dawn meats ireland unlimited company

Dawn Meats Ireland Unlimited

Company

Carroll’s Cross, Kilmacthomas, Co. Waterford

Appendix 7-1-3-4 -

Emissions Overview -

Impact Assessment Report

-

Air

August 2018

Redkite Environmental Ltd Registered Office: Hunter’s Moon, Ballykeane Road, Redcross, Co. Wicklow, Ireland

Registration No: 542716

Siobhan Maher Managing Director Paul Whelan Director

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Control Sheet

Document Title: Appendix 7.1.3.4 – Emissions

Overview - Impact Assessment

Report - Air

Document

No.

P018_01_7.1.3.4

Rev Description Originator Reviewer Change Date 01 Document S. Maher S. Maher Final 29/8/2018

Redkite Environmental Ltd Registered Office: Hunter’s Moon, Ballykeane Road, Redcross, Co. Wicklow, Ireland

Registration No: 542716

Siobhan Maher Managing Director Paul Whelan Director

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Dawn Meats Ireland Unlimited Company Carroll’s Cross

Kilmacthomas

Co. Waterford

Appendix 7-1-3-4 – Emissions Overview – Impact

Assessment Report - Air

Contents

1. Introduction .................................................................................................................. 1

2. Methodology ............................................................................................................... 1

3. Existing Conditions ..................................................................................................... 2

4. Impact Assessment .................................................................................................... 2

5. Conclusions and Recommendations ................................................................... 3

6. References ................................................................................................................... 4

Appendices

Appendix 1 Odour Impact Assessment Report, Odour Monitoring

Ireland

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Dawn Meats Ireland Unlimited Company

Carroll’s Cross, Co. Waterford Aug 2018

Appendix 7.1.3.4 – Emissions Overview - Impact Assessment - Air

Redkite Environmental Ltd. Page 1 of 4

1. Introduction

This attachment sets out the assessment of impacts on air arising from the

operation of the Dawn Meats Ireland Unlimited Company (DMIUC) facility at

Carroll’s Cross.

1.1 Statement on Emissions of Main Polluting Substances

SI 137/2013 Environmental Protection Agency (Industrial Emissions) (Licensing)

Regulations, 2013 set out an indicative list of the principal polluting substances

to be taken into account by the Agency when setting Emission Limit values.

The following can be stated in this regard:

• Emissions of sulphur oxides, nitrogen oxides and particulates can arise

infrequently from the back-up boiler and emergency generator on site.

• There are no emissions from the facility of any other other principal

polluting substances to air as listed in the Schedule.

• The thermal input of the boiler on site is 500KW in size and is used as a

back-up only to the heat recovery system. A 2 MW generator is present

on site however this is only for emergency use. Less than 1 m3 of gasoil

was used in 2017 thus demonstrating the insignificant potential for

impairment of air quality from emissions of sulphur oxides, nitrogen oxides

and particulates to air from these sources.

• There are no process point sources to air.

Accordingly, there are no significant or major point source emissions to air.

Fugitive emissions may occur from elements of the Waste Water Treatment

System (WWTS). Accordingly, an odour assessment is presented in this

attachment.

A separate receiving environment report has not prepared for this thematic

because there are no point source emissions of significance to be assessed that

could potentially impact on the ambient air quality and the main impact under

the thematic air is odour assessment.

2. Methodology

The odour assessment which forms the main aspect of this attachment was

completed by Dr. Brian Sheridan of Odour Monitoring Ireland (OMI).

The odour assessment was performed in accordance with currently

recommended international guidance and practice for the assessment of

odours (UK Environment Agency H4 and Irish EPA AG4 guidance documents).

Odour sampling and measurement was conducted at the WWTS and

dispersion modelling was used to assess the predicted odour concentrations

on the surrounding area.

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A copy of the full OMI report is contained in Appendix 1 including a detailed

description of the methodology employed.

3. Existing Conditions DMIUC has not received any odour complaints from surrounding Odour

Sensitive Locations (OSLs). Within the site boundary, odour has been noted at

the Drum Screen Room, Settlement Ponds 1 and 2 and also in association with

some Ponds e.g. 1 – 6.

The predicted overall emission odour rates from the existing WWTS elements

following on site sampling has been completed by OMI. Full details are

presented in OMI’s full report contained in Appendix 1, Table 4.1. A summary

table is provided below.

