HERTFORDSHIRE COUNTY COUNCIL
DEVELOPMENT CONTROL COMMITTEE
WEDNESDAY 26 MARCH 2014 AT 10.00 AM
Agenda No.
5
EAST HERTS DISTRICT
APPLICATION FOR THE CONSTRUCTION AND OPERATION OF A
LEACHATE
TREATMENT
FACILITY,
CONTROL
ROOM
AND
ASSOCIATED PLANT FOR DISCHARGE TO THE SEWER AT WESTMILL
LANDFILL SITE, WESTMILL ROAD, WARE, HERTFORDSHIRE, SG12
0ES.
Report of the Chief Executive and Director of Environment
Author:
Iain Leech
Tel: 01992 556225
Local Member: David Andrews
1
Purpose of Report
1.1
To consider planning application reference 3/0183-14 for the
construction and operation of a leachate treatment facility, control room
and associated plant for discharge to the sewer at Westmill landfill site,
Westmill Road, Ware, Hertfordshire, SG12 0ES.
2
Summary
2.1
This application seeks planning permission for a leachate treatment
facility, control room and associated plant at Westmill Landfill site.
Leachate is a liquid that accumulates within landfills. It can comprise
rainwater that percolates into the landfill and through the waste, picking
up contaminants from the waste as it percolates down towards the base
of the landfill. It can also arise from the waste itself and can be produced
as waste decomposes for example.
2.2
The proposed facility would provide sufficient capacity to meet
increasing leachate levels and would avoid the need to tanker leachate
off site to a licensed treatment facility i.e. a sewage treatment works.
The main objective of the plant is to reduce ammonia levels by 90% prior
to discharge to the foul sewer. It would also reduce the levels of
dissolved methane, dissolved organic matter, and odours.
2.3
The original planning permission for a new leachate plant (3/0894-08)
was permitted on 22nd July 2008, but was not implemented within 3
years of the date of permission. That permission was renewed under
planning permission 3/1426-11 which was also not implemented.
2.4
There is an existing leachate plant on site. This is located along the
south eastern boundary of the site adjacent to the A10. It is proposed
that this be mothballed but be retained on site as a back up facility in the
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event that any new leachate plant ceased operating.
2.5
The current application proposes a larger leachate plant than the
previous two planning applications. It is also proposed that leachate from
other landfill sites (without leachate treatement plants) would be brought
to the site in tankers for treatment at the proposed plant.
3
Description of the site and proposed development
3.1
The site is located along the boundary of the A602 and A10 roads on the
north-western edge of Ware. It is also bounded by a small business
park to the south and Westmill Quarry to the north. The nearest
residential properties are located in Downfield Court, 520 metres northeast of the application site.
3.2
The site covers an area of approximately 0.1ha. Existing buildings on
the site include associated plant for landfill operations and site office
accommodation. The site is an active quarry and landfill. Sand and
gravel is extracted. The resulting void space is then lined and filled with
waste. Mineral extraction commenced in the 1950s and planning
permission for landfilling was granted in 1980. The current planning
permission requires landfilling operations to cease and for the the site to
be restored by the end of 2017.
3.3
This application seeks planning permission for a leachate treatment
facility, control room and associated plant at Westmill Landfill site. The
proposed facility would avoid the need to tanker leachate off site to a
licensed treatment facility i.e. a sewage treatment works. The main
objective of the plant is to reduce ammonia levels by 90% prior to
discharge to sewer. It would also reduce the levels of dissolved
methane, dissolved organic matter, and odours.
3.4
The original planning permission (3/0894-08) was permitted on 22nd July
2008, but was not implemented within 3 years of the date of permission
This permission was renewed in 2011 but was also not implemented.
3.5
The previous consented facility had a development footprint measuring
approximately 38m by 17.5m. The current proposed plant would have a
development footprint of 60m by 17.5m. The plant would comprise:

two cylindrical concrete leachate treatement tanks (measuring
approximately 6.9m high and 12m wide)

two leachate balancing tanks placed horizontally
approximately 13.2m lomg, 4m high and 3.7m wide),

one treated leachate holding tank, placed horizontally (measuring
approximately 11.7m in length, 4m high and 3.7m wide)

a caustic soda dosing tank (meauring approximately 5m high and 4m
wide)
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(measuring

two ISO containers (these are steel freight containers, each measuring
2.8m wide x 6.1m long x 2.6m high) housing a plant room and control
room which would be stacked one upon the other to a total height of
5.2m.

