ANNEX 2
Environment Sub-committee
Visit to the North West, 11th
- 12th March 1998
Participants:
Andrew Bennett (Chairman)
Tom Brake
John Cummings
Louise Ellman
Alan Whitehead
Elizabeth Payne (Clerk)
David Taylor (Specialist Assistant)
Jacqueline Recardo (Committee Assistant)
David Mills (Adviser)
Judith Petts (Adviser)
Howard Tollit (Adviser)
The Sub-committee began its visit at Liverpool Town
Hall, where it was welcomed to the city by Frank Prendergast,
Leader of Liverpool City Council, and by Councillor Paul Brant
of the Environmental Strategy Sub-committee. In attendance were
representatives of the community from the city's partnership areas
and from Liverpool Environmental Forum. The 11 partnership areas
cover the 54 per cent most deprived areas of the city and were
set up under the Objective 1 strategy. It is hoped to build up
these areas through a combination of public-private partnerships
and Local Agenda 21 strategies for sustainable development. The
Liverpool Environmental Forum is funded by the Council to facilitate
dialogue between individuals, the voluntary sector and the Council.
Councillor Prendergast told the Sub-committee that
while, historically, Liverpool's environmental strategy had not
been strong, recent progress had led to a commendation from the
Tidy Britain Group. Different opportunities had been noted for
environmental improvement, including those provided by the Environmental
Task Force, Local Agenda 21 and the Groundwork Trust. Initiatives
for green waste and construction waste recycling had been introduced
and it was also hoped to increase recycling through the new refuse
management contract which would commence in August 1998.
Dennis Salamon of the Merseyside Innovations Centre
provided a short introduction to waste management in Liverpool.
The Centre was established to assist in the economic
regeneration of the city, with a specific technological bias.
This has led to a close involvement with the local authorities
in looking at municipal waste management. Mr Salamon identified
eight underlying issues which had affected progress towards environmental
improvement since 1993. At the beginning of the list came low
GDP, decreasing population and rising unemployment which had contributed
to the city's status as a poor urban area. Low levels of educational
awareness had contributed to the 'downward spiral'. The environmental
quality of the area, with derelict land and river pollution, was
comparatively poor. Business competitiveness had decreased, leading
to a lower priority on investment for environmental improvement.
A failing export market and lack of inward investment completed
the list.
As a result of this decline, the area had been classified
as an Objective 1 area for European Union regeneration funding.
Through the Objective 1 strategy derelict land had been cleared,
river pollution controlled and the urban environment improved
by tree planting. The voluntary sector had been stimulated by
Local Agenda 21, with seventy active local groups and a similar
number of national organisations represented on Merseyside. With
improved business competitiveness, it had become easier to persuade
industry of the benefits associated with investment in the environment.
Obstacles to improvement had been the previous lack of awareness
of such benefits, a lack of incentives to positive change and
insufficient support for initiatives from the market. This had
been particularly significant in the case of recycling schemes,
when market prices for items such as waste paper were subject
to "wild" oscillations.
Liverpool City Council had adopted the waste hierarchy
presented by the Government in Making Waste Work; however
disposal remained a very cheap option in spite of the landfill
tax. This made progress towards the 'higher' options in the hierarchy
difficult. Mr Salamon suggested as a personal view that the landfill
tax would have to be raised to levels similar to those in Germany
and Denmark - about £200 per tonne - in order to prompt significant
change.
Key initiatives for environmental improvement on
Merseyside are: CREATE, a scheme for the recycling and trading
of 'white' goods such as washing machines; the Merseyside Environmental
Trust, an umbrella organisation of voluntary groups; Liverpool
City Council's waste collection services contract, green waste
recycling scheme and the Environmental Forum; and the Merseyside
Waste Disposal Authority's recycling initiative. The latter had
had particular success in encouraging the use of recycling centres:
one centre had experienced an increase in recycling from 5% to
20% in one year.
Twenty six companies had joined an Objective 1 funded
waste minimisation demonstrator project on Merseyside. This had
found £5 million worth of annual savings, £1.3 million
of which were waste disposal costs.
Considering drivers for change, Mr Salamon emphasised
the importance of a coherent strategy. Small scale projects often
were not viable. More successful projects had combined the commercial
and voluntary sectors, with support from the Government Office
for the North West. Financing for projects also had to be coherent
and fiscal controls exercised. Awareness of the need for change
had to be increased, and plans properly integrated through a co-ordinating
body such as a Government Office for the Regions. Initiatives
in the Merseyside area which had proved successful included: Objective
1; the Housing Action Trust Project, experimenting with material
re-use by householders; the Merseyside Prospecting Initiative,
increasing the commerciality of voluntary sector recycling projects;
the Groundwork Trust; and a new Environmental Help Line, providing
information to small and medium sized businesses.
Open discussion between the community representatives
and the Sub-committee followed.
