reply to queries raised by the epa under regulation 18 (3) (b) of … · 2012. 10. 15. · in...
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Reply to Queries Raised by the EPA under Regulation 18 (3) (b) of the
Waste Water Discharge (Authorisation) Regulations 2007
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With regard to the Waste Water Discharge (Authorisation) Regulations S.I. No. 684 of 2007,
Galway County Council submitted an application for a waste water discharge licence, for the
agglomeration of Glennamaddy, in June 2009.
In summary, the application for the discharge licence included details in respect of :
1. the waste water treatment works (primary treatment only),
2. the existing discharge (BOD, COD and SS are exceeded on a continued basis),
3. the existing receiving waters (Glennamaddy Turlough cSAC),
4. scheduled improvements and the WSIP,
5. the Water Quality (Dangerous Substances) Regulations 2001.
In February 2010, and in accordance with Regulation 18 (3) (b) of S.I. 684/2007, the EPA wrote to
Galway County Council and later, on 31st July 2012, requested that the response be submitted
electronically via the new EDEN portal.
The letter from the EPA, dated February 2010, the following queries.
1. “According to Section B.9, the population equivalent of the Glenamaddy agglomeration is
952. However it also suggests that the projected population equivalent for the year 2024 is
952. Confirm these figures. Confirm also whether there are any further plans to increase
treatment process capacity at the Glenamaddy treatment works. Provide timeframes and
dates for completion of any proposed upgrade works and confirm that emissions from the
upgraded plant will comply with the provisions of the Council Directives specified in section
G.1.
2. Provide full assimilative capacity calculations for all parameters for both current and future
treatment capacity. Provide clarification as to how the effluent standard will ensure
compliance with the water quality standards as set out in the European Communities
Environmental Objectives (Surface Waters) Regulations 2009 (S.I. No. 272 of 2009).
3. Noting that downstream of Glenamaddy there is a Special Area of Conservation, complete
the flow diagram in Circular L8/08 ‘Water Services Investment and Rural Water
Programmes – Protection of Natural Heritage and National Monuments’ issued by the
DoEHLG, to determine if an appropriate assessment is required. Provide details of
answers to each section of this flow diagram. If an appropriate assessment is required,
submit a copy of the report of the assessment.
4. Noting that there are drinking water abstraction points around of Glenamaddy, provide
comprehensive information as to any potential impacts from the discharge on the
abstraction points and all mitigation measures in place to ensure that the treatment works
will not have a significant effect on the water quality at these abstraction points.
Additionally, fill in Table F2 for each abstraction point.”
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Query No. 1
With regard to Query No. 1, the application for the discharge licence included reference to three
calculated estimates of “population equivalent”. These references are as follows :
1. Section B.9 (i) The existing population equivalent (p.e.) of the agglomeration to be,
or being, served by the waste water works should be provided and the period in
which the population equivalent was complied should be indicated.
Detail Provided : The existing population equivalent (p.e.) of the agglomeration to
be served = 952p.e. (NB. This Information has now been updated to read 680p.e.
see revised Table B9.2)
2. Appendix A1.0 Non-Technical Summary
Detail Provided : The proposed scheme is currently at design/concept stage where
it is proposed to demolish the existing wastewater treatment works (WWTW) and
construct a new Phase 1 WWTW on a greenfield site to cater for a population
equivalent of 762p.e.
3. Appendix B.9 (ii) Pending Development
Detail Provided : Two future population projections have been established for
Glennamaddy, namely ;
• Phase 1 Population Projection of 762p.e. which caters for the existing
population plus potential immediate infill development within the
agglomeration detailed in Attachment B.1.
• Phase 2 Population Projection of 952p.e. which caters for the future
developments and population increase within the agglomeration up to the
year 2024A.D.
Query No. 1 asked the following questions :
a. Confirm these figures.
b. Confirm also whether there are any further plans to increase treatment process capacity at
the Glenamaddy treatment works.
c. Provide timeframes and dates for completion of any proposed upgrade works and
d. confirm that emissions from the upgraded plant will comply with the provisions of the
Council Directives specified in section G.1.
By way of confirmation, we have now reviewed Table No. B9.2 of the application and this revised
table is presented as follows.
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Table No. B9.2 Estimated Population Equivalent for the Glennamaddy Agglomeration
Category
Existing Phase 1
Population
Equivalent
(2008)
Immediate
(Phase 1)
Population
Equivalent
Phase 2
Population
Equivalent
(Up to the Year
2024 AD)
Domestic 506 p.e. 557 p.e. 747 p.e.
Non-Domestic 174 p.e. 205 p.e. 205 p.e.
Total 680p.e. 762 p.e. 952p.e.
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a. Confirm these figures.
