Landfill and deposit for recovery: aftercare and permit surrender

Q: 6. Completion criteria: leachate

Read completion criteria for leachate .

Q: 13. Surrender: landfills that deposited inert waste

You must use the risk assessment process . If the Environment Agency permitted your site before the Landfill Directive, you may have fewer records or they may be less reliable. Follow the guidance in prepare to surrender your permit to identify what records you have and whether you need additional evidence to support your surrender application. If you are operating a landfill for inert waste, permitted in accordance with the Landfill Directive, your permit will require you to protect the environment through controls on waste acceptance and a geological barrier . It will also require you to keep records until you apply to surrender your permit of: the wastes you deposited relevant monitoring data You will normally be able to show through these records that the waste you accepted was inert and is not presenting a risk. To satisfy the Environment Agency that the waste presents an acceptable risk of pollution you must show that you complied with waste acceptance controls during the life of the site. If you cannot confirm this, you may need to do additional monitoring or a site investigation .

Question 1

1. Aftercare

Accepted Answer

For sites permitted under the Landfill Directive, aftercare is the period between the time the Environment Agency issues an aftercare permit until they accept the surrender of your environmental permit.

Other permitted landfills are in aftercare if they closed before July 2001 or in accordance with article 14 of the Landfill Directive.

If your deposit for recovery permit requires you to monitor, you will need to carry out aftercare monitoring to confirm the waste is physically and chemically stable. There is no closure process or aftercare permit for a deposit for recovery activity.

During aftercare you must continue to manage, maintain and monitor your site to make sure it does not cause pollution. You must comply with your permit and your approved operating techniques, working plan or closure report.

The length of aftercare will vary depending on the:

sensitivity of your site’s setting
site engineering
types of waste you accepted

1.1 Check the settlement behaviour of the waste

Where it is required by your permit, you must carry out an annual topographic survey of your site during aftercare.

You must do this yearly until:

you have completed all reprofiling work
the change in ground level is not statistically significant when you compare it to the previous 2 annual surveys

The Environment Agency considers statistically significant means that the variance in the data is less than 5%.

You must calculate the rate of settlement of the waste by comparing the levels with the levels in previous surveys.

Your topographic survey must pick up dips and hollows on the site surface.

At landfills for inert waste or landfills that have taken a single consistent waste stream (for example, pulverised fuel ash), you must do annual topographic surveys for at least 2 years after definite closure. This is to demonstrate that the waste is physically stable. If the change in level is not statistically significant, the Environment Agency will normally agree that you do not need to carry out further topographic surveys.

You must get written agreement from the Environment Agency before you stop the annual topographic surveys.

If your site includes a cell for stable non-reactive hazardous waste, asbestos or gypsum, you must show that there is no differential settlement from the different compaction rates you applied to these wastes.

Where you have installed a cap, you must maintain its integrity. Read the guidance on landfill capping.

You must carry out regular inspections of the surface of your landfill or bespoke deposit for recovery activity. You must look for unstable slopes. You must do this at least once a year. You must inspect the site more often if your site has:

any steep slopes (greater than 1 in 6)
a history of unstable slopes

You must include your inspection regime in your operating techniques, working plan or closure report.

For all classes of landfill, if you have stopped your annual topographic surveys and find unstable slopes during your routine inspections, you must restart them.

1.2 Opening a closed landfill

Once your site is in aftercare, your permit will not normally allow you to accept waste for disposal. You may accept waste for restoration if you have a permit that authorises it.

If you want to re-open your landfill to accept waste for disposal, you must apply to change (vary) your permit. Your application must show how you will meet the Landfill Directive standards.

1.3 Beneficial use of closed landfill

Once your site is in aftercare, you or the landowner can make use of the land. Use will normally be specified by planning permission. The Environment Agency supports using closed landfills for development if it:

will not have a negative effect on the environment
provides economic benefit
provides environmental benefit

You must continue to comply with your permit unless you transfer it as part of any sale or handover. You must maintain access to the landfill to comply with the conditions. You may need to set up a legal contract with the landowner to do this. If you cannot reach agreement to maintain access, you can apply to vary your permit so that the landowner must allow you access to the site. The landowner can claim compensation. The requirements are explained in the Environmental Permitting Regulations (EPR) 2016, Regulation 15(2) and schedule 5, part 2.

You must maintain the pollution prevention infrastructure (for example, the cap, gas and leachate extraction wells and pipework) to make sure it’s fit for purpose.

If required by your permit, you must tell the Environment Agency before you carry out or stop any activity or works. You may have to change your operating techniques, working plan or closure report if the activity or work is likely to have an impact on:

the inspection, maintenance or integrity of the cap
base and side wall containment engineering
site restoration
landfill gas, including in-waste monitoring and uncontrolled emissions
maintenance and monitoring of landfill gas infrastructure
maintenance and monitoring of leachate infrastructure
maintenance and monitoring of groundwater infrastructure
surface water management or the quality of run off
assessing the settlement behaviour of the wastes (for example, by doing topographic surveys)
evidence that the waste meets the completion criteria for a surrender application

1.4 Development work on a closed landfill

The Environment Agency regulates activities authorised by your environmental permit. Your local planning authority regulates land use.