Ann Gorton (Parks Pathway Partnership Authority)
and Hazel Tilley (Toxteth PPA) noted the concern of consumers
about over-packaging. Whilst the amount of packaging is perhaps
most noticeable in relation to large or luxury goods purchased,
the primary concern is the over-use of packaging, particularly
plastics, for food.
Mick Gillan, (North Liverpool PPA), noted that voluntary
groups there, with the support of the local authority, had set
up a successful paper recycling initiative; however, the lack
of paper banks accessible without private transport had been a
barrier to progress. He suggested that schools could adopt a more
positive approach to recycling by installing recycling bins and
banks to reinforce the waste awareness message taught in the classrooms.
The sale of recyclables could also prove a source of additional
income for the schools and education authorities. Alison Ball
of the Liverpool Environmental Forum noted that one school in
Knowsley MBC gained £500 per year through recycling credits,
which is considered a significant sum.
Frank Vaudrey (580 PPA) commented on the long history
of voluntary involvement in Merseyside, which had formed the basis
for much of the pathway partnership work with the City Council.
Particular problems for his area are the policing of fly-tipping,
especially since responsibility was transferred from the local
authority to the Environment Agency, and the difficulty faced
by voluntary groups seeking to register with environmental trusts
set up through the landfill tax. The latter was considered particularly
frustrating as it led to funds being channelled into one or two
large organisations when smaller community organisations might
perhaps use them more effectively.
Alison Ball agreed that the rules for registration
with these environmental trusts are written in very complex legal
language. Funds from Objective 1 were also difficult to obtain
since many organisations were 'chasing' the money. Ann Gorton
attributed the increase in fly-tipping to those seeking to avoid
paying the landfill tax. Alison Ball also expressed frustration
at Liverpool City Council's failure to appoint a recycling officer
who could provide essential support and encouragement for the
city in seeking to achieve the government's 25% target for recycling
of municipal wastes. Mark Sullivan, also of the Forum, pointed
out that the city's current rate of recycling is just over 1%.
There was a need for a co-ordinated strategy to avoid duplication
of effort.
Gwen White (Speke/Garston PPA ) said that for many
in the deprived areas of the city recycling is very hard work,
requiring repeated trips to central facilities to dispose of waste
materials. She described it as a "luxury many can't afford".
She suggested there is a need to have a perceived benefit within
the local area to act as an incentive to recycling. Frank Burke
(Leap PPA ), noting that sustainable development includes employment,
suggested that the establishment of small scale community recycling
businesses would provide such an incentive.
Kate Senior (Stanley PPA ) noted that bottle banks
often are not emptied promptly, causing 'overflowing' glass to
create nuisance. This has discouraged businesses and schools from
installing banks. She suggested that this should be addressed
in the new waste management contract, or arrangements might be
made for kerbside collection of recyclables.
Ann Gorton repeated that the responsibility should
rest primarily with manufacturers to take back packaging, since
re-use avoided such problems.
The Chairman of the Sub-committee noted the argument
by supermarkets that different types of packaging represent choice
for the consumer.
Ann Gorton said that the consumer had not been consulted.
Mick Gillan agreed that the manufacturer should provide facilities
for the return of packaging. At present, consumers had no choice
but to dispose of packaging once it had been taken home; however,
given an incentive to return it-for example through a returnable
deposit-people would do so.
Tuesday 10th March
Green waste processing, Otterspool
Giles Nance, Team Leader, Tree and Woodland Management
gave a short presentation to the Sub-committee.
Mr Nance explained that the facility was developed
after discussions 2 years ago. All green waste from the city's
activities is now diverted to the site. The site also takes waste
from Mersey Waste which must be screened for contamination by
concrete and metal before further processing. Problems have been
encountered when public green waste has been accepted at the site:
the public's perception of green waste apparently includes items
such as old deck-chairs and other large household articles. The
waste ultimately becomes mulch, soil-conditioner or peat substitute.
No household waste is taken at present although the
amount of waste could be increased by setting up a Green Waste
Collection Scheme or setting up bins at Civic Amenity sites. Such
schemes might need the waste to be screened at source. Also, a
new location would be required if commercial/household waste were
taken as well - there is no room to windrow on the present site,
even with the existing amounts of waste incoming. Instead of windrows,
the material is simply stockpiled and this makes for a much slower
composting process.
The operation takes place on a small site and is
aggressive, noisy and messy. The site has one operator with responsibility
for keeping the site clean and ensuring that the waste delivered
to the site is clean.
In setting up the site, there was a need to gain
planning permission and also an exemption from the Environment
Agency. The latter was granted largely because the site deals
almost completely with organic matter. To ensure compliance with
the site licence, all litter material must be kept in skips to
ensure that no leachate escapes into the ground. The site was
originally a Grounds Maintenance Depot and the relatively small
change of purpose for the land was instrumental in gaining planning
permission.
