waste management a guide to landfill 1998

8/17/2019 Waste Management a Guide to Landfill 1998

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Waste Management

A G u i d e t o L a n d f i l l


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Waste Management

A Guide to Landfil l


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Please note: References to the masculine include, where appropriate,the feminine

Published by RICS Business Services Limiteda wholly owned subsidiary of The Royal Institution of Chartered Surveyorsunder the RICS Books imprint12 Great George StreetLondon SW1P 3AD

No responsibility for loss occasioned to any person acting orrefraining from action as a result of the material included inthis publication can be accepted by the author or publisher.

ISBN 0 85406 883 X

© RICS September 1998. Copyright in all or part of this publicationrests with the RICS, and save by prior consent of the RICS, no part or parts shall be reproduced by any means electronic, mechanical,photocopying, recording or otherwise, now known or to be devised.

Printed by Oakdale Printing Company Ltd, Dorset


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RICS Guidance Notes

This is a Guidance Note. It provides advice to Members of the RICS on aspects

of the profession. Where procedures are recommended for specific professional

tasks, these are intended to embody ‘best practice’, i.e. procedures which in the

opinion of the RICS meet a high standard of professional competence.

Members are not required to follow the advice and recommendations containedin the Note. They should however note the following points.

When an allegation of professional negligence is made against a surveyor, the

Court is likely to take account of the contents of any relevant Guidance Notes

published by the RICS in deciding whether or not the surveyor had acted with

reasonable competence.

In the opinion of the RICS, a Member conforming to the practices recommended

in this Note should have at least a partial defence to an allegation of negligence

by virtue of having followed those practices. However, Members have the

responsibility of deciding when it is appropriate to follow the guidance. If it is

followed in an appropriate case, the Member will not be exonerated merely

because the recommendations were found in an RICS Guidance Note.

On the other hand, it does not follow that a Member will be adjudged negligent

if he has not followed the practices recommended in this Note. It is for each

individual surveyor to decide on the appropriate procedure to follow in any

professional task. However, where Members depart from the practice

recommended in this Note, they should do so only for good reason. In the event

of litigation, the Court may require them to explain why they decided not to adopt

the recommended practice.

In addition, Guidance Notes are relevant to professional competence in that each

surveyor should be up to date and should have informed himself of Guidance

Notes within a reasonable time of their promulgation.


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Contents

RICS Guidance Notes 3

1. Introduction 7

2. General Background 7

3. Details of Landfill Legislation 8

Planning legislation and development control 8

Development plans 8

Planning permission 8

Waste management licensing 9

Protection of water quality 10

Nuisance 11

Rating 11

4. Site Licensing 11

Long-term funding 11

Use of a bond 11

Pollution 11

The application 11

Monitoring 12

5. Inert Waste Landfills 12

6. Landfill Practice 13

7. Monitoring 13

Closed sites 13

Operational sites 14

8. Development 14Development of land adjacent to landfill sites 14

Development of land on and around landfill sites 14

9. Accelerated Stabilisation 15

Description 15

Effects on site engineering 15

Filling methods 15

10. Factors Considered when Assessing Completion 16

11. Agricultural Considerations 17

Introduction 17Waste management 17

Landfill gas management 18

Leachate 19

Compaction and settlement 20

Aftercare 21

Afteruse 21

Appendix A List of Abbreviations 22

Appendix B Practical Points 23

Appendix C Essential Questions 25

Appendix D Legislation Relevant to Operation, Monitoring 26

and Control

Bibliography 27


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1. INTRODUCTION

1.1 The purpose of this Guidance Note is to act as a reference for surveyors.

Its aim is to be an aide-mémoire, information source and reference for

more detailed information. It concentrates on landfill but many of the

issues raised are of wider relevance.

1.2 In making any reference to the document chartered surveyors should beaware that there are others in the profession who specialise in waste

management matters. A list of contacts may be obtained from the RICS

Information Centre (tel: 0171 222 7000).

1.3 Waste management is becoming an increasingly complex topic but

remains an important area for rural practice and other surveyors. It is

also an area where both legislation and site practice are changing and

this has both short- and long-term implications for site negotiation and

management.

1.4 Landfill tax is not included as a separate item in this guidance.

Information is available from the RICS on this topic as well as from

HM Customs & Excise.

1.5 Landfill is a complex process but proceeds in discrete stages usually

initiated by the granting of a planning permission and subsequent waste

management licence. It is important that landfill is seen as a continuing

process with inputs from all involved in the process to ensure the

integration of all objectives. It is essential that the proposed afteruse

and restoration parameters are discussed and built into the process at

the planning stage and not left until the site is nearing completion.

2. GENERAL BACKGROUND

2.1 Before a formal application for planning permission is made, discussions

between an applicant for a potential landfill site and the relevant planning

authority are essential. The Environment Agency (EA) and in some

cases the Ministry of Agriculture, Fisheries and Food (MAFF) or the

Forestry Authority should also be consulted. The applicant can then

draw up proposals and undertake any necessary site assessments with

a view to a chosen afteruse, taking into account the likely requirements

of the planning authorities and other bodies.

2.2 The Planning Compensation Act 1991 gave powers to local planning

authorities to impose after-care conditions on planning permission,

revocation orders and discontinuance orders in respect of development

involving the depositing of any types of refuse or waste materials. This

applies to landfill sites. Advice on the imposition of aftercare conditions

in respect of mineral workings is given in Minerals Planning Guidance

Note (MPG) 7, the Reclamation of Mineral Workings, and may to some

extent be helpful for the reclamation of landfill sites.