You must maintain contact with the landowner. If they propose works on site, you must make sure they do not prevent you complying with your permit. The landowner is not allowed to deliberately prevent you from complying with your permit.

Your permit will require you to prevent or minimise pollution. You must normally install passive control measures. Where you or the landowner propose development work on site, you must normally avoid ground investigation or other activities that will penetrate the passive control measures. This will include the cap, base or side slopes of your site. You must consider non-penetrative methods instead. You must speak to your local Environment Agency office:

before you design a site investigation
where you or the landowner propose any development work on site

You must send the Environment Agency your construction proposals and construction quality assurance plan where your activity may affect landfill infrastructure such as the cap or monitoring and extraction boreholes.

1.5 Active control measures

The Environment Agency will not accept an application to surrender an environmental permit where it requires you to maintain active control measures.

Active control measures require your intervention or maintenance, for example:

using a pumping system to maintain leachate levels below the surrounding groundwater level
extracting landfill gas to prevent uncontrolled emissions
clearing surface water ditches
clearing soakaways

During aftercare, if you want to remove the active control measures and any related compliance limits your permit requires, you must apply to vary your permit. Your application must show that:

removing the active controls will not increase the risk of pollution
your passive measures will continue to work as intended

1.6 Passive control measures

Passive control measures do not need ongoing intervention or maintenance. The risk assessments you submitted with your permit application will specify their standard. They will attenuate or mitigate emissions from your site. Some will degrade or deteriorate over time. Examples include:

a geological barrier to the base or sidewalls
biological oxidation layer

Question 2

2. Prepare to surrender your permit

Accepted Answer

You must follow the steps in this guide to decide what information to send the Environment Agency to support your surrender application.

You must gather information and start to prepare your surrender application during the operational and aftercare phases. This will avoid delays or additional work when you apply to surrender your permit.

Your permit will normally require you to monitor activities and emissions from your site. This is to demonstrate that:

your pollution control systems are working
emissions from your site are acceptable

This monitoring may not be sufficient to support an application to surrender your permit. If you have not done sufficient monitoring, you may need to do more to develop your surrender risk assessment.

The Environment Agency can give you pre-application advice before you apply to surrender your permit.

Question 3

3. Surrender risk assessment

Accepted Answer

You must do a risk assessment to show whether your site is a pollution risk. You must consider:

the source of pollution
any pathways for emissions from the site
all relevant receptors

You must develop a conceptual site model. This must include any information you gathered during the construction and operation of your site.

If you prepared one for your original application, refer to your:

environmental setting and site design report
environmental setting and installation design report

3.1 Source

The main source of pollution will be the waste you accepted for disposal or recovery. For example, you can characterise the source using records of:

the waste types and quantities you deposited while the site was operational and evidence that you only deposited those wastes
the wastes you were permitted to deposit and evidence that you only deposited those wastes
any non-compliant waste you deposited and where you did not remove it, its potential to present a pollution risk
waste acceptance criteria leach test results
waste sample test results, for example from on-site verification
the results of any monitoring you did while the site was operational or during the aftercare phase, for example for landfill gas or leachate composition
the results of any additional monitoring you have done
the results of any intrusive site investigation

You can use this information to characterise the waste you deposited in the area authorised by your permit. This must include all the waste within the permit boundary. The permit boundary will be the:

perimeter of the disposal area on the site map
final level (post-settlement) contour plan

For permits issued under the Landfill Directive or EPR, it will include the base of any engineered attenuation layer.

If you can show that the waste is not a source of pollution, see the section on surrender criteria.

3.2 Pathways and receptors

You must confirm whether any of the pathways or receptors have changed since you made your original permit application. For example:

new properties near the site boundary
changes in groundwater levels around the site
changes in groundwater flow direction around the site
new habitat or designated conservation areas near the site

You must assess the risk to any receptor based on the pollution arising from the waste, for example from landfill gas or leachate.

You must consider the likelihood of that pollution causing an unacceptable impact at a receptor. You can support your application using evidence you gathered when:

you made your original application
monitoring for compliance purposes during the operational or aftercare phases

You must consider barriers to emissions, for example the:

permeability of the geology around your site
permeability of any attenuation layer you installed – an engineered soil or clay layer
site containment design, leachate collection layer and extraction infrastructure

You must also consider evidence from any:

landfill gas monitoring data from perimeter or off-site monitoring points
groundwater quality data from groundwater in-flow and out-flow regions of the site (up and down hydraulic gradient)
surface water quality data from discharge points to surface water
surface water quality data taken up and downstream from a nearby water course or water body (such as a pond, lake or wetland)

Where your site discharges to water, you must confirm that it is no longer a water discharge activity. For the meaning of a water discharge activity see section 3 of schedule 21: water discharge activities.

3.3 Pathway characterisation

You must characterise the pathway between your site and any receptors you identify in your conceptual site model.

Your surrender application may include one or all of:

a construction quality assurance validation report showing that the geological barrier or attenuation layer was constructed to an approved standard
evidence that the geology around the site will limit the migration of emissions
a review of off-site environmental monitoring data
evidence from your conceptual site model that the site is isolated

3.4 Monitoring infrastructure

Where you provide environmental monitoring data to support your surrender application, you must include evidence that you got it from monitoring infrastructure that is fit for purpose. You must include evidence that you maintained the standard of that monitoring infrastructure.

