- Who manages the site?
- What type of waste is contained within the landfill site?
- Does the council know the source of all of the waste?
- How is the waste contained?
- How is the waste managed?
- What happens on site regarding the monitoring and treatment of contaminants?
- How is the leachate treated and where does it go?
- Is there a licence to discharge leachate to the Severn Trent Water sewer system and how can you be sure it’s safe?
- Is leachate taken off site by tankers for treatment elsewhere?
- What happens to the methane gases?
- Is regular testing undertaken and what have been the results?
- Are surrounding water courses impacted?
- Are there any risks to residents in nearby developments?
- Should the public be concerned?
- What’s the ecology like at Stoneyhill landfill site?
- What happens to the rainwater at the site?
- Are there any bad smells linked to the site?
- Why are there brown bubbles in the leachate treatment tank at Stoneyhill?
- Are all the monitoring points and boreholes inside the site within the landfill waste?
- Is the site accessible to the public?
- Has toxic waste been tipped at the site?
- Is toxic waste leaving the site in an uncontrolled manner?
- Why can orange colouration be seen in the Coalbrookdale watercourses?
- Has there been an ‘unconsented discharge’?
- Are there other landfill sites in the borough that Telford & Wrekin Council is responsible for and are they managed the same way?
- Is the site considered to have contaminated land status?
- Did the Environment Agency (EA) test samples from Stoneyhill?
- Did the EA test the water quality in the streams and water bodies around Stoneyhill?
- Does a stream run through Stoneyhill closed landfill site?
- Has Telford and Wrekin Council tested the water quality in the streams and water bodies around Stoneyhill?
- Did Monsanto deposit polychlorinated biphenyls (PCBs) in Stoneyhill landfill?
Who manages the site?
Telford & Wrekin Council owns and manages the site. The council employs a specialist contactor, currently Veolia, to support in day to day management of the site including regularly monitoring data collection relating to gas concentrations and leachate levels.
The site is checked daily to ensure all the pumps are working and to ensure any required maintenance issues are dealt with promptly.
What type of waste is contained within the landfill site?
Stoneyhill was issued a waste disposal licence in 1984 to accept controlled waste. The site was operated by Shropshire County Council during the period from 1985 to 1991. The controlled wastes were mainly domestic, commercial and industrial. Lesser amounts of other wastes such as medical, surgical and veterinary wastes were also permitted.
Does the council know the source of all of the waste?
Telford & Wrekin Council does not hold the daily ‘tickets’ which recorded the detail of what was deposited within the landfill during its time of operation.
Telford & Wrekin Council does however hold a significant volume of reports and paperwork passed on from Shropshire County Council. The paperwork includes letters, invoices, planning documents and working plans of the landfill.
Information confirms that, of the waste deposited:
- 53% was household
- 35% was inert
- 6% was industrial
- and 2% was special and commercial waste, please note special waste includes, for example, asbestos or animal carcasses.
The remaining 4% comprises of soil that was added daily to cover the waste.
How is the waste contained?
The waste within the site is fully contained within a clay ‘bowl’ formed within the historic opencast mining space.
As is common with landfills of this type, the base and sides are constructed from clay (low permeability). The ‘cap’, which covers the entire landfill, also comprises clay which is recorded as being from 2.5m to several meters in thickness.
How is the waste managed?
Generally waste in landfill sites decomposes (breaks down) and as part of this process both water and gas are produced. The council manage this decomposition and associated water / gas (known as contaminants) on a daily basis, to ensure these waste bi-products of decomposition are treated and disposed of safely.
What happens on site regarding the monitoring and treatment of contaminants?
Telford & Wrekin Council actively manages the site with continuous monitoring throughout the year. The key elements to manage are methane gas and water ‘leachate’.
Landfill leachate is essentially rainwater which mixes with the waste within the landfill site.
Both gas and leachate are collected through a series of complex wells and infrastructure across the site.
The methane gas, generated from the decomposition, is pumped to a storage tank where it is then burned at a temperature in excess of 1000 degrees Celsius.
The leachate is pumped separately and collected in a holding tank and continually circulated to remove the methane gas contained within it. The leachate is then tested and, once compliant, discharged under licence to Severn Trent’s sewage system.
A picture of gas flare which burns landfill gas (methane).
A picture of a leachate pre-treatment plant.
How is the leachate treated and where does it go?
Leachate is pumped from wells constructed across the site and collected in a holding tank. The leachate is then circulated around a number of open tanks to remove the methane naturally through aeration.
Ongoing chemical tests are carried out on the leachate within the system until it has reached a level whereby the water is deemed safe by Severn Trent to be released into the sewage system. At this stage, the water is discharged under licence to a Severn Trent drain (sewer).
Is there a licence to discharge leachate to the Severn Trent Water sewer system and how can you be sure it’s safe?
Telford & Wrekin Council has a licence to dispose of leachate into the sewage system. This licence is more specifically called an ‘Agreement for the discharge of trade effluent to the public foul water sewer’.