We can confirm that the existing population equivalent (p.e.) of the agglomeration is 680 p.e..
b. Confirm also whether there are any further plans to increase treatment process
capacity at the Glenamaddy treatment works.
We can also confirm that the current proposals associated with the Glennamaddy Sewerage Scheme, as contained in the Water Services Investment Programme, include for the construction of a new waste water treatment plant to replace the existing primary settlement (Imhoff) tanks. The proposals include for a new wastewater treatment plant that will be designed and constructed over two phases to cater for :
a. infill development within the village of Glennamaddy with a design capacity population equivalent of 762p.e.
b. a future Phase 2 (by the year 2024 AD) population equivalent of 952p.e.
The Glennamaddy Sewerage Scheme is currently in its planning stages and planning consent will
be sought for the future capacity of 952p.e.
c. Provide timeframes and dates for completion of any proposed upgrade works
The Planning Stage for the proposed scheme is programmed to continue for the remainder of
2012 and depending on the outcome and time required to liaise with the required Statutory Bodies
it is expected that construction of the project will commence in Q3 of 2013.
d. Confirm that emissions from the upgraded plant will comply with the provisions of
the Council Directives specified in section G.1.
Table B10.2 of the application submission summarised the proposed final effluent standards for
the new wastewater treatment plant in Glennamaddy.
Table B10.2 is reproduced here for clarity.
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Table B10.2. Envisaged Final Effluent Standards for the Proposed Wastewater Treatment Plant
Parameter Preliminary Report
dated April 2005
Suggested Improved
Discharge
Standards
Design Review
Report 2008
BOD 10 mg/l 10 mg/l
Suspended
Solids 10 mg/l 10 mg/l
Total Phosphorus 1.0 mg/l 0.5 mg/l
Total Ammonia 1.0 mg/l 1.0 mg/l
Nitrogen 15 mg/l 15 mg/l
We can confirm that the current proposals associated with the Glennamaddy Sewerage Scheme,
including the final effluent standards detailed in Table B10.2 can be achieved and that these
standards will be detailed in the tender documentation and contract documentation used to
construct and operate the proposed works.
We would note, however, that the position with regard to proposed reductions in pathogen
concentrations in the final treated effluent, is the subject of review with the EPA and consideration
may be given to the use of UV treatment.
Query No. 2
Provide full assimilative capacity calculations for all parameters for both current and future
treatment capacity. Provide clarification as to how the effluent standard will ensure compliance
with the water quality standards as set out in the European Communities Environmental
Objectives (Surface Waters) Regulations 2009 (S.I. No. 272 of 2009).
The Glennamaddy Sewerage Scheme is at early stage of the planning process and as such
studies have been limited to desktop based research. The project has not reached the stage
whereby field studies have been implemented, and gaps in available data have been addressed,
and therefore full assimilative capacity calculations, as requested, are difficult to undertake at the
present time.
However, based on the data available from other studies, and historic chemical data analysis in
the area, an overview assimilative capacity analysis has been undertaken.
In this regard the gaps which exist at the present time are :
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� the proportion of MRP in the discharge,
� the background concentrations upgradient of the Glennamaddy Turlough are unknown,
� the mean spring flow at Lettera is unknown. However, Drew, 1983 and data from Daly, 1995
indicate that the flow generated at Lettera is of the order of 30,000m3/d.
We have however, conducted assimilative capacity calculations using a number of permutations
and assumptions and these are as follows :
1. The proposed design standard leaving the proposed wastewater treatment plant will be
0.5mg/l Total P. (i.e., any benefit gained from the proposed percolation area integrated
constructed wetland has not been utilised.)
2. The Lettera ZOC is based on topographic divides to the turlough and the tracing elements
and the work done in Gortgarrow SPZ. Recharge is based on Gortgarrow SPZ report and
we have determined the approximate ZOC to be of the order of 33km2. There are however
uncertainties regarding the ZOC.
3. Lettera data presented by Daly, 1995 suggests a flow of the order of 0.45 to 0.74m3/sec .
We have used an estimate of 0.35m3/s for this purpose.
4. In terms of assessing the assimilative capacity beneath or immediately downgradient of a
possible percolation area/ICW, we have used scenarios with high and low aquifer
properties.
This analysis is presented in Figure 1.
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Figure 1 Assimilative capacity
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By using a theoretical percolation area/ICW area, the assimilative capacity calculations indicate that there is no capacity available even using the high aquifer flow conditions. However, there would appear to be an opportunity to improve water quality in the area by constructing the proposed Glennamaddy WWTW. Table 1 presents data, from the recording period 1998 to 2008, for the existing concentrations of
BOD, suspended solids and Ortho P which enter the Glenamaddy Turlough.