See the design requirements the Environment Agency expects.

Where you have financial provision you may be able to use that to replace or repair monitoring infrastructure. Your financial provision agreement with the Environment Agency tells you when you can use the financial provision.

3.5 Isolated sites

You must consider how isolated the waste is from a receptor. Isolated sites are those where it is unlikely that any emission arising from the waste will reach a receptor in enough quantities to cause pollution. The Environment Agency will normally accept that a site is isolated by, for example:

surrounding geology and geological features
topography
man-made structures (such as highways and railway lines)
naturally high groundwater levels close to the ground surface

Question 4

4. Landfill gas monitoring

Accepted Answer

In this guidance, landfill gas means any gas produced by the degradation of waste in your site. That includes deposit for recovery activities.

Where you accepted biodegradable waste or where your permit requires you to monitor landfill gas within the waste, you can use that data to support your surrender application. You must provide enough data to show that your site will have an acceptable impact on land, air and people.

You must monitor from permanent monitoring points installed within the waste. You must use enough monitoring points to get results that are representative of the full depth of the waste across the whole site.

The Environment Agency can give you pre-application advice if you want to discuss the monitoring you need to support your surrender application.

4.1 Landfill gas monitoring: environmental conditions

You must provide landfill gas monitoring data over a range of environmental conditions, including:

when the site surface is sealed, for example if the ground is saturated or frozen
when atmospheric pressure is less than 1000mbar and falling
during or immediately following a rapid fall in atmospheric pressure (a drop of at least 6 mbar within a 3 hour period)

4.2 Landfill gas: continuous monitoring

If you intend to use continuous monitoring, you must agree that in writing with your local Environment Agency office before you install any equipment. Continuous monitoring normally uses an instrument that you can place in or on top of the borehole. It will periodically measure substances at a fixed time interval. The data is stored electronically in the instrument. You can then extract it to a hand-held device, print it out or send it to a remote base station.

5.1 Completion criteria 1

You must show that:

methane concentration within the waste mass is less than or equal to 1.5%v/v
carbon dioxide concentration within the waste mass is less than or equal to 5%v/v

You must provide a minimum of 12 datasets from regular monitoring. You can monitor monthly for a year or over a longer period.

You can use continuous monitoring to replace or supplement your regular monitoring. Where continuous monitoring replaces your routine monitoring, this must be for a minimum of 6 months. The Environment Agency will accept a shorter period where continuous monitoring supplements your routine monitoring.

You must meet these limits throughout the waste. You must not exceed the gas concentrations at any time during the monitoring period.

The Environment Agency will accept that you have met the gas completion criteria if you can show that the concentration of methane and carbon dioxide within the waste is no greater than background concentrations (either natural sources or because of non-landfill activities) in the surrounding environment.

5.2 Completion criteria 2

If you cannot satisfy gas completion criteria 1, you must provide a minimum of 24 datasets from regular monitoring. You can monitor monthly for 2 years or over a longer period.

Where you use continuous monitoring to replace or supplement your regular monitoring you must do it for a minimum of 6 months.

5.3 Completion criteria 2: flow monitoring

Relying on gas concentration within the waste means you may have to wait before you can apply to surrender your permit. The concentration of gas does not reflect the risk if there is a low likelihood of your site emitting that gas.

Where your methane concentrations are greater than 1.5%v/v you can assess the gas flow rate in your in-waste monitoring boreholes. You must monitor the flow rate from all in-waste boreholes for at least 2 years.

The site will meet gas completion criteria where the maximum landfill gas flow rate (Qhgs as defined by BS 8485:2015):

in in-waste monitoring boreholes is less than 0.7l/h
recorded in any individual in-waste borehole is less than 70l/h

You must not exceed the maximum flow rate of 70l/h at any borehole during the monitoring period.

This Qhgs is for the whole site. You must assess the results from individual boreholes and calculate the maximum methane flow rate. You can apply normal statistical tests to the results to confirm the variance in the data.

The standard defined in BS 8485:2015 is to assess the risk associated with developing buildings on contaminated land. The Environment Agency will accept this method to assess whether your site is likely to emit acceptable amounts of landfill gas.

The gas completion criteria reflect the characteristic gas situation 2 in BS 8485:2015.

5.4 Other gases

You may have accepted waste types that have the potential to produce gases other than methane and carbon dioxide, for example hydrogen sulphide. You must show that emissions of these gases are unlikely to cause pollution or that you have the necessary measures in place to manage them.

Question 6

6. Completion criteria: leachate

Accepted Answer

Read completion criteria for leachate.

Question 7

7. Completion criteria: settlement and slope stability

Accepted Answer

For any landfill or bespoke deposit for recovery activity you must show that waste settlement has stopped and all slopes are stable. The Environment Agency will not accept an application to surrender your permit where:

there is evidence of waste settlement
any waste slope or retaining structure is unstable, for example where the slope is likely to fail
there is a potential unstable slope because of erosion in the foreseeable future, for example coastal or river erosion

There is uncertainty regarding the rate, amount and duration of climate change and the effect this will have on coastal or inland water erosion. You must consider a range of timescales and climate change scenarios.

