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Attachment 6 - Odour Impact Assessment - Katestone · 132005.638.06
Noosa Composting Odour Assessment Prepared for: Noosa Council September 2026 Final Prepared by: Katestone Environmental Australia Pty Ltd www.katestone.global ABN 21 680 559 095 [email protected] Level 4, 154 Melbourne Street, South Brisbane Ph +61 7 3369 3699 Queensland, 4101, Australia
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Document Control
Deliverable #: D25072-8
Title: Noosa Composting Odour Assessment
Version: 1.0 (Final)
Client: Noosa Council
Document reference: D25072-8 Noosa Composting Odour Assessment.docx
Prepared by: Joel von Treifeldt, Daniel Gallagher
Reviewed by: Ricky Gellatly
Approved by:
Ricky Gellatly
17 September 2026
Disclaimer
https://katestone.global/legals/
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This document, electronic files or software are the copyright property of Katestone Environmental Australia Pty. Ltd. and the
information contained therein is solely for the use of the authorised recipient and may not be used, copied or reproduced in
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Environmental Australia Pty. Ltd. makes no representation, undertakes no duty and accepts no responsibility to any third party
who may use or rely upon this document, electronic files or software or the information contained therein.
© Copyright Katestone Environmental Australia Pty. Ltd.
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Contents
Executive summary .........................................................................................................................................iv
1. Introduction ........................................................................................................................... 1
2. Existing and proposed operations ....................................................................................... 3
2.1 Existing operations ..................................................................................................................... 3
2.2 Proposed composting operations ............................................................................................ 3
2.3 Odours from composting and proposed controls .................................................................. 4
3. Legislative framework for air quality .................................................................................... 6
3.1 Environmental authority ............................................................................................................ 6
3.2 EP Act and Air EPP ..................................................................................................................... 6
3.3 Guideline: Odour Impact Assessment from Developments ................................................... 7
4. Assessment methodology .................................................................................................... 8
4.1 Existing environment .................................................................................................................. 8
4.2 Operational emissions ............................................................................................................... 8
4.2.1 Composting operation .............................................................................................. 8
4.2.2 Landfill ....................................................................................................................... 10
4.3 Meteorology ............................................................................................................................ 11
4.4 Dispersion modelling................................................................................................................ 11
4.5 Presentation of results .............................................................................................................. 12
4.6 Limitations and uncertainty .................................................................................................... 12
5. Existing environment ........................................................................................................... 13
5.1 Local terrain and land-use ...................................................................................................... 13
5.2 Sensitive receptors ................................................................................................................... 14
5.3 Existing sources of emissions .................................................................................................... 15
5.4 Meteorology ............................................................................................................................ 15
6. Emissions to the atmosphere .............................................................................................. 16
7. Results ................................................................................................................................... 18
8. Conclusions .......................................................................................................................... 20
9. References ........................................................................................................................... 21
Appendix A Meteorological and dispersion modelling methodology ............................................... 25
Tables
Table 1 Odour emission rates for composting operations ................................................................................ 9
Table 2 Odour emission rates for landfill operations ........................................................................................ 10
Table 3 Sensitive receptors included in the dispersion model ........................................................................ 14
Table 4 Composting operations odour emission rate summary ..................................................................... 16
Table 5 Landfill operations lower bound odour emission rate summary ....................................................... 17
Table 6 Landfill operations upper bound odour emission rate summary ...................................................... 17
Table 7 Maximum dispersion modelling results for sensitive receptors........................................................... 19
Table A1 A comparison of the observational meteorological data with the TAPM output for 2020 at the
location of the BoM Tewantin monitoring station .............................................................................. 29
Figures
Figure 1 Location of Noosa Resource Recovery Centre ................................................................................... 2
Figure 2 Layout of odour sources at the proposed composting facility ........................................................... 9
Figure 3 Layout of odour sources at the existing landfill facility (four layouts tested).................................... 11
Figure 4 Terrain of the area surrounding the Noosa Resource Recovery Centre .......................................... 13
Figure 5 Locations of nearest sensitive receptors ............................................................................................. 14
Figure 6 Annual wind rose for the site for 2020 (extracted from TAPM/CALMET) ........................................... 15
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Plate 1 Predicted maximum (99.5th percentile) 1-hour average ground-level concentrations of odour due to
emissions from composting operations in isolation ............................................................................ 22
Plate 2 Predicted cumulative maximum (99.5th percentile) 1-hour average ground-level concentrations of
odour due to composting operations emissions and lower-bound landfill operations emissions .. 23
Plate 3 Predicted cumulative maximum (99.5th percentile) 1-hour average ground-level concentrations of
odour due to composting operations emissions and upper-bound landfill operations emissions . 24
Figure A1 Annual wind roses for Tewantin between 2018 and 2022 ................................................................. 26
Figure A2 Annual frequency distribution plots for Tewantin between 2018 and 2022 (highlighting year selected
2020) ...................................................................................................................................................... 26
Figure A3 Z scores for Tewantin between 2018 and 2022................................................................................... 27
Figure A4 Probability density functions comparing 2020 observational data (blue) with TAPM data (red) at the
location of the BoM Tewantin monitoring station .............................................................................. 29
Figure A5 2020 annual distribution of winds predicted by TAPM/CALMET ........................................................ 31
Figure A6 2020 seasonal distribution of winds predicted by TAPM/CALMET ..................................................... 32
Figure A7 2020 diurnal distribution of winds predicted by TAPM/CALMET ........................................................ 32
Figure A8 Frequency distribution of atmospheric stability conditions predicted by TAPM/CALMET .............. 33
Figure A9 2020 diurnal profile of mixing height predicted by TAPM/CALMET ................................................... 34
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Glossary
Term Definition
° degrees
m metres
m/s metres per second
m2 square metres
ou odour units
ou/m2/s odour units per metre squared per second
ou/s odour units per second
Abbreviation Definition
AHD Australian Height Datum
Air EPP Environmental Protection (Air) Policy 2019
AWS automatic weather station
BoM Bureau of Meteorology
CSIRO The Commonwealth Scientific and Industrial Research Organisation
DEM Digital Elevation Model
DETSI Department of the Environment, Tourism, Science and Innovation
EA Environmental Authority
EP Act Environmental Protection Act 1994
EPA Environment Protection Authority
ERA Environmentally Relevant Activity
FOGO Food organics and garden organics
HES high efficiency sediment
IOA index of agreement
QLD Queensland
RMSE root mean square error
TAPM The Air Pollution Model
UTM Universal Transverse Mercator
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EXECUTIVE SUMMARY Katestone Environmental Australia Pty Ltd has been commissioned by Noosa Council to conduct an odour assessment of a proposed in-vessel composting activity to be located at the existing Noosa Resource Recovery Centre at 561 Eumundi–Noosa Road, Doonan. Dispersion modelling of odour emissions has been conducted using the approved regulatory dispersion model, CALPUFF. Ground-level concentrations of odour associated with the proposed composting operations have been predicted at nearby sensitive receptors and across a Cartesian grid of receptors. A cumulative assessment has been conducted including the addition of odour emissions from the existing landfill facility on the same site. The assessment has demonstrated that the composting facility will have a negligible odour impact, being highly unlikely to lead to odour impacts at sensitive receptors. The maximum predicted 99.5th percentile 1-hour average odour concentration at a sensitive receptor as a result of emissions from the composting operation in isolation is just 0.4 ou. The assessment has identified a greater likelihood of the landfill operations contributing to odour impacts, which is consistent with the small number of complaints received in relation to the landfill operations. The modelling, when applying highly conservative upper bound emission rates for landfill activities, has identified the potential for exceedance of the Odour Guideline of 2.5 ou at three properties (maximum concentration of 3.0 ou). Bearing in mind that odour impacts as a result of landfill operations have only been predicted in the worst-case upper bound emissions scenario, it is considered that consistent application of best practice management measures for controlling odours from landfills (such as consistent and comprehensive application of day cover, and prompt installation of gas extraction following filling of landfill cells) should be adequate to ensure that impacts are minimised, if not entirely prevented. The proposed composting operation, provided it is well-managed, will contribute negligibly to any odour impacts. Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page iv
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1. INTRODUCTION
Katestone Environmental Australia Pty Ltd (Katestone) has been commissioned by Noosa Council to conduct an
odour assessment of a proposed in-vessel composting activity to be located at the existing Noosa Resource
Recovery Centre at 561 Eumundi–Noosa Road, Doonan (Figure 1).