Table 1 Existing Effluent Quality
Flow
m3/day
Average
BOD
mg/l
Average
Suspended Solids
mg/l
Average
Ortho Phosphate
as P (mg/l)
Average 137 240 140 7.9
Maximum 411 345 369 21.8
Average Load ---- 12000
kgBOD/year 7000 kg SS/year 395kg P/year
The data in Table 1 indicates that at an average daily flow of 137m3/day and at an average
concentration of 7.9mg/l P, the total phosphorus load entering the turlough could be of the order of
395 kg P/ year, (i.e., this load is entering the groundwater system which is assumed to ultimately
discharge to the rivers west of the turlough – Sinking and Clare rivers).
Table 2 summarises the proposed design standards currently envisaged for the new wastewater
treatment plant and these standards do not include any benefit gained from discharging through a
percolation/infiltration area or integrated constructed wetland.
Table 2 Proposed Treated Effluent Design Standards
Parameter Design
Standards
Average
Design
Hydraulic
Load
Average
Loading
Potential
% Reduction
when
compared with
Table 2
BOD 10 mg/l
137m3/day
500 kg
BOD/year
96%
Suspended Solids 10 mg/l 500 kg SS/year 93%
Total Phosphorus 0.5 mg/l 25 kg P/year 94%
Total Ammonia 1.0 mg/l --- ---
Nitrogen 15 mg/l --- ---
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The data in Table 3 indicates that at an average daily flow of 137m3/day and at an average
concentration of 0.5mg/l P, the total phosphorus load which will enter the turlough, following the
proposed wastewater treatment plant upgrades, could be of the order of 25 kg P/ year, (i.e., a 94%
reduction in nutrients entering the ground water system).
Query No. 3
Noting that downstream of Glenamaddy there is a Special Area of Conservation, complete the flow
diagram in Circular L8/08 ‘Water Services Investment and Rural Water Programmes – Protection
of Natural Heritage and National Monuments’ issued by the DoEHLG, to determine if an
appropriate assessment is required. Provide details of answers to each section of this flow
diagram. If an appropriate assessment is required, submit a copy of the report of the assessment.
As noted in the Licence Application the Glennamaddy Sewerage Scheme is currently at
concept/planning stage where a complete review of the Preliminary Report has been completed.
The review took into account the implications of changes in legislation and regulations which have
come into force since the time of submission of the original Preliminary Report in April 2005.
A number of different options have been examined for the location of the proposed wastewater
treatment plant and receiving waters.
These options were listed in Table B10.1 of the Application and are reproduced in the following
table.
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Table B10.1. Options for the Location of the proposed WWTW and Receiving Waters
Locate WWTP
at Existing
site
Locate WWTP at new
site
Receiving Waters
Extent of Treated Effluent Pipelines
Required
Sewer Network
Requirements
Option No.
Option 1 � -- Glennamaddy
Turlough
Maintain use of existing Gravity
Outfall
Sewer Extensions and Sewer
Rehab
Option 2 -- � Glennamaddy
Turlough
Circa 375m of Rising Mains and
375m of new gravity outfall from new site to existing
outfall
Sewer Extensions and Sewer
Rehab
Option 3 -- � Sinking River Circa 4,750m of Foul
Rising Mains
Sewer Extensions and Sewer
Rehab
Option 4 -- � Shiven River Circa 10,500m of Foul
Rising Mains
Sewer Extensions and Sewer
Rehab
Option 5 -- � Springfield
River Circa 7,500m of
Foul Rising Mains
Sewer Extensions and Sewer
Rehab
Option 6 -- � Discharge to
Ground
Circa 375m of Rising Mains and new percolation area required
Sewer Extensions and Sewer
Rehab
Taking into account the requirements of “The Habitats Directive” (92/43/EEC) and following a
review of the options listed in Table B10.1 a Screening Report was prepared in June 2009 in
accordance with Article 6 of the Habitats Directive and this Screening Report has established that
the development of wastewater treatment infrastructure such as :
i) a new raw sewage pumping station along the Creggs Road but not within the cSAC,
and
ii) a new wastewater treatment facility outside the cSAC but within the Glennamaddy
environs,
will not have a significant impact on the Lough Lurgeen Bog/Glennamaddy cSAC.
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It is also concluded that the improved final effluent discharge standards (to ground via percolation
area outside the cSAC) will have a positive impact on water quality within the cSAC as it replaces
the existing untreated and poor quality effluent currently discharging into the turlough.
However, the difficulty now arises as to where the proposed treated effluent will be directed. The
options are :
1. Provision of a wastewater treatment plant with a new discharge to ground via an
Integrated Constructed Wetland (ICW) and/or percolation area. The ICW could be
located on low permeability subsoils with overflow to a percolation area located on the
moderately permeable subsoils to the north of Glenamaddy.
2. Provision of a new wastewater treatment plant and a new an Integrated Constructed
Wetland (ICW). The ICW could be located on low permeability subsoils which may
provide some ground infiltration with an overflow to the Glenamaddy Turlough.