Table 1: Predicted Overall Emission Odour Rates from On-site Sources

Odour Source Odour Emission Rate (OER)

(OuE/s)

Drum Screen Room 5,430

MBBR 888

Settlement Pond 1 1,617

Settlement Pond 2 1,621

Pond 1 10,127

Pond 2 835

Pond 3 453

Pond 4 742

Pond 5 796

Pond 6 1,533

Pond 7 3,349

Pond 8 2,012

Pond 9 916

Pond 10

927

Total OER 31,244

4. Impact Assessment

Odour Impact Criterion for Odours

The odour impact criterion chosen for the analysis of the output data from the

dispersion model is based on recommended levels in EPA / EA guidance for

such operations. The 1-hour average shall be less than 3.0 OuE/m3 at the 98th

percentile of worst case total annual hours, as measured at the nearest OSL. In

order to comply with recent guidance provided by the EPA and EA, five years

of meteorological data was screened and the worst-case year used to present

data (yr 2015 Cork Airport was considered worst case) (AG4 Guidance

document and EA - ADMU).

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Model Output – Existing

Aermod Prime (18081) was used to determine the odour impact of the existing

operational WWTS emission sources. The output data was analysed to

calculate predicted odour emission contribution of the overall existing

operational WWTS during routine operation to odour plume dispersal at the

98th percentile for an odour concentration of less than or equal to 3.0 OuE.m-3.

The visual assessment of the odour plume spread is shown in Figure 7.2

contained in the OMI Report in Appendix 1. In summary, the nearest OSLs,

Carroll’s Cross Inn (R1) to the north and Cross Electric (R2) to the northeast are

predicted to perceive an odour concentration in the range of 2.1 – 2.6 OuE.m-

3 for the 98%ile of hourly averages which is below the criterion.

As shown in Figure 7.2, Appendix 1, parts of the Waterford Greenway are

predicted to be greater than 3.0 OuE/m3 for the 98%ile of worst case total

annual hours (175 hours). Duration and frequency are important considerations

in this context as well as the non-static nature of receptors. Users of the

Greenway will pass by the facility quickly therefore any negative impact will be

momentary at most. The frequency is likely to be insignificant when considering

the frequency of occurrence (175 hours) and the frequency of use by individual

users. Accordingly, no significant impacts are anticipated.

The modelling undertaken by OMI assessed the existing operational conditions

of approx. 95 tonnes per day. The WWTS has adequate capacity for additional

flows that could arise from maximum production capacity. Existing measures

to ensure that odour is minimised will continue to be implemented including:

• Implementation of operational manuals prepared by the MBBR and ICW

designers;

• Ensuring that the main factors affecting potential odour generation are

maintained including optimal water depths in the ponds and ensuring

waste CAT1 material is regularly removed from the Drum Screen.

5. Conclusions and Recommendations

There are no major point source emissions present at the DMIUC facility at

Carroll’s Cross. The back-up boiler represents a minor emission point (A3-1). The

emergency generator represents an abnormal emission (A4-1).

Fugitive emissions can occur from elements of the WWTS. Odour sampling and

odour dispersion modelling were completed to assess the impact off-site at

sensitive receptors.

The main conclusion from the assessment is that predicted level of odour from

the operational WWTS is not likely to generate odour impact in the vicinity of

the facility. A number of discrete OSLs (Carroll’s Cross Inn and Cross Electric)

were incorporated into the model. Each discrete OSL will perceive an odour

concentration in in the range of 2.10 to 2.60 OuE/m3 for the 98th percentile of

hourly averages which are below the criterion.

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The existing WWTS has adequate capacity to treat wastewater arisings from full

production capacity. Accordingly, it is not anticipated that an odour issue is

likely to arise from a full production capacity scenario. DMIUC implement

operational manuals for both the ICW and MBBR which include for measures

to minimise odour generation such as maintaining optimum water depths in the

ICW ponds.

The facility has never received any complaints from the public regarding

odour.

6. References

Refer to OMI report in Appendix 1.