The Noosa Resource Recovery Centre includes an existing landfill operation and a green waste mulching
operation. Approximately 17,000 tonnes per year of green waste is currently accepted at the facility, being shredded
and stockpiled prior to export as mulch. The proposed development will see this green waste composted instead,
and the capacity increased such that up to 25,000 tonnes per year of green waste can be processed by aerated
in-vessel composting (with extraction of air to biofilter) as the basis of design, with the potential to increase capacity
to 30,000 tonnes per year in the future within the built infrastructure.
Up to 2,000 tonnes per year of food waste with an odour risk rating of Low or Medium (such as coffee grounds)
may also be added to the process, but High or Very High risk food wastes will not be accepted (ratings according
to the Queensland Government’s Best Practice Environmental Management Guideline ERA 53(a)—Organic
material processing by composting).
The proposed composting operations align with Noosa Council’s From Waste to Resource: Draft Waste Plan 2023
– 2028, and the community endorsed goal of 100% diversion of organic waste from landfill by 2030 (Orez, 2026).
This report consists of the following sections:
• Detailed description of the existing and proposed odour-generating operations (Section 2)
• Legislative framework (Section 3)
• Assessment methodology (Section 4)
• Existing environment (Section 5)
• Emissions to the atmosphere (Section 6)
• Results (Section 7)
• Conclusions (Section 8)
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Figure 1 Location of Noosa Resource Recovery Centre Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 2
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2. EXISTING AND PROPOSED OPERATIONS
2.1 Existing operations
The Noosa Resource Recovery Centre is the main waste management and recycling facility serving the Noosa
Shire. It is a resource recovery and recycling hub where residents and businesses can responsibly dispose of
waste and recycle a wide range of materials. The facility operates between the hours of 7am – 5pm daily.
In terms of odour sources, the existing waste facility includes:
• Vehicles delivering odorous loads of waste
• Unloading, handling and processing of odorous wastes
• Landfilling operations receiving primarily municipal solid waste, including emissions from waste deposited
at the active tipping face, fugitive emissions of landfill gas and emissions associated with leachate
management
• Stockpiling and shredding of green waste prior to being exported as mulch
The existing waste facility receives approximately 17,000 tonnes of green waste per year (between 1 July 2024 –
30 June 2025), being shredded and stockpiled prior to export as mulch.
Operations at landfill must be conducted according to Environmental authority EPPR01855314 (Department of
Environment and Science, 2024). Odour mitigation measures currently used at the landfill include the application
of day cover (soil) and final cover (clay), and gas extraction across the entire landfill.
Katestone understands there has been a small number of odour complaints from nearby residents, which have
been attributed to landfill operations. There is no history of odour complaints associated with emissions from green
waste storage and handling.
2.2 Proposed composting operations
The proposed operations described below are based on the PR25001 Noosa Composting Facility Process Design
Strategy (Orez, 2026).
The proposal will see food waste and green waste processed by aerated in-vessel composting to produce high-
quality compost rather than the mulch that is currently produced from the green waste currently accepted at the
site. The composting facility will be designed to process 25,000 tonnes per year of green waste initially, with the
flexibility to accommodate growth up to 30,000 tonnes per year within the built infrastructure. This represents a
diversion of the green waste already accepted at the existing waste facility, along with an 8,000 - 13,000 tonne
increase in capacity for green waste processing.
Green waste will be delivered, stockpiled and shredded in the same manner that occurs currently, but instead of
the shredded green waste being stockpiled in open piles, it will be transferred to the aerated in-vessel composting
system for the initial pasteurisation phase (approximately 21 days) of the composting process. The in-vessel
composting system will be enclosed and maintained under negative pressure, with the extracted air passed through
a biofilter for odour control prior to emissions to the atmosphere. Aeration will ensure aerobic conditions, which
minimise the generation of offensive odours while speeding up the composting process and producing a higher
quality final product.
Up to 2,000 tonnes per year of food waste may also be delivered to the in-vessel composting facility and mixed
with the green waste prior to in-vessel composting. Noosa Council has advised that this may include Low or Medium
odour risk wastes (per the odour ratings set out in the Queensland Government’s Model Operating Conditions and
Best Practice Environmental Management Guideline documents for ERA 53(a)—Organic material processing by
composting) but will not include High or Very High risk food wastes. This food waste will be delivered directly into
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the food waste receival hopper, a sealed vessel fitted with a hydraulic lid that will remain closed except during deliveries. Material will be transferred from the hopper by an enclosed screw conveyor to the shredder, which will be fed simultaneously with green organics so that blending occurs entirely within the shredding step. There will be no mixing of food waste in the open. The mixed material will be promptly transferred to the in-vessel composting system, minimising the time that this material has the potential to generate odour emissions to air. Air from within the in-vessel system is extracted to biofilter. Once pasteurisation has been achieved, the compost will be removed from the in-vessel system and stored in under cover maturation bays for approximately 6 weeks before being sold as finished compost. This area being covered will prevent ingress of water, which will minimise the potential for leachate generation and allow better management of moisture levels in the compost. 2.3 Odours from composting and proposed controls The delivery and storage of green waste can be expected to represent a minor odour source, except in cases when that waste is contaminated. In such cases, the odour potential may be high but effective management plans will ensure that highly odorous materials will be dealt with such that their emissions to air are either minimised or captured and treated (prioritised either for immediate shredding and composting or for disposal in the landfill). The Queensland Government’s Model Operating Conditions and Best Practice Environmental Management Guideline documents for ERA 53(a)—Organic material processing by composting set out odour ratings for different compost feedstocks, with each feedstock type rated either Low, Medium, High or Very High. Green waste is rated Low. Shredding of green waste generates odour, but these odours are not normally strong or offensive, and this activity is already taking place at the site. The delivery and storage of food waste rated Low or Medium will have greater odour potential, but this waste will be delivered directly into a sealed hopper, minimising the potential for odour emissions to air. Once fed to the shredder and mixed with green waste, the mixed material will be promptly transferred to the in-vessel composting system, minimising the time that this material will generate odour emissions to air. The green waste will also act as an in-situ biofilter once mixed with the food waste, reducing the potential for significant odour emissions from the food waste during the short period of time that it spends in the intermediate storage area prior to delivery to the in- vessel composting system. The pasteurisation phase of composting has the greatest odour-generating potential and the greatest potential to generate strong or offensive odours, as organic material is aerobically broken down by microbes. However, with this process taking place in-vessel with extraction of emissions to biofilter, the actual emissions to atmosphere will be small in magnitude and inoffensive in nature. Well-maintained biofilters typically achieve at least 90% odour removal efficiency and the residual odours that are emitted are generally inoffensive, being earthy/woody in character. Biofilters represent best practice odour control for this activity according to the Queensland Government’s Best Practice Environmental Management Guideline ERA 53(a)—Organic material processing by composting. Odour generation potential of the compost is significantly reduced once pasteurisation has been achieved. The maturation bays containing finished product can be expected to represent the main source of odour emissions to air from the proposed composting operations, due to their areal extent and their emissions not being captured and treated like those from the in-vessel composting system, but their emissions will be low in intensity and offensiveness, similar to store-bought compost. Odour emissions from finished product stored in maturation bays will be managed through routine monitoring of key compost parameters and regular turning to ensure continued stability and prevention of the development of anaerobic conditions. Given the reduced biological activity and controlled handling at this stage of the process, strong and/or offensive odour emissions during maturation are not expected. Therefore, the maturation bays represent a minor to moderate odour source. Odour emissions may Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 4
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increase during turning of the compost or export of material, but again these emissions can be expected to be low
in offensiveness.
