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West Schofields Precinct Level 2/3 Odour Assessment
Document Control Number: AQU NW 001 20975
Date: 17 July 2018
Project Name:West Schofields Precinct Level 2/3 Odour Assessment
Document Control Number:AQU-NW-001-20975
Prepared For:Department of Planning and Environment
Approved For Release By:Jane Barnett
Disclaimer & Copyright:This report is subject to the copyright statement located at www.pacific- environment.com © Pacific Environment Operations Pty Ltd ABN 86 127 101 642
Version Date Comment Prepared by Reviewed by
01 28/05/2017 Draft 1 Liza McDonough/ Francine
Manansala Francine Manansala/Jane Barnett
02 13/11/2017 Draft 2 Liza McDonough/ Francine
Manansala Francine Manansala/Jane Barnett
03 05/06/2018 Final Liza McDonough/ Francine
Manansala Francine Manansala/Jane Barnett
04 17/07/2018 Final v2 Liza McDonough/ Francine
Manansala Francine Manansala/Jane Barnett
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This assessment was completed to determine the potential for odour impacts on the West Schofields Precinct (the Project).
The Project is located in a semi-rural/residential area that currently comprises houses on rural properties.
Commercial activities in the Project area include (but are not limited to) brick and paving businesses, plaster lining services, distribution services, drilling contractors, firewood suppliers and pet food and stockfeed suppliers.
Potential odour sources surrounding the Project study area include poultry operations, intensive piggeries, a meat rendering operation, a green waste recycling facility, mushroom farms and sewage treatment plants (STPs).
A Level 1 odour impact assessment was conducted (Appendix A) consistent with the Technical framework:
Assessment and Management of Odour from Stationary Sources in NSW (NSW DECC, 2006a) and the associated Technical Notes (NSW DECC, 2006b). The Level 1 study found that a small number of poultry operations in the vicinity of the Project study area have the potential to individually impact on the proposed development area. These are largely around the northern, eastern and western borders of the Project area.
The seven poultry operations and recycling centre which were determined to have potential impacts on the Project have been assessed in detail in this report using a Level 2/3 odour impact assessment, and the results used to establish the likely area of potential odour influence.
The modelling results indicate that all poultry operations modelled do not cause an exceedance of the 2 odour unit (OU) criterion within the boundary of the Project. Modelling of the Northwest Recycling Centre does however result in an exceedance of the OU criterion within the middle-north western edge of the Project boundary. This is to be expected due to the recycling centre’s location within the Project boundary however, this exceedance does not occur in proposed residential areas of the Precinct.
This report provides options to consider in the planning process in order to mitigate the potential odour impacts.
The recommendations that have been provided for development control in this area incorporate an expectation that the measures would be revised, progressively, by the relevant planning body on the basis of more detailed specific assessments for future individual developments provided through the Development Application process.
Table of contents
1. Introduction ... 1
1.1 Background ... 1
1.1.1 Sydney’s North West Growth Area ... 1
1.1.2 Precinct Planning ... 1
1.2 Project description ... 2
1.2.1 Surrounding land use ... 5
1.3 Objectives of the study ... 5
1.4 Scope of work... 5
2. Odour legislation and guidelines ... 7
2.1 Legislation ... 7
2.2 Guidelines... 7
2.2.1 Odour impact assessment criteria... 8
2.2.2 Peak-to-mean ratios ... 9
3. Existing environment... 10
3.1 Meteorology... 10
3.1.1 Local wind data ... 10
3.1.2 Local climate ... 11
4. Odour impact assessment ... 12
4.1 Approach ... 12
4.2 Odour sources ... 13
4.3 Assessment methodology ... 16
4.3.1 Introduction... 16
4.3.2 Emissions Estimation ... 16
4.3.3 Dispersion modelling ... 19
4.4 Assessment of Impacts ... 25
5. Recommendations ... 28
5.1 Potential Development Control Plan provisions ... 28
5.2 Alternative measures... 29
6. Conclusions ... 30
7. References... 31
Appendix A... 1
Appendix B... 1
Appendix C ... 1
List of FiguresFigure 1.1: West Schofields Precinct Project Study Area ... 3
Figure 1.2: West Schofields Draft Indicative Layout Plan ... 4
Figure 4.1: Hourly odour emission rates for the chicken sheds ... 19
Figure 4.2: Overview of modelling methodology ... 21
Figure 4.3: 99th percentile 1-second average odour concentration contours (OU) associated with the operation of the seven closest poultry farms ... 26
Figure 4.4: 99th percentile 1-second average odour concentration contours (OU) associated with the operation of the Northwest Recycling Centre ... 27
List of TablesTable 2.1. Odour assessment performance criteria ... 9
Table 2.2: Factors for estimating peak concentrations on flat terrain ... 9
Table 3.1:Temperature, Humidity and Rainfall Data for Richmond RAAF... 11
Table 4.1. List of odour sources considered in the assessment ... 13
Table 4.2 Farm-specific parameters used within the chicken shed odour emissions model ... 18
Table 4.3 General parameters used within the chicken shed odour emissions model .. 18
Table 4.4: Meteorological Parameters used for CALMET... 23
Table 7.1. Recommended separation distances from other sources... 19
In March 2017, Pacific Environment completed a Level 1 odour assessment for the proposed West Schofields Precinct (the Project), in West Schofields, NSW (Appendix A). The outcomes of that assessment concluded that an additional level of assessment was required in relation odour, as prescribed by the NSW Environmental Protection Authority (EPA).
The West Schofields Precinct is bounded by Eastern and Bells Creeks, Garfield Road West to the north and Railway Terrace, Townson Road and the Colebee subdivision to the south.