As with any licence, numerous conditions must be adhered to for compliance to be met. In this case, thirteen conditions are set out as well as additional quality control conditions.
To be compliant for safe discharge into the sewage system, the treated leachate at the site must meet the quality control standards which include strict upper limits of specific chemicals present in the liquid.
Is leachate taken off site by tankers for treatment elsewhere?
No.
Leachate was historically tankered from the site for treatment prior to the construction of the on-site leachate treatment plant and discharge licence in 2012.
Although leachate is not currently tankered, Telford & Wrekin Council may use tankering from time to time during periods of infrastructure and equipment upgrade or maintenance works.
Currently, all leachate is treated on site.
What happens to the methane gases?
Methane gas from the site is treated in two ways:
- it is collected from wells across the site and burned at a very high temperature (see above)
- Methane from the site that has become dissolved in the leachate cannot be burned off. In this case, the water containing leachate is aerated in a controlled system until compliant prior to being released, under licence, into the sewage system.
Is regular testing undertaken and what have been the results?
Yes.
Regular testing is carried out both on site and beyond as part of the active management of the site.
The testing includes:
- weekly leachate testing by Telford & Wrekin Council / Veolia prior to discharge into the sewage system under licence. (Please note Severn Trent carry out frequent check tests)
- groundwater samples are taken from wells within the site and ponds to the north and east of the main site on a quarterly basis
- gas analysis is carried out on a weekly basis
- a full round of gas monitoring is carried out around the perimeter of the landfill on a quarterly basis to check no methane is leaving the site outside of the clay cap
- leachate depth measurements within the landfill are collected on a monthly basis to measure the varying levels of leachate underground and allow us to model this and ensure our management of the site is sufficient
- tests for polychlorinated biphenyls (PCBs) – industrial products or chemicals is carried out annually. None of these results have been above laboratory detection limits, therefore we have no evidence of such waste being present on this closed landfill site.
Of all the testing results collated to date, none has presented any cause for concern.
Through proactive management and monitoring, all testing results to date have been within allowable limits and have been classified as acceptable.
Are surrounding water courses impacted?
No.
Three ponds are located adjacent to the west and north of the site.
Water taken from these ponds is routinely tested for chemicals and key indicators of possible harm to the environment. Testing results to date have identified no contamination issues arising from the site.
In 2023, samples of water were taken at three points from the Lyde Brook which runs to the west of the landfill site. These samples were comprehensively tested for contaminants with no contamination issues identified.
Are there any risks to residents in nearby developments?
No.
Conditions placed on developments near to the site mean that developers must demonstrate that land and air quality are complaint with national requirements. This information is cross checked by experts to ensure compliance. These safeguards have been followed in the case of developments near to the site.
Additionally, Telford & Wrekin Council manages and monitors the landfill site to ensure there is no uncontrolled leakage or discharge of gas or leachate, as evidenced by the regular testing schedule, the results of which have not presented any cause for concern.
Should the public be concerned?
No.
Former landfill sites such as Stoneyhill exist across the country and are subject to strict regulations regarding their safe management.
The public do not need to be concerned about Stoneyhill landfill site, as regular testing continues to show that the site is not negatively impacting the surrounding environment, waterways or neighbouring properties.
The council and its specialist contractor fulfils their duties to ensure the landfill site and its contents are managed and controlled.
What’s the ecology like at Stoneyhill landfill site?
An independent Phase One Habitat Survey Report was prepared for the site in October 2009 and it concluded that “the habitats found at the site have demonstrated their importance for species of plant and animal” including mammals and twenty three species of birds.
Since its closure as an active landfill site, the site ecology has thrived and the site is now populated by numerous species of mammals, reptiles and birds.
Telford & Wrekin Council has no concerns in relation to the ecology at the site.
What happens to the rainwater at the site?
Some of the rainwater which falls on Stoneyhill landfill site percolates through the thick clay landfill cap and, in time, becomes leachate which is then managed as described above.
Some rainwater simply runs along the top of the domed landfill cap into a perimeter shallow ditch around the site.
Parts of this rainwater pipework (blue corrugated pipes) can be seen across the site and does not form part of the managed leachate process.
Are there any bad smells linked to the site?
There is a large open tank in the site and the purpose of this is to create a large area for the leachate to be exposed to atmosphere.
This allows methane and other gases which are dissolved in the leachate to escape from the liquid as a gas while it is being circulated – this is called aeration.
Methane must be reduced before being discharged under licence to ensure compliance with Severn Trent Water’s requirements.
The system is purposely designed to do this and occasionally the site close to the treatment area will smell of these gases which is perfectly normal and actually desirable as it demonstrates that treatment (aeration) is successful.
However, we would not expect this to be smelt by anyone outside of the site boundary.
Why are there brown bubbles in the leachate treatment tank at Stoneyhill?
As the leachate is circulated around the tanks to remove the dissolved methane, it mixes with organics.
These organics interact with the moving and cascading water causing tiny air bubbles to form which can stabilise and cause a foam.
Natural foam build-up is more prevalent in streams and rivers after rainfall because there's more water moving through the ground and more organic matter being dissolved.