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Ap

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ODOUR IMPACT ASSESSMENT OF THE WASTE WATER TREATMENT SYSTEM LOCATED IN

DAWN MEATS IRELAND LTD, CARROLS CROSS, WATERFORD, CO. WATERFORD

PERFORMED BY ODOUR MONITORING IRELAND ON BEHALF REDKITE ENVIRONMENTAL LTD

PREPARED BY: Dr. Brian Sheridan ATTENTION: Ms. Siobhan Maher DATE: 01

st July 2018 Ver.1 & 05

th July 2018 Ver.2

REPORT NUMBER: 2018297(2) DOCUMENT VERSION: Document Ver. 002 REVIEWERS: Ms. Siobhan Maher

ODOUR MONITORING IRELAND LTD Unit 32 De Granville Court, Dublin Rd, Trim, Co. Meath Tel: +353 46 9437922 Mobile: +353 86 8550401 E-mail: [email protected] www.odourireland.com

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Owner

Attachment 9.1

Owner

Document No. 2018297(2) Dawn Meats Ireland Ltd

www.odourireland.com i

TABLE OF CONTENTS Section number Page number

1. Executive Summary .................................................................................. iii 2. Introduction ................................................................................................ 1

3. Materials and Methods .............................................................................. 2

3.1. Odour sampling and analysis ......................................................................................... 2

3.1.1. Odour sampling ...................................................................................................... 2

3.1.2. Olfactometry ........................................................................................................... 2

3.1.3. Odour measurement in accordance with the EN13725:2003 ................................... 3

3.1.4. What is an odour unit? ............................................................................................ 3

3.1.5. Odour emission rate calculation. ............................................................................. 3

3.2. Model assumptions ....................................................................................................... 4

3.3. Dispersion modelling ..................................................................................................... 5

3.3.1. Atmospheric dispersion modelling of odours: What is dispersion modelling? ........... 5

3.3.2. AERMOD Prime ..................................................................................................... 5

3.4. Odour impact criterion for odours ................................................................................... 6

3.5. Meteorological data. ...................................................................................................... 6

3.6. Terrain data. .................................................................................................................. 6

4. Results ........................................................................................................ 7

4.1. Odour emission dataset for Scenario 1 .......................................................................... 7

4.2. Results of odour dispersion modelling for Scenario 1 ..................................................... 9

5. Discussion of results ............................................................................... 10

5.1. Odour plume dispersal for Scenario 1 – Model 1 .......................................................... 10

6. Conclusions ............................................................................................. 11

7. Appendix I - Odour dispersion modelling contour results ................... 12

7.1. Facility layout, boundary and receptor locations ........................................................... 12

7.2. Predicted odour contour plots for odour emissions for Model 1. ................................... 13

8. References ................................................................................................ 14

9. Appendix III - Meteorological data examined and used in the dispersion modelling exercise......................................................................... 15

Total 15

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www.odourireland.com ii

Document Amendment Record

Client: Redkite Environmental Ltd

Title: Odour impact assessment of the waste water treatment system located in Dawn Meats

Ireland Ltd located in Carrols Cross, Waterford, Co. Waterford.

Project Number: 2018297(1)

Document Reference: Odour impact assessment of the waste water treatment system located in Dawn Meats Ireland Ltd located in Carrols Cross, Waterford, Co. Waterford.

2018297(1) Document for review BAS JWC BAS 01/07/2018

Revision Purpose/Description Originated Checked Authorised Date

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www.odourireland.com iii

1. Executive Summary Odour Monitoring Ireland Ltd was commissioned by Redkite Environmental Ltd to carry out an odour sampling and odour dispersion modelling assessment of odour emissions from the operational Waste water treatment system located in Dawn Meats Ireland Ltd, Carrols Cross, Waterford, Co. Waterford. The purpose of this assessment was to determine the potential for the generation of odour impact on the surrounding population from operations at the existing waste water treatment system. Following a site assessment utilising odour sampling and analysis techniques, one odour emission dataset was developed to determine the potential odour impact of odour emissions from the operational waste water treatment system. This included: Ref Scenario 1: Predicted overall odour emission rate from existing operational waste

water treatment system during routine operation (see Table 4.1) – Model 1

Details of Model 1 is described in Section 3.2. Aermod Prime (18081) was used to determine the overall odour impact of the operational existing waste water treatment system as set out in odour impact criteria presented in Section 3.5. The output data was analysed to calculate:

• Model 1 - Predicted odour emission contribution of overall existing operational waste water treatment system during routine operation (see Table 4.1), to odour plume dispersal at the 98

th percentile for an odour concentration of less than or equal to 3.0 OuE

m-3

(see Figure 7.2). These computations give the odour concentration at each Cartesian grid receptor location that is predicted to be exceeded for 2% (175 hours) over 5 years of screened hourly sequential meteorological data (Cork Airport 2011 to 2015 inclusive). The Cartesian receptor grid was 20 and 50 m spaced given a total receptor number of 1894 over an area of 3.07 km

2.

