PART 3 ANALYSIS OF THE PROPOSALS
(continued)
THE
POTENTIALLY HARMFUL
EFFECTS OF
LANDFILL
35. As we have seen,
Article 1 of the Directive aims "to prevent or reduce...negative
effects on the environment...from landfilling of waste".
Some witnesses criticised the Directive for being based on the
premise that the effects of landfill were by definition "negative",
in particular the Local Authority Waste Disposal Companies Association,
who described it as "blind prejudice" (p 162),
and the Environmental Services Association (ESA), (p 89).
However, it seemed right to enquire of witnesses how seriously
they felt landfill posed risks for the main environmental receptors-water,
soil and air (cf table at paragraph 8).
Surface and groundwater
pollution
36. We received conflicting
evidence on the impact of landfill operations on groundwater quality.
The Environment Agency told us that there had been few significant
incidents of pollution from landfills in England and Wales; while
Friends of the Earth took an opposing view (Q 130; p 51).
The Scottish Environment Protection Agency (SEPA) believed that
with careful siting, good design and good practice, landfill was
not a significant pollution risk: groundwater monitoring had always
been limited in Scotland, since only about 4 per cent
of Scottish drinking water supplies came from groundwater, but
such pollution as had occurred was thought to be due mainly to
older, unlined landfill sites. Far more significant was the pollution
of aquifers by hydrocarbons, nitrate from agricultural sources,
ferruginous minewater and saline intrusion from over-pumping (pp 185,
190-1). Dr Krämer, for the Commission, said: "Whenever
groundwater is examined, the biggest source of contamination is
found to come from landfills." He also spoke of "ticking
timebombs" (QQ 275, 278).
37. We note the considerable
body of research conducted by the Department of the Environment
during the 1970s (known as "the Brown Book"), which
was focused on the effects of landfill disposal on groundwater
quality: this recorded that extensive experience in the UK over
a long period of time had shown very few documented cases of significant
groundwater contamination resulting from landfill sites.[27]
Nevertheless while concluding that the natural processes of dilution
and attenuation were effective in mitigating the effects of groundwater
contamination by landfills, the research did record incidents
of both ground and surface water contamination. We were told by
English Nature of serious ground and surface water pollution at
Holt Heath National Nature Reserve in Dorset, which was due to
an adjacent and now closed landfill (Q 52).
38. Research into groundwater
quality in the UK has continued, and the Environment Agency drew
our attention the conclusion of its 1996 report on groundwater
pollution in England and Wales: "Categories of land-use activities
which present the greatest threat to groundwater quality have
been identified. Landfill sites are numerically the most significant
category, but in terms of their actual and perceived impacts on
groundwater are considered to be somewhat less of a problem than
other sources and types of pollutants. The data collected is [sic]
biased towards those land-use categories which are highly regulated
and therefore likely to be better monitored. It is therefore not
surprising that waste disposal activities are so prominent in
the study."[28]
The Agency also emphasised that of the reported occurrences of
groundwater contamination due to waste disposal, half were concerned
with suspected contamination only (p 22).
39. The Agency made
the point that since the introduction of the 1994 Waste Management
Licensing Regulations, landfill sites had been subject to statutory
minimum frequencies for leachate and groundwater monitoring (Q 11).
40. We asked the Agency
to comment on Dr Krämer's remarks and the apparent discrepancy
in the evidence. In response, it highlighted some important differences
between the situation in the UK and that in some other Member
States: "Long before the introduction of site licensing in
1976, we have benefitted from planning and other legislation that
has sought to control the siting of waste management and other
facilities in order to protect the local environment, particularly
water resources. Several of our European partners have neither
benefitted from such legislation nor have they fully implemented
the Waste Framework Directive....Consequently some, including
Germany, have experienced major pollution incidents as a result
of poorly controlled landfill operations. Such experiences have
caused a tendency to reject such practices as bioreactive sites
and codisposal, to overregulate and to shy away from
a riskbased approach to regulation" (p 22).
41. Dr Krämer's
concern may well be justified in relation to landfill in parts
of continental Europe, but we are satisfied that the high standards
of monitoring and regulation developed over the years by the Environment
Agency, by its predecessor the National Rivers Authority and by
the equivalent bodies in the rest of the United Kingdom, coupled
with the important safeguards provided by the planning system,
have been effective in minimising the risks to groundwater from
landfill.