2.3 The controls on the surrender of site licences under the Environmental

Protection Act 1990 are complex and far-reaching. It is likely that

pollution controls over a particular landfill site will remain in force long

after the restoration and aftercare requirements under the planning

permission have been completed and the afteruse of the site com-

menced. In such circumstances, if the pollution control monitoring and

remedial activities affect such land there may need to be provision toremedy any damage. A provision may still be in force, or, in the case of

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new planning permission this will be done through a planning obligation

or other agreement.

2.4 A checklist of the key matters which will be considered by the EA

should be made. When drafting licences, this is available from the EA

regional office. Some issues will need to be discussed with the local

Planning Authority at the planning application stage if there are to be

significant planning implications, for example where effective leachateand gas control systems are important to achieve afteruse objectives.

This list is a useful aide-mémoire for considering impacts and relevant

points to be covered in negotiation.

3. DETAILS OF LANDFILL LEGISLATION

Planning legislation and development control

3.1 Development control is exercised through the local planning authorities.

The relationship between the planning system and pollution control

legislation is explained in Planning Policy Guidance Note 23 Planning

and Pollution Control (PPG23) (England). The planning system focuseson whether the development itself is an acceptable use of land rather

than on the control processes and substances which have potentially

harmful effects on the environment.

3.2 The Town and Country Planning Act 1990 and the Planning Compensation

Act 1991 control the use of land for waste disposal through:

• development plans;

• the grant or refusal of planning permission.

Development plans

3.3 Development plans are prepared at both county and district levels inEngland and Wales, and must have regard to national and regional

planning policy guidance. Any determination under the Planning Acts

must have regard to the development plan, and the determination shall

be made in accordance with the plan unless material considerations

indicate otherwise. Development plans must also comply with EC

requirements, including the Framework Directive on Waste (75/442/EEC,

as amended by 91/156/EEC and 91/692/EEC). Development plans

comprise county-wide structure plans and district-wide local plans. In

London the metropolitan areas and unitary authorities are combined into

unitary development plans. Special arrangements apply in National

Parks. These plans give strategic advice on the development and use of

land in a particular area and include policies in respect of potentially

polluting development.

3.4 Other relevant plans for landfill development include waste disposal

plans and waste local plans. The development plan framework provides

an opportunity for the requirements and constraints of waste disposal

strategies to be considered in the context of the overall development

and use of land and, where appropriate, sets out broad criteria to be

applied in identifying waste disposal sites. Every opportunity should be

taken to refer to and input into waste plans as it is these which direct

and control waste issues within an area.

Planning permission

3.5 The determination of landfill applications is the responsibility of the

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county or unitary authorities in England and district councils in Wales

and Scotland. Planning permission is required for the use of land for

waste disposal, except for certain permitted development under the

Town and Country Planning (General Permitted Development) Order

1995. Environmental issues are one of the material considerations

which planning authorities have to take into account when dealing with

applications.

3.6 For developments which are likely to have significant environmental

statement effects on the environment, developers may be required to

submit an environmental statement with their planning application, in

accordance with the Town and County Planning (Assessment of

Environmental Effects) Regulations 1988.

3.7 The Environmental Assessment Regulations and circulars describe the

process of environmental assessment, and the specified information to

be reported in the environmental statement. In summary, this information

comprises:

• a description of the development, incorporating the site, the design

and scale of the proposals;

• baseline data to identify and assess the main environmental effectsof development; and

• a description of the likely environmental effects of the development,

whether direct, indirect, permanent, temporary, positive or negative,

and measures proposed to mitigate adverse effects.

3.8 Projects to dispose of special waste fall within Schedule 1 of the EA

Regulations, where environmental assessment is mandatory. Other

waste disposal activities fall within Schedule 2 where environmental

assessment is required if a development is judged likely to give rise to

significant environmental effects. Guidance given in Department of the

Environment (DoE) Circular 15/88 on indicative criteria thresholds for

environmental assessment of Schedule 2 projects indicates a thresholdlevel of 75,000 tonnes per year waste capacity for waste disposal

installations, including landfill sites. The key criteria is the likelihood of

significant environmental effects. Many landfill proposals will fall into this

category and so may require environmental assessment, even where

proposed input is less than the indicative threshold.

Waste management licensing

3.9 The Environmental Protection Act 1990 prohibits the deposit of

controlled (directive) waste, in or on land, unless a waste management

licence authorising the deposit is in force. It also prohibits the disposal

of waste in a manner likely to cause pollution of the environment or

harm to human health.

3.10 The purpose of licensing is to ensure that the disposal of controlled

waste does not give rise to:

• pollution of the environment;

• harm to human health; or

• serious detriment to the amenities of the locality (unless a planning

consent is already valid).

Licences are issued subject to conditions designed to ensure that the

development and operation of a landfill site will not cause any of these

problems.

3.11 An application for a waste management licence must be made to the EA.Guidance on the preparation and content of licences is contained in

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Waste Management Paper (WMP) 4. The applicant is required to set out

in a working plan how the landfill is to be prepared and operated. This is

a detailed document which shows how the landfill will be built and

operated.

3.12 During the preparation and operational phases of the landfill, the EA

will inspect the site regularly to ensure that the development is in

accordance with the licence and working plan.

