment of range of olfactory impact of plant to mechanical-biological treatment 
of municipal waste, Chemical Engineering Transactions, 54, 247-252  DOI: 10.3303/CET1654042 

247



In Poland the regulation [1, 2], which established formal widths of the so-called protection zones (now called 
the limited use areas in which shall be no residential properties and other public utility facilities) was in force in 
the period from the mid 60s to the end of the 90s of the last century. For waste management facilities (landfill 
sites, composting plants, thermal biological treatment plants, municipal waste utilisation plants, organic waste 
storage facilities), the widths of the protection zones were from 500 m to 1,000 m (Oniszk-Popławska & Kulig 
2014). From the formal point of view, it can be added that in Poland until 1990, social activity in the field of the 
environment to a great extent had the character of so-called direct actions, using the institution of civil 
disobedience or necessary self-defence (demonstrations, happenings, sit-ins, blocking, etc.). 
Only after the Constitution of the Republic of Poland from 1997 which ensure that ”everyone has the right to 
information about the state and protection of environment”, and ”public authorities support the activities of 
citizens to protect and improve the environment” [3]. The next step for the public participation in the decisions 
on the location was the adoption of the Act of 9 November 2000 on access to information on the environment 
and its protection and environmental impact assessment [4]. This Act has been repealed with effect from 30 
September 2001, after the entry into force of Act of 27 April 2001- Environmental Protection Law [5]. Currently, 
is in force an Act from 3 October 2008 on disclosure of environmental information, public participation in 
environment protection and on environmental impact assessment [6], according to which ”any person shall 
have the right to submit the petitions and conclusions in proceedings conducted with public participation” (art. 
3). The above provisions have been implemented in the environmental impact assessment procedure for 
planned projects and issuing of the so-called environmental decisions and building permits. Complaint 
procedure on the onerous impact upon plants (industrial installations) operated is less precise in Poland. Both 
at the stage of assessment of the planned undertaking and existing facility, there is a need for an answer to a 
question – what is the scope of the olfactory impact of installation (plant). These two cases differ possibilities 
of methodological solutions. In the first case, may be used the forecasting methods of range of the impact of 
the odorant emission sources, in this, mainly mathematical modelling. In the second case, the preference 
obtains methods of direct surveys (measurements and observations). In Poland, unfortunately, have not yet 
established a formal (legal) and methodological standards of olfactory impact assessments for planned and 
operated installations. The only element is a standard that specifies the conditions for the carrying out 
organized emission of the odour (PN-13725, 2007). 
A big impact on the way and range of the olfactory impact of the object has a type of odorant source and 
conditions of pollution dispersion (Sironi et al. 2006.). In the case of multiple facilities of waste management, 
emission source is a surface nature with a small gravity-related height and without a significant dynamic and 
thermal uplift. Only in the case of the plants of the thermal treatment of waste, in this waste-incineration plants, 
emitter / emission device is a point source (chimney) with a height of several dozen metres, with additional 
dynamic and thermal uplift. Conditions of pollution dispersion determine the local climatological conditions (eg. 
the distribution of wind directions, the so-called wind rose) and instantaneous meteorological conditions (inter 
alia wind velocity, the vertical distribution of temperature, the occurrence of atmospheric precipitation), as well 
as topography and land surface development, characterized by the so-called roughness coefficient zo. 

2. A brief characterization of the test object 

The site where the measuring campaigns were conducted is an plant of the mechanical-biological treatment of 
waste (MBT installation) in Central Poland. The object to be analysed is MBT installation of mixed municipal 
waste [the quantities are taken unsorted wastes were altered from approx. 100 thousand of Mg in 2012 across 
147 thousand of Mg in 2013 to 208 thousand of Mg in 2014], to which the provisions of the European Union 
are applicable concerning the prevention of the pollution of air, water and soil (the IPPC installation, of 
integrated pollution prevention and control) and Regional Municipal Waste Treatment Facility. Waste Disposal 
Plant, located on the outskirts of the town of one of the 16 provincial cities in Poland, consists of the MBT 
installation and the accompanying the composting plant of green waste and waste landfill. A detailed 
assessment of the range of the olfactory impact has been carried out only for the MBT installation, that is the 
cause of complaints and disputes resulting from its nuisance for residents. The surface of waste composting 
piles covered with the membrane is about 14 400 m2 (36 piles with 8 m width & 50 m length each). 
In the vicinity of the MBT installation is: land covered with high green/greenery and the area of uncultivated 
(idle) agricultural land with a width of approximately 320 m from the north side, and behind it - intense low 
detached houses; from the eastern and south-east side, just behind the public street, is a large forest complex 
(Forest Park) with a width of up to 2 km; from the southern side is a waste landfill, and behind it (at a distance 
of approximately 600 m) another part of the forest complex; directly from the western side is situated a railway 
track, behind it is a square of composting plant of green waste, and further wasteland, street and industrial 
plants areas. Residential areas are located along the street running from the north side (low detached houses 
at a distance of approximately 330-500 m) and high multi-family houses (apartment buildings) at a distance of 

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over 2000 m from the south-east side. In the area of the location of MBT installation is located a few other 
establishments (plants) - objects that are a potential source of odour (eg. storage station of liquid fuels, 
bitumen mastic production plant and mixed municipal waste sorting station together with the MBT installation 
for municipal waste). The potential impact of these objects has been taken into account and eliminated from 
the further analysis. 