Where you have provided a cap, you must ensure it remains effective. Where required by your permit, you must carry out topographic surveys. You must inspect the site surface for signs of instability at least once a year.

Following the completion of settlement, you must review the integrity of the cap. You must visually inspect the cap or restoration layer and monitor emissions from the site where you accepted biodegradable waste. You must confirm the integrity of the cap in your permit surrender application.

Where you provided a stability risk assessment with your permit application or closure report, you must show that the final landform (through the topographic surveys) has a stable profile. You must also provide evidence in your surrender report that the waste slopes are stable. Where you identify an unstable slope you must tell the Environment Agency how you stabilised it.

You will need to provide a stability risk assessment to demonstrate the landform is stable, where there is either:

a history of unstable waste or slopes
evidence of active erosion, for example surface water, coastal or river erosion

Where you have not provided a stability risk assessment, you must review the stability of the final landform. You must determine the likelihood of failure using an appropriate analytical or modelling approach for the level of risk posed by the slope.

The Environment Agency will not require a risk assessment for shallow slopes with a gradient less than 1 in 6 unless they show signs of instability.

You must provide justification for the factors of safety you use for your assessments.

Question 8

8. Apply to surrender your permit

Accepted Answer

You must provide evidence based on the risk of pollution your site poses.

Read the guidance on preparing to surrender your permit for:

landfills that deposited inert waste and deposit for recovery activities
landfills that deposited hazardous or non-hazardous wastes

This tells you what additional information you may need to support your surrender application.

You must complete a site condition report for any area of the site that you have not deposited waste on. Read the H5 guidance on preparing a surrender site condition report.

You must provide a site condition report for the partial surrender of any area of a landfill or deposit for recovery activity that you have never used. You must include evidence that you have never deposited waste in that area.

8.1 Surrender criteria

To accept an application to surrender an environmental permit, you must satisfy the Environment Agency that you have taken the necessary measures to:

avoid the risk of pollution from the activity
return the site to a satisfactory state

The Environment Agency will accept that you have avoided the risk of pollution where either:

you can show that the waste is not a source of pollution
the risk is acceptable without any necessary measures

The Environment Agency’s surrender decision will assume that the waste mass will remain undisturbed. Your surrender report must consider the risk of:

disturbance of the waste where the planning authority has approved development at the site
potential damage caused by animal burrowing
a change in the course of a stream or river in the foreseeable future causing erosion of the necessary measures
collapse of a culvert through or below the waste
damage to the necessary measures due to coastal erosion in the foreseeable future

8.2 Necessary measures

Necessary measures are passive control measures you put in place. They may be measures you installed to comply with your permit or additional measures to ensure any pollution from your site has an acceptable impact at a receptor.

Your surrender application must confirm that the necessary measures are adequate to prevent or minimise pollution.

Question 9

9. Application types and charges

Accepted Answer

The Environment Agency use 3 types of surrender application. For more information see Regulatory Guidance Note 9.

The type of application will dictate the charge you must pay.

The Environment Agency can give you pre-application advice to help you decide which type of application to make. They can also tell you what information you must send them to support your application.

9.1 Low risk surrender application charge

The low risk surrender charge applies to activities that require the Environment Agency to carry out minimal assessment of your application. This is normally because the evidence is readily available to you. For a landfill for inert waste or deposit for recovery activity it includes where you have done additional monitoring or a site investigation.

The Environment Agency must confirm that you can pay the low risk surrender charge before you make your application. See the Environmental permits and abstraction licences: tables of charges, part 2, paragraph 7. Without this confirmation, you must pay the surrender application charge.

Your surrender report must show that your site presents an acceptable risk of pollution.

9.2 Surrender application charge

The surrender application charge applies to disposal and recovery activities that require the Environment Agency to carry out a technical assessment of your application.

See table 1.17 in the Environmental permits and abstraction licences: tables of charges.

Question 10

10. Surrender report: general

Accepted Answer

You must normally send the Environment Agency a surrender report to support your surrender application. They will not duly make an application for surrender if you do not include a surrender report.

You do not need to provide a surrender report for a standard rule deposit for recovery permit where you complied with your permit.

Your surrender report must satisfy the Environment Agency that you have taken the necessary measures to avoid a pollution risk and will return the site to a satisfactory state.

You will not normally need to re-submit reports you supplied to comply with your permit. However, you must provide the monitoring data you are relying on as evidence of acceptable emissions. You must clearly reference all supporting evidence including title, date and author.

Read the sections on preparing to surrender your permit for landfills that:

deposited inert waste and deposit for recovery activities
deposited hazardous or non-hazardous wastes

10.1 Minimise risks during decommissioning

Your surrender report must describe how you will minimise risks during decommissioning. You must, for example:

You may need the agreement of the landowner and the local planning authority if you intend to leave any infrastructure in place once you leave the site.

You do not need to decommission all infrastructure before the Environment Agency accepts the surrender of your permit. Your surrender report must confirm how you will safely decommission structures to leave the site in a satisfactory state.

Question 11

11. Restoration

Accepted Answer

If your landfill permit includes a restoration activity you can apply to surrender it separately, for example as a partial surrender.