The following conclusions were gathered from the study:

• With regards to Scenario 1 – Model 1, as can be observed, it is predicted that the levels of odours from the operational waste water treatment system is not likely to generate odour impact in the vicinity of the facility. A number of discrete sensitive receptors were incorporated into the model (R1 to R2). Receptor R1 and R2 will perceive an odour concentration in in the range of 2.10 to 2.60 OuE/m

3 for the 98

th percentile of hourly

averages (see Figure 7.2).

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www.odourireland.com 1

2. Introduction Odour Monitoring Ireland was commissioned by Redkite Environmental Ltd to perform an odour survey and dispersion modelling assessment of the operational existing Waste water Treatment system emissions located in Dawn Meats Ireland Ltd utilising dispersion modelling software Aermod Prime (18081). Like the majority of facilities, the operation of the WWTS is faced with the issue of preventing odours causing impact to the public at large. Utilising the existing site design and measured odour emission data of the existing operations within the waste water treatment system dispersion-modelling techniques were used to establish the predictive odour impact beyond the boundary of the facility in accordance with the standard requirements. One odour emission scenario was developed to take account of routine operations and design for the existing facility. This odour emission rate and specified source characteristics were inputted into Aermod Prime in order to determine the overall odour impact beyond the boundary of the facility. This assessment was performed in accordance with currently recommended international guidance and practice for the assessment of odours (Environment Agency H4 and Irish EPA AG4 guidance documents).

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3. Materials and Methods This section will describe the materials and methods used for the odour sampling and dispersion modelling assessment. 3.1. Odour sampling and analysis This section will provide the materials and methods used to sample and analyse odours from the operational WWTS.

3.1.1. Odour sampling

Point sampling In order to obtain air samples for odour assessment, a static sampling method was used where air samples were collected in 40 to 60 litre pre-conditioned Nalophan

NA bags using a vacuum

sampling device over a 15 minute period. The sampler operates on the 'lung principle', whereby the air is removed from a rigid container around the bag by a battery powered SKC vacuum pump at a rate of 4 l min

-1. This caused the bag to fill through a stainless steel and PTFE tube whose

inlet is placed in ambient air, with the volume of sample equal to the volume of air evacuated from the rigid container. All odour-sampling bags were pre-conditioned and flushed with odourous air to remove any interference from the sample material. Area flux hood sampling In order to measure the odour emission rate from area odour surfaces a calibrated wind tunnel method was used. This calibrated sampling hood allowed for the accurate determination of odour emission rate from the surface of the tanks. In combination with the point source static sampling method a 60-litre sample was obtained (Jiang et al., 2002, USEPA, 1998).

3.1.2. Olfactometry

Olfactometry using the human sense of smell is the most valid means of measuring odour (Dravniek et al, 1986) and at present is the most commonly used method to measure the concentration of odour in air (Hobbs et al, 1996). Olfactometry is carried out using an instrument called an olfactometer. Three different types of dynamic dilution olfactometers exist:

• Yes/No Olfactometer

• Forced Choice Olfactometer

• Triangular Forced Choice Olfactometer. In the dynamic dilution olfactometer, the odour is first diluted and is then presented to a panel of screened panellists of no less than four (CEN, 2003) Panellists are previously screened to ensure that they have a normal sense of smell (Casey et al., 2003). According to the CEN standard this screening must be performed using a certified reference gas n-butanol. This screening is applied to eliminate anosmia (low sensitivity) and super-noses (high sensitivity). The odour analysis has to be undertaken in a low odour environment such as an air-conditioned odour free laboratory. Analysis should be performed preferably within 8 to 12 hours of sampling.

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3.1.3. Odour measurement in accordance with the EN13725:2003

An ECOMA TO8 dynamic yes/no olfactometer was used throughout the measurement period to determine the odour threshold concentration of the sample air. The odour threshold concentration is defined as the dilution factor at which 50% of the panel can just detect the odour. Only those panel members who pass screening tests with n-butanol (certified reference gas, CAS 72-36-3) and who adhered to the code of behaviour were selected as panellists for olfactometry measurements (CEN, 2003). Odour measurement was carried out in an odour free laboratory in accordance with EN13725:2003. The analyses were carried out in the laboratory of Odour Monitoring Ireland in Trim Co. Meath.