3. Materials and methods 

3.1.The research programme 
The research programme included twelve series of measurements with field olfactometers and odorimetric 
observations performed from 24.06.2014 to 26.05.2015. The research was performed at the measuring and 
observational points (receptors), located within and around the MBT installation. In each series has been 
marked background of air pollution by odorants (on the upwind side of the MBT installation). The location of 
the test points shown in Figure 1. 

 
Figure 1. The location of the measuring and observational points (receptors) 

 
3.2. Method of the odour tests 
Olfactometric research have been conducted with a method for identifying and characterising the trail of the 
odour emitted from the source under test. The intensity of the odour has been assessed in the sensory tests 
according to the six level scale (0-5), however, measurements of the concentration of the odour have been 
made using the Nasal Ranger® portable olfactometers. Receptor points were determined mainly by the area in 
which the odours were uniquely identifiable as to their origin. 
 
3.3. Method of meteorological measurements 
During in-situ testing, olfactometric measurements were accompanied by control (measurements and 
observations) of the current meteorological situation (wind direction and velocity, temperature and relative 
humidity of the air, the degree of cloudiness). Information about meteorological conditions was used directly 
during tests and each time was recorded at the results of the measurements, as the necessary data for 
analysis of air quality status. Meteorological parameters were defined in each of the receptor points. Wind 
direction was determined with the method of the trail each time before starting the observation and 
measurement. Wind velocity measurement has been performed using the Kestrel 4500 NV manual 
anemometer with vane impeller (rotor). Measuring the direction and velocity of the wind were performed at a 
height of 2 m. Measurement of temperature and relative humidity of air were performed at a height of 1.5 m. 
For measuring was used the Rotronic HygroPalm psychrometer (wet-and-dry-bulb thermometer) with the 
HygroClip2 HC2-S3 sensor. It was also specified the degree of cloudiness. 

4. Results and discussion 

4.1. The results of the direct impact of an object 
In the case of the spread/dispersion of trail of polluted air in the field without major obstacles - having a 
relatively small roughness of the earth surface (the coefficient of the aerodynamic roughness of terrain 
zo < 1.0 m), dispersal has a local character, in the immediate vicinity of the installation. In such conditions, 

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usually occurs a reduction in the concentration of odour depending on the distance from the emission source. 
In Figure 2 are summarised results of the assessment of odour intensity, while in Figure 3 - the results of the 
determination of the odour concentration during the field tests. In the Figures have been presented numbers 
determining the maximum range of individual impacts. 

 
Figure 2. The spatial distribution of the odour intensity during the tests in 1-12 series and ”intervention” series 

 
Figure 3. The spatial distribution of the odour concentration during the tests in 1-12 series 

 
At points located outside the MBT installation, the intensity of the odour was from 0 to 5, while the 
concentration of odour – from 0 to 26 ou/m3. The highest values of the intensity of the odour (i = 5) have been 
recorded at points situated at a distance of 280 m from the plant fencing. The concentration value of odour 
greater than or equal to 10 ou/m3, has been found in the seven measuring points, located at a maximum 
distance from the fence of the plant of 850 m. In this distance was recorded the value of the odour 
concentration of 26 ou/m3. The results of the intensity assessment and the concentration of odour as a 
function of distance from the MBT installation have been presented respectively in Fig. 4 and 5. 
4.2. The case of “the long-range impact” 
It results from numerous own research studies (Kulig, 2004), carried out in the area and around the waste 
management facilities (as low, usually superficial sources) that range of impact of these objects/facilities is 
limited to a few hundred, at least, up to 1000 m. In the case of notifications (reports) of occurrence of the 
unpleasant odour from the MBT installation in the area of residential developments, situated at a distance of 
over 2 km from the potential emission source, the problem required a more detailed analysis. It has not been 
present in such distances in the summertime and early autumn. It is worth to add, that these are periods of 
most common complaints against wastewater and waste management facilities in the municipal sector (Kulig, 
2004). Why so problems with the impact of odour in the surroundings of the MBT installation have intensified 
in the second half of October 2014 and occurred in the long distances? 

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Figure 4. The dependence of the intensity of the odour as a function of distance from the MBT installation 

 
Figure 5. Dependence of concentration of the odour as a function of distance from the MBT installation 

 
On the 7th of November 2014 around 22oo, has been carried out "intervention" site inspection in the area of the 
MBT installation at the time when was recorded the occurrence of unpleasant odour at a large distance from 
the source of emission. During inspection found that on the area of the MBT installation was not carried out 
any technological works associated with unloading or the export of wastes or dislocating piles. Piles “worked” 
in accordance with the technological regime, giving back (emitting) water-vapour into the atmosphere. 
However, together with this steam, the air escaped and part of the odoriferous substances (odorants). Due to 
the temperature difference: of heated air from piles with the steam and cool air masses, was the convection 
raising of polluted air at the height of more than a dozen metres (Figure 6, 7 and 8). 
 