Question 12

12. Landfills that deposited inert waste and deposit for recovery activities

Accepted Answer

This section will help you prepare an application to surrender your permit where you operate a:

landfill for inert waste
deposit for recovery activity

It tells you what additional evidence you may need.

12.1 Prepare to surrender your permit

Your surrender application must include records of the waste types you deposited during the operational phase. If they are unavailable, you must include the waste types your permit allowed you to accept. In both cases, you must provide evidence that you only deposited the waste your permit allowed.

You do not need to provide waste records for a standard rules deposit for recovery activity if you complied with your permit.

You can use evidence from Environment Agency compliance assessment or site inspection reports to support your records.

You must include records of any non-compliant waste you deposited. You must provide evidence that you either:

removed all the deposited non-compliant waste
have assessed the contribution that non-compliant waste will have on emissions and confirmed their significance

Where required by your permit, you must include the results from any in-waste landfill gas monitoring. This must show that the concentration of landfill gas within the waste meets the gas completion criteria.

You can use standard statistical tests to confirm if the variance in the data is significant.

Where you have waste analysis information, for example from leach tests or waste sampling, you must provide it.

If you cannot characterise the source using records of the waste you deposited, you may need to do additional monitoring or site investigation.

If you find landfill gas in the waste, that will inform your risk assessment. You must consider the likelihood of the gas migrating off site and having an impact at a receptor. If you have off-site gas monitoring boreholes you can use data from those to confirm if your site is emitting landfill gas.

High concentrations of methane that are under pressure (have a flow rate) are a greater threat. To find out what monitoring you need to do read landfill gas completion criteria. If there is a risk to a receptor you must consider how you can manage that risk using necessary measures. You may need to install additional monitoring points between your site and the nearest receptor.

12.2 Monitor the source

There was no definition of inert waste before the Landfill Directive took effect in 2001. Before that inert waste did not normally include organic waste. The standards of monitoring and reporting required by a permit has also changed. Deposit for recovery activities may include wastes that are not inert.

The Environment Agency accept that additional monitoring will be an unwelcome cost. You should discuss any additional monitoring with your local Environment Agency office before you start work or issue contracts. If you want to discuss this with the Environment Agency’s Geoscience Team they offer an enhanced pre-application service.

Where you cannot characterise the source from your records, you can get information about the waste. For example:

install in-waste monitoring boreholes to determine if there is landfill gas in the waste
do a walkover survey to determine if the site is emitting landfill gas from its surface, for example using flame ionisation or infrared methods
install porous cups (lysimeters) or boreholes to sample water quality (see potential pollutants within the waste)
do a site investigation

Where you install in-waste landfill gas monitoring boreholes, you must use your risk assessment to decide how many to install and where to put them. For example, you may want to install more where:

you know you deposited organic waste that you did not remove
there are receptors near the site boundary

If you need landfill gas data for the whole site, the Environment Agency will normally accept 2 boreholes per hectare. You can ask your local Environment Agency office about the location and number of boreholes. You can also ask for enhanced pre-application advice.

You can get information about the waste while drilling boreholes. You should analyse waste samples for the potential pollutants within the waste).

Where you install landfill gas monitoring boreholes, you must monitor them for long enough to get representative data over a range of environmental conditions. You must satisfy the gas completion criteria.

You may need to monitor for longer if there is significant variance in the data. You can apply normal statistical tests to decide whether the variance is significant.

Where water has saturated a proportion of the waste, for example at sub-water table sites, you will need to design a site-specific strategy to gather information. You must consider monitoring:

off-site water receptors
the waste
in-waste gas concentrations and flow, where necessary

The Environment Agency will not accept data from spike (or searcher bar) monitoring once you have restored the site. Spike monitoring will not provide representative results for the full depth of the waste.

12.3 Waste from a single source

If you only deposited waste from a single source with a low organic content (for example a single large excavation, road or railway cutting) the Environment Agency will normally accept waste acceptance records or analysis of the waste. If you can confirm that there is no significant organic content you will not need to do additional in-waste landfill gas monitoring.

Where they are available, you can use a site investigation report that characterised the waste from the producer. You must confirm that:

there was no suspicion of contamination
any investigation was carried out in accordance with the appropriate standard, for example, guidance on ground investigations or designing a soil monitoring programme

12.4 Monitor the pathway: landfill gas

Where your source characterisation suggests that your site is emitting landfill gas at concentrations that could affect a receptor, you must consider monitoring the extent of that emission. This will help you confirm the likelihood of an impact.

Where they are not already present, you must consider installing landfill gas monitoring boreholes between the site and the nearest receptor. The receptor may be a building but may also be a habitat site, woodland, agricultural grassland or crop.

Where your off-site landfill gas monitoring identifies methane concentrations at or above the compliance limit in your permit or 1% v/v above background concentrations, you must refine your risk assessment to confirm the impact at the receptor. You must consider whether the gas is being emitted from your site or coming from natural sources, for example peat, wetland or coal-gas.

12.5 Monitor water

Where your site is in a sensitive groundwater area, your permit will normally require you to monitor groundwater around your site. If your source characterisation suggests that your site is producing leachable pollutants, you may need to install boreholes to monitor for emissions.