3.1.4. What is an odour unit?

The odour concentration of a gaseous sample of odourant is determined by presenting a panel of selected screened human panellists with a sample of odourous air and varying the concentration by diluting with odourless gas, in order to determine the dilution factor at the 50% detection threshold. The Z50 value (threshold concentration) is expressed in odour units (OuE m

-3).

The European odour unit is that amount of odourant(s) that, when evaporated into one cubic metre of neutral gas (nitrogen), at standard conditions elicits a physiological response from a panel (detection threshold) equivalent to that elicited by one European Reference Odour Mass (EROM) evaporated in one cubic meter of neutral gas at standard conditions. One EROM is that mass of a substance (n-butanol) that will elicit the Z50 physiological response assessed by an odour panel in accordance with this standard. n-Butanol is one such reference standard and is equivalent to 123µg of n-butanol evaporated in one cubic meter of neutral gas at standard conditions (CEN, 2003).

3.1.5. Odour emission rate calculation.

The measurement of the strength of a sample of odourous air is, however, only part of the problem of quantifying odour. Just as pollution from a stack is best quantified by a mass emission rate, the rate of production of an odour is best quantified by the odour emission rate. For a chimney or ventilation stack, this is equal to the odour threshold concentration (OuE m

-3) of the

discharge air multiplied by its flow-rate (m3 s

-1). It is equal to the volume of air contaminated every

second to the threshold odour limit (OuE s-1

). The odour emission rate can be used in conjunction with dispersion modelling in order to estimate the approximate radius of impact or complaint (Hobson et al, 1995). Area source mass emission rates/flux were calculated as either OuE m

-2 s

-1 or OuE s

-1 depending

if they are being represented as discrete point sources or area sources in the atmospheric dispersion model. The overall odour emission rates for the existing scenario is presented in Table 4.1.

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3.2. Model assumptions The following model assumptions were used to construct and generate the output results from the dispersion model. These include:

• The input data used within the dispersion model was obtained from measurements carried out on site.

• One scenario was assessed to take account of client requirements. Ref Scenario 1: Predicted overall odour emission rate from existing operational waste


• AERMOD Prime (18081) dispersion model was used to assess the predicted odour concentrations on the surrounding area.

• Five years of hourly sequential meteorological data was screened within the dispersion model in order to provide statistical sound predictions for the impact assessment. Cork Airport 2011 to 2015 inclusive was used for the operation of the dispersion model while Cork Airport 2015 was determined as worst case impact year. This is in keeping with current national and international recommendations (EPA Guidance AG4 and EA). In addition, AERMOD incorporates a meteorological pre-processor AERMET PRO. The AERMET PRO meteorological preprocessor requires the input of surface characteristics, including surface roughness (z0), Bowen Ratio and Albedo by sector and season, as well as hourly observations of wind speed, wind direction, cloud cover, and temperature. The values of Albedo, Bowen Ratio and surface roughness depend on land-use type (e.g., urban, cultivated land etc) and vary with seasons and wind direction. The assessment of appropriate land-use type was carried out to a distance of 10km from the meteorological station for Bowen Ratio and Albedo and to a distance of 1km for surface roughness in line with USEPA recommendations

• The 98th percentile of maximum hourly predicted concentrations was used to provide the

output data from the dispersion model.

• Emissions to the atmosphere from the existing operations were assumed to occur 24 hours each day / 7 days per week over a standard year at 100% output for all sources.

• All building wake affects were assessed within the dispersion model.

• Terrain effects were accounted within the model using AERMAP software and digital data from OSI (10 m spaced).

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3.3. Dispersion modelling 3.3.1. Atmospheric dispersion modelling of odours: What is dispersion modelling? Any material discharged into the atmosphere is carried along by the wind and diluted by wind turbulence, which is always present in the atmosphere. This process has the effect of producing a plume of air that is roughly cone shaped with the apex towards the source and can be mathematically described by the Gaussian equation. Atmospheric dispersion modelling has been applied to the assessment and control of odours for many years, originally using Gaussian form ISCST 3 and more recently utilising advanced boundary-layer physics models such as ADMS and AERMOD (Keddie et al. 1992). Once the odour emission rate from the source is known, (OuE s