3. Provision of a new wastewater treatment plant, an Integrated Constructed Wetland
(ICW), percolation area and new discharge location. The ICW could be located on low
permeability subsoils in Glennamaddy with an overflow requiring pumping to a
percolation area on the moderately permeable subsoils located several kilometres to
the west of Glenamaddy.
We are now considering all of the above options with the EPA and whilst the discharge of
pollutants to ground water is prohibited under the Ground Water Regulations, the EPA have
informed us that they have currently engaged the services of a specialist firm of consultants to
examine difficulties encountered with similar proposed or existing discharges throughout Ireland.
The result of these examinations being undertaken by the EPA are expected to be available in
September 2012, by which time the EPA may be able to provide guidance as to the proposed
solutions to our particular difficulties with the Glennamaddy Sewerage Scheme.
Whilst a screening report was prepared in accordance with Article 6 of the Habitats Directive, the
proposed scheme (as considered in 2009) is under review, the report and subsequent conclusions
will be the subject of further revisions and therefore it is premature to provide a copy of the current
version of the report and its findings.
We can confirm that the requirements of Article 6 of the Habitats Directive will be complied with
once the approach to the proposed disposal route for treated effluent has been considered in full.
We can also confirm that requirements of the recent European Union (Environmental Impact
Assessment and Habitats) (No. 2) Regulations S.I. No. 584 of 2011 will also be addressed once
the approach to the proposed disposal route for treated effluent has been considered in full.
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Query No. 4
Noting that there are drinking water abstraction points around of Glenamaddy, provide
comprehensive information as to any potential impacts from the discharge on the abstraction
points and all mitigation measures in place to ensure that the treatment works will not have a
significant effect on the water quality at these abstraction points. Additionally, fill in Table F2 for
each abstraction point.”
Referring to the data presented in Table 1 it can be seen that the existing total phosphorus load
entering the turlough could be of the order of 395 kg P/ year, (i.e., this load is entering the
groundwater system which is assumed to discharge ultimately to the rivers west of the turlough
(i.e., the Sinking and Clare rivers).
Referring to the data presented in Table 2 it can be seen that the total phosphorus load which will
enter the turlough, following the proposed wastewater treatment plant upgrades, could be of the
order of 25 kg P/ year, (i.e., a 94% reduction in nutrients entering the ground water system).
It is therefore expected that the proposed waste water treatment works will have a beneficial impact on the water quality in the area. As noted under the heading of assimilative capacity, the Glennamaddy Sewerage Scheme is at
the Planning Stage whereby desktop studies have been undertaken to date. However, the project
has not reached the stage whereby field studies have been implemented and gaps in available
data have been addressed. Therefore comprehensive information as to any potential impacts on
abstraction points are difficult to undertake at the present time.
The drinking water abstraction points around Glennamaddy are :
1. The Gortgarrow Spring located to the west of Glennamaddy
2. The Bushtown Spring located to the north of Glennamaddy
Whilst there have been no intrusive site investigations undertaken to date on the project a desktop
review shows that the area comprises Karstified limestones overlain mainly by tills of varying
thickness and permeability and there are a number of large springs and turloughs and swallow
holes as shown in Figure 1.
The ZOC for the Gortgarrow Spring and the Lettera Spring are also outlined in Figure 1.
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Figure 1 Main hydrogeological features: Glenamaddy turlough, Lettera, Gortgarrow and
Bushtown springs, Tracer Data, ZOC for Gortgarrow, estimated ZOC for Lettera
From Figure 1 it can be seen that the Glenamaddy Turlough, into which the existing discharge is
inputted directly, has been traced to Lettera Spring, some 3.5km west (Drew, 1983) and the tracer
work indicates the flow patterns are predominantly east to west and indicates the broad
groundwater divides.
The Lettera Spring is not used as a drinking water source so proposals to discharge treated
effluent to the turlough or to an ICW located within the Glennamaddy can be assumed to have
minimal impact on the Gortgarrow Spring or the Bushtown Spring.
We can confirm that the impacts of the proposed waste water treatment on the downstream water
abstractions will be considered in the ongoing planning stage of the project once the approach to
the proposed disposal route for treated effluent has been considered in full.
Table 3 provides details on the Drinking Water Abstraction Points in the area.
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Table F.2. Drinking Water Abstraction Points
ABS_CD AGG_Served ABS_VOL PT_CD DIS_DS EASTING NORTHING VERIFIED
Gortgarrow Spring Dunmore
Glennamaddy PWS
1,227m3/day 1200PUB1018 6km
(Southwestern Direction)
157100 259499 No
Bushtown Spring Glennamaddy Town Supply
550m3/day 1200PUB1021 <1km
(Northern Direction)
162305 264702 No
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