If you install monitoring boreholes to support your surrender risk assessment, you must install a minimum of one in the groundwater in-flow region (up hydraulic gradient) and two in the groundwater outflow region (down hydraulic gradient). You must monitor groundwater for long enough to detect an emission from the source. You can work out how long that will be from a hydrogeological risk assessment. The up hydraulic gradient samples will provide the background groundwater quality.

Where your risk assessment suggests that your site presents a risk to surface water, or where surface water monitoring is required by your permit, you must provide evidence that your site is not having an unacceptable impact. You can use surface water quality data you obtained during the operational and aftercare phases.

If you want to sample flowing water to gather evidence for your surrender application, you must sample from at least one point upstream of your site and one point downstream. The upstream samples will provide the background surface water quality. You must monitor surface water for long enough to get results over a range of high and low flow conditions.

12.6 Site investigation

If your review of your waste acceptance records and monitoring data shows you cannot characterise the source, you must consider a site investigation. You must take representative samples of the waste from the site for analysis to confirm its pollution potential.

Your sampling must extend throughout the site, across the full area and depth of the waste. You must use either:

You must increase the frequency of sampling and monitoring in any area where you deposited non-compliant waste that:

you have not removed
will increase the pollution risk from your site

You can use compliance assessment or site inspection reports from the Environment Agency that identified non-compliant waste.

To characterise the deposited waste you must use a combination of:

a visual inspection
an odour assessment
an assessment of organic matter
a chemical analysis for the concentration of the common pollutants (including metals, salts and organic substances) and compounds associated with the wastes you deposited

Where you chemically analyse waste samples, you must use leach tests (for example BS EN12457, part 2 or 3) for the following components. You should also test for the presence of landfill gas.

12.7 Potential pollutants within the waste

Metals

Antimony (Sb)
Arsenic (As)
Barium (Ba)
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Lead (Pb)
Mercury (Hg)
Molybdenum (Mo)
Nickel (Ni)
Selenium (Se)
Zinc (Zn)

Others

Chloride (Cl)
Fluoride (F)
Sulphate (SO4)
Total dissolved solids (TDS)
Dissolved organic carbon (DOC)
Phenol index

Organic indications

Total Organic Carbon (TOC)
BTEX (Benzene, toluene, Ethylbenzene and Xylenes)
Polychlorinated biphenyls (PCBs)
Mineral oil (C10 to C40)
Polycyclic aromatic hydrocarbons (PAHs)

For metals and others, use the leaching tests in BS EN 12457:2002, part 2 or 3.

For organic indicators, use total concentrations.

You must assess the results against background groundwater and surface water quality and any environmental quality standard.

Question 13

13. Surrender: landfills that deposited inert waste

Accepted Answer

You must use the risk assessment process. If the Environment Agency permitted your site before the Landfill Directive, you may have fewer records or they may be less reliable. Follow the guidance in prepare to surrender your permit to identify what records you have and whether you need additional evidence to support your surrender application.

If you are operating a landfill for inert waste, permitted in accordance with the Landfill Directive, your permit will require you to protect the environment through controls on waste acceptance and a geological barrier. It will also require you to keep records until you apply to surrender your permit of:

the wastes you deposited
relevant monitoring data

You will normally be able to show through these records that the waste you accepted was inert and is not presenting a risk.

To satisfy the Environment Agency that the waste presents an acceptable risk of pollution you must show that you complied with waste acceptance controls during the life of the site. If you cannot confirm this, you may need to do additional monitoring or a site investigation.

Question 14

14. Surrender: deposit for recovery activities

Accepted Answer

There are 2 types of permit for the recovery of waste on land:

For all deposit for recovery permits, you must provide a copy of the final topographical survey of the completed landform.

Where you have a standard rules deposit for recovery permit but you have not complied with it you must provide a surrender report.

You do not need to provide a stability assessment for a standard rules recovery permit.

To surrender your bespoke deposit for recovery permit, you must use the risk assessment process. You must provide a surrender report.

Question 15

15. Landfills that deposited hazardous or non-hazardous waste

Accepted Answer

This section will help you prepare an application to surrender your permit where you operate a landfill for:

hazardous waste
non-hazardous waste

It tells you what additional evidence you may need.

15.1 Prepare to surrender your permit

You must monitor for pollutants before you submit a surrender application if:

your permit requires active control measures
you deposited hazardous or non-hazardous waste

This can involve monitoring:

pollutants within the waste
the impact of pollutants on the surrounding environment

15.2 Aftercare monitoring

The degradation of waste in different parts of the site will occur at different rates. You must collect data about the generation of pollutants across the whole site throughout its life.

You must monitor pollutants in the site and the condition of the landform during the aftercare phase. You must do this until you can show that the waste in your site presents an acceptable risk to the environment and human health. You must not apply to surrender your permit until the concentration of pollutants in the site meets the completion criteria. See completion criteria: landfill gas and leachate completion criteria.

You must continue to monitor surrounding groundwater, surface water and landfill gas to see if your site is producing unacceptable emissions. The duration of aftercare monitoring will be site specific. You must consider:

the stabilisation of conditions, including gas volume and pressure, and leachate strength and level after removing any active control measures
the degradation of passive control measures
travel time between the waste and the external monitoring infrastructure

The Environment Agency will not accept an application to surrender an environmental permit while it requires active control measures. Once you stop those controls, it can take decades for the conditions at the site to stabilise. Your operating techniques, working plan or closure report must explain the method, monitoring and contingency measures for removing active controls.