3.13 Once issued, a licence may only be surrendered if the EA is prepared

to accept it back. Normally this will only be once the EA is assured that

the site has stabilised and it is satisfied that the site is unlikely to cause

pollution of the environment or harm to human health. Details of how a

landfill can be assessed for completion are given in WMP26A.

3.14 The Environmental Protection Act 1990 introduced the requirement for a

‘fit and proper person’ to hold a waste management licence. Guidance in

WMP4 sets out the criteria for this based on three components:

• conviction for a relevant offence;

• technical competence; and

• financial provision.

Protection of water quality

3.15 The Water Resources Act 1991 is concerned with the pollution of

‘controlled waters’, which include rivers and other inland surface and

underground water, estuaries and territorial waters. It is an offence if a

person causes or knowingly permits any poisonous, noxious or polluting

matter, or any solid waste matter, to enter any controlled waters.

3.16 To comply with the Water Resources Act 1991, a landfill development

may require discharge consent in addition to planning permission and

a waste management licence. Under the Water Industry Act 1991,discharges to ground and surface watercourses are the responsibility

of the EA while any disposal to a sewer will require consent from the

relevant sewerage authority.

Nuisance

3.17 Nuisance from noise, odour, smoke and fumes is covered in the provi-

sions of the Environmental Protection Act 1990, which is regulated by

local authority environmental health officers.

3.18 The holistic approach to landfill development encompasses landfill

engineering, landscape design and planned afteruse, with the landscape

architect playing an important role in the restoration concept. The land-

fill designer must therefore take account of the landscape and planned

afteruse requirements in the technical design of the engineering layers.

3.19 Afteruse considerations may require that a complex landform is produced.

However, the fundamental objectives and performance criteria of the

engineering cap must not be compromised, and the designer should

overcome such additional constraints by specific measures. These may

include locally strengthening the engineering cap, or creating the

required surface undulations within the restoration layer above a more

uniformly sloping capping membrane. The engineering designer should

work with the landscape architect/afteruse designer to produce a

landform appropriate to both its engineering and projected afterusefunctions.

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Rating

3.20 Occupiers should be aware that, in the majority of cases, rates will be

payable on landfill operations. Under normal circumstances the rating

assessment will reflect the quantity of materials deposited within or on

the site.

4. SITE LICENSING - DETAIL

Long-term funding

4.1 All landfill licences in future will subsist well beyond the cessation of

landfilling.

The period of post-closure control and monitoring may last 30 years or

more and could be longer than the actual landfilling operations. Once

the site ceases accepting waste it will not be generating income from

the waste disposal.

Use of a bond

4.2 In some cases, the local planning authority may have obtained a planning

agreement with the applicant involving the use of a bond to secure the

preliminary restoration of the site after the cessation of landfilling.

To secure the desired result, detailed specification of the work to be

carried out under the bond needs to be set out.

Pollution

4.3 The EA must assess, among other things, the facility’s potential for

causing environmental pollution, and the applicant’s proposals formitigating it.

• The EA would expect to be consulted by those undertaking

environmental assessments during the assessment process.

• If any pollution is likely to affect land use, either at the site in question

or in the surrounding area, the local planning authority may need to

take account of it, and may also need to consider whether anti-

pollution systems and controls are compatible with, or adequate in

view of, the wider planning objectives.

Having said the above, it should be remembered that planning controls

are not an appropriate means for the detailed control of pollution from

waste management facilities. This should always be done by the EA

through the licensing system. In the same way, licence conditions

should not cover issues which are fundamentally about development

and land use, except where there is no planning permission.

4.4 If a waste facility might cause pollution, that possibility will almost

certainly be a material consideration in the determination of a planning

application for the facility. In particular, many waste management

facilities will need to be subjected to an environmental assessment.

The application

4.5 All waste management licence applications should include at least thefollowing information:

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(a) the location of the facility, specifying any existing development

within 250 metres of the boundary of the site. If the facility (as

with a landfill) is likely to cause mechanical disturbance, be a

source of spillages, or otherwise put underground services at

risk, ‘existing development’ will include underground services;

(b) the location of the boundaries, specifying what identifies them on

the ground;

(c) the ownership of the site; the applicant’s interest in the land;

(d) the planning permission; or the established used certificate; or

the certificate of lawful use; or the appeal decision letter; or a

planning application; or a statement showing why none of these

is required;

(e) any relevant convictions; the technical competence of the

licensee; the financial provision to be made by the applicant;

(f) an assessment of the physical environment of the site - this will

normally include the site topography, meteorology, geology andhydrogeology; the quality of air, surface water and groundwater,

and soil, although the scope may vary with the type of facility;

(g) the working plan - among other things, this should cover:

(i) the infrastructure to be provided, used or converted, including

the construction and location of all storage facilities; and

(ii) detailed descriptions of the water management processes

to be carried out on the site.

(h) full details of the pollution controls measures and monitoringarrangements; and

(i) for landfill sites, the operator’s plans for the management of gas

and leachate, and for capping and restoration.

Monitoring

4.6 As a guide to the monitoring detail, four survey points per hectare are

recommended for settlement measurements.

Once any control systems have been phased out, sampling should be

carried out for sufficient time to ensure that any changes in the

condition of the waste have been detected. Two periods are

recommended - five years in cases where no significant appropriate

monitoring has been carried out at the site, and two years where the

site is already reasonably well characterised.

5. INERT WASTE LANDFILLS

5.1 Many sites were licensed under the Control of Pollution Act 1974 (the

forerunner of the Environmental Protection Act) to accept ‘inert’ wastes.