42. As we were told
by the Geological Society and the British Geological Survey, no
landfill site, however well engineered and lined, can be expected
to retain its integrity indefinitely (QQ 194-6). Ultimately
all landfills will leak. In the case of active sites, strict containment,
monitoring and leachate control, together with a capacity on the
part of the operator to deal with emergencies, should be sufficient
to prevent groundwater pollution, and we note that the provisions
of Annex III to the Directive would effectively extend to other
Member States a régime comparable that of the UK 1994 Waste
Management Licensing Regulations. It is the longterm position
that concerns us, and particularly the Directive's proposals for
the long-term storage of hazardous material in hazardous waste
only sites. We were told by the Environmental Services Association
that its members were seriously concerned that the required Certificates
of Completion would not be forthcoming for such sites, which could
mean that the operator would retain liability indefinitely
(see paragraphs 102-6).
Soil contamination
43. We received little
evidence on the impact of landfill on soil contamination. In their
written evidence, Friends of the Earth referred to almost 6500
closed landfills in the UK and subsequently told us that the total
number of former landfills was unknown (p 51; Q 136).
This was consistent with the findings of the Royal Commission
on Environmental Pollution (RCEP) in its 19th Report, Sustainable
Use of Soil.[29]
The RCEP also recorded that there could be of the order of 100,000
contaminated sites in the UK and that former landfills were the
most numerous category of such sites.
44. Considering that
greater emphasis should be placed in future on preventing pollution
of soil, the RCEP recommended that the Department of the Environment
should pave the way for the eventual segregation of wastes and
phasing out of landfill based on the practice of codisposal
(see paragraphs 83-91). The last Government, in its response
to the RCEP's Report,[30]
took the view that carefully controlled codisposal remained
an acceptable way of disposing of certain industrial wastes. For
this reason, the DETR told us that Ministers were concerned about
the Directive's proposed ban on codisposal (Q 163).
45. We are concerned
at the lack of useful statistics relating to land which has been
contaminated by past landfill activities, although this is an
inevitable legacy of unregulated times. We note that the provisions
of the Environment Act 1995 for contaminated land registers remain
unimplemented. We would hope that the possibility of implementing
those provisions will be given careful consideration in the Government's
current review of waste management policy.
Air pollution
46. One of the products
of the anaerobic decomposition[31]
of biodegradable waste is landfill gas-a mixture of about 60 per cent
methane and 40 per cent carbon dioxide (CO2),
with small elements of others (eg hydrogen sulphide). Both
are important greenhouse gases-ie gases which, in the atmosphere,
absorb thermal radiation emitted from the Earth's surface and
have a blanketing effect upon it, thus contributing to global
warming. A key question raised in the enquiry was whether the
proposals in the Directive were the most effective way of reducing
the contribution which current landfill practices made to global
warming.
47. We received conflicting
evidence as to the relative contributions of CO2 and
methane to global warming-ie their "global warming
potential" (GWP). If the GWP of CO2 is taken as
1, the estimates of the GWP of methane which we received ranged
from 8 to 70. The value of the GWP attributed to methane depends
upon the time horizon which is assumed, and according to evidence
from Professor Porteous the range of values just quoted would
represent an inverse range of time horizons of between 500 years
and 20 years respectively (p 177). Methane in the atmosphere
is destroyed by chemical reaction with hydroxyl (OH) radicals:
it decays more rapidly than CO2, but is considerably
more damaging than CO2 initially because of the GWP
factor.
48. In a report for
the Environment Agency, consultants W S Atkins have
suggested that the life of methane in the atmosphere is 12 to
17 years, compared with CO2 at 500 to 2,000 years.[32]
On this basis it is logical to assume a GWP for methane towards
the higher end of Professor Porteous' 8-70 range of values, ie
using the shorter time horizon. The Atkins report also cites evidence
that stabilisation of current atmospheric methane concentrations
could be achieved by a reduction of 10 per cent of annual
global anthropogenic methane emissions. There are therefore
sound policy reasons, notwithstanding the scientific uncertainty,
for tackling methane first, rather than carbon dioxide, when seeking
to reduce the contribution which landfill operations make to global
warming.
49. The Commission's
Communication on a strategy for reducing methane emissions (COM(96)557
Final, 15 November 1996) identified landfills as accounting
for about 32 per cent of known methane releases in the European
Community. The Communication also found that the collection of
methane through highly efficient systems was a cost-effective
means of reducing emissions: "These options (energy generation
or flaring) would eliminate either completely (up to 100 per cent)
or almost completely (up to 95 per cent) the harmful effects
of methane gas emitted from landfills".