You must monitor the conditions at the site to show when you no longer need to maintain the active control measures. The types of monitoring will be different for the various control measures you use.

You must consider how the components of the landfill lining system will deteriorate. The Environment Agency will not accept a surrender application until you can show that predicted degradation of the lining system will not cause unacceptable emissions.

15.3 Stabilising the site after removing active control measures

The following are examples of measures you can use to show:

that the controls are no longer necessary
the timeframe for conditions to stabilise

For control of groundwater levels you can:

stop pumping groundwater from around the site
monitor the levels until they are consistent with the local water table

For control of leachate levels you can:

stop extracting leachate from the waste
monitor the change in leachate levels until they are consistent

For extraction of landfill gas you can:

stop extracting gas from the waste
monitor landfill gas concentration, volume and pressure until the gas generation rate remains consistent

For control of water infiltration you can:

install and maintain a low permeability cap
monitor the settlement of the cap, including visual assessment for cracks or depressions
monitor gas emission rates through the cap to identify failures
monitor changes in leachate level through a water balance assessment

For the collection and discharge of surface water you can:

monitor the quality of the discharge until it is consistent with background surface water quality

Question 16

16. Leachate completion criteria

Accepted Answer

You must develop site specific completion criteria if your site produces contaminated leachate. You must do this for each priority pollutant in the leachate. You must set the leachate completion criteria at concentrations that will not have an unacceptable impact on groundwater or surface water. You can calculate this from a hydrogeological risk assessment.

Figure 1 shows how you can use leachate quality data to track progress towards the completion criteria.

The stippled line shows how leachate quality changes over time. It will normally peak while the site is operational. After the peak, leachate strength will reduce. Leachate quality is not a solid line to show its variance.

Groundwater quality is shown as a solid line. This is in the outflow region (down hydraulic gradient) of the landfill. It may vary while the site is operational. It should stabilise as leachate strength and emissions reduce.

In figure 1, the numbers show:

Leachate completion criteria determined from a hydrogeological risk assessment.
Groundwater environmental quality standard or site specific quality.
Leachate concentration that meets the completion criteria.
Leachate concentration that consistently meets the completion criteria – this is shown by the time difference between points 3 and 4.
Travel time from the waste to the compliance point.
Time when you have met the completion criteria and can apply to surrender the permit.

16.1 Figure 1: Review leachate quality data to decide when you can surrender your permit

When you set the completion criteria you must consider the permeability, retardation and attenuation characteristics of the lining system. You must consider:

likely leakage rate through the liner
travel time to the receptor

You must set the completion criteria so that it shows you are compliant with both of the following:

See the risk assessment guidance for:

16.2 Leachate monitoring

You could only develop indicative completion criteria when you developed your site and early in its operational phase. These normally include wide concentration ranges for the priority pollutants you expected the waste to generate. You should have used these ranges in your risk assessment to ensure that you provided appropriate pollution control measures at the site.

As the site develops, you can get a better understanding of leachate quality through monitoring. You can refine your predictions to reduce the size of the uncertainty in these concentration ranges.

Where leachate may break out, for example by overtopping the leachate containment systems, you must consider the impact from contact with people, water, plants and animals. When the leachate reaches its completion criteria it must not contain any substances at a concentration that could harm human health or the environment.

Some older landfills (or parts of landfills) were designed without a low permeability lining. They may not have the infrastructure to collect samples of leachate. Without this, it will be difficult for you to assess pollutant concentrations in the leachate. You must therefore consider an alternative method to confirm the leachate completion criteria. For example, you may:

sample leachate from perched levels within the site
extract pore water from solid samples by centrifugation

These samples are unlikely to characterise leachate for the whole site. You may use a combination of monitoring the:

impact on groundwater around the landfill
landfill gas generation rate

16.3 Groundwater monitoring

Once your leachate has reached the completion criteria, you must continue to monitor groundwater. This is to show that your site is not having an unacceptable impact. You must base the monitoring period on the travel time from the waste to the compliance point.

You must monitor groundwater using a minimum of one up hydraulic gradient and two down hydraulic gradient boreholes per groundwater system. The down gradient boreholes must be a maximum of 100 metres apart.

Where you assess leachate completion criteria based on groundwater quality, the Environment Agency will consider the site to have met these where you can show that the emissions from the site are not causing a breach of a compliance limit in the permit. Where you identify a pollutant in the leachate and there is no compliance limit in the permit, you must demonstrate that there is no significant increase in the groundwater quality over background quality for that pollutant.

Where you do this, there is a risk that you assess the results too soon in the aftercare phase. You must only consider this once you have collected sufficient data. You must allow enough time for:

substantial degradation of the waste
the waste to become physically and chemically stable

You can use gas generation records from the site to support this.

16.4 Landfill gas: monitoring

Read landfill gas monitoring.

16.5 Landfill gas: completion criteria

Where your site contains biodegradable waste, it will produce landfill gas. If you identify gas, you must not apply to surrender your permit until you can show through monitoring data that the site is not producing gas at a significant rate. You must consider this rate on a site specific basis.