This foam is not detrimental to the treatment system. In fact, organics are occasionally added to the leachate tank as they help strip away unwanted materials converting them to harmless gases.
More organics results in more bubbles.
Are all the monitoring points and boreholes inside the site within the landfill waste?
No.
There are numerous wells within the landfill area which are monitored and from which leachate and gas are extracted.
A ring of boreholes also lie outside the landfill area but within the site boundary that are monitored to ensure gas and leachate are not escaping from the landfill liner.
One monitoring point sits at the very edge of the cap in the shallowest part of the landfill.
This well occasionally appears wet at the surface due to site topography and rainwater runoff over the surface of the site.
Is the site accessible to the public?
No.
The site is not accessible to the public because it features a number of hazards including a network of pipes, wells, pumps and associated equipment, and because it generates landfill gases meaning it falls under the Dangerous Substances and Explosive Atmosphere Regulations 2002.
For these reasons, the site is securely fenced and monitored by closed-circuit television (CCTV) and public access is not permitted.
Has toxic waste been tipped at the site?
There is no evidence in the records received from Shropshire County Council that toxic materials or waste were tipped in Stoneyhill landfill.
Records also confirm that Monsanto (an agrochemical and agricultural biotechnology company) had a licence to deposit materials within the site and correspondence confirms its acceptance.
However, there is no evidence to suggest this material is problematic, and EA records confirm that chemical waste from Monsanto delivered to the site was “not toxic”.
Is toxic waste leaving the site in an uncontrolled manner?
The council’s active management strategy is ongoing, ensuring that landfill gases and leachate generated by the landfill are handled and discharged in a controlled manner.
Why can orange colouration be seen in the Coalbrookdale watercourses?
Occasionally the waters in the Coalbrookdale watercourse and other streams and brooks in Telford and across the UK appear orange in colour.
A significant area of Telford is underlain by old mine workings made of iron through which groundwater flows. When this water meets with air, the ferrous iron dissolved in the water begins to oxidise (in a similar way to rust) and stains the water orange.
This iron is not linked to the Stoneyhill site, however as part of the active management of the site, the watercourse at Coalbrookdale is regularly tested.
The EA became aware of orange discolouration at Furnace Pool in 2017 and attended the site to take a comprehensive set of samples in 2017. The results were reviewed and a sampling programme was made by a technical specialist. The EA concluded that this was a mine water issue which was traced back to one of the tributaries of Furnace Pool. Further investigation showed that a historical mine entrance was discharging iron rich mine water into Furnace Pool explaining the orange discolouration.
Has there been an ‘unconsented discharge’?
No.
Are there other landfill sites in the borough that Telford & Wrekin Council is responsible for and are they managed the same way?
There are many designated landfill sites within Telford and Wrekin but the majority of these are more accurately described as areas of filled land which do not require active management or maintenance such as Stoneyhill.
There are no other similar landfill sites in the borough which the council actively manages in the same way as Stoneyhill.
Is the site considered to have contaminated land status?
No.
A detailed assessment and review was carried out by the EA in 2008 and as a result the site is not considered a harm to the local environment.
Did the EA test samples from Stoneyhill?
In February 2024, the EA independently took a sample from a ditch immediately adjacent to stoneyhill. The EA confirmed that they found phenols and their experts concluded that these results were directly associated with historic mines water issues and were not of concern. The EA confirmed that “at no stage have we found any matters of concern from this site”.
Did the EA test the water quality in the streams and water bodies around Stoneyhill?
The EA independently attended the site to conduct invertebrate monitoring at two points on the Lyde Brook. The first site was upstream of Furnace Pool (but downstream of the landfill) and the second point was downstream of Furnace Pool. Results from the samples collected at both sites showed no signs of environmental pollution. Families ‘heptageniidae’ and ‘perlodidae’ were found in high numbers at both sites. This is significant as both are indicators of clean water.
Does a stream run through Stoneyhill closed landfill site?
No.
There are nearby water bodies and streams but there are no water bodies running through the closed landfill site.
Has Telford and Wrekin Council tested the water quality in the streams and water bodies around Stoneyhill?
Yes.
Telford and Wrekin Council has sampled and tested from a number of water bodies outside the landfill. The two plans below show the sampling locations for the waters tested.
Plan A - sample locations include ponds immediately adjacent to the landfill, as shown in the map below:
Plan B - samples were taken from Loamhole Dingle (LD), upstream (US) and downstream (DS) from Loamhole Dingle, as shown in the map below:
The samples were comprehensively tested for general inorganics, metals, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), polychlorinated biphenyls (PCBs) and pesticides. The test results raised no cause for concern, download the water quality test results.
Did Monsanto deposit polychlorinated biphenyls (PCBs) in Stoneyhill landfill?
There is no written record of any company, including Monsanto, tipping these chemicals at Stoneyhill. Furthermore, Telford and Wrekin Council has tested the leachate within the landfill and the surrounding water bodies (outside the landfill) for these chemicals and none were found.
Last updated: 08/08/2024 09:58
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