However, experience has shown that ‘inert’ was a misnomer. A very high

proportion of these sites contained slowly degrading materials, such as

wood from demolition waste, and that subsequently gave rise to theproduction of landfill gas and leachate.

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Therefore, only genuinely inert waste should be permitted at sites

licensed for inert waste. For such sites, licence conditions should

specify the individual types of waste that will be acceptable, such as

soil, sand, clay, stone, concrete, bricks, slate, glass and ceramics. The

conditions should avoid the use of the term ‘inert waste’, except where

categorising the licence.

5.2 Conditions which set arbitrary limits - for example, on paper and cardboardtypically at 5% or 10% of the waste input - in order to allow an amount

of accidental or adventitious contamination, are ineffective and enforceable.

Source-based descriptions, such as ‘waste from the construction

industry’, should also be avoided.

6. LANDFILL PRACTICE

6.1 Landfill designers must consider probable changes in landfill practice

and waste input that may occur over the whole lifetime of the landfill,

from conception to completion of aftercare, and should, where possible,

make provision for these changes, or allow for them to be incorporatedat a later stage. A process of periodic review should be used throughout

the life of the site and prior to the design at later stages. The EA

reviews licences on a five-year rolling programme.

6.2 The design of the landform is the starting point of the design of a

landfill at a given location. The landform is a key factor in determining

the standard of restoration achievable, afteruse and waste capacity of

the site, and its design needs to take into account the likely waste input

to the facility and the landscaping requirements in the context of the

surrounding land. The key factors affecting the landform are:

• maximum and minimum surface gradients;

• capacity;• settlement; and

• waste density.

6.3 Initial settlement values of 12-17% have been reported for household

waste sites in the UK with long term (30-year) values of approximately

20%. Values of 15-20% are accepted as being typical of the surcharge

of allowance that may need to be made when considering the void

capacity and final pre-settlement contours of a household waste landfill.

The effects of settlement need to be considered in quarry landfills, or in

landfills whose base is non-uniform (or stepped), and measures need to

be taken to avoid problems due to differential settlement, which can

lead to stresses and breaks in the engineering cap, and possible

drainage problems.

6.4 The responsibility for the assessment and monitoring of closed sites

for which there is no licence rests primarily on the land-owner. The

Environmental Health Authority should also assess the likely risk to

public health or of nuisance and decide in the light of evidence

available what action should be taken.

7. LANDFILL GAS MONITORING

Closed sites

7.1 The majority of closed sites are unlikely to have monitoring boreholes.

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Where it is concluded by the site assessment that no gas is being, or is

likely to be, produced and there is no risk to development, then there

should be no need to undertake monitoring (see paragraph 4.6). For

other sites the frequency of monitoring should be determined by the site

assessment. As a guide, waste management guidance recommends

that rural sites with no control system installed should be monitored four

times per annum. This frequency should be increased at sites with

control systems. Monthly inspection is recommended where there isbuilding development or where there are services within 250 metres of

the deposited wastes. Sites should be monitored at least weekly where

any development is within 50 metres of a waste disposal containing

significant amounts of biodegradable materials. Where gas migration

has been identified, more frequent monitoring may be necessary.

Operational sites

7.2 The assessment should determine the frequency of monitoring for sites.

As a guide, however, for isolated rural sites, where quantities of

biodegradable wastes have been deposited, gas monitoring frequency

should, initially, be on a monthly basis. For routine monitoring this may

be extended to three-monthly intervals. For all sites taking or whichhave taken biodegradable wastes, and that have buildings or services

within 250 metres of the limit of filling, monitoring should initially take

place at least weekly, or more frequently, if gas migration has been

identified. The monitoring frequency should be subject to regular review.

8. DEVELOPMENT

Development of land adjacent to landfill sites

8.1 Where development is proposed within 250 metres of a landfill site,

whether operational, awaiting restoration or restored, the developer willneed to take account of the proximity of the proposed development to

the landfill and investigate the geology and topography of the area.

Under the Town and Country Planning Development Order 1988,

planning authorities are now required to consult the EA on development

within 250 metres of a landfill site either active or closed within the last

30 years. Local authority registers of land which may be contaminated,

compiled under Section 143 of the Environmental Protection Act, record

the locations of both closed and operational landfills and provide an

additional aid to identify such sites. For operational sites, whilst all gas

should be controlled, it is possible that some minor escape, which may

originally have been acceptable, could become significant by a change

in use of land around the site.

Development of land on and around landfill sites

8.2 Afteruse of landfill sites should normally be restricted to agriculture or

similar uses. Where control systems permit, the land may be used for

public open space, conservation or recreation. It is recognised that

there will be pressures for other forms of development. This should be

possible, provided adequate precautions are taken. In particular, older

landfills in urban areas can be developed for non-housing uses, such as

supermarkets and light industrial units, subject to detailed investigation

and design in accordance with current advice and guidance. It is recom-

mended that no housing be built within 50 metres of any landfill site with

gas concentrations in excess of the limits given in Paragraph 7.9 of WMP27 or which still has the potential to produce large quantities of

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gas. Gardens of houses should not extend to within ten metres of any

such site. Great care should be taken with any development which takes

place within 250 metres of in-filled wastes. Where development is taking

place on or adjacent to a landfill site, the developer should take account

of the need for the assessment and monitoring of any risk to the

development posed by the site.