1.1.1 Sydney’s North West Growth Area
Sydney’s North West Growth Area (NWGA) covers approximately 10,000 hectares, located within the Local Government Area (LGA) boundaries of The Hills, Blacktown and Hawkesbury. It will be supported by a major centre at Rouse Hill and will contain about 90,000 new homes. It is made up of 16
‘Precincts’, which are areas that will be progressively released over the next 30 years.
1.1.2 Precinct Planning
Precinct Planning is a detailed process which analyses the development potential of each Precinct in the Growth Areas. It will be carried out as a partnership between the NSW Government and the relevant Local Council.
Precinct Planning will involve detailed investigations into appropriate land use options, physical
environment constraints (i.e. topography, vegetation, bushfire mapping, mapping of water courses etc.) and infrastructure requirements. The process looks at issues including riparian zones, conservation zones, locations of town centres, the mix and type of housing, and key transport routes. It does this at the Precinct level, saving the need to revisit many issues at Development Application stage.
The analysis will include extensive background studies including Aboriginal and European Heritage, land capability, contamination, noise, odour, transport, biodiversity, bushfire, economics and
employment and community facilities and open space.
These studies help to form an Indicative Layout Plan which will be used to test the feasibility of development scenarios with State agencies.
Each Precinct Planning package will include:
A Precinct Planning report.
The draft Indicative Layout Plan.
A draft Amendment to the Growth Centres State Environmental Planning Policy (SEPP) to facilitate rezoning.
A draft Development Control Plan (DCP).
Supporting background studies.
Further information about Sydney’s Growth Areas and Precinct Planning has been prepared by the Land Release and Strategy team of the DP&E and is available at http://www.planning.nsw.gov.au/Plans-for- your-area/Priority-Growth-Areas-and-Precincts.
1.2 Project description
The Project is located in the southern, central section of the North West Priority Growth Area and is wholly located within the Blacktown LGA.
The Precinct is bounded by Riverstone, Quakers Hill and Marsden Park, between the M7 (Westlink), Richmond Road, Garfield Road East and Old Windsor Road.
The Project currently consists of a mix of urban areas and farming lands.
Figure 1.1 shows the location of the Project site, with proposed residential development areas shown in Figure 1.2.
Figure 1.1: West Schofields Precinct Project Study Area
Figure 1.2: West Schofields Draft Indicative Layout Plan
1.2.1 Surrounding land use
To the east of the Project area is the Alex Avenue Precinct. The area includes the suburb of West Schofields, a semi-rural area that currently comprises houses on rural properties as well as commercial activities such as livestock. A number of poultry farms are located in this area. To the west is the Marsden Park Precinct, which is a predominantly large, open rural area. To the south is the Colebee Precinct, which is largely open rural area. To the north and north-east of the Project is the Riverstone Precinct which contains a mix of urban areas, semi-rural residential and land uses including poultry farms and a piggery. The densely-populated town of Riverstone also lies to the north.
1.3 Objectives of the study
The study objectives are to:
Investigate and identify any source or sources of odour on or in the vicinity of the subject land, including from any ongoing agricultural activities on the subject land.
Investigate the implications of any existing odours for the staging of the development of the land.
Recommend management strategies to maximise development opportunities under the existing odour situation and into the future.
Make recommendations for controlling impacts from odour-generating activities in proposed residential areas and associated land uses.
Develop land use recommendations that provide adequate buffers or transition zones between residential and employment/industrial areas, both proposed and existing.
1.4 Scope of work
The study was conducted in two stages. The scope of work required for Stage 1 of the study (already completed) included:
Investigation of any potential sources of odour that may impact on future development, including from existing agricultural activities on the subject land and neighbouring areas.
Develop an understanding of the nature of any odour producing activities identified.
Conduct a Level 1 Odour Impact Assessment, as outlined in the then NSW Department of Environment, Climate Change (NSW DECC) Draft Odour Policy and associated Technical Notes, resulting in recommended separation distances. NSW DECC is now known as NSW Environment Protection Authority (NSW EPA).
Prepare a report outlining the findings of the Odour Impact Assessment, including maps outlining where urban development would encroach onto the separation distances determined by the study, and make a recommendation for any Stage 2 work if required.
Provide recommendations to control odour impacts from odour generating development on
proposed residential development and associated land uses (including open space) as appropriate.
As part of this study an extensive visit of the area was conducted to collect relevant data on odour producing activities, the surrounding areas and meteorological conditions for input to the Level 1 Odour Impact Assessment.
As a result of the outcomes from Stage 1 of the study, the Stage 2 work was recommended. The scope of work conducted for Stage 2 includes:
Conducting a Level 2/3 Odour Impact Assessment, as outlined in NSW DECC Draft Odour Policy and its associated Technical Notes, using CALPUFF dispersion model.
Updating this report to:
- Incorporate the results of the modelling and limitations of the data.
- Review strategies for managing odour impacts.
- Predict odour impacts on the future development of the site, considering management recommendations.
- Provide recommendations for controlling odour impacts from odour generating
development on proposed residential development and associated land uses, in the form of development control provision for inclusion in a development control plan.
Modelling was conducted using the CALPUFF dispersion model and based on a representative 1-year meteorological dataset.
2. Odour legislation and guidelines
The three most important pieces of legislation for preventing and controlling odour are the:
Environmental Planning and Assessment Act 1979 (EP&A Act).
Protection of the Environment Operations Act 1997 (POEO Act).
Local Government Act 1993 (LG Act).
The EP&A Act deals with land-use planning, development, assessment and approvals.
The POEO Act requires that no occupier of any premises causes air pollution (including odour) through a failure to maintain or operate equipment or deal with materials in a proper and efficient manner. The operator must also take all practicable means to minimise and prevent air pollution (sections 124, 125, 126 and 128 of the POEO Act).
The POEO Act includes the concept of “offensive odour” (section 129) and states it is an offence for scheduled activities to emit “offensive odour”.