You must consider the likelihood of gas escaping from the site and causing an unacceptable impact at a receptor. This can include emissions to the atmosphere, human receptors, plants and animals.

The Environment Agency will not normally accept a surrender application where off-site boreholes show gas concentrations above a compliance limit.

The Environment Agency will not normally accept a surrender application where gas is causing harm to plants on or around the site. Where there is evidence that gas is having an impact on the surrounding environment, you must provide evidence to show that pollution has stopped. For example, you could provide monitoring data of gas concentration in the ground between the waste and the affected plants.

Read the landfill gas completion criteria.

Question 17

17. Hazardous wastes

Accepted Answer

Where you deposited hazardous or special wastes in your site, you must ensure that the technical measures you used to isolate the waste from the surrounding environment will stay in place. Your surrender application must include a description of the wastes you deposited and a review of those technical measures. The presence of hazardous waste does not mean that the Environment Agency will reject a surrender application.

You must make sure that any hazardous waste is isolated by a suitable thickness of soil or capping layer. This is to prevent direct contact with people or animals. As the hazard from some hazardous wastes will not reduce over time, you must design the separation layer or cap based on the potential harm the waste can cause.

You must consider the reasonably foreseeable impact of:

potential damage caused by animal burrowing
a change in stream or river courses causing erosion
damage due to coastal erosion

To develop your surrender application, you must use the waste acceptance and deposit records you collected during the operational phase of the site. For landfills:

for hazardous waste under the Landfill Directive you must provide a summary of the different waste types and their hazards within each phase or cell
for non-hazardous waste under the Landfill Directive you must provide details of the location of any cell you used for the deposit of asbestos or stable non-reactive hazardous waste, a summary of the wastes accepted and their associated hazards
that closed before the Landfill Directive, you must provide details of the phases and cells that contain hazardous waste or co-disposed hazardous and non-hazardous waste, their location within the site and their associated hazards

Where these records are not available or are unreliable, you must consider whether to treat the whole phase or site as if it contains the hazardous waste permitted. If you are uncertain, you must do a site investigation.

For landfills for hazardous wastes that closed under the Landfill Directive you would have completed this assessment in your closure report. For all other sites you must include the results of your assessment in the next review of your operating techniques, working plan or closure report. You can include your results when you consider the site’s completion criteria.

For the Environment Agency to accept the surrender of your permit, you must satisfy them that:

your technical measures will not be compromised
the wastes will not be disturbed

Question 18

18. Surrender: landfills that deposited hazardous or non-hazardous waste

Accepted Answer

You must base your surrender report on the information you collected and assessed during the whole life of the site. You must review the progress of the site towards the completion criteria at each stage of the life of the site, for example at closure or when you switch off active control measures.

You must normally include an assessment of the progress towards the completion criteria in your risk assessment reviews and regular compliance reports. You should be confident that your site will meet the completion criteria before you apply to surrender your permit.

Question 19

19. Surrender report: summary

Accepted Answer

The information you need to provide in your surrender report will depend on the type of surrender application you make.

For all site types, your surrender report must include:

1. A review of the history of the operation, including:

a conceptual model for the facility including cross sections
key dates in the development of the permit (such as changes between different regimes, variations, transfers and partial surrenders)
location and sensitivity of environmental receptors
aquifer status
proximity and sensitivity of surface water courses
proximity of housing and human receptors
Natura 2000 sites and Sites of Special Scientific Interest
pollution control measures installed at the site
confirmation of completion in accordance with permit conditions

2. Characterisation of waste deposited at the site, including the:

description of the waste
waste acceptance procedures
audits or inspections of waste acceptance procedures (including frequency and outcomes)

3. Details of any non-compliant waste you deposited, including:

characterisation of the waste
location and extent of the non-compliant waste
evidence that non-compliant waste has been removed (include evidence of on-site checks and the disposal route)
risk assessments that show the potential impact of any non-compliant waste you did not remove

For landfills that deposited hazardous or non-hazardous waste your surrender report must include the following. You may also need to include it where your landfill deposited inert waste or is a deposit for recovery activity.

4. The completion criteria for each pollutant generated within the site and a description of how you established them. You must include any risk assessment you derived the criteria from.

5. Details of the construction of any pollution control measure you used at the site, including the geological barrier, attenuation layer or geology beneath the site. You must include:

the design
the construction quality assurance
the effective lifespan – include dates they were turned off or no longer required
any accident or incident that has affected their effectiveness or integrity

6. A review of any changes to the performance of the pollution control measures during the life of the site.

7. Details of the components and generation rate of any leachate and how leachate components have changed over the life of the site.

8. Details of the components and generation rate of any landfill gas and how the landfill gas components have changed over the life of the site.

9. Topographical surveys of the final landform. You must include an assessment of the stability and settlement of the waste at sites with unstable slopes.

10. Details of monitoring infrastructure, including:

borehole logs, response zones and construction details
evidence that the monitoring points are fit for purpose

11. A review of the monitoring results that show an acceptable impact at any receptor including, where necessary:

leachate quality
groundwater quality
surface water quality
landfill gas (within the waste and surrounding the site)

For all site types you may need to include the results of any investigations of the deposited waste. You must include the investigation:

extent
date
findings

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