-1),

the impact on the vicinity can be estimated. These models can effectively be used in three different ways: firstly, to assess the dispersion of odours and to correlate with complaints; secondly, in a “reverse” mode, to estimate the maximum odour emissions which can be permitted from a site in order to prevent odour complaints occurring; and thirdly, to determine which process is contributing greatest to the odour impact and estimate the amount of required abatement to reduce this impact within acceptable levels (McIntyre et al. 2000). In this latter mode, models have been employed for imposing emission limits on industrial processes, odour control systems and intensive agricultural processes (Sheridan et al., 2002). 3.3.2. AERMOD Prime The AERMOD model was developed through a formal collaboration between the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (U.S. EPA). AERMOD is a Gaussian plume model and replaced the ISC3 model in demonstrating compliance with the National Ambient Air Quality Standards (Porter et al., 2003) AERMIC (USEPA and AMS working group) is emphasizing development of a platform that includes air turbulence structure, scaling, and concepts; treatment of both surface and elevated sources; and simple and complex terrain. The modelling platform system has three main components: AERMOD, which is the air dispersion model; AERMET, a meteorological data pre-processor; and AERMAP, a terrain data pre-processor (Cora and Hung, 2003). AERMOD is a Gaussian steady-state model which was developed with the main intention of superseding ISCST3 (NZME, 2002). The AERMOD modeling system is a significant departure from ISCST3 in that it is based on a theoretical understanding of the atmosphere rather than depend on empirical derived values. The dispersion environment is characterized by turbulence theory that defines convective (daytime) and stable (nocturnal) boundary layers instead of the stability categories in ISCST3. Dispersion coefficients derived from turbulence theories are not based on sampling data or a specific averaging period. AERMOD was especially designed to support the U.S. EPA’s regulatory modeling programs (Porter at al., 2003) Special features of AERMOD include its ability to treat the vertical in-homogeneity of the planetary boundary layer, special treatment of surface releases, irregularly-shaped area sources, a three plume model for the convective boundary layer, limitation of vertical mixing in the stable boundary layer, and fixing the reflecting surface at the stack base (Curran et al., 2006). A treatment of dispersion in the presence of intermediate and complex terrain is used that improves on that currently in use in ISCST3 and other models, yet without the complexity of the Complex Terrain Dispersion Model-Plus (CTDMPLUS) (Diosey et al., 2002).

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3.4. Odour impact criterion for odours The odour impact criterion chosen for the analysis of the output data from the dispersion was based on recommended levels in EPA / EA guidance for such operations. The 1 hour average shall be less than 3.0 OuE/m

3 at the 98

th percentile of worst case total annual hours, as measured

at the nearest odour sensitive location. In order to comply with recent guidance provided by the EPA and EA, five years of meteorological data was screened and the worst case year used to present data (yr 2015 Cork Airport was considered worst case) (AG4 Guidance document and EA - ADMU). 3.5. Meteorological data. Cork Airport met station 2011 to 2015 inclusive was used for the operation of Aermod Prime 18081. This allowed for the determination of dispersion for 5 years of meteorological data for the determination of overall odour impact from the existing WWTS operations beyond the boundary of the facility. Section 9 presents the windrose and tabular statistics for Cork Airport meteorological station for years 2011 to 2015 inclusive. 3.6. Terrain data. Topography affects in the vicinity of the site were accounted for in the model utilising topo data as gathered from OSI. All building wake effects are accounted for in the modelling scenario (i.e. building effects on point sources) as this can have a major effect on the odour plume dispersion at short distances. This was performed using the BPIP Prime algorithm.

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4. Results

This section will present the results obtained from the odour measurement and dispersion modelling study. 4.1. Odour emission dataset for Scenario 1 One data set for odour emission rates were calculated to determine the potential odour impact of the existing WWTS facility operations utilising odour emission data as gathered on site. These scenarios included: Ref Scenario 1: Predicted overall odour emission rate from existing operational waste


Aermod Prime (18081) was used to determine the overall odour impact of the WWTS emission sources as set out in odour impact criteria presented in Section 3.4.

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Table 4.1 illustrates the odour emission input data measured and utilised within the dispersion model for existing scenario. The measured overall odour emission rate from the WWTS is 31,244 OuE/s on this day of monitoring. Table 4.1. Predicted overall odour emission rate from existing operational Dawn Meats Ireland WWTS (ref Scenario 1 – Model 1).

Model 1 - Existing Waste water treatment system

Odour Sources Exposed Area

(m2)

Diameter (m) Source type Average Odour threshold conc.