The LG Act gives local councils the power to deal with public nuisance, including odour emissions.
Odour is one of the most widespread and complex local air pollution problem in Australia. It accounts for the majority of complaints received by environmental authorities and can be a major source of annoyance and stress in affected communities.
In November 2006, NSW EPA released two guidance documents: Technical Framework for the Assessment and Management of Odour from Stationary Sources in NSW and its associated Technical Notes for the Assessment and Management of Odour from Stationary Sources in NSW. The discussion in this report draws extensively from those documents, which outline the NSW EPA’s proposed approach for the assessment of odour emissions, using a three-level system of odour impact assessment of increasing complexity and detail. Depending on the individual characteristics of a new development and its proposed location, a varying degree of investigation into the potential for odour impacts may be required.
Level 1 is a screening-level technique based on generic parameters for the type of activity and site.
It requires minimal data and uses simple equations to provide a broad estimate of the extent of any odour impact. It may be used to identify the potentially affected zone and site suitability for a proposed facility or new neighbouring development or expansion of an existing facility.
Level 2 is a screening-level dispersion modelling technique, using worst-case input data (rather than site-specific data). It is more rigorous and more realistic than a Level 1 assessment. It may be used to assess site suitability and odour mitigation measures for new, modified or existing
Level 3 is a refined-level dispersion modelling technique using site-specific input data. This is the most comprehensive and most realistic level of assessment available. It may be used to assess site suitability and odour mitigation measures for new, modified or existing activities.
It is noted that for this project, site-specific meteorological and terrain data were used in the dispersion modelling. Where possible, site-specific data for emissions calculations (i.e. bird numbers and shed dimensions) will be used however, detailed information for each farm such as staging and life cycles are not available and therefore best and conservative estimates were made. In these respects, the Stage 2 assessment is considered a Level 2/3 odour assessment and will be referred to as such in subsequent sections of this report.
2.2.1 Odour impact assessment criteria
Odour impacts are determined by several factors. The most important factors (the so-called FIDOL factors) are:
The Frequency of the exposure.
The Intensity of the odour.
The Duration of the odour episodes.
The Offensiveness of the odour.
The Location of the source.
In determining the offensiveness of an odour it needs to be recognised that for most odours the context in which an odour is perceived is also relevant. Some odours, for example the smell of sewage, hydrogen sulfide, butyric acid, landfill gas etc., are likely to be judged offensive regardless of the context in which they occur. Other odours such as the smell of jet fuel may be acceptable at an airport, but not in a house, and diesel exhaust may be acceptable near a busy road, but not in a restaurant.
In summary, whether or not an individual considers an odour to be a nuisance will depend on the FIDOL factors outlined above and although it is possible to derive formulae for assessing odour annoyance in a community, the response of any individual to an odour is still unpredictable.
The NSW EPA framework documents include some recommendations for odour criteria. The criteria have been refined by NSW EPA to take account of population density in the area. Table 2.1 lists the odour criteria, to be exceeded not more than 1% of the time, for different population densities.
The difference between odour criteria is based on considerations of risk of odour impact rather than differences in odour acceptability between urban and rural areas. For a given odour level there will be a wide range of responses in the population exposed to the odour. In a densely-populated area there will therefore be a greater risk that some individuals within the community will find the odour unacceptable than in a sparsely populated area.
The criteria assume that 7 odour units (ou) at the 99th percentile would be acceptable to the average person, but as the number of exposed people increases there is a chance that sensitive individuals would be exposed. The criterion of 2 ou at the 99th percentile is considered to be acceptable for the whole population.
- Table 2.1. Odour assessment performance criteria
Population of Affected Community Odour Units
Rural single residence ( ~2) 7
Urban (~2000) and/or schools and hospitals 2
Source: NSW DEC, 2006a, p.21
2.2.2 Peak-to-mean ratios
It is common practice to use dispersion models to determine compliance with odour criteria. This introduces a complication because Gaussian dispersion models are only able to directly predict
concentrations over an averaging period of 3-minutes or greater. The human nose, however, responds to odours over periods of the order of a second or so. During a 3-minute period, odour levels can fluctuate significantly above and below the mean depending on the nature of the source.
To determine more rigorously the ratio between the one-second peak concentrations and three-minute and longer period average concentrations (referred to as the peak-to-mean ratio) that might be predicted by a Gaussian dispersion model, the OEH commissioned a study by Katestone Scientific Pty Ltd (1995, 1998). This study recommended peak-to-mean ratios for a range of circumstances. The ratio is also dependent on atmospheric stability and the distance from the source. For this assessment peak-to-mean ratios have been applied to each source type accordingly. A summary of these factors is shown in Table 2.2.
Table 2.2: Factors for estimating peak concentrations on flat terrain
Source Type Pasquill Gifford stability class
Near field P/M60*
Far field P/M60
A, B, C, D 2.5 2.3
E, F 2.3 1.9
Line A – F 6 6
A, B, C 12 4
D, E, F 25 7
A, B, C 17 3
Tall wake-free point
D, E, F 35 6
Wake affected point A – F 2.3 2.3
Volume A – F 2.3 2.3
*Ratio of peak 1-second average concentrations to mean 1-hour average concentrations
The Approved Methods for the Modelling and Assessment of Air Pollutants in New South Wales (NSW DEC, 2005) hereafter referred to as the ‘Approved Methods”) takes account of this peaking factor and the criteria shown in Table 2.1 are based on nose-response time.
3. Existing environment
3.1.1 Local wind data
Odour impacts in the Project study area will be influenced by local meteorology. Meteorological conditions, such as wind speed, wind direction and atmospheric turbulence, affect how often receptors are likely to be downwind of an odour source as well as how well the odour disperses in the atmosphere.