The other potential source of odour from the composting operation will be leachate. Leachate may be generated
from wastes in the uncovered mixing and intermediate storage areas, product in the covered maturation bays and
by the in-vessel compost. Most leachate will be generated from the uncovered green waste stockpiles during and
following high rainfall events. All leachate will be captured and managed to minimise emissions.
Odour emissions from leachate will be managed by minimising the amount of leachate formed and capturing and
re-processing leachate where possible. While the leachate management strategy is under development, it is
currently anticipated that leachate and stormwater runoff will be managed as follows:
• Stormwater runoff from the green waste stockpiles will be directed to a high efficiency sediment (HES)
basin with integrated floating wetland for treatment. Stormwater from the green waste stockpiles is unlikely
to generate strong or offensive odours due to the relatively fresh nature of the organic matter in the
stockpiles, thus a HES basin is a suitable treatment option for this runoff. The HES basin will be dosed
with flocculant to assist with the removal of sediment.
• Leachate from the mixing and intermediate storage areas, static piles in the in-vessel composting system,
and from the maturation bays, will be collected and reused as process water in the in-vessel system.
Process water will be added to the piles upon formation for optimal moisture content and can continue to
be added during the pasteurisation phase to maintain optimal levels. Microorganisms that are contained
with the leachate can speed up the composting process.
• The process water will be stored in an enclosed tank ventilated into the tunnels building, so that any odour
emissions are treated by the biofilter.
• Leachate drainage systems will be inspected regularly and cleaned and desilted as needed, with any
residual material being incorporated into the compost mixing process.
• Visual inspections will be conducted to identify any areas of pooled leachate, and any leachate pools will
be cleaned up via sucker truck or absorbed with green waste to ensure that standing leachate is not
present for extended durations.
Leachate is not, therefore, expected to represent a significant potential source of odour emissions to air at the
composting facility.
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3. LEGISLATIVE FRAMEWORK FOR AIR QUALITY
3.1 Environmental authority
The existing waste facility operates under Environmental authority EPPR01855314 (Department of Environment
and Science, 2024), which includes the following Environmentally Relevant Activities (ERAs):
• ERA 54(2)(c)
• ERA 60(1)(a)
• ERA 62(1)(b)
• ERA 62(1)(c)
• ERA 62(2)
The proposed composting activities fall under ERA 53(a) – Organic material processing by composting and
therefore require an EA Amendment.
3.2 EP Act and Air EPP
Management of the air environment in Queensland is addressed under two key publications, the overarching
Environmental Protection Act 1994 (EP Act) which outlines fundamental principles, objectives, and powers related
to environmental regulation, including air quality management and the subordinate regulation to the EP Act, the
Environmental Protection Regulation 2019 (EP Regulation) which elaborates how the principles and objectives of
the EP Act are to be implemented and enforced.
The EP Act gives the Department of Environment, Tourism, Science, and Innovation (DETSI) the power to create
Environmental Protection Policies that identify, and aim to protect, environmental values of the atmosphere that
are conducive to the health and well-being of humans and biological integrity. The specific policy relating to air
quality is The Environmental Protection (Air) Policy and its amendment the Environmental Protection (Air)
Amendment Policy 2024 (Air EPP).
The objective of the Air EPP is:
...to identify the environmental values of the air environment to be enhanced or protected and to achieve the
objective of the Environmental Protection Act 1994, i.e. ecologically sustainable development.
The environmental values to be enhanced or protected under the Air EPP are the qualities of the environment that
are conducive to:
• Protecting health and biodiversity of ecosystems;
• Human health and wellbeing;
• Protecting the aesthetics of the environment, including the appearance of building structures and other
property; and
• Protecting agricultural use of the environment.
Section 8 of the Air EPP defines the management hierarchy to be implemented to the extent that is reasonable to
do so for emissions that affect, or may affect, an environmental value, as having the following order of preference:
avoid emissions e.g. using technology that avoids air emissions; recycles air emissions e.g. re-using air emissions
in another industrial process; minimises air emissions e.g. using technology, materials or industrial processes that
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minimise air emissions; manages air emissions e.g. suitably locating sources, treating emissions before release,
or sufficiently dispersion air emissions to minimise impacts.
The administering authority must consider the requirements of the Air EPP when it decides an application for an
environmental authority, amendment of a licence or approval of a draft environmental management plan. Schedule
1 of the Air EPP specifies air quality indicators and objectives for specific air pollutants.
Further to the Air EPP, DETSI has provided the Guideline: Application requirements for activities with impacts to
air, ESR/2015/1840 (Impacts to Air Guideline) which focuses on the types of impacts that an ERA can have on air.
The Guideline is relevant to the Noosa Resource Recovery Centre and the proposed composting operations and
outlines the information to be provided to DETSI as part of an ERA application process. In general, the Guideline
considers three key areas to be identified and addressed through an ERA application process:
• Identifying the environmental values of the receiving air environment including the identification of any
nearby sensitive places (Section 5)
• Identifying the possible impacts of the proposed activity and all associated risks to the environmental
values (Section 7)
• Identifying the strategies to mitigate the identified risks to the environmental values (Section 2)
The term ‘environmental value’ is generally used to describe the physical, aesthetic, social and cultural values of a
location or proposed site. Specific environmental values relevant to air are defined in the Air EPP. This memo has
been prepared in line with guidance provided in the Impacts to Air Guideline.
3.3 Guideline: Odour Impact Assessment from Developments
DETSI has published the Guideline: Odour Impact Assessment from Developments, ESR/2024/6828 (Odour
Guideline) to set out “various approaches to assess potential [odour] impacts from new development proposals”.
In addition to approaches to odour impact assessment, the Odour Guideline also provides guidance on modelling
approaches, odour impact assessment criteria, and supporting guidance on measurement, sampling, modelling
and meteorology. The Odour Guideline was most recently updated in 2024.
This assessment has been conducted in accordance with the guidance provided in the Odour Guideline.
The Odour Guideline specifies an impact assessment criterion of 2.5 ou as a 1-hour average, 99.5th percentile for
ground-level sources and wake-affected stacks, which has been adopted for this assessment.
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4. ASSESSMENT METHODOLOGY
4.1 Existing environment
The assessment includes an analysis of the characteristics of the existing environment (Section 5) that are
important for the dispersion of air pollutants. Characteristics include terrain features, regional land uses, existing
sources of emissions, and the locations of sensitive receptors relative to the sources.
4.2 Operational emissions
The following subsections describe the methods used to determine representative, conservative odour emission
rates from the composting and landfill operations that have been assessed. No odour sampling has historically
been conducted at the Noosa Resource Recovery Centre and, given that the composting facility does not yet exist,
it is necessary to rely on the scientific literature for representative odour emission rates. Emission rates have been
identified from a literature review considering assessments of similar facilities, many of which incorporated odour
sampling. 15 odour assessments of composting facilities have been reviewed, alongside 18 assessments of
landfills.