 
Figure 6. View of piles – vapours 
do not escape from the isolated 
edging, but from the membrane 
surface 

Figure 7. View of rising vapours 
and floating above the 
membrane surface (November 
7th, 2014 at 22oo) 

Figure 8. Convection air stream, 
water vapour and odoriferous 
substances, with the temperature 
greater than the ambient 
temperature 

In such conditions, the odorant stream was abducted by the masses of air flowing over the area of piles and 
raised over forest complex until the area of the housing building development. At the same time, was excluded 

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the presence of other potential sources of odorants on the road of air masses inflowing into the area of the 
residential development. In other thermal conditions, ”wall” of the forest constitutes the effective reduction 
(limitation) of dispersal of pollutants of low surface sources (hence the concept of not only areas of limited use, 
but also the so-called protection zones mainly in the 70s and 80s of the last century into force). 
Of course, this case does not concern the long-range impact within the meaning of the Convention UN/ECE 
(United Nations Economic Commission for Europe) on Environmental Impact Assessment in a Transboundary 
Context (Espoo in Finland, 1991). However, translocation of the air polluted with odorants from the 
composting plant at a distance of over 2000 m, may not be classified as local impact. The presented case it 
should be assessed as very negative due to the thermal uplift of polluted air to a height of more than a dozen 
metres, and then its transport over the surface of the forest to the area of large residential development. The 
thermal conditions causing such a situation do not occur in temperate climate zone in the warm season of the 
year (in the summer), that usually is assessed as less favourable due to the olfactory impact of waste 
management facilities (mechanical and biological treatment and waste storage). 

5. Conclusions 

As a result, of the odorimetric research carried out in the conditions specific for four seasons, taking into 
account the changing of technical and technological conditions slightly, it has been found that: 
1. The air inflowing on the area of the plant is pure in respect of odour. The level of the so-called background 

for the intensity and concentration of odour is 0. In all analysed cases, the area of the real olfactory impact 
was the consequence of odorant emission from the MBT installation. This means that there are no sources 
of odorant emissions (they have not been identified), the impact of which would overlap on the impact of 
tested objects. 

2. On the area of the MBT installation and outside its fence, the odour intensity changes in the full range 
(from i = 0 to i = 5). The greatest values of the intensity of the odour (i = 5 – very strong odour) were found 
during tests in the "intervention" series. 

3. At the background level of 0 ou/m
3, the range of values of the odour concentration on the area of the MBT 

installation is from 0 to 50 ou/m3. Outside the area of the MBT installation, the concentration of odour 
generally decreases along with the distance from the emission source, However, the maximum value for 
this parameter exceeds 20 ou/m3. 

4. The results of the odour intensity assessment well correlate with the results of the measurement of odour 
concentration. 

5. Impact range of odour emitted from the area of plant is more than 2000 m. However, the odour of intensity 
i = 3 (faint odour), perceptible by more than 50% of people and onerous for minority reaches up to 1500 m. 

6. The concentration of odour greater than or equal to 2 ou/m3 was detected up to a distance of 1300 m from 
the leeward side of the fence of MBT installation. 

References 

Kulig A., 2004. Measurement-calculation methods in the environmental impact assessment of the municipal 
infrastructure. Warsaw University of Technology, Warsaw. 

Oniszk-Popławska A., Kulig A. 2014: Application of odour predictions to spatial planning the case of 
agricultural biogas. Chemical Engineering Transactions 40, 277-282, DOI: 10.3303/CET 1440047. 

PN-EN 13725, 2007, Air quality – Determination of Odour Concentration by Dynamic Olfactometry, Committee 
for European Normalization (CEN) and Polish Committee for Standardization (PKN). 

Sironi S., Capelli L., Centola P., Del Rosso R., Il Grande M. 2006. Odour emission factors for the prediction of 
odour emissions from plant for the mechanical and biological treatment of MSW. Atmospheric Environment 
40, 39, p. 7632-7643. 

Legal acts 
[1] The ordinance of the President of the Central Office of Water Management of the 30th of May 1967 on the 

width of the protection zone it sets for air protection against pollution (M.P. 1967 No. 32, item 152). 
[2] The ordinance of the Minister of Administration, Land Development and the Environment Protection of the 

9th of November 1982 on the detailed procedure for determining the boundaries and areas of protection 
zones, indicative indicators for their width (M.P. 1982 No. 27, item 241). 

[3] The Constitution of the Republic of Poland passed by the National Assembly on 2nd April 1997, approved 
by the Nation in the Constitutional Referendum on 25 May 1997, signed by the President of the Republic 
of Poland on 16 July 1997 (Journal of Laws No. 78, item 483 as amended). 

[4] The Act of 9th November 2000 on access to information on the environment and its protection and 
environmental impact assessment (Journal of Laws No.109, item 1157). 

[5] The Act of 27th April 2001- Environmental Protection Law (Journal of Laws No. 62, item 627 as amended). 
[6] The Act of 3 October 2008 on disclosure of environmental information, public participation in environment 

protection and on environmental impact assessment (Journal of Laws No. 199, item 1227 as amended). 

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