The closest meteorological station to the site is at the Riverstone STP, off Bandon Road, Vineyard. The Vineyard site was commissioned in February 1994 and is maintained by the Office of Environment and Heritage (OEH). The following meteorological variables are measured at Vineyard:
Wind speed, wind direction and sigma theta (the standard deviation of the wind direction),
A representative meteorological dataset was chosen by analysing the most recent five years’ worth of data from the OEH Vineyard site. Annual and seasonal windroses were compiled for five years from 2011 to 2015 and are presented in Appendix B.
The OEH Vineyard windroses show that wind patterns for years 2011 to 2015 are similar with dominant winds from the north and north-northeast.
During summer the wind distribution pattern is fairly similar for all directions from the north to the south- southwest. In autumn, the dominant wind directions are from the north and north-northeast, spring follows a similar distribution with elevated wind speeds. During winter, winds predominately occur from the north, north-northeast, and south. The 2013 and 2014 windroses show a higher percentage of winds from the western and eastern quadrants annually and notably, a high percentage of winds from the west in the winter months of 2014.
The annual average percentage of calms (wind speeds less than 0.5 m/s) is between 16.6 and 26.1% for all years. It is noted that 2013 and 2014 were between 5% and 9% lower than the other years.
The annual average wind speed (m/s) for the five years is between 1.3 and 1.6 m/s.
The year 2015 was chosen for dispersion modelling as it is the most recent set of data analysed and the wind patterns, annual average wind speed and annual average percentage of calms are similar to the majority of the data. It was deemed representative when compared to the previous four years of meteorological data collected at the OEH Vineyard site.
3.1.2 Local climate
This section describes the general climate in the study area to give a more complete picture of the local meteorology.
Table 3.1 presents the temperature, humidity and rainfall data for the nearby Bureau of Meteorology site located at Richmond RAAF, approximately 12 km northwest of the site. Presented are monthly averages of maximum and minimum temperatures, 9 am and 3 pm temperatures and humidity. Rainfall data consist of mean monthly rainfall and the average number of rain days per month.
The annual average maximum and minimum temperatures experienced are 24.2°C and 11.1°C. July is the coldest month, with an average minimum temperature of 3.7°C. January is the hottest month, with an average maximum temperature of 30.2°C.
Rainfall data show that February is on average the wettest month, with a mean rainfall reading of 114.9 mm, over 8.1 rain days. July is the driest months with an average rainfall of 29.6 mm, over an average of 4.1 rain days. The average annual rainfall is 740.5 mm and the average number of rain days annually is 73.6.
Table 3.1:Temperature, Humidity and Rainfall Data for Richmond RAAF
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Daily Maximum Temperature (°C)
Mean 30.2 29.2 27.0 24.0 20.8 18 17.6 19.7 22.7 25.3 27.1 28.7 24.2
Daily Minimum Temperature (°C)
Mean 17.7 17.8 15.8 11.6 7.6 5.2 3.7 4.5 8.1 11.0 14.2 16.1 11.1
9 am Mean Temperatures (°C) and Relative Humidity (%)
Mean 22.1 21.3 19.1 17.0 13.1 10.0 8.9 11.4 15.4 18.3 19.2 20.9 16.4
Humidity 72 78 80 76 82 83 80 69 63 58 68 68 73
3 pm Mean Temperatures (°C) and Relative Humidity (%)
Mean 28.5 27.4 25.8 23.0 19.7 17.0 16.5 18.7 21.5 23.5 25.2 27.5 22.9
Humidity 47 52 52 49 53 53 48 39 39 40 46 44 47
Mean 84.4 114.9 80.1 60.6 47.5 54.3 29.6 33.9 46.1 47.4 79.5 69.7 740.5
Rain days (Number)
Mean 7.9 8.1 8.0 6.4 5.4 5.7 4.1 3.6 4.7 5.4 7.6 6.7 73.6
Station Number 067105, Latitude: -33.60 South, Longitude: 150.78 East, Elevation: 19 m Source: Bureau of Meteorology, 2017
4. Odour impact assessment
An investigation of the Project study area and the surrounding land was conducted to identify potential sources of odour that may impact future development and to develop an understanding of the nature of any odour producing activities.
Sources of information used to identify potential odour sources included aerial maps, Yellow Pages searches, internet research and previous assessments for Precinct Planning (Benbow Environmental (BE), 2008a &
2008b; PAEHolmes, 2010; Renzo Tonin & Associates and Todoroski Air Sciences, 2016). A comprehensive site visit was conducted to gather as much data as possible about the odour sources and other factors required for the assessment (outlined in Section 4.2). The information on bird and shed numbers were obtained from Blacktown City Council in 2010 for the Schofields Precinct Planning odour assessment (PAEHolmes, 2010).
Blacktown City Council no longer maintains records of bird and shed numbers for individual farms, thus for the purposes of this assessment it has been assumed that the bird and shed numbers have not changed.
The data were used to assess areas of potential odour impact around each identified odour source using the Level 1 odour impact assessment methodology provided by Technical Notes for the Assessment and Management of Odour from Stationary Sources in NSW (NSW DECC, 2006b). Where Level 1 odour impact assessment methodologies were not published for particular potentially odorous sources, a recommended buffer distance was applied, based on alternative guidance. It should be noted however that the buffer distance approach is generally more limited than the NSW DECC Level 1 assessment as it usually takes no account of local factors or scale of operation.
Where the area of odour influence of local odour sources was predicted to either encroach on the area or be in proximity of the Project study area when assessed using a Level 1 assessment, it was recommended to further refine the assessment using a Level 2/3 odour impact assessment. Whilst a Level 1 assessment is a screening- level technique based on generic parameters for the type of activity and site, Level 2/3 assessment is a refined- level dispersion modelling technique using site-specific input data, including terrain and meteorological data. The predicted separation distances will vary in different directions around an odour source when based on a Level 2/3 assessment, as opposed to the uniform circle centred on the source provided by Level 1. The Level 2/3
assessment may be used to assess site suitability and odour mitigation measures for new, modified or existing activities and would provide a better appreciation for the locations within the Project study area that are likely to be most affected by odour.