Steel access ladders and platforms located over the ISO containers to
provide access to the top of the two leachate treatment tanks
3.6
Leachate would be drawn from the landfill site in pipes and pumped, via
the leachate balancing tanks, to the two treatment tanks. Bacteria within
the leachate convert ammonia to a nitrate as part of an aerobic process.
Optimum conditions for the bacteria require sufficient levels of dissolved
oxygen, heat and alkalinity. Alkaline conditions can be maintained by the
addition of caustic soda as necessary. An aeration system would provide
oxygen and heat to maintain aerobic conditions within the treatement
tanks. Once treated, the ‘clean’ leachate would then be discharged to
the foul sewer, with the residual effluent pumped to the effluent
balancing tank from where it would be collected by tanker once a month.
3.7
The plant would treat all of the leachate currently being produced within
the landfill (approximately 50 to 75 cubic metres a day) and have
capacity to treat an additional 75m3 of leachate daily. It is proposed that
leachate arising from other local landfill sites (which do not have on site
leachate treatment plants) would be brought to site by tanker to make
use of this additional treatment capacity. This leachate would come
predominantly from North Herts Landfill (now closed and restored) and
Ugley landfill in Essex.
3.8
Leachate would only be tankered onto site on a temporary basis whilst
spare capacity existed within the plant. As landfilling continues, the
strength and volume of leachate in the landfill is likely to increase and
would be required to be treated by the plant, reducing any spare
capacity for treating off site leachate.
3.9
It is estimated that up to 30 tankers a week could arrive at the site to
import leachate from other landfills.
3.10 The site for the proposed treatment facility would be centrally located
within the site, adjacent to the existing quarantine building, which is used
to isolate unsuitable waste types brought into site. The facility would be
required beyond the lifespan of the landfill operations for a minimum
period of 30 years, but would be removed and the land restored once
the need for leachate treatment has ceased. The treatment facility would
be automated and operational 24 hours a day, 7 days a week.
3.11 At present leachate is treated on site at the existing facility adjacent to
the south eastern site boundary prior to discharge to the sewer, however
this planning application proposes to provide an upgraded treatment
facility on the north-western site boundary.
3.12 The applicant has stated that they wish to retain the existing leachate
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treatment plant located in the south east of the site, adjacent to the A10,
as an emergency back up unit. It would be moth balled but retained in
case of any operational breakdown or maintenance of the new plant.
3.13 It is proposed that the construction of the plant would take place
between the hours of 0700 to 2000 Monday to Friday and 0700 to 1700
on Saturdays with no working on Sundays.
3.14 Construction would take approximately 20 weeks with construction traffic
amounting to approximately 84 HGV movements (42 in and 42 out) over
this 20 week period. The applicant advises that the highest number of
daily HGV movements during the construction period would be 20 (10 in
and 10 out) when concrete was being poured.
4
Consultations
4.1
East Herts District Council does not object.
4.2
The Environment Agency has no objection to the proposal.
4.3
Natural England does not object.
4.4
Bengeo Rural, Thundridge Parish Council and Hertford and Ware Town
Councils have not responded.
4.5
Hertfordshire County Council as Highways Authority does not wish to
restrict the grant of permission.
4.6
The Ramblers Association (Hertfordshire and North Middlesex Area)
request that two rights of ways (to be reinstated across the site following
restoration) would not be affected by the proposed development.
4.7
Neighbours / Publicity
A site notice was erected on 14 February 2014 and an advert placed in
the Hertfordshire Mercury on 13 February 2014.
474 properties were consulted on the application and 6 letters objecting
to the application were received. A 50 signature petition was also
submitted, objecting to the proposal. The main issues raised were:
Increasing odour arising from the provision of the proposed plant.
Increased HGV movements and increased congestion and noise
associated with increase in HGV movements and loss of highway safety.
Queuing of HGVs outside of residential properties with associated noise
and disturbance.
The site is turning into a waste processing facility and account needs to
be taken of all the operations on the site.
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Fear and risk of pollution to groundwater and local water courses.
5
Planning considerations
5.1
The relevant development plan policies are:
Hertfordshire Waste Core Strategy adopted November 2012
Policy 1A (Presumption in favour of sustainable development),
Policy 11 (General Criteria),
Policy 13 (Road Transport and Traffic)
Policy 16 (Soil, Air and Water).
East Herts Local Plan Second Review, Adopted April 2007
Policy GBC1 (Appropriate Development in the Green Belt)
Other relevant material considerations are:
The National Planning Policy Framework
Technical Guidance to the National Planning Policy Framework
5.2
The principal issues to be taken into account in determining this
application are:




Need
Impact on the Green Belt
Odour
Visual Impact
Need
5.3
Leachate is a liquid that accumulates within landfills. It can comprise
rainwater that percolates into the landfill and through the waste, picking
up contaminants from the waste as it percolates down towards the base
of the landfill. It can also arise from the waste itself and can be produced
as waste decomposes for example.
5.4
As landfilling progresses and the volumes of waste within the landfill at
Westmill increase, the strength and volume of leachate is increasing and
requires removal from the landfill. It will be necessary to provide
ongoing treatment for up to 30 years after the landfill has ceased
accepting waste and been restored.
5.5
The proposed treatment plant would provide sufficient capacity to treat
leachate produced within the landfill now and for the coming years.
5.6
Without it, the existing leachate treatment plant would not be able to
treat all the leachate that is likley to be produced in the future as the
amount of waste within the landfill increases with subsequent increases
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in leachate. In addition, the levels of ammonia within the leachate are
increasing due to changes in the composition of the waste (due to
increased recycling and pre treatment of waste) This would mean that
untreated leachate would need to be stored on site and then tankered off
for treatment elsewhere.
5.7
Furthermore, build up of leachate within the base of the landfill can
create difficulties with gas extraction as it can affect landfill gas
permeability. Of further concern is the risk of pollution to groundwater if
leachate is not properly managed as well as the increased risk of odour
from leachate within the landfill and whilst being stored. As such, there
would be a clear need and benefits associated with the proposed
leachate treatment plant.
5.8
Policy 1A of the Hertfordshire Waste Core Strategy contains a
presumption in favour of sustainable development. The proposal would
constitute sustainable development by providing a long term solution for
managing and treating leachate arising on site, reducing the risk of water
pollution and odour, and eliminating travel distances involved in treating
the leachate elsewhere.
5.9
Additionally, the proposed treatment of leachate from North Herts
provides a closer treatment facility than existing (leachate from North
Herts is currently tankered to a site in Milton Keynes).
Green Belt
5.10 Policy GBC1 of the East Herts Local Plan and the NPPF require very
special circumstances to be demonstrated that clearly outweigh the
harm of a proposal by reason of inappropriateness and any other harm
when considering proposals for inappropriate development within the
Green Belt.
5.11 The impact upon openness of the Green Belt would be a long term one
although it would be temporary with the plant being removed and the
land restored once the requirement to treat leachate has gone. There
would not be any permanent adverse impact upon the openness of the
Green Belt in this location and the site would be fully restored (with
restoration taking place progressively) and would not therefore conflict
with any of the purposes of including land within the Green Belt.
5.12 The construction of a leachate treatment plant within the Green Belt
would be considered inappropriate development. However, it is
considered that the benefits associated with the provision of a plant (as
set out in paragraphs 5.4 to 5.9 above) would constitute very special
circumstances that would clearly outweigh the harm to the Green Belt
and any other harm as identified below.
Visual Impact
5.13 The landfill site is proposed to be restored upon completion in
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accordance with the existing planning permission and it is proposed that
a condition be imposed stating that upon removal of the leachate
treatment facility, this land also be restored in accordance with the
landfill restoration scheme.
5.14 The new proposed leachate plant would have minimal visual impact due
to its location within the existing landfill along the north eastern
boundary. The facility would be screened by an existing bund to the
north east, and would be located adjacent to existing plant and
compound facilities associated with the landfill and mineral works. The
existing landfill would screen any potential views from residential
properties on Westmill Road or from Ware. Neither would there be any
direct views from residential properties at Downfield Court.
5.15 It is considered that the retention of the existing leachate treatment
facility would not be visually intrusive or have further impact upon the
openess of the Green Belt as the existing facility is already established
and is situated along the boundary of the A10 and is on land at a lower
level than the rest of the landfill, so is not visible from the surrounding
area. Therefore it is proposed that the existing facility be permitted to be
