MWH Environmental Quantitative Risk Assessment (EQRA)
2
www.mwhglobal.com Planning & Environmental Permitting Environmental Quantitative Risk Assessment (EQRA) Facilities falling under the Environmental Permitting regime in the UK are required to prevent, reduce and eliminate pollution by prioritising efforts on the most significant industrial and agricultural activities. To gain an Environmental Permit, Operators will have to show that they have systematically developed proposals to apply the sector specific Best Available Techniques (BAT) and meet certain other requirements, taking account of relevant local factors The continuing use of underground or partially underground vessels or pipework without secondary containment can be an obstacle to obtaining a Permit as they do not reflect sector specific BAT standards due to the inability to undertake a regular inspection and maintenance programme. However, the replacement of existing assets with above-ground structures, for example, double-skinned vessels with leakage detection, can be economically challenging when the replacement costs outweigh the environmental benefits . However, such departures from BAT can be justified at the installation level by taking into account the technical characteristics of the installation concerned, its geographical location and the local environmental conditions. The Environmental Quantitative Risk Assessment (EQRA) has been developed to provide such justification and can be equally applied to both new and existing assets. It works by assessing the source-pathway-receptor linkage of specific assets and identifies those assets with potential to cause harm to controlled waters through fugitive emissions. The source-pathway-receptor linkage model is commonly used as the basis for risk assessment methodologies with respect to environmental releases, particularly for contaminated land analysis. The theory dictates that for harm to occur there must be a pollutant linkage. Such a linkage is deemed to exist if there is a potential contaminative source present, a receptor sensitive to that contamination and a pathway that would allow the contamination to pass between the two. Where at least one of these three elements is not present, no harm can occur. The Environmental Quantitative Risk Assessment (EQRA) assesses this pathway in a manner which is repeatable, robust, transparent and acceptable to the Environment Agency. e Environmental Quantitative Risk Assessment has been developed to justify departures from the indicative Best Available Techniques standards for both new and existing assets.
-
Upload
mwh-uk-ltd -
Category
Documents
-
view
213 -
download
0
description
The Environmental Quantitative Risk Assessment has been developed to justify departures from the indicative Best Available Techniques standards for both new and existing assets.
Transcript of MWH Environmental Quantitative Risk Assessment (EQRA)
www.mwhglobal.com
Planning & Environmental Permitting
Environmental Quantitative Risk Assessment (EQRA)
Facilities falling under the Environmental Permitting regime in
the UK are required to prevent, reduce and eliminate pollution
by prioritising efforts on the most significant industrial and
agricultural activities. To gain an Environmental Permit,
Operators will have to show that they have systematically
developed proposals to apply the sector specific Best
Available Techniques (BAT) and meet certain other
requirements, taking account of relevant local factors
The continuing use of underground or partially underground
vessels or pipework without secondary containment can be
an obstacle to obtaining a Permit as they do not reflect sector
specific BAT standards due to the inability to undertake a
regular inspection and maintenance programme. However, the
replacement of existing assets with above-ground structures,
for example, double-skinned vessels with leakage detection,
can be economically challenging when the replacement costs
outweigh the environmental benefits .
However, such departures from BAT can be justified at
the installation level by taking into account the technical
characteristics of the installation concerned, its geographical
location and the local environmental conditions.
The Environmental Quantitative Risk Assessment (EQRA)
has been developed to provide such justification and can be
equally applied to both new and existing assets. It works by
assessing the source-pathway-receptor linkage of specific
assets and identifies those assets with potential to cause harm
to controlled waters through fugitive emissions.
The source-pathway-receptor linkage model is commonly
used as the basis for risk assessment methodologies
with respect to environmental releases, particularly for
contaminated land analysis.
The theory dictates that for harm to occur there must be a
pollutant linkage. Such a linkage is deemed to exist if there is
a potential contaminative source present, a receptor sensitive
to that contamination and a pathway that would allow the
contamination to pass between the two. Where at least one of
these three elements is not present, no harm can occur.
The Environmental Quantitative Risk Assessment (EQRA)
assesses this pathway in a manner which is repeatable,
robust, transparent and acceptable to the Environment
Agency.
The Environmental Quantitative Risk Assessment has been developed to justify departures from the indicative Best Available Techniques standards for both new and existing assets.
0813
- E
QR
A-0
413
Nick GillEnvironmental Consultant
t: + 44 (0)1925 845219
The EQRA approach is based on a two-stage assessment
process comprising preliminary screening followed by a
detailed EQRA for appropriate assets.
Each asset is screened to determine whether the existing
infrastructure materially complies with the requirements
of BAT. Where this is the case, in line with the EA’s
guidance, fugitive surface and groundwater emissions from
infrastructure should not occur during normal operations.
Consequently it is considered that no further assessment of
the assets is required.
Remaining assets are then subject to a quantitative risk
ranking to determine priorities for further action.
The assessment has been developed based upon a
numerical system that assigns scores according to the
perceived likelihood of fugitive emissions causing harm to
controlled waters. This final risk rating score is a function of
the likelihood of the asset to leak, the potential severity of
that leak should it occur, the readiness that any pathways
present would transmit contaminants and the sensitivity
of receptors that may be impacted upon. Assets are then
banded based upon this total score (or any component of it)
into Band A, Band B or Band C.
The absence of a source-pathway-receptor linkage is
demonstrated by a score of 0 in the relevant section. This
means that the model generates a final asset ‘Risk of Harm’
of 0, indicating that there is no risk of harm.
Band C assets, those with the lowest total score, are those
reflecting the same low pollution risk as assets that comply
with BAT standards. For assets which score higher and cannot
be shown to meet the BAT equivalent standards, the ERQA
allows the Operator to run mitigation improvement scenarios to
determine to most cost effective improvements
In broad terms the model is designed to assign a numerical
score to each of the three parts of the source-pathway-
receptor model and then multiply those scores. Multiplication
of section scores has the added benefit of resulting in a
greater spread of risk ratings allowing easier identification of
those assets that require improvement works.
Peter DuncanEP/PPC Team Leader
t: + 44 (0)1925 845207
Printed on 100% recycled material. © This document and the material
contained therein remain the property of MWH UK Limited.
Total Leak Likelihood
Total Pathway Rating
Total Receptor Rating Risk of Harmx x =