4.2 Odour sources
Potential odour sources identified as part of the assessment include poultry operations (broiler, breeder and layer chickens and ducks), intensive piggeries, mushroom production, a green waste recycling facility, a meat
rendering plant, an abattoir and wastewater treatment plants.
The sites investigated as potential odour sources for this study are shown in Table 4.1. Figure 4.1 shows the locations of these sources in relation to the Precinct. Those sources identified as ‘no longer operational’ or further than 5 km away, have not been shown.
Table 4.1. List of odour sources considered in the assessment
Poultry Operations Intensive Piggeries Other Sources
Gordon Rd, Schofields (piggery) – A J Bush & Son, Riverstone Meat 100 Worcester Rd, Rouse Hill (layer farm) site visit confirmed that this farm is Rendering Operations (meat
no longer operational rendering)
181 Cudgegong Rd, Rouse Hill (layer farm) – site visit confirmed that this farm is no
101 Hambledon Rd, Schofields (piggery)
920 Richmond Rd, Marsden Park - Marsden Park Landfill 89 Schofields Rd, Rouse Hill (layer farm) –
site visit confirmed that this farm is no longer operational
1200 Richmond Rd, Marsden Park (piggery) – this site is no longer
Quakers Hill STP (Sewage Treatment Plant)
68 Schofields Farm Rd, Schofields (layer 132 Burfitt Rd, Richmond North West
farm) – site visit confirmed that this farm is Recycling Centre (green waste
no longer operational recycling facility)
73 Boundary Rd, Schofields (layer farm) – site visit confirmed that this farm is no
Riverstone STP (Sewage Treatment Plant)
95 Tallowong Rd, Schofields (broiler farm) Elf Mushroom (mushroom
20 Clarke St, Riverstone (broiler farm) White Prince Mushroom (mushroom
16 Clarke St Riverstone (broiler farm) 496 Windsor Rd, Vineyard
(mushroom farm) 54 Pelican Rd, Schofields (broiler farm) –
site visit confirmed that this farm is no longer operational
Elf Farm Supplies (mushroom composting) – more than 5 km away
2 Pelican Rd, Schofields (broiler farm) Rouse Hill STP (Water Recycling
Plant) – more than 5 km away McGraths Hill STP (Sewage
93 Hambledon Rd, Schofields (broiler farm) Treatment Plant) – more than 5 km
98 Hambledon Rd, Schofields (broiler farm) South Windsor STP (Sewage
– site visit confirmed that this farm is no Treatment Plant) – more than 5km
longer operational away
96 Hambledon Rd, Schofields (duck farm) – site visit confirmed that this farm is no
14 Hill View Rd, Kellyville (duck abattoir) – more than 5 km away
25 Schofields Rd, Schofields (broiler farm) St Mary’s STP (Sewage Treatment
Plant) - more than 5 km away 26 Schofields Farm Rd, Schofields (broiler
34-36 Schofields Rd, Schofields (duck farm) – site visit confirmed that this farm is
no longer operational
37-39 Boundary Rd, Schofields (layer farm) 47 Argowan Rd, Schofields (broiler farm) –
site visit confirmed that this farm is no longer operational
45 Farm Rd, Riverstone (duck farm) 169 Clifton Rd, Marsden Park (layer farm) –
site visit confirmed that this farm is no longer operational
138 Clifton Rd, Marsden Park (broiler farm) 1148 Richmond Rd, Marsden Park
264A South St, Marsden Park (broiler farm) 306 South St, Marsden Park (broiler farm)
1132 Richmond Rd, Marsden Park (layer farm)
14 Hillview Rd, Kellyville (duck farm) – more than 5 km away
31-33 Boundary Rd, Box Hill (layer farm) – site visit confirmed this site is no longer
466 Windsor Rd, Vineyard (breeder farm) 199 Stahls Rd, Oakville (broiler farm) 472 Windsor Rd, Vineyard (broiler farm) 205 Maguires Rd, Maraylya (breeder farm)
– more than 5 km away 115 Wolseley Rd, Oakville (broiler farm) –
more than 5 km away
372 Windsor Rd, Vineyard (broiler farm) – more than 5 km away
Dunns Rd, Maraylya (broiler farm) – more than 5 km away
22 Withers Rd, Kellyville (broiler farm) – more than 5 km away 23 Withers Rd, Kellyville (broiler farm) –
more than 5 km away 28A Foxall Rd, Kellyville (layer farm) –
more than 5 km away
421 - 427 Flushcombe Rd, Blacktown (Red Lea chicken abattoir) – more than 5 km
291 Fairey Rd, South Windsor – more than 5km away
Pirovic Family Farms (egg layer), 138 Sixth Ave, Llandilo – more than 5 km away
Figure 4.1: West Schofields Precinct Project Study Area
Investigations have revealed that some operating facilities are located at a significant distance from the Project and are highly unlikely to have any impact. Potential odour sources that were found to be located more than 5 km from the Project area have not been included in the assessment.
Site visits identified that a number of facilities are no longer operating, largely due to extensive development in and around the West Schofields area and surrounds.
4.3 Assessment methodology
As previously discussed, poultry operations in the vicinity of the West Schofields study area were originally assessed using a Level 1 odour impact assessment (Pacific Environment, 2017). The A J Bush & Son meat rendering facility, two piggeries, the Quakers Hill Sewage Treatment Plant (STP) and Riverstone STP, and a green waste recycling facility were also included in the Level 1 assessment provided in Appendix A. The conservative nature of the Level 1 assessment produced results for seven poultry operations that indicated an area of influence that encroached on some of the Project area. These sources were therefore modelled in the Level 2/3 assessment.