kept, with planning conditions imposed ensuring that this facility would
be removed at some stage during the operational works on site and that
the site is restored at a future date .
Odour
5.16 In terms of odour concerns, the proposed facility would enable leachate
to be discharged faster, reducing the volume of untreated leachate
present within the landfill site at any one time thus minimising odour
generated by untreated leachate.
5.17 The treatment process would take place within an enclosed system
which would minimise odour release from the facility. Leachate that was
tankered into the site for treatment would be discharged directly into the
leachate plant and would remain enclosed.
5.18 As the leachate levels are currently increasing in both volume and
strength, odour problems could worsen if not tackled. Without the
increased leachate treatment capacity provided for by the proposed
facility, the additional untreated leachate would need to be stored onsite, until such time that it can be tankered elsewhere to be treated.
Therefore, the proposal should reduce odour by way of treating leachate
and enabling discharge to foul sewer as soon as is possible.
Highways
5.19 The current planning permission for the site has no restriction on HGV
movements associated with the landfill. They number an average of 160
a day (80 in and 80 out) but can exceed 200 (100 in and 100 out) on
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busier days such as after Easter or Christmas.
5.20 The site is well located in terms of proximity to the major highway
network. The site is accessed directly off the A602 Westmill Road and is
located approximately 730m from the A10.
5.21 It is considered that the proposed additional HGV movements
associated with construction and also with tankering leachate onto site
(up to 30 a week) would represent a modest increase and would be for a
temporary period. These numbers would not be noticeable in terms of
the daily HGV movements associated with the site and would be
absorbed as part of daily fluctuations in HGV movements to and from
the site.
5.22 Representations have raised concerns with regards to HGVs parking
along Westmill Road in the early morning outside residential properties
whilst waiting for the landfill to open. They state that HGVs parked in this
manner cause noise disturbance to these properties as well as
obstructing the highway and vehicular access from these properties onto
Westmill Road.
5.23 Whilst this issue is not directly associated with the current planning
application for a leachate treatment plant (but appears to be associated
with existing operations and HGVs importing restoration soils to the site),
officers have raised these complaints with site management in order for
them to investigate and for any problems to be promptly addressed. The
applicant has advised that they have recently written to all their
customers reminding them of the site opening hours and requesting that
HGVs do not turn up before 7am. They have also restricted access to
tipper lorries to after 8am to prevent them arriving early and queuing on
the highway.
Rights of Way
5.24 Thundridge footpaths 022 and 052 have been temporarily stopped up for
the duration of quarrying and landfilling on site. These routes would be
reinstated as part of final site restoration. Neither route would be
affected by the proposed leachate plant which would not be located near
either route.
6
Conclusions
6.1
The proposed leachate plant would constitute inappropriate
development within the Green Belt. However, it is considered that the
environmental benefits associated with the proposed plant would
constitute very special circumstances that would clearly outweigh the
harm to the Green Belt and any other harm. It would have minimal visual
impact and is not in the immediate vicinity of any residential properties
and would assist in controlling odour associated with leachate.
6.2
It is therefore recommended that, subject to the application needing to
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be referred to the Secretary of State because the development sits
within the Green Belt and him not wishing to call the application in for a
decision, the Chief Executve and Director Enviroment should be
authorised to grant planning permission subject to the following
conditions:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Time limit for commencement of development
Approved plans
Hours of construction
Location of contractor parking and compound area
Resistance to corrosion
Containment of the tanks
Containment of jetting in the event of failure
Landscaping
Restoration of the land following removal of the infrastructure.
Background information used by the author in compiling this report
Planning application reference 3/1426-11
Planning permission reference 3/0894-08
Consultee responses
Relevant policy documents
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