Odour emission rates (ou/s), provided in full in Section 6, were calculated by multiplying the odour emission rate
(ou/m2/s) by the area of emission of the corresponding source.
Modelled emission rates have been chosen to be conservatively representative of the activities occurring at the
site, and to be consistent with previous assessments of composting and landfill facilities within Queensland. The
emission rates used are considered high for the types of waste proposed (noting that the proposed composting
operation will only accept Low and Medium odour risk wastes, whereas most composting facilities accept higher
odour risk waste) and therefore the predictions of the dispersion modelling exercise can be considered worst-case,
and likely an over-prediction of actual impacts.
4.2.1 Composting operation
The modelled sources of odour produced by the composting operations (and their identified odour emission rates)
are detailed in Table 1. The locations of the odour sources as modelled are presented in Figure 2. The emission
rates were sourced as follows:
• The odour emission rate of 2.4 ou/m2/s used for green waste is based on sampling of green waste at a
composting facility in Swanbank, QLD. It is by far the highest odour emission rate for green waste
identified in the literature review – in most cases emission rates for green waste are well below 1 ou/m2/s.
It is, therefore, highly conservative.
• The odour emission rate of 4.0 ou/m2/s used for freshly mixed waste is based on the emission rate for
food organics and garden organics (FOGO) from the EAQ Consulting report for Red Hill Waste
Management Facility in Western Australia (2020). This emission rate is considered highly conservative
for the proposed composting operation, given that it will not accept FOGO, rather mixing some Low and
Medium odour risk food wastes with green waste.
• The odour emission rate of 1.85 ou/m2/s used for the biofilter was taken from an assessment of a proposed
in-vessel composting facility in Swanbank, QLD. This facility accepts solid and liquid waste with High and
Very High odour risk ratings and would, therefore, be expected to have significantly higher odour
emissions treated by its biofilter, as compared to the proposed composting operation. Well-maintained
biofilters are typically at least 90% efficient at removing odour and given that the proposed composting
operation will only accept Low and Medium odour risk wastes, it can reasonably be expected that
emissions from the biofilter will be well below 1.85 ou/m2/s. Therefore, the use of this emission rate is
conservative.
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• The odour emission rate of 0.672 ou/m2/s used as the average for the maturation bays has been taken
from the assessment of another composting facility in QLD, one which received a mixture of green waste,
solid wastes, and liquid wastes with a higher odour risk rating than the proposed composting operation.
The emission rate represents a scaled average based on odour sampling of compost of age 4, 6, 10 and
16 weeks. Given the wastes accepted at the sampled facility, it is considered likely to represent a
conservatively high average odour emission rate for the maturation bays at the proposed composting
operation.
Overall, the types of wastes and procedures assessed by the selected literature are likely to be suitably
representative of operations and odour generation at the proposed composting facility.
Table 1 Odour emission rates for composting operations
Odour emission rate
Odour emission source Site-specific sources
(ou/m2/s)
Green waste Commercial drop1, Public drop 2.4
Freshly mixed waste Bunker, Freshly mixed compost 4
Air from tunnels and other enclosed areas Biofilter 1.85
Pasteurised compost Maturation bays 0.672
Table note:
1
The area marked commercial drop was originally understood to be a location for a green waste stockpile. This has since
been revised so that this stockpile (of the same area) is to be located to the southwest, where it is annotated “STOCKPILE
285 m2”. This source being located ~30 m further to the west than where it has been modelled will not have a material
influence on the modelling outcomes or assessment conclusions. This is discussed further in Section 7.
Figure 2 Layout of odour sources at the proposed composting facility
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4.2.2 Landfill
The modelled sources of odour produced by the landfill operations (and their odour emission rates) are detailed in
Table 2. The locations of the odour sources as modelled are presented in Figure 3. Four different spatial layouts
have been assessed to reflect the range of possible operations at landfill. Where cumulative results incorporating
the landfill emissions are presented, these are the maximum 99.5 th percentile of 1-hour average concentrations at
each receptor across any of the landfill layout scenarios after combination with the contribution of the proposed
composting operation.
The emission rates were sourced as follows:
• The active tip face is typically the most significant source of odour from a landfill receiving municipal solid
waste (MSW). Active tip face odour emissions can be highly variable, therefore lower and upper bound
emission rates have been identified to represent a realistic range of potential impacts.
o The lower bound odour emission rate of 1.27 ou/m2/s used for the active tip face was derived
from sampling at a landfill in QLD that receives primarily construction and demolition (C&D)
waste. It is relatively low for a landfill active tipping face, but likely representative of emissions
from the Noosa Resource Recovery Centre landfill active tip face much of the time.
o The upper bound odour emission rate of 7.06 ou/m2/s used for the active tip face was derived
from sampling at a landfill in Stapylton, QLD that receives a mix of wastes, including MSW. It is
a very high odour emission rate and emissions from the Noosa Resource Recovery Centre
landfill active tip face are likely to be much lower than this the majority of the time. Modelled
concentrations that assume this emission rate throughout the day are, therefore, likely to
represent over-estimates of the impact of the landfill.
o Noosa Council has estimated that, at night, the active tip face is covered with 70% consistency;
therefore, between 6pm – 6am, the active tip face has been modelled with an emission rate that
assumes 70% day cover and 30% uncovered active tip face emissions.
• The day cover odour emission rate of 0.35 ou/m2/s was derived from sampling at the same landfill in
Stapylton as the upper bound active tipping face emission rate, and represents a high emission rate for
covered material, compared to other literature values. It has been used across the upper and lower bound
scenarios as a conservative emission rate for covered waste.
• The final cover emission rates of 0.03 ou/m2/s and 0.10 ou/m2/s were also derived from sampling at the
same landfill in Stapylton, QLD. The lower bound emission rate is the maximum from sampling of final
capped areas, while the upper bound emission rate is the average emission rate from interim capped
areas, applied as a conservative representation of potential emissions bearing in mind that the application
of final cover tends to occur in stages.
Table 2 Odour emission rates for landfill operations
Odour emission rate (ou/m2/s)
Odour-generating area
Lower bound Upper bound
Active tip face 1.27 (day) 0.63 (night) 7.06 (day) 2.36 (night)
Day cover 0.35
Final cover 0.03 0.10
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Figure 3 Layout of odour sources at the existing landfill facility (four layouts tested) 4.3 Meteorology The same meteorological input files to the CALPUFF dispersion model have been used as were used in a previous Katestone assessment of the Noosa Resource Recovery Centre. That assessment selected 2020 as the representative year, which is still considered representative and is therefore used in this assessment. The modelling was conducted using the most recent versions of the TAPM (version 4.0.5) and CALMET (version 6.5.0) models at the time of undertaking the modelling. A site-specific meteorological data file was generated for the facility by coupling the prognostic model TAPM with the diagnostic meteorological model CALMET. The coupled TAPM/CALMET modelling system was developed to enable high resolution modelling capabilities for regulatory and environmental assessments. The modelling system incorporates synoptic, mesoscale, and local atmospheric conditions, detailed topographic and land use categorisation schemes to simulate synoptic and regional scale meteorology for input into pollutant dispersion models such as CALPUFF. Technical details of the TAPM and CALMET model configurations are provided in Appendix A, including a validation of the generated data and a summary of the meteorological data generated for the study area. 4.4 Dispersion modelling The CALPUFF model (version 7.2.1) was used for dispersion modelling. CALPUFF is an advanced non-steady- state air quality modelling system. Twelve months of modelled meteorological data was used as input for the dispersion model in order to include all weather conditions likely to be experienced in the region during a typical year, as described in Appendix A. Emission sources were configured in CALPUFF based on the emissions information and geometry for each source detailed in Section 4.2 and in Appendix A. Details of the model configuration are provided in Section A2 of Appendix Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 11
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A. While some sources at the composting facility (such as the maturation bays) will be covered to prevent ingress
of rainfall, all sources have been modelled as open area sources.