The STPs, meat rendering plant and piggeries did not show any impact on the Project area and were therefore not included in the Level 2/3 assessment.
The Level 2/3 odour impact assessment methodology, based on an advanced modelling system using the models TAPM and CALMET/CALPUFF, has been used in this study to model the dispersion of odour from the poultry farms and green waste recycling facility that were predicted to have an area of odour influence that either encroaches or is in proximity to the West Schofields study area. The model requires meteorological data (e.g.
wind speed, wind direction, atmospheric stability and mixing height) together with emission rates from the sources. The meteorological data that were used are further discussed in Section 22.214.171.124.
4.3.2 Emissions Estimation 126.96.36.199 Poultry Farms
Odour emission rates (OERs) for this assessment have been estimated using a modelling approach based on data from a variety of meat chicken farms in New South Wales and Queensland, as well as theoretical
considerations. Details on the method can be found in Ormerod and Holmes (2005).
The approach generates hourly varying emission rates from each shed based on the following factors:
The number of birds, which varies later in the batch as harvesting takes place.
The stocking density of birds, which is a function of bird numbers, bird age and shed size.
Ventilation rate, which depends on bird age and ambient temperature.
Design and management practices, particularly those aimed at controlling litter moisture.
The predicted OER from a shed at any given stage of the growth cycle is given by Equation 1:
OER = 0.025 K A D V0.5 (1)
OER = odour emission rate (ou.m³/s) A = total shed floor area (m²)
D = average bird density (in kg/m²) V = ventilation rate (m³/s)
K = scaling factor between 1 and 5 where 1 represents an extremely well designed and managed shed, i.e., state of the art.
Bird density (D) at a point in time is related to the age of the birds (from which their weight can be estimated) and the stocking density (i.e. the number of birds placed per unit area). It is common practice within the meat chicken industry to vary the stocking density with the time of year and market demands. Lower ambient temperatures during the winter months allow for higher bird densities.
The ventilation rate (V) used at any given time is a function of the age of the birds, wind speed and the ambient temperature and humidity. Given the lack of available data on naturally ventilated sheds it has been assumed that the ventilation requirements for a tunnel ventilated shed may be used to approximate those of naturally ventilated sheds. This is consistent with the conclusions of the Poultry Odour Modelling Workshop Outcomes (see RIRDC, 2012).
Farm-specific parameters used for the chicken sheds in the emissions model are shown in Table 4.2 and general parameters applying to all farms are shown in Table 4.3
The parameters shown in Table 4.3 are based on experience of typical values adopted for assessment of poultry farms. It was also assumed that all four farms would start their cycle on Day 1 which is s conservative approach as this would result in all farms having peak emissions at the same time.
Table 4.2 Farm-specific parameters used within the chicken shed odour emissions model
Parameter 2 Pelican Rd, Schofields
138 Cilfton Rd, Marsden
264A South St, Marsden
306 South St, Marsden
20 Clarke St, Marsden
45 Farm Rd, Riverstone
Birds per sheda 19,711 25,000 13,171 25,000 28,514 14,000 12,500
Number of sheds 2 3 4 3 5 5 6
Shed length (m)b 90 91 62 124 137 51 66
Shed width (m) 15 16 14 14.5 21 17 13
Shed Area (m2) 1,350 1,456 868 1,798 2,896 887 842
(Birds/m2) 14.6 17.2 15.2 13.9 9.8 15.8 14.8
Ventilation Rate 197,110 250,000 131,708 250,000 285,142 140,000 125,000
Maximum vertical velocity
0.31 0.35 0.24 0.42 0.23 0.17 0.27
a Due to lack of detailed information, it has been assumed that the total number of birds is split evenly amongst all sheds.
b Taken as longest shed.
Table 4.3 General parameters used within the chicken shed odour emissions model
Assumed maximum ventilation (m3/hr/bird) 10
Assumed number of fans 10
K Factor 41
Total length (days) 55
Days cleanout 10
Thinning 1 - day 32 (% chickens remaining) 75
Thinning 2 - day 38 (% chickens remaining) 50
Thinning 3 - day 44 (% chickens remaining) 25
Hourly odour emission rates for the chicken sheds are shown in Figure 4.2, which were calculated using the inputs in Table 4.2 and Table 4.3 and the meteorological data for the modelling period.
OERs gradually increase over the 55-day growth cycle and peak towards the end of the cycle. OERs then decrease to zero once the chickens are removed and the sheds are cleaned ten days. OERs were predicted to be lower for the cycle starting around day 130 as this represents winter in which ambient temperatures were lower than the target temperature for the sheds and therefore less ventilation is required.
1 A K factor of 4 was used to reflect that the farms are old. Testing at numerous farms over the last five years has shown that the K factor for a modern, well managed farm is typically equal to or below K=2.
Figure 4.2: Hourly odour emission rates for the chicken sheds
188.8.131.52 Green waste recycling
The Northwest Recycling Centre is a green waste recycling facility at 132 Burfitt Rd, Riverstone. The waste is ground with a horizontal grinder and then stockpiled for approximately 5 weeks. Aerial imagery from Google Earth indicates that there are two sections of waste on the site. These include a section of fresh green waste on approximately half of the site towards the front of the property, and a section of older, shredded green waste further back on the site.