(OuE/m3)

Average Odour emission flux (OuE/m

2/s)

Volume flow

(m3/hr)

Odour emission rate (OuE/s)

Notes

Drum screen room1

2 m2 opening - Volume 1,448 - 3.75 5,430 -

MBBR Tank 68.80 4.68 Area - 12.90 - 888 -

Settlement pond 1 109.3 - Area - 14.80 - 1,617 -

Settlement pond 2 109.5 - Area - 14.80 - 1,621 Settlement pond 1 data was used to represent Settlement pond 2 data

Pond 1 1235.0 - Area - 8.20 - 10,127 -

Pond 2 417.6 - Area - 2.00 - 835 -

Pond 3

226.7 - Area - 2.00 - 453 Pond 2 data was used to represent Pond 3 data

Pond 4

370.9 - Area - 2.00 - 742 Pond 2 data was used to represent Pond 4 data

Pond 5 397.8 - Area - 2.00 - 796 Pond 2 data was used to represent Pond 5 data

Pond 6 766.6 - Area - 2.00 - 1,533 Pond 2 data was used to represent Pond 6 data

Pond 7 1674.6 - Area - 2.00 - 3,349 Pond 2 data was used to represent Pond 7 data

Pond 8 2872.3 - Area - 0.70 - 2,011 -



Total OER (OuE/s) - - - - - - 31,244 -

Notes:

1 denotes leakage rate based on Valentine model and assuming and average wind speed of 5 m/s.

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4.2. Results of odour dispersion modelling for Scenario 1 Aermod Prime (18081) was used to determine the overall odour impact of the existing operational WWTS emission sources as set out in odour impact criteria in Section 3.4. The output data was analysed to calculate:

• Model 1 - Predicted odour emission contribution of overall existing operational waste water treatment system during routine operation (see Table 4.1), to odour plume dispersal at the 98

th percentile for an odour concentration of less than or equal to 3.0 OuE

m-3

(see Figure 7.2). These odour impact criterions were chosen so as to allow for visual assessment of the odour plume spread from the emission sources located within the waste water treatment system. These computations give the odour concentration at each Cartesian grid receptor location that is predicted to be exceeded for 2% (175 hours) for worst case year Cork Airport 2015 meteorological data. The Cartesian receptor grid was 20 and 50 m spaced. This will allow for the predictive analysis of any potential impact on the neighbouring sensitive locations while the facility is in operation. It will also allow the operators of the facility site to assess the effectiveness of their odour abatement/minimisation strategies. The intensity of the odour from two or more sources from the facility operation will depend on the strength of the initial odour threshold concentration from the sources and the distance downwind at which the prediction and/or measurement is being made. Where the odour emission plumes from a number of sources combine downwind, then the predicted odour concentrations may be higher than that resulting from an individual emission source. It is important to note that various odour sources have different odour characters. This is important when assessing those odour sources to minimise and/or abate. Although an odour source may have a high odour emission rate, the corresponding odour intensity (strength) may be low and therefore it is easily diluted. Those sources that express the same odour character, as an odour impact should be investigated first for abatement/minimisation before other sources are examined as these sources are the driving force behind the character of the perceived odour.

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5. Discussion of results This section will discuss the results obtained during the study. 5.1. Odour plume dispersal for Scenario 1 – Model 1

The plotted odour concentrations of ≤ 3.0 OuE m-3

for the 98th percentile for the existing

operational WWTS operation is illustrated in Figure 7.2. A number of discrete sensitive receptors were incorporated into the model (R1 to R2). Receptor R1 and R2 at these locations will perceive an odour concentration in in the range of 2.10 to 2.60 OuE/m

3 for the 98

th percentile of hourly averages.

Table 5.1 presents the predicted odour concentration at each receptor location for each of the Model scenario. Table 5.1. Predicted worst case 98

th percentile odour concentrations at each sensitive receptor

(Model 1) for worst case meteorological year – Cork Airport 2015.

Receptor identity X coordinate

(m) Y coordinate

(m)

Model 1 - 98%ile odour value worst case yr. Cork Airport 2015

(OuE/m3)

R1 644944.58 608456.43 2.20

R2 645124.20 608370.94 2.60

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6. Conclusions The following conclusions were gathered from the study:

• With regards to Scenario 1 – Model 1, as can be observed, it is predicted that the levels of odours from the operational waste water treatment system is not likely to generate odour impact in the vicinity of the facility. A number of discrete sensitive receptors were incorporated into the model (R1 to R2). Receptor R1 and R2 will perceive an odour concentration in in the range of 2.10 to 2.60 OuE/m

3 for the 98

th percentile of hourly averages

(see Figure 7.2).