4.5 Presentation of results
Dispersion modelling results are presented for the composting facility in isolation, and in combination with existing
odour sources at the site (the landfill).
Odour emissions from the composting operation can be expected to be very different in character to those of the
landfill operations, being more earthy/woody/compost as compared to the sweet/rotten/pungent/sulphurous odours
commonly generated by landfill operations. Such different odours do not tend to have a cumulative effect in terms
of the odours from the different activities combining to make a stronger or more offensive odours; odours simply
do not tend to combine or interact in such a way. However, to provide a conservative estimate of the impact of
odour emissions due to the Noosa Resource Recovery Centre as a whole, this report presents odour from the
landfill and composting operations cumulatively.
4.6 Limitations and uncertainty
This study relies on the accuracy of a number of data sets that feed into the dispersion model, all of which will have
uncertainties associated with them. The input data sets include:
• Operational information for the Noosa Resource Recovery Centre provided by Noosa Council
• Emissions data derived from literature
• Meteorological monitoring observations from the Bureau of Meteorology
• Synoptic and surface information datasets from CSIRO.
It is also important to note that numerical models are based on an approximation of governing equations and will
inherently be associated with some degree of uncertainty. The more complex the physical model, the greater the
number of physical processes that must be included. There will be physical processes that are not explicitly
accounted for in the model and, in general, these approximations tend to lead to an over prediction of air pollutant
levels.
The dispersion model has been configured with conservative assumptions and, therefore, the assessment is likely
to overpredict the potential impacts of the proposed composting operations.
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5. EXISTING ENVIRONMENT 5.1 Local terrain and land-use The Noosa Resource Recovery Centre is located approximately 7.6 km from the Queensland coastline, southwest of Noosa. The terrain of the area (Figure 4) is relatively low lying, with the site at around 30 m above Australian Height Datum (m AHD). Terrain to the east towards the coastline is relatively low lying between 0 and 20 m AHD, including Lake Weyba located just over 2 km to the east. Elevation increases in areas west of the site, up to a peak of around 240 m AHD, 5 km to the west. There are no significant terrain features in the immediate area surrounding the Noosa Resource Recovery Centre. Figure 4 Terrain of the area surrounding the Noosa Resource Recovery Centre Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 13
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5.2 Sensitive receptors
Nearby sensitive receptors included in the model are identified in Table 3 and Figure 5. The receptors are a mix of
residential and commercial premises, as well as the Noosa Pengari Steiner School, located approximately 1.5 km
south of the Noosa Resource Recovery Centre. A Cartesian grid of receptors has also been modelled to enable
production of contour plots of odour concentrations.
Table 3 Sensitive receptors included in the dispersion model
Receptor ID Description Location
R1 to R14 Residential ~ 1.4 to 1.7 km east
R15 Commercial (Noosa Horse Riding) ~ 1.4 km east
R16 to R20 Noosa Pengari Steiner School ~ 1.0 km south
R21 to R22 Residential ~ 0.8 km south
R23 Residential ~ 0.6 km southwest
R24 to R26 Commercial ~ 0.4 km southwest
R27 to R29 Commercial ~ 0.4 km southwest
R30 to R36 Residential ~ 0.5 to 0.8 km west
R37 to R41 Residential ~ 0.7 to 0.9 km northwest
R42 to R45 Residential ~ 0.2 to 0.6 km north-northwest
R46 to R50 Residential ~ 0.9 to 1.0 km north-northeast
Figure 5 Locations of nearest sensitive receptors
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5.3 Existing sources of emissions National Pollutant Inventory (NPI) reporting data for industries with significant emissions to air for the period 2024/2025 was reviewed to identify other potentially odorous major industries near to the Noosa Resource Recovery Centre. The nearest industry likely to produce odours is the Noosa Coastal Sewage Treatment Plant approximately 6.2 km to the northeast. The Sewage Treatment Plant is likely to exhibit a different odour profile to sources at the Noosa Resource Recovery Centre and is sufficiently distant that cumulative impacts are considered highly unlikely. Therefore, there are no nearby sources that are likely to have significant emissions of odour that are similar to the composting and landfill odour characters. 5.4 Meteorology Local meteorology is of paramount importance for dispersion of odour emissions generated by the facility’s activities; key features are wind speed, wind direction, atmospheric stability and boundary layer mixing height. Conditions in the local area, as derived from the meteorological modelling carried out for the assessment, are discussed in detail in Section A1.5 of Appendix A, but can be summarised in simple terms based upon the wind rose presented in Figure 6, which summarises the wind speed and direction in 2020. Predicted annual average wind speed at the site in 2020 was 1.87 m/s, with winds most commonly coming from the southeast through to south-southwest. Average dispersion of pollutants can be expected to follow this general pattern; however, peak odour impacts may occur under specific meteorological conditions and odour impact contours should not necessarily be expected to align with the prevailing wind conditions. Figure 6 Annual wind rose for the site for 2020 (extracted from TAPM/CALMET) Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 15
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6. EMISSIONS TO THE ATMOSPHERE
Modelled source areas, odour emission rates, and total odour emissions for the proposed composting operations
are presented in Table 4. Further details of the source configuration in the dispersion modelling assessment are
provided in Section A2 of Appendix A. The layout of modelled sources is shown in Figure 2.
For the composting facility, the modelled areas were determined based on the provided site layout, while also being
informed by the precise design areas; the drawn areas are all marginally greater than the design areas, which is
conservative. Noosa Council provided the following design areas for individual sources:
• Commercial drop / green waste stockpile – 285 m2
• Public drop – 394 m2
• Maximum area occupied by freshly mixed compost - 140 m2
• Biofilter – 200 m2
• Maturation bays – 1,128 m2
Table 4 Composting operations odour emission rate summary
Modelled source area Emission rate Emission rate
Source
(m2) (ou/m2/s) (ou/s)
Commercial drop 287.0 2.4 688.7
Public drop 384.3 2.4 922.3
Bunker 109.4 4.0 437.6
Freshly mixed compost 140.1 4.0 560.3
Biofilter 212.6 1.9 393.3
Maturation bays 1,551.4 0.7 1,042.5
Total odour emissions - 4,044.7
Modelled source areas, odour emission rates, and total odour emissions for the landfill operations are presented
in Table 5 for the lower bound emissions scenario and in Table 6 for the upper bound emissions scenario. The
areas and emission rates presented are for the layout whereby the active tip face is located to the southwest of the
landfill (bottom left in Figure 3), but care has been taken to ensure that differences in source areas and total
emissions rates between the four scenarios are minimal. Further details of the source configuration in the dispersion
modelling assessment are provided in Section A2 of Appendix A.
For the landfill, modelled source areas were determined based on specific information provided by Noosa Council
alongside staged filling plans. The following key inputs were considered:
• Noosa Council advised that the active tip face area can range from 900-1,500 m2. The maximum stated
area has been used, which is conservative.
• Noosa Council advised that the area covered with day cover only typically averages 12,000 m 2.