The success of the scheme is demonstrated by the
fact that the city used to buy in 12,000 cubic metres of mulch
(in the form of processed conifer bark). This year, for the first
time, there is no longer any need to do so. The mulch from Otterspool
is beneficial in that it is pH-neutral and stable in windy conditions,
whereas the conifer-bark material is acidic and tends to blow
around. The city also benefits by avoiding landfill charges and
tipping fees. When originally set up, the scheme was given 12
months to prove its cost-effectiveness - it is now estimated that
the scheme saves the city between £80,000 and £100,000
annually.
The commercial viability of the facility is put down
to the combination of the effects of the landfill tax and a stable
market for the end product (which is sold back to the City). To
remain viable, there is a need for large amounts of green waste:
the site takes material arising from around 440,000 trees on highways,
in parks and from woodlands.
The Sub-committee were shown fenceposts for the site
which had been milled from wood delivered to the facility. However,
only a small proportion of the wood received is of suitable quality
because of the Forestry Department's policy of only felling trees
when dead or dangerous. Some wood is also left in situ
in wooded areas to provide habitats for insects and wildlife.
Everything else is then cross-cut and shredded. The raw green
waste is piled up every week to reduce the volume and save space
on the site.
The Sub-committee were then shown the shredder which
is hired every 4-5 weeks and consists of a large hopper (with
rubber flails forming a hood to reduce throw-out), shredding drum
and conveyer belt. Before passing through the shredder, an electro-magnet
is used to pick out any metal in the green waste. The material
is put through the shredder twice (using different gauge shredding
drums). Horse manure is added into the hopper with the green waste
material to speed up the decomposition process. The machine costs
£180 per hour to hire, can achieve output levels of around
200 cubic metres/hour and is capable of dealing with material
up to the size of 1.2m diameter tree-trunks.
A pilot project last year involved the collection
of leaves from roads. As the leaves are highly contaminated with
oil and litter the original intention was to mix them in with
the other waste in the shredder. This had to be abandoned after
the leaves were found to clog the shredder. The material is now
being piled separately with some horse manure and will ultimately
be screened to decontaminate it. The site has also taken Christmas
trees for recycling this year with 6,822 collected in total from
12 satellite compounds.
CREATE
En route to Speke, Mr Nic Frances, acting Director,
provided an introduction to the CREATE project. The initiative
began in the late 1980s as the Furniture Resource Centre Ltd.
Its objective, in refurbishing second-hand furniture, was primarily
to support those setting up home rather than to recycle. Two years
ago the Centre, in partnership with Thorn plc, set up a new project
entitled CREATE to refurbish unwanted 'white' goods such as washing
machines and cookers whilst providing salaried training for the
long term unemployed. The CREATE scheme has been very successful
and the Furniture Resource Centre now has plans that include tendering
for the City Council's bulky goods collection, the establishment
of 30 new salaried traineeships in connection with the Government's
`Welfare-to-work' programme, and expansion into the recycling
of 'brown' goods such as televisions and vacuum cleaners. The
Furniture Resource Centre's existing town centre shop is to be
completely refurbished, marketing "community friendly"
products with a one-year guarantee. The CREATE scheme pays a minimum
wage of £4.64 to staff (just under £10,000 per annum).
The Sub-committee was shown around the CREATE plant
by Nick Hughes, Manager. It opened in June 1996 and currently
employs thirty staff, previously long-term unemployed. It is supported
by Dixons, Electrolux and Thorn, who donate machines received
in part-exchange deals, and ex-rental appliances. Machines are
also received from Halton and Liverpool Borough Councils and from
individuals: two vehicles make local collections daily, bringing
in 20-30 appliances each per day. At the depot, cookers and refrigerators
are separated from washing appliances, and each is given a reference
number for identification. The highest recycling rate is for appliances
donated by companies (about 40-50%); the lowest is for appliances
sent by local authorities (25-100%). Those which cannot be recycled
are stripped for spare parts. In addition each refurbished machine
requires new spare parts costing on average £2.50 - £3.50.
Parts which can be salvaged include motors and copper wiring,
but it is often the 'cosmetic' parts such as plastic control panels
which are most expensive to replace and therefore provide the
most value in recovery. CFC gases are removed from old refrigeration
equipment. The scheme is being expanded to include gas cookers
since there is a demand for the product, but also because trained
fitters of gas appliances are in demand: therefore, it is seen
as a way of increasing the employability of trainees.
Lee Wells, a trainee, demonstrated the assessment
procedure which is used to determine the state of repair of appliances
on arrival. Insulation is tested as a first step, to ensure the
safety of the employees, followed by a short test of each machine's
operation. Faults are noted and corrected. A final check is made
of the insulation before the machine is passed to quality control.
While a few of the machines only require minor repairs most need
an extensive overhaul, taking up to three days. Machines are typically
about ten years old. If it is considered that the machine will
be uneconomic to repair it is scrapped and stripped for parts.
Work is being carried out with Sheffield Hallam University on
developing an assessment procedure for the energy efficiency of
the models.
It is likely that the European Community will develop
producer responsibility legislation