9. ACCELERATED STABILISATION

Description

9.1 Accelerated stabilisation will affect the operational practice and

restoration programming rather than restoration design. This method is

promoted by the Department of the Environment, Transport and the

Regions (DETR) in WMP26B and involves the encouragement of rapid

degradation of the landfill through management of the waste, including

controlled irrigation and interim capping.

Effects on site engineering

9.2 The effects of accelerated stabilisation on engineering will include

more onerous management for acceptance of waste, and increased

production rates and strength of leachate and of gas.

Accelerated stabilisation is therefore likely to require inter alia changes

to:

• waste characteristics;

• heat retention and insulation characteristics of the base, walls and

cap;

• surface sealing and potential for air admission;

• leachate (and possibly gas) recirculation, pH adjustment and heating;

• leachate removal and treatment;• gas abstraction;

• daily cover usage;

• barriers and bunds;

• materials specifications; and

• filling methods - this is of most interest to rural practice surveyors

and is described below.

Filling methods

9.3 Increased rates of settlement, albeit for a shorter period, would be a

probable result of accelerated stabilisation. This may require initial filling

to a higher level than with present practice, and would require the

design of a cap, and leachate gas control systems, which can accom-

modate considerable vertical movement while still retaining the required

properties. Alternatively, a temporary cap could be provided to allow

periodic refilling to achieve final topographic levels.

9.4 Particular attention will need to be paid to surface water drainage

systems, leachate and gas management systems, and other aspects of

site infrastructure. The designer and operator will need to take account

of this when planning and constructing the site, and in the site,

restoration and post-closure management.

9.5 The landscape master plan should be prepared in consultation with theowner/operator and the engineering design team, taking into account

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the requirements of the planning authority and other relevant consultees.

The design team as a whole should consider what specific provisions

will be necessary to accommodate the landscape and afteruse proposals

without compromising the performance of the engineering cap, and

should consider the overall profile of the capping system required.

WMP26E deals specifically with the restoration layers of the final cap,

including the handling and placing of the soil layers and the require-

ments for vegetation establishment. The depth of the soil cover will besite-specific, consistent with the planned afteruse and the presence of

environmental control systems.

9.6 The landfill designer, landscape architect and restoration specialists

should ensure that the landscape proposals and the landfill require-

ments are compatible, for example:

(a) the size and the layout of phases should be organised where

possible to reflect existing or proposed land use patterns,

enabling field boundaries to be established as part of a phased

restoration scheme;

(b) adequate storage areas for on-site or imported soils should beplanned within the site boundary to allow separate handling,

storage and maintenance of soil quality in respect of landscape

and restoration materials;

(c) the use of many and varied soil types in one restoration phase

should be avoided;

(d) the layout of pipework and environmental monitoring points

should be designed to enable the use and maintenance of the

planned landscape to take place with minimal disruption; and

(e) access routes, provided for monitoring and maintenance of thelandfill gas and leachate management systems, should be

planned to avoid compromising the planned afteruse.

Being a relatively new technique, accelerated stabilisation is not proven.

Therefore no experience exists on which to make or base judgements.

The theory is sound: however, it can only be considered as experimental

until site practice proves otherwise.

10. FACTORS CONSIDERED WHEN ASSESSING COMPLETION

10.1 Within the limits of current knowledge, completion may be recognised

only by showing that the landfill has stabilised according to the criteria

set. It is not yet possible to predict the point in time when the relevant

criteria will have been met for any given site, or the interval over which

a site will become stable, although monitoring data can show that this

stage is being approached or has been reached. WMP4 recommends

that regular reports compiled by the operator comprising a review of

monitoring data and its interpretation should form the basis both of

routine meetings between the operator and the EA and of the application

to surrender the licence.

10.2 Routine monitoring therefore informs the site operator and the EA of the

current state of the site and its progress towards completion. Where a

complete record of monitoring is available this should provide all theinformation needed for the application to surrender a licence.

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10.3 Evidence should be provided that the information is sufficiently reliable

and comprehensive. Where sites are operated under quality assured

systems, a considerable part of the necessary evidence should have

been generated and should ensure confidence in the reliability of the

data. Otherwise the EA should require the operator to request verification

of the data obtained, which may include details of the laboratories used

and the appropriate analytical methods employed. The laboratories

themselves may operate under quality assured procedures or beaccredited. All such supporting information should assist the EA in

determining the quality of the data provided.

10.4 The design of the site monitoring schemes should be carefully thought

out. The operator and the EA will tend to rely more on sampling and

analytical procedures which have been subject to quality assured/quality

controlled schemes. General guidance on this is given in WMP4 and

more detailed guidance on landfill monitoring will be issued in a revision

of WMP26E.

10.5 The 1990 EPA sets out a condition for deciding whether or not a landfill

site may receive a certificate of completion. This is that the authority

must be satisfied that the condition of the land is unlikely to causepollution of the environment or harm to human health. This condition is

referred to here as the ‘completion condition’. The most important way

in which a landfill might cause pollution or harm to human health is by

the release of pollutants in gas or leachate. WMP4 deals mainly with

the risk of harmful quantities of such pollutants being released into the

environment, it also considers the physical stability of the site, and the

possibility that dangerous wastes might be present.

11. AGRICULTURAL CONSIDERATIONS

Introduction

11.1 The aim in restoration and afteruse terms is to ensure that land will

meet the criteria set out at the beginning of the project assuming time

and satisfactory inputs.