• It was assumed that the remainder of the landfill area had final cover applied – Noosa Council has advised
that gas extraction covers the entire landfill, therefore this is a reasonable assumption, and the upper
bound emission rate may over-state odour emissions from the covered areas of the landfill.
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Table 5 Landfill operations lower bound odour emission rate summary
Modelled source Emission rate (ou/m2/s) Emission rate (ou/s)
Source
area (m2) Day Night Day Night
Active tip face 1,504.2 1.27 0.63 1,914.8 943.0
Day cover 12,020.7 0.35 4,207.2
Final cover 35,201.6 0.03 1,056.0
Total odour emissions - - 7,178.1 6,206.3
Table 6 Landfill operations upper bound odour emission rate summary
Modelled source Emission rate (ou/m2/s) Emission rate (ou/s)
Source
area (m2) Day Night Day Night
Active tip face 1,504.2 7.06 2.36 10,619.4 3,554.4
Day cover 12,020.7 0.35 4,207.2
Final cover 35,201.6 0.10 3,520.2
Total odour emissions - - 18,346.8 11,281.8
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7. RESULTS
Table 7 presents the maximum modelled odour concentrations at any of the specific sensitive receptors (detailed
in Table 3) for the composting in isolation, and for the composting and landfill facilities combined, with the results
reflecting the landfill with both lower-bound and upper-bound emission rates. A contour plot of the proposed
composting operation’s modelled contribution in isolation is presented later in Plate 1, and in combination with the
landfill in Plate 2 (lower bound landfill emissions) and Plate 3 (upper bound landfill emissions).
The results demonstrate the following:
• The footprint of odour impacts from the composting operations in isolation is very small, with a maximum
99.5th percentile 1-hour average odour concentration at a sensitive receptor of just 0.4 ou, and the contour
in Plate 1 demonstrating that odour impacts will largely be confined within the facility boundary. Given
how small the contribution of the landfill is to odour concentrations, it is obvious that the change of location
of the green waste stockpile referred to as “Commercial drop”, as described in Table 1, is of no
consequence in terms of potential odour impacts.
• When considered cumulatively with the lower bound landfill odour emissions, impacts remain small, with
a maximum 99.5th percentile 1-hour average concentration of 1.4 ou. The contribution of the composting
operation to cumulative concentrations is negligible.
• When considered cumulatively with the upper bound landfill odour emissions, the maximum 99.5th
percentile 1-hour average concentration exceeds the odour guideline at three properties to the southwest
of the facility. The contribution of the composting operation to these cumulative concentrations is
negligible. These predictions likely over-state the probable impacts of the combined Noosa Resource
Recovery Centre operations, but at the same time are consistent with there having been complaints
associated with the landfill operations.
In simple terms, the results demonstrate that the composting facility will have a negligible odour impact, being
highly unlikely to lead to odour impacts at sensitive receptors. There will remain a potential for the landfill operations
to cause impacts, but consistent application of best practice management measures for controlling odours from
landfills (such as consistent and comprehensive application of day cover, and prompt installation of gas extraction
following filling of landfill cells) should be adequate to ensure that impacts are minimised, if not entirely prevented.
The proposed composting operation, provided it is well-managed, is highly unlikely to contribute meaningfully to
any odour impacts.
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Table 7 Maximum dispersion modelling results for sensitive receptors
99.5th percentile 1-hour average (ou)
Receptor
Description Composting in Cumulative with landfill
ID
isolation Lower bound Upper bound
R1 to R14 Residential 0.1 0.3 0.6
R15 Commercial (Horse Riding) 0.1 0.3 0.6
R16 to R20 School 0.2 0.6 1.2
R21 to R22 Residential 0.3 0.8 1.6
R23 Residential 0.4 0.9 1.9
R24 to R26 Commercial 0.4 1.4 3.0
R27 to R29 Commercial 0.4 1.1 2.4
R30 to R36 Residential 0.3 0.7 1.2
R37 to R41 Residential 0.1 0.2 0.3
R42 to R45 Residential 0.4 0.8 1.4
R46 to R50 Residential 0.4 0.7 1.1
Max at any receptor (and % of odour
0.4 (18%) 1.4 (57%) 3.0 (121%)
guideline)
Odour guideline 2.5 ou
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8. CONCLUSIONS Katestone Environmental Australia Pty Ltd (Katestone) was commissioned by Noosa Council to conduct an odour assessment of a proposed in-vessel composting activity to be located at the existing Noosa Resource Recovery Centre at 561 Eumundi–Noosa Road, Doonan. Dispersion modelling of odour emissions has been conducted using the approved regulatory dispersion model, CALPUFF. Ground-level concentrations of odour associated with the proposed composting operations have been predicted at nearby sensitive receptors and across a Cartesian grid of receptors. A cumulative assessment has been conducted including the addition of odour emissions from the existing landfill facility on the same site. The assessment has demonstrated that the composting facility will have a negligible odour impact, being highly unlikely to lead to odour impacts at sensitive receptors. The maximum predicted 99.5th percentile 1-hour average odour concentration at a sensitive receptor as a result of emissions from the composting operation in isolation is just 0.4 ou. The assessment has identified a greater likelihood of the landfill operations contributing to odour impacts, which is consistent with the small number of complaints received in relation to the landfill operations. The modelling, when applying highly conservative upper bound emission rates for landfill activities, has identified the potential for exceedance of the Odour Guideline of 2.5 ou at three properties (maximum concentration of 3.0 ou). Bearing in mind that odour impacts as a result of landfill operations have only been predicted in the worst-case upper bound emissions scenario, it is considered that consistent application of best practice management measures for controlling odours from landfills (such as consistent and comprehensive application of day cover, and prompt installation of gas extraction following filling of landfill cells) should be adequate to ensure that impacts are minimised, if not entirely prevented. The proposed composting operation, provided it is well-managed, is highly unlikely to contribute meaningfully to any odour impacts. Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 20
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9. REFERENCES Department of Environment and Science, 2024, Environmental Authority EPPR01855314 DETSI, 2024, Guideline – Odour Impact Assessment from Developments, ESR/2024/6828 DETSI, 2025, Guideline – Application requirements for activities with impacts to air, ESR/2015/1840 EAQ Consulting, 2020, Desktop Odour Impact Assessment of Proposed FOGO Stage 1 Noosa Council, 2023, From Waste to Resource: Draft Waste Plan 2023 – 2028 Orez, 2026, PR25001 Noosa Composting Facility Process Design Strategy Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 21
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Plate 1 Predicted maximum (99.5th percentile) 1-hour average ground-level
concentrations of odour due to emissions from composting operations in
isolation
Location: Averaging period: Data source: Units:
Noosa, Queensland 1-hour CALPUFF ou
Type: Objective: Prepared by: Date:
Contour plot 2.5 ou (DETSI odour Joel von Treifeldt September 2026
guideline)
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Plate 2 Predicted cumulative maximum (99.5th percentile) 1-hour average ground-level
concentrations of odour due to composting operations emissions and lower-
bound landfill operations emissions
Location: Averaging period: Data source: Units:
Noosa, Queensland 1-hour CALPUFF ou
Type: Objective: Prepared by: Date:
Contour plot 2.5 ou (DETSI odour Joel von Treifeldt September 2026
guideline)
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Plate 3 Predicted cumulative maximum (99.5th percentile) 1-hour average ground-level
concentrations of odour due to composting operations emissions and upper-
bound landfill operations emissions
Location: Averaging period: Data source: Units:
Noosa, Queensland 1-hour CALPUFF ou
Type: Objective: Prepared by: Date:
Contour plot 2.5 ou (DETSI odour Joel von Treifeldt September 2026
guideline)
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APPENDIX A METEOROLOGICAL AND DISPERSION MODELLING
METHODOLOGY
A1 Meteorology
The meteorological modelling methodology for the assessment included the following steps:
• Selection of a representative year
• TAPM modelling and validation
• CALMET modelling
The same meteorological input files to CALPUFF have been used as were used in a previous Katestone’s 2024
assessment (Katestone deliverable D23098-2). Refer to the previous report for details of the meteorological model
configuration.