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7. Appendix I - Odour dispersion modelling contour results 7.1. Facility layout, boundary and receptor locations

Figure 7.1. Existing Dawn Meats Ireland facility layout, location and receptor locations

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7.2. Predicted odour contour plots for odour emissions for Model 1.

Figure 7.2. Predicted odour emission contribution of Dawn Meats Ireland facility for Model 1 to odour plume dispersal for an odour concentration of less than or equal to 3.0 OuE m

-3 ( ) at the 98

th

percentile of hourly averages for worst case meteorological year Cork Airport 2015.

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8. References 1. Callan, B.T., (1993). Noses Knows Best. In malodour measurement and control. Proceedings of

the International Tydnall School, September. 134-145. 2. CEN, (2003). EN13725-Air-quality-Determination of odour concentration by dynamic

olfactometry. Brussels, Belgium. 3. DOE, (1993). Report by the Inspector on a Public Inquiry into the Appeal by Northumbrian

Water Limited for Additional Sewage treatment facilities on land adjacent to Spitial Burns, Newbriggin-by-the-Sea, Northumberland in March 1993. DoE ref APP/F2930/A/92/206240.

4. Dravniek, A., (1986). Atlas of odor character profiles. ASTM Committee on sensory evaluation of materials and products, ASTM data series. Baltimore, MD, USA.

5. EPA, (2001). Odour impacts and odour emission control measures for intensive agriculture. Commissioned by the Environmental Protection Agency (Ireland). OdourNet UK Ltd.

6. Longhurst, P., (1998). Odour impact assessment of an extension to the Brogborough landfill site. IREC, Cranfield University, England.

7. McIntyre, A., (2000). Application of dispersion modelling to odour assessment; a practical tool or a complex trap. Water Science and Technology, 41 (6). 81-88.

8. Sheridan, B.A. (2002). In house odour intensity and hedonic tone profile data of different odourous sources. Unpublished.

9. Sheridan, B.A., (2001). Controlling atmospheric emissions-BAT Note Development, UCD Environmental Engineering Group, Department of Agricultural and Food Engineering, UCD, Dublin 2.

10. Sheridan, B.A., Hayes, E.T., Curran, T.P., Dodd, V.A., (2003). A dispersion modelling approach to determining the odour impact of intensive pig production units in Ireland. Bioresource Technology. Published.

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9. Appendix III - Meteorological data examined and used in the dispersion

modelling exercise

Table 9.1. Tabular illustration of Cork Airport meteorological files for Years 2011 to 2015 inclusive (5 years).

5 year Meteorological file for Cork Airport 2011 to 2015 inclusive

Dir \ Speed <= 1.54

m/s <= 3.09

m/s <= 5.14

m/s <= 8.23

m/s <= 10.80

m/s > 10.80

m/s Total

0.0 0.09 0.30 1.53 1.33 0.36 0.11 3.72

22.5 0.03 0.17 1.04 0.42 0.20 0.08 1.95

45.0 0.07 0.20 0.97 0.85 0.18 0.02 2.30

67.5 0.09 0.22 1.15 0.46 0.16 0.01 2.08

90.0 0.08 0.34 2.09 1.23 0.30 0.06 4.10

112.5 0.13 0.46 2.08 1.34 0.28 0.10 4.39

135.0 0.11 0.34 2.02 1.40 0.65 0.15 4.67

157.5 0.24 0.33 1.96 1.01 0.32 0.01 3.87

180.0 0.24 0.94 3.93 1.81 0.50 0.15 7.57

202.5 0.25 0.79 3.76 2.62 1.01 0.30 8.72

225.0 0.15 0.89 6.82 4.03 0.81 0.19 12.89

247.5 0.17 0.55 5.93 3.39 0.39 0.02 10.45

270.0 0.38 0.67 4.42 2.35 0.58 0.10 8.49

292.5 0.27 0.59 4.44 2.36 0.82 0.18 8.66

315.0 0.18 0.67 4.58 2.65 0.72 0.08 8.88

337.5 0.09 0.20 2.33 2.86 0.75 0.17 6.41

Total 2.57 7.66 49.03 30.11 8.04 1.74 99.16

Calms - - - - - - 0.75

Missing - - - - - - 0.09

Total - - - - - - 100.00

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Figure 9.1. Windrose illustration of meteorological files Cork Airport 2011 to 2015 inclusive.

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