For modelling purposes, the site was divided into two area sources. The emission rates for these area sources were taken from odour measurements carried out at a similar facility on stockpiles of green waste of various ages (ranging from 1 week to 3 months). The results of this monitoring identified that the highest odour emission rates (OERs) were detected from the 1 week old green waste (0.236 ou.m3/m2/s) and the lowest emissions were detected from the 3-month-old green waste (0.164 ou.m3/m2/s). For conservatism, the OER for approximately half of the windrow area was estimated to be equivalent to the 1 week old green waste and the other half of the site was assigned an OER equivalent to the 4 weeks old green waste.
A shredder was modelled on the south-western border of the recycling centre, closest to the centre of the Project site for conservatism and was assumed to run for 4 hours per day, based on the size of the operation.
4.3.3 Dispersion modelling
The Level 2/3 Odour Impact Assessment used air dispersion modelling based on an advanced modelling system using the models TAPM and CALMET/CALPUFF. This system substantially overcomes the basic limitations of
the steady-state Gaussian plume models such as AUSPLUME. These limitations are most severe in very light winds, in coastal environments, and where terrain affects atmospheric flow.
The modelling system works as follows:
TAPM is a prognostic meteorological model that generates gridded three-dimensional meteorological data for each hour of the model run period.
CALMET, the meteorological pre-processor for the dispersion model CALPUFF, calculates fine resolution three-dimensional meteorological data based upon observed ground and upper level meteorological data, as well as observed or modelled upper air data generated for example by TAPM.
CALPUFF then calculates the dispersion of plumes within this three-dimensional meteorological field.
Further details about the TAPM and CALMET/CALPUFF modelling system are provided in Section 184.108.40.206, Section 220.127.116.11 and Section 18.104.22.168)
Figure 4.3 presents an overview of the modelling system and the details on the model configuration and data inputs are provided in the following sections.
Figure 4.3: Overview of modelling methodology
The Air Pollution Model, or TAPM, is a three-dimensional meteorological and air pollution model developed by the CSIRO Division of Atmospheric Research. Detailed description of the TAPM model and its performance is provided in Hurley, 2008.
TAPM solves the fundamental fluid dynamics and scalar transport equations to predict meteorology and (potentially) pollutant concentrations. It consists of coupled prognostic meteorological and air pollution
concentration components. The model predicts airflow important to local scale air pollution, such as sea breezes and terrain induced flows, against a background of larger scale meteorology provided by synoptic analyses.
Upper air data in the form of a 3-D.dat file were generated over the Project area using TAPM. The TAPM- generated data and observed surface meteorological data were then entered into the CALMET diagnostic meteorological model, which is discussed below.
CALMET is a meteorological pre-processor that includes a wind field generator containing objective analysis and parameterised treatments of slope flows, terrain effects and terrain blocking effects. The pre-processor produces fields of wind components, air temperature, relative humidity, mixing height and other micro-meteorological variables to produce the three-dimensional meteorological fields that are used in the CALPUFF dispersion model.
The hourly TAPM-generated data and observed data for the period of analysis were used as input to the CALMET pre-processor to create a fine resolution, three-dimensional meteorological field for input into the dispersion model. CALMET uses the meteorological inputs in combination with land use and geophysical information for the modelling domain to predict gridded meteorological fields for the region.
Terrain data has been sourced from the NASA Shuttle Terrain Mission dataset. The spatial resolution of these data is approximately 90 m.
Meteorological information collected at the Vineyard OEH monitoring station, Sydney Airport BoM station and TAPM-generated surface information were used as input into the CALMET model. The data were additionally supplemented with upper air data derived from TAPM simulations.
A summary of the data and parameters used for the meteorological component of this study are shown in Table 4.4.
Table 4.4: Meteorological Parameters used for CALMET
TAPM (v 4.0)
Number of grids (spacing) 4 (30 km, 10 km, 3 km, 1 km) Number of grid points 25 x 25 x 35
Year of analysis 2015
Centre of analysis -33.42.5 S, 150.51.5 E CALMET (v. 6.334)
Meteorological grid domain 15 km x 15 km Meteorological grid resolution 0.1 km
TERRAD 2 km
BIAS (NZ) -1, -0.5, -0.5, 0, 0, 0, 0
R1 1 km
R2 1 km
RMAX1 2 km
RMAX2 2 km
Surface meteorological stations Vineyard OEH Monitoring Station - Wind speed
- Wind direction - Temperature - Relative Humidity Sydney Airport AMO
(Bureau of Meteorology, Station No. 066037) - Cloud content and height
TAPM (to supplement missing data only) - Wind speed
- Wind direction - Temperature - Relative humidity - Sea Level Pressure
Upper air Data extracted from TAPM
CALPUFF is a multi-layer, multi-species non-steady state puff dispersion model that can simulate the effects of time and space varying meteorological conditions on pollutant transport, transformation and removal (Scire et al., 2000). The model contains algorithms for near-source effects such as building downwash, partial plume
penetration, sub-grid scale interactions as well as longer-range effects such as pollutant removal, chemical transformation, vertical wind shear and coastal interaction effects. The model employs dispersion equations based on a Gaussian distribution of pollutants across the puff and takes into account the complex arrangement of emissions from point, area, volume, and line sources.
In March 2011, the NSW EPA published generic guidance and optional settings for the CALPUFF modelling system for inclusion in the Approved Methods (TRC, 2011). The model set up for this study has been conducted with consideration of these guidelines.
As with any air dispersion model, CALPUFF requires inputs in three major areas:
Emission rates and source details.
Terrain and surface details, as well as specification of specific receptor locations.
Further details on the CALPUFF model set up are provided in Appendix A.