The following sections describe each step of the meteorological modelling conducted. A summary of the
meteorological data generated is provided in Section A1.5.
A1.1 Selection of representative year
A representative year is required to be selected at the beginning of the meteorological modelling process. Using a
representative year in the air quality assessment ensures that the typical conditions experienced at the
development site are reflected in the model. Selection of a representative year has been done through statistical
analysis of historical meteorological observations at the Bureau of Meteorology (BoM) automatic weather station
(AWS) located at Tewantin. Meteorological observations from five years (2018 to 2022) at Tewantin were analysed
to assess the inter-annual variability.
Figure A1 presents annual wind roses for the five years and shows that inter-annual conditions are typically very
similar. Figure A2 presents frequency distribution plots for humidity, wind direction, wind speed, and temperature
and demonstrates that there is relatively little variation in the distribution of these variables year-on-year. Figure A3
presents Z-Scores for each variable for each year, these being a measure of the variation of values in each
individual year against the mean of values across all years.
The calendar year 2020 has been used for the modelling as it is judged to be the year with the least variation from
the mean when averaged across all of the parameters considered.
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Figure A1 Annual wind roses for Tewantin between 2018 and 2022
Figure A2 Annual frequency distribution plots for Tewantin between 2018 and 2022 (highlighting
year selected 2020)
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Figure A3 Z scores for Tewantin between 2018 and 2022
A1.2 TAPM meteorological modelling configuration
TAPM (The Air Pollution Model) was developed by the CSIRO and has been validated by the CSIRO, Katestone
and others for many locations in Australia, in south-east Asia and in North America (CSIRO, 2008). Katestone has
extensive experience with TAPM for sites throughout Australia and in parts of America, Bangladesh, New
Caledonia and Vietnam. The model performs well in simulating regional wind patterns and has proven to be a
useful tool for simulating meteorology in locations where monitoring data providing the vertical distribution of
meteorological parameters are unavailable.
TAPM is a prognostic meteorological model which predicts the flows important to regional and local scale
meteorology, such as sea breezes and terrain-induced flows from the larger-scale meteorology provided by the
synoptic analyses. TAPM solves the fundamental fluid dynamics equations to predict meteorology at a mesoscale
(20 km to 200 km) and at a local scale (down to a few hundred metres). TAPM includes parameterisations for
cloud/rain micro-physical processes, urban/vegetation canopy, soil type and radiative fluxes.
TAPM requires synoptic meteorological information for the region. This information is generated by a global model
similar to the large-scale models used to forecast the weather. The data were supplied on a grid resolution of
approximately 75km, and at elevations of 100m to 5km above the ground. TAPM uses this synoptic information,
along with specific details of the location such as surrounding terrain, land-use, soil moisture content and soil type
to simulate the meteorology of a region as well as at a specific location.
TAPM version 4.0.5 was configured with the following parameters:
• Modelling period from 1 January 2020 to 31 December 2020
• 48 x 48 grid point domain with nesting resolutions of 30 km, 10 km, 3 km, 1 km, and 300 m
• 25 vertical levels
• Grid centred on latitude -26° 26.5’, longitude 153° 1.5’
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• Geoscience Australia 9 second DEM terrain data
• TAPM default land cover data edited to be consistent with aerial imagery
• Default options selected for advanced meteorological inputs
• Data from the BoM AWS located at Tewantin assimilated over one vertical level with a radius of influence
of 5km and a quality factor of 0.9.
A1.3 Comparison of TAPM output with observational data
A1.3.1 Overview
The model validation in this section compares observational data with data derived from running TAPM after
assimilating data from the BoM station at Tewantin. TAPM was originally run without data assimilation and the
predicted meteorological data was compared to observational data at the Tewantin station. The initial model
validation, prior to the assimilation of the BoM Tewantin data, showed that the model generally performed well at
simulating the meteorology across the region; however, the model was underpredicting calm winds (< 1 m/s) from
the south-southwest through to north-northwest as well as stronger winds from the south and northeast directions.
TAPM was also over-predicting the frequency of southeast direction.
The second iteration was run using the assimilation of the observational data at the BoM station at Tewantin in
order to improve the accurately of the model’s predictions to align more closely with the observational
meteorological data.
A1.3.2 Validation of TAPM modelling
The following section presents the results of the validation of the final TAPM run that was used for the dispersion
modelling assessment. The model validation compares the BoM Tewantin observational meteorological data with
data extracted from TAPM at the location of the Tewantin monitoring station.
Figure A4 shows probability density functions that graphically compare statistical distributions of meteorological
parameters between the TAPM output and BoM observational data. Table A1 presents statistical comparisons of
TAPM output (wind speed and temperature) to meteorological data recorded at the BoM monitoring station. The
TAPM output was extracted from the closest inner grid point to the location of the weather station.
The following statistical measures of model accuracy are presented in the tables:
• The mean bias, which is the mean model prediction minus the mean observed value. Values of the mean
bias close to zero show good prediction accuracy.
• The root mean square error (RMSE), which is the standard deviation of the differences between predicted
values and observed values. The RMSE is non-negative and values of the RMSE close to zero show
good prediction accuracy. The RMSE is given by
1 N
RMSE = ( Pi − Oi ) 2
N i =1
where N is the number of observations, Pi are the hourly model predictions and Oi are the hourly
observations
• The index of agreement (IOA), which takes a value between 0 and 1, with 1 indicating perfect agreement
between predictions and observations. The IOA is calculated following a method described in Willmott
(1982), using the equation
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N
(P − O )
i i
2
IOA = 1 − N i =1
(| P − O
i =1
i m ean | + | Oi − Om ean |) 2
where N is the number of observations, Pi are the hourly model predictions, Oi are the hourly observations
and Omean is the observed observation mean.
The probability density functions illustrate good agreement between predicted and observed meteorological data,
which is to be expected given the assimilation of data at the Tewantin monitoring station. The wind speeds and
temperatures generated by TAPM are within the benchmark ranges for Bias, RMSE and index of agreement for
the BoM Tewantin monitoring station.
The results of the validation showed that the model generally performed well at simulating the meteorology across
the region, with assimilation of the BoM Tewantin observational data significantly improving the model’s predictions.
Figure A4 Probability density functions comparing 2020 observational data (blue) with TAPM data
(red) at the location of the BoM Tewantin monitoring station
Table A1 A comparison of the observational meteorological data with the TAPM output for 2020
at the location of the BoM Tewantin monitoring station
Wind speed Temperature
“Good”
Statistic Observational Observational
value Benchmark TAPM Benchmark TAPM
data data
Mean - - 2.6 2.6 - 21.1 21.0
SD - - 1.6 1.4 - 4.6 3.9
Min - - 0.0 0.0 - 5.7 8.7
Max - - 8.6 7.6 - 34.1 33.7
Bias 0 <±0.5 m/s -0.02 <±0.5 m/s -0.11
Close to
RMSE < 2 m/s 0.73 - 1.87
0
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Wind speed Temperature
“Good”
Statistic Observational Observational
value Benchmark TAPM Benchmark TAPM
data data
Close to
IoA >0.6 0.94 >0.6 0.95
1
A1.4 CALMET meteorological modelling configuration
CALMET is an advanced non-steady-state diagnostic 3D meteorological model with micro-meteorological modules
for overwater and overland boundary layers. The model is the meteorological pre-processor for the CALPUFF
modelling system. CALMET is capable of reading hourly meteorological data as data assimilation from multiple
sites within the modelling domain; it can also be initialised with the gridded three-dimensional prognostic output
from other meteorological models such as TAPM. This can improve dispersion model output, particularly over
complex terrain as the near surface meteorological conditions are calculated for each grid point.