11.2 There are some particular considerations in connection with landfill

design which may have an influence on agricultural afteruse.

Waste management

11.3 Historically, the UK’s waste strategy has been towards landfill - 85% of

controlled waste has been deposited in this manner. The UK’s sustain-

able development strategy requires that each generation should deal

with its own waste and not pass the problem on to future generations.

The present strategy is towards re-use, recovery and disposal; however,

the scale of current practice suggests that landfill will remain the major

approach for some time.

11.4 The National Rivers Authority document Policy and Practice for the

Protection of Groundwater has been instrumental in bringing about a

sea-change in modern waste practice. It gives the following as examples

of the time required to stabilise the landfill with different methods:

The table overleaf gives a clear indication of the timescales of landfill

and the basis for the preferred hierarchy. It is necessary to put thesetimescales in perspective with afteruse and aftercare.

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Landfill gas management

11.5 There is a range of designs of landfill gas wellheads. The simplest

structures involve capping large diameter plastic pipes with manhole

covers flush with the ground. Other structures involve 30-40 cm high

plastic boxes which occupy about 0.5 m2, whilst the largest involve a

1-2 m2 post and rail enclosure containing gas pipes which protrude 1-2 m

above the ground.

11.6 The effect of obstructions such as wellheads on agricultural afteruse

is a difficult area. It will depend upon the necessary cultivation and

agricultural operations, and the number, pattern and design of the

obstacle and field pattern. Wellheads, like parkland trees or pylons

widely spaced, are unlikely to create a serious obstruction to cultivation

and can be overcome. However, if, for example, a 40 m grid is installed

to a loose specification, then the resultant obstacle course could be a

serious impedance to arable cropping, and may also limit grass cropping.

11.7 The spacing of wellheads also varies based on a number of engineering

factors, but as a guide, is 40-60 m in a normal layout pattern. The

concern here is the pattern of the grid which is unlikely to be regular.Closer spacing is common for passively vented wells and for perimeter

wells 5-50 m in diameter.

11.8 Operators differ in their views as to the life of gas wells. Some consider

that wells will not need to be replaced, others feel that any permeable

lining around the well pipe is likely to clog if the permeable material is

too fine. WMP26B states that wells with an internal diameter of less

than 150 mm can become unserviceable and need replacing in three to

four years. Where a well has to be replaced, redrilling in the same

location may appear to be technically unfeasible, expensive or counter-

productive.

11.9 On some sites wells are built up progressively and, on others, drilled

after capping or soiling. The well is sealed in the cap and some method

(such as a telescopic fitting) used to allow the wellhead to settle with

the cap. The distribution pipes need to be laid to a fall to allow the

condensate to flow into a condensate trap or back to the well. A fall of

1:20 is suggested as a minimum for these pipes.

11.10 Agricultural problems may be encountered:

(a) the design of the wellhead is a hidden obstruction to agricultural

cultivation;

(b) the distribution of wellheads presents a series of obstacles in

practical terms, and curtails the range of agricultural operationsthat are possible; and

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TABLE 1 – TIME REQUIRED TO STABILISE LANDFILL

Methods Time to stabilise

Containment – dry tombing 300–500 years

Attenuation – dilute and disperse 50–300 years

Accelerated stabilisation 30–50 years


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(c) the distribution system is at such a height in the soil profile that it

impedes or precludes agricultural drainage.

11.11 Some sites bring gas to a manifold which houses individual controls for

each well, enabling sampling and adjustments to be made. This arrange-

ment allows the restored area to be obstacle-free in the short term.

11.12 On modern sites it may be possible to agree that landfill wells beconnected to a manifold where there is efficient base engineering to

collect and control leachate. On older consented areas, where leachate

is managed less easily, this is not a practical option.

11.13 It is not necessary to place wellheads in the same vertical plane as the

well. However, it is possible to offset and take piping in the agreed

distribution zone to the wellhead location. If the landfill gas system is

below the cap there is generally no conflict with agricultural requirements.

Leachate

11.14 Leachate is formed by a combination of infiltration of rainfall during and

after waste infilling, moisture within the waste and the acidic products of decomposition. If allowed to build up, the head of leachate on the bottom

of the landfill will inhibit the degradation process of the submerged

waste, and also increase potential for leakage through the base. Site

licence requirements usually limit the permitted head of leachate to one

metre above the base of the site.

11.15 Landfill engineering practice usually splits each site into cells. Cell size

is based on water balance calculations aimed at limiting the quantity of

rainfall in each cell. Modern cells are engineered with basal slopes of

between 1:40 and 1:100. In containment sites base liners are highly

engineered often with multi-liner systems and a drainage blanket with

drainage pipes, which all allow leachate to drain to the low engineeredpoint. A leachate monitoring well, sited at the engineered low point, is

usually constructed progressively as infilling continues.

11.16 The lower points may be drained into an arterial leachate drainage

system, taking the leachate to one or more points at the side of the site.

The system may be connected to rodding chambers at the surface to

allow jetting. WMP26A provides guidance on the number of leachate

sampling points in each cell (two minimum). Cell size varies between

two and five hectares. Where a well is built progressively it often gets

knocked and pushed out of alignment, hence affecting the position on

the surface.

11.17 On older sites the base is unlikely to have been engineered to modern

high standards and leachate control is more difficult. The combination

of day-cover - preventing even percolation through the fill - and the lack

of a drainage blanket or engineered slopes hinders the lateral move-

ment of leachate. Pumping to control leachate levels may be required at

several locations. On some sites the wells may be dual-purpose gas and

leachate. Pumping may be by a submersible pump or eductor. Pumps

require an electrical supply with a control system. An eductor requires

three pipes: one for leachate being pumped into the well, one for

leachate being pumped out and the third for gas.

11.18 Where treatment beds and/or lagoons are to be considered, the location

of the structures in relation to field boundaries should be assessed andplanned at an early stage. Tracking routes for monitoring, pumping and

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removal of leachate off-site should be agreed and construction criteria

finalised.

Compaction and settlement

11.19 The amount of settlement depends on the proportion of degradable

material in the fill, and the depth of the tipped fill.

11.20 The actual methodology of waste placement and compaction is usually

considered an operational matter that does not require licensing

conditions. However, poor site management can result in differential

settlement, which may jeopardise the afteruse. The consensus appears

to be that pre- and post-settlement contours are a matter for planning,

not working practice. However, as the operational practice has a major

effect on contour, this point does need consideration.

11.21 WMP4 requires that there should be topographical information with the

licence application and makes it clear that conditions covering topography

should be applied. The paper also requires that monitoring includes a

record of levelling and deformation surveys. WMP26A requires similar

information for completion monitoring and specifies the number of survey points. As this provides the EA with the statistics to verify settle-

ment rates, it seems reasonable to suggest that the EA has a duty of

care to comment where settlement rate information is lacking or seems

inappropriate.

11.22 WMP26B discusses settlement and gradients and gives some general

guidance as follows:

• most settlement should occur in the first 30 years, with the majority in

the first five years; and

• there should be gradients of max 1:4 and min 1:25 (settled) to

ensure adequate drainage and minimise ponding.

11.23 Differential settlement can cause disruption to agricultural drainage

systems. This is particularly marked where there are engineering

differences (for example roads, cell walls, edges and accelerated

settlement around wells).

11.24 PPG23 tries to address the problem of differentiating between those

matters which can be controlled by planning conditions and those which

should be controlled by waste management licence. While planning

conditions are mainly concerned with land use matters there are

operational points which directly affect the afteruse. These can be

summarised as follows:

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TABLE 2 – OPERATIONAL POINTS AFFECTING AFTERUSE

Site Practice Influence on the afteruse

Waste placement and compaction 1. Surface becomes too uneven

for mechanical cultivation

2. Ponding occurs in hollows

Settlement centred on wells Localised accelerated movement

Control equipment and rate of pumping Number of inspections requiredto monitor and control equipment


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Aftercare

11.25 When working with minerals it is recognised that aftercare commences

when the restoration condition is complied with. In practice, this occurs

when the topsoils have been spread to the satisfaction of the Mineral

Planning Authority. However, when working with waste there is a difficulty

with this as following soiling there is a period of five years when post-

closure engineering is at its busiest. Consideration should therefore begiven to postponing aftercare, promoting an interim restoration or making

specific provision for repair of damage and remedial works outside the

planning framework. It is important that this issue is addressed early on

to ensure that agricultural practice and future land use is not unduly

compromised.

Afteruse

11.26 Any mineral working or waste disposal operation offers opportunities to

consider afteruse and plan the restored landscape. The afteruse is

influenced by many factors, however, often outside the direct control of

the site. Nevertheless, sites should be considered as an opportunity and

all steps taken to influence the required outcome. It is never too early toplan the afteruse as steps taken in the site design and working can, as

described, greatly influence land-use in the long term.

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APPENDIX A: LIST OF ABBREVIATIONS

EA Environment Agency

EA Regulations Environmental Assessment Regulations

EPA Environmental Protection Act 1990

LFG Landfill Gas

LPA Local Planning AuthorityMAFF Ministry of Agriculture, Fisheries and Food

MPG7 Minerals Planning Guidance Note 7

PPG23 Planning Policy Guidance Note 23

WMP4 Waste Management Paper 4 (1994)

WMP26A Waste Management Paper 26A (1994)

WMP26B Waste Management Paper 26B (1995)

WMP26E Waste Management Paper 26E (in draft 1996)

WMP27 Waste Management Paper 27 (1989)

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APPENDIX B: PRACTICAL POINTS

Sell or lease

Long lease What indemnity will be retained in the longer term? Will risk

liability be accepted by the waste company after they leave the

site?

What is the solvency of the operator, what will happen to the site

and what are the risks in the case of insolvency?

Is insurance available for risks, and who will pay any premiums?

Freehold Beware any retained liability.

Advantages in linking with mineral operation rather than selling

for one or the other.

What are the implications if the scheme does not progress as

planned? No control over the working and afteruse.

Buildings

Consider values within curtilage of landfill sites.

What is the effect on values of the long-term use of a site as a

landfill?

Lease or sale considerations - how will each be affected?

Consider measures to protect properties at an early stage -

bunding, direction and method of working.

Position of gas flare and impact on properties.

Tenants and Tenancies of Landfill Sites

Obtain all the information prior to advising to take restored land

that has been landfilled. Limitations as to use or farming practice

will be par ticularly relevant.

Restoration standards crucial to future potential of land.

Worth taking land on a short-term basis to assess potential and

any inherent problems.

Farming Practice

What limitations are placed on the site by the aftercare scheme?

Restoration methods and the presence of gas/leachate

infrastructure can constrain farming.

Obtain full details of site requirements for monitoring, access and

leachate disposal.

Check position with regard to Integrated Administration Control

Scheme and requirements for forage areas (may need grazingwhere stock may not be allowed).

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Other Items

Footpaths Require detailed consultation as to reinstatement and use.

Determine insurance requirement to cover any liability resulting

from previous use.

Tree planting Possible on landfill sites (see the DETR’s publication The

Potential for Woodland Establishment on Landfill Sites) butensure that correct species and area for planting are chosen.

Check planning permission for requirements.

Amenity Consider potential uses but balance against limitations of site

and long-term site constraints.

Monitoring Long-term access requirement necessary for leachate and gas

monitoring. Determine liability for access post restoration.

Certificate of Liability retained by operator or, by default, the landowner unless

completion licence accepted back by the EA. If handed back, check in detail

any conditions or outstanding concerns. Always request sight of

certificate if available.

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APPENDIX C: ESSENTIAL QUESTIONS

1. Certificate of Completion:

(a) what does it say?

(b) what are the limitations it imposes?

2. Who is the licence holder? Is this person still on site or in the locality?

3. What are the requirements for monitoring. As set out in the licence and

planning permission?

4. Do the planning permission and licence require the same site

objectives?

5. Who is responsible for liabilities as existing and in default?

6. What are the benefits and potential liabilities for sale or lease?

7. What are the implications for valuation? Is the valuation covered by the

Red Book (contaminated land) and P.I. insurance?

8. What is the long-term potential for the site? Has it any potential?

9. When selling land that has been filled, has full information been given

and obtained?

10. Have risks and liabilities been inherited when buying filled land from the

receiver?

11. Are there advantages in setting up environmental areas/bodies through

the provisions of landfill tax?

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APPENDIX D: LEGISLATION RELEVANT TO OPERATION, MONITORING

AND CONTROL

Control of Substances Hazardous to Health Regulations (Northern Ireland) 1990

Control of Substances Hazardous to Health Regulations 1988 SI. 1988 (No.

1657) as amended

Health and Safety at Work etc. Act 1974

Health and Safety at Work etc. Order (Northern Ireland) 1978

Planning & Compensation Act 1991

Planning (Assessment of Environmental Effects) Regulations (Northern Ireland)

1989 SRO (No. 20)

Pollution Control And Local Government Order (Northern Ireland) 1978

Public Health Act (Scotland)1897

Public Health Act 1936

Public Health Acts (Ireland) 1878-1907

The Control Of Pollution Act 1974

The Environmental Assessment (Scotland) Regulations 1988 SI. 1988 S.122 (No.

1221)

The Environmental Protection Act 1990

The Reporting of Injuries, Diseases And Dangerous Occurrences Regulations

1985 as amended

The Reporting of Injuries, Diseases And Dangerous Occurrences Regulations

(Northern Ireland) 1986

The Town & Country Development Order 1973

The Town & Country Development Order 1988 SI. 1988 (No. 1813) as amended

Town & Country Planning (Assessment of Environmental Effects) Regulations

1988 SI 1988 (No. 1199)

Town & Country Planning Act (Scotland) 1972

Town & Country Planning Act 1990

Town & Country Planning Order 1991

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BIBLIOGRAPHY

Environmental Protection Act 1990, HMSO

Minerals Planning Guidance Note 7 - The Reclamation of Mineral Workings,

HMSO, 1989

Planning Policy Guidance Note 23 - Planning and Pollution Control, HMSO, 1994

Policy and Practice for the Protection of Groundwater, National Rivers Authority,

1992 (ISBN: 1 873160 37 2)

The Potential for Woodland Establishment on Landfill Sites, Department of the

Environment, Transport and the Regions, 1993

Town and Country Planning (Assessment of Environmental Effects) Regulations

1988, HMSO

Town and Country Planning Act 1990, HMSO

Town and Country Planning Compensation Act 1990, HMSO

Waste Management Papers, Department of the Environment:

4: Licensing of Waste Management Facilities, HMSO, 1994

26A:Landfill Completion, HMSO, 1994

26B:Landfill Design, Construction and Operational Practice, HMSO, 1995

26E:Landfill Restoration and Post-Closure Management, HMSO (in draft 1996)

27: Landfill Gas, HMSO, 1989

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Waste Management

A G u i d e t o L a n d f i l l

Waste management is becoming an increasingly complex topic for the surveyor, and

as legislation and site practice continually change there are both short and long-term

implications for site negotiation and management. This new title provides rural practice

and other surveyors with the guidance they need to deal with the various aspects of waste

management concerning landfill, and raises a number of wider issues in the process.

This Guidance Note focuses on the various discrete stages involved in the landfill process.

From initiation, usually through the granting of planning permission and a subsequent waste

management licence, to monitoring, stabilisation, competition, and finally aftercare and

afteruse, the Note offers a guide to the right approach for the surveyor to adopt. Relevant

legislation is referred to throughout and, while the authors are careful to avoid becoming

too technical, there is a separate chapter which covers the legal aspects of landfill in detail.

The authors also believe that it is essential to consider the parameters of afteruse and

restoration at the planning stage, and therefore they include a comprehensive section on

the agricultural considerations of landfill. This covers waste management, landfill gaswellheads and leachate among other topics.

Waste Management: A Guide to Landfill includes in its appendices a list of practical points

and essential questions, a guide to abbreviations, legal references and a useful bibliography.

It provides not only essential guidance, but will also be useful as an aide-mémoire,

information source and a starting point for locating further resources.

waste management a guide to landfill 1998

Documents