50. The Commission's
conclusion is broadly in accord with the Environment Agency's
evidence-that instantaneous efficiencies of 90 per cent are
achievable at modern landfills for the collection of landfill
gas, but that to allow for older sites an average efficiency of
80 per cent is realistic; and that an overall reduction of
emissions of 80 to 90 per cent is achievable by
modern controls at landfills (the W S Atkins report
estimated that efficiencies of over 90 per cent were achievable
by this means).
51. This evidence was,
however, contradicted by Dr Krämer, who told us that the
Commission's research showed that 90 per cent efficiency
of methane capture from landfills was unattainable: he said a
more realistic optimum would be between 60 and 70 per cent,
although normally it would be much lower (Q 284). Information
subsequently submitted by Dr Krämer in support of his assertion,
in the form of a paper by Hans Willumsen of LFG Consult, Denmark,
states that only about 25 to 50 per cent of the gas produced
in landfills is recoverable.[33]
52. Referring to a report
produced by the Energy Technology Support Unit, Harwell (ETSU),
for the Department of Trade and Industry,[34]
Friends of the Earth told us that landfill gas schemes currently
in operation were unlikely to capture more than 50 per cent
of the gas (Q 155). The ESA, on the other hand, referred
us to the W S Atkins report as containing the most up
to date and reliable estimate of the efficiency of landfill gas
recovery (p 109).
53. The ESA also argued
that landfill acted as a carbon sink, "locking in" some
30 per cent of the carbon in municipal solid waste (MSW);
whereas if it were incinerated, the carbon would be emitted as
carbon dioxide (CO2). Professor Porteous, however,
claimed that Energy from Waste (EfW) incineration effected a net
greenhouse gas reduction by eliminating landfill methane emission
and by displacing (ie substituting for) CO2
emitted from energy generation direct from fossil fuels.
54. The lack of consistent
data on these key issues-the efficiency of methane capture in
landfill and the relative GWP of methane and CO2-substantially
weakens what has been one of the main arguments of the principal
UK witnesses-that the Directive would not achieve reductions in
methane emissions in the most effective manner. In particular,
we wish to draw attention to the apparent discrepancy between
Dr Krämer's evidence and the assumptions in the Commission's
methane reduction strategy (paragraphs 49-51). The only possible
conclusion is that, on the basis of the evidence received so far,
the Global Warming Potential issue remains unresolved: the comparative
environmental benefits of engineered methane recovery from landfill
as opposed to upstream avoidance of methanogenesis remains a matter
of conjecture. It is therefore important that research on the
matter should continue. We note, however, that the Royal Commission
on Environmental Pollution, in its 1993 Report on Incineration
of Waste,[35]
based its conclusion in favour of incineration of municipal waste
(see paragraph 141) on the conservative assumption that only
40 per cent of landfill methane would be captured .
55. As we conclude
in Part 4, when discussing the waste management hierarchy,
there is no overriding science-based principle to determine choices
objectively between different waste disposal options. Nevertheless,
the fundamental aim of sustainability is that it is better to
prevent, reduce and recycle waste than to burden the environment
with waste in the crude form in which it is generated or discarded
by the consumer. We see no contradiction between our recommendations
on the desirability both of maximising methane recovery from landfill
sites (paragraph 91) and of using incineration with energy
recovery (paragraph 144): in both cases it is a question
of finding the BPEO which best suits the particular circumstances
and makes best use of the opportunities offered.
27
Department of the Environment, Report of the Co-operative Programme
of Research on the Behaviour of Hazardous wastes in Landfill Sites,
DoE, 1978. Back
28
Environment Agency, Groundwater Pollution: evaluation of the
extent and character of groundwater pollution from point sources
in England and Wales, 1996. Back
29
RCEP 19th Report, Sustainable Use of Soil, Cm 3165, HMSO,
February 1996. Back
30
Sustainable Use of Soil: Government Response to the Nineteenth
Report of the Royal Commission on Environmental Pollution,
HMSO, C0428, January 1997. Back
31
ie decomposition without
the presence of oxygen. Back
32
W S Atkins Environment, Methane Emissions from Different Landfill
Categories, March 1997. Back
33
Willumsen H (1997), Production and Use of Landfill Gas: Energy
Recovery, paper for International Conference on Solid Waste
Management and Technology, Associacão Portuguesa para Estudos
de Saneamento Básico, Lisbon, 8-10 October 1997,
LFG Consult, Houlkjarshojen 9, DK-8800 Viborg,
Denmark. Back
34
ETSU, Landfill Gas Development Guidelines, 1996. Back
35
RCEP 17th Report, Incineration of Waste, Cm 2181, HMSO,
May 1993. Back
| 