CALMET version 6.5.0 was used to simulate meteorological conditions in the region. The CALMET simulation was
initialised with the gridded TAPM 3D wind field data from the 300 m grid. CALMET treats the prognostic model
output as the initial guess field for the CALMET diagnostic model wind fields. The initial guess field is then adjusted
for the kinematic effects of terrain, slope flows, blocking effects and 3D divergence minimisation.
CALMET was configured with the following selections:
• Modelling period from 1 January 2020 to 31 December 2020.
• 120 x 120 grid point domain with 100 m resolution, nested within the TAPM inner domain.
• 12 vertical levels at heights of 20, 60, 100, 150, 200, 250, 350, 500, 800, 1600, 2600 and 4600 metres.
• Prognostic wind fields generated by TAPM input as MM5/3D.DAT at surface and upper air for “initial
guess” field (no-observations mode).
• Gridded cloud cover from prognostic relative humidity at all levels.
• No extrapolation of surface wind observations to upper layers.
Terrain radius of influence of 3.0 km.
A1.5 Summary of site meteorology
The following sections provide a description of the CALMET outputs as utilised in the CALPUFF dispersion
modelling for the meteorological parameters that are important for the dispersion of air pollutants in the atmosphere,
namely wind speed, wind direction, atmospheric stability, and mixing layer height. These parameters have been
extracted from the TAPM/CALMET dataset at the proposed development site.
A1.5.1 Wind speed and wind direction
The annual distribution of winds predicted by TAPM/CALMET for 2020 is presented in Figure A5. The seasonal
and diurnal distribution of winds are presented in Figure A6 and Figure A7, respectively.
Winds across the study area are predominantly light to moderate (up to around 5 m/s) and from the southeast to
south-southwest, with a slightly lower frequency from the north-northwest through to east-southeast direction. The
lowest frequency of winds occurs from the west to northwest direction.
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The seasonal breakdown of winds shows that the predominant southeast to southwest winds are lighter and most frequent during the cooler autumn and winter months. Summer, and to a lesser extent spring, are characterised by stronger winds and an increase in frequency from the north-northwest to east direction. The diurnal breakdown of winds shows that the strongest winds are predicted during the afternoon (midday to 6pm) when winds are predominantly from the north-northeast to south-southeast. During the evening (6pm to midnight) winds are lighter and from the southeast to southwest and from the north-northwest to north-northeast. Winds drop in strength during the night (midnight to 6am) and increase in frequency direct from the south-southwest. Morning winds (*6am to midday) show the transition through to afternoon winds, increasing in strength as well as in the frequency from the southeast. Figure A5 2020 annual distribution of winds predicted by TAPM/CALMET Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 31
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Figure A6 2020 seasonal distribution of winds predicted by TAPM/CALMET Figure A7 2020 diurnal distribution of winds predicted by TAPM/CALMET A1.5.2 Atmospheric stability Stability classification is a measure of the stability of the atmosphere and can be determined from wind measurements and other atmospheric observations. The stability classes range from A Class, which represents Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 32
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very unstable atmospheric conditions that may typically occur on a sunny day, to F Class, which represents very stable atmospheric conditions that typically occur during light wind conditions at night. Unstable conditions (Classes A to C) are characterised by strong solar heating of the ground that induces turbulent mixing in the atmosphere close to the ground. This turbulent mixing is the main driver of dispersion during unstable conditions. Dispersion processes for Class D conditions are dominated by mechanical turbulence generated as the wind passes over irregularities in the local surface. During the night, the atmospheric conditions are generally stable (often Classes E and F). Figure A8 shows the distribution of stability classes extracted from the TAPM/CALMET dataset at the development site, where Class A represents the most unstable conditions and Class F represents the most stable. Neutral (D class) conditions are present throughout the day, comprising 54% of total time. Stable (E class) and very stable (F class) conditions are the next most frequent, comprising 28% of total time, and only occur between 5 pm and 7 am. Figure A8 Frequency distribution of atmospheric stability conditions predicted by TAPM/CALMET A1.5.3 Mixing height The mixing height defines the height of the mixed atmosphere above the ground (mixed layer), which varies diurnally. Air pollutants released at or near the ground will become dispersed within the mixed layer. During stable atmospheric conditions, the mixing height is often quite low, and dispersion is limited to within this layer. During the day, solar radiation heats the ground and causes the air above it to warm, resulting in convection and an increase to the mixing height. The growth of the mixing height is dependent on how well the warmer air from the ground can mix with the cooler upper-level air and, therefore, depends on meteorological factors such as the intensity of solar radiation and wind speed. Strong winds cause the air to be well mixed, resulting in a high mixing height. Mixing height information extracted from the TAPM/CALMET at the development site dataset are presented as a diurnal frequency (box and whisker) plot in Figure A9. The plot shows that, on average, the mixing height begins to increase around 6am and peaks around 3pm before descending rapidly into the evening. Katestone Environmental Australia Pty Ltd 17 September 2026 D25072-8 Noosa Council - Noosa Composting Odour Assessment - Final Page 33
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Figure A9 2020 diurnal profile of mixing height predicted by TAPM/CALMET
A2 Dispersion modelling
CALPUFF simulates the dispersion of air pollutants to predict ground-level concentration and deposition rates
across a network of receptors spaced at regular intervals, and at identified discrete locations. CALPUFF is a non-
steady-state Lagrangian Gaussian puff model containing parameterisations for complex terrain effects, overwater
transport, coastal interaction effects, building downwash, wet and dry removal, and simple chemical transformation.
CALPUFF employs the 3D meteorological fields generated from the CALMET model by simulating the effects of
time and space varying meteorological conditions on pollutant transport, transformation, and removal.
CALPUFF takes into account the geophysical features of the study area that affect dispersion of pollutants and
ground-level concentrations of those pollutants in identified regions of interest. CALPUFF contains algorithms that
can resolve near-source effects such as building downwash, transitional plume rise, partial plume penetration, sub-
grid scale terrain interactions, as well as the long-range effects of removal, transformation, vertical wind shear,
overwater transport and coastal interactions. Emission sources can be characterised as arbitrarily varying point,
area, volume and lines or any combination of those sources within the modelling domain.
Key features of CALPUFF used to simulate dispersion:
• Domain area of 80 by 80 grids at 0.1 km spacing, a subset of the domain defined in CALMET
• 365 days modelled (1 January 2020 to 31 December 2020)
• Gridded 3D hourly-varying meteorological conditions generated by CALMET
• Partial plume path adjustment for terrain modelled
• Dispersion coefficients calculated internally from sigmas v and w using micrometeorological variables
• Transitional plume rise and PDF used for dispersion under convective conditions
All other options set to default.
The following source parameters were used for dispersion modelling:
• For sources at the composting facility, an effective height of 3m and a sigma z of 0.75 was used for all
sources
• For sources at the landfill, an effective height of 5m for the active tip face and 1m for day cover and final
cover was used. A sigma z of 1.25 for the active tip face and 0.25 for day cover and final cover was used.
All four landfill layout scenarios used the same values for effective height, sigma z and total source areas.
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Used in these records
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