22.214.171.124 Poultry farm source details
Traditionally, emissions from animal husbandry buildings have been modelled as volume sources (e.g. Jiang &
Sands, 2000). In dispersion models such as CALPUFF, volume sources are not capable of incorporating thermal plume buoyancy. However, there are times when air vented from poultry sheds is significantly warmer than the ambient temperature, and at these times some buoyancy effect leading to plume rise might be expected. Even temperature differentials as small as 1-2°C may have a significant effect on near-field ground level concentrations (Ormerod et al. 2005). The effects of plume buoyancy on ground level concentrations of odour are generally confined to distances of less than 1 km or so from the sheds, under stable conditions with light winds. However, if there is significant vertical wind shear (change of wind direction with height) even a slightly elevated plume may end up being transported in a different direction than would occur without plume buoyancy included in the calculations (if a three-dimensional dispersion model is used).
The most recent research from the Rural Industries Research and Development Corporation2 (RIRDC) concluded that air exhausted from broiler sheds is frequently warmer than ambient air, and will therefore usually rise due to thermal buoyancy. Realistic emission temperatures should therefore be used during dispersion modelling rather than ignoring thermal buoyancy. On this basis, a conservative estimate of thermal buoyancy has been included in this assessment.
Emissions from standard tunnel-ventilated poultry sheds are directed horizontally, with no significant vertical component. Therefore, any plume rise will occur as a result of thermal buoyancy of the emissions only, with no plume rise component due to vertical momentum. To deal with the effects of thermal buoyancy for this study, each standard shed has been modelled as a single point source per shed (with no mechanically-generated plume rise) whilst maintaining the thermal mass of the plume (i.e. vertical momentum is switched off within CALPUFF by
2 Separation Distances for Broiler Farms Verifying methods and investigating the effects of thermal buoyancy by Mark Dunlop, David Duperouzel and Lyle Pott. June 2010. RIRDC Publication No 10/073. RIRDC Project No. PRJ-002747.
using the rain hat options). This incorporates the effect of plume movement due to the initial horizontal momentum, and is separated slightly in the vertical.
Exhaust temperatures from the sheds have been assumed to be at or slightly above target temperature (see PAEHolmes (2011)). The target temperature is that which the farmer aims to achieve to optimise the bird growth.
In reality, these temperatures incorporate wind chill in the sheds, thus the exhaust temperature is often well above these. By conservatively adopting the target temperatures, the influence of thermal buoyancy is reduced compared to the actual exhaust temperatures, which are often up to 10ºC higher than the target temperatures (with wind chill included).
Emissions from the green waste facility were taken from measurements made on a similar source, as discussed in Section 126.96.36.199.
4.4 Assessment of Impacts
Figure 4.4 presents the results of the Level 2/3 dispersion modelling for the predicted 99th percentile odour concentrations for the Northwest Recycling Centre and the seven most influential poultry operations in proximity of the Project study area. The 2 OU contour represents the OEH guideline value, which is applicable for urban areas (i.e. exposure greater than 2000 people (see Section 2.2.1)). The limited impact from the chicken farms is expected due to their relatively small size compared to the larger, modern farms which are located in rural areas.
The model results show a reduced area of influence on the Project study area when compared with the Level 1 assessment results (see Appendix A) and show that there are no areas of the Project that are predicted to exceed the 2 OU guideline as a result of the poultry farms.
It should also be noted that this Level 2/3 assessment is based on a conservative assumption that all chicken sheds are operating on the same cycle, i.e. the highest odour emission rates are being released from all of the sheds at the same time. In reality this scenario would be unlikely. This assessment is therefore considered conservative.
The model results for the Northwest Recycling Centre shows an exceedance of the 2 OU criterion in the mid- eastern border of the Project Boundary. This is due to the centre being located within the Project Boundary. This will not affect residential developments proposed for West Schofields due to the situating of housing away from the northern and eastern boundaries of the Project site (Figure 1.2).
Notwithstanding the above conclusions, recommendations to limit odour impacts are given in Section 5.
Figure 4.4: 99th percentile 1-second average odour concentration contours (OU) associated with the operation of the seven closest poultry farms
Figure 4.5: 99th percentile 1-second average odour concentration contours (OU) associated with the operation of the Northwest Recycling Centre
5.1 Potential Development Control Plan provisions
Whilst the odour assessment predicts no adverse odour impacts on the residential developments, the following are considered good practice development controls to manage the potential for odour impacts on the proposed development. Potential options applicable to both existing sources and potential future sources on the site are listed below for further consideration:
Plan a transition of land use zones that locates sensitive uses in areas that are not adjacent to odour generating activities;
Consider introducing specific zoning categories for odour-generating activities, e.g. agriculture, intensive agriculture, minerals/metal processing, waste industries;
Ensure that sensitive (residential) uses are located outside the 2 odour unit buffer;
Plan compatible land uses in areas closest to odour sources, e.g. car parks, industrial areas. Residential areas should be away from odour sources;
Orientate buildings to provide adequate air flow, i.e. no dead end courtyards, long narrow spaces, or areas where air may stagnate. Design buildings to encourage air flow;
Ensure that air intake to buildings is not from the direction of odour sources (however be certain to consider air intakes on the other side of the building to any major road also);
Consider ventilation and air conditioning and design buildings so living and work areas of buildings do not face odorous sources;
Build continuous dense landscaping around local odour sources or Precinct boundaries to assist in reducing odour by increasing dispersion;
Consider removing a separation buffer and removing development restrictions if an odour source ceases operation and has no prospect of restarting;
Implement new buffer zones where shorter separation distances can be determined for some odour sources, either with or without changing the operation of the source, for example, through further study;
Evaluate whether the nature of a development is compatible with odour affected lands and if odour nuisance will be detrimental to the successful long-term function of the completed development; and,
Purchase or long-term lease neighbouring properties to provide a secure buffer zone around a facility and increase the separation distance between the site of the odour emissions and existing or potentially sensitive use.
When odour assessment criteria are being exceeded at receptors despite avoidance and mitigation measures at the source or in the pathway, consideration could be given to measures that would manage the reaction of the receptors and increase their willingness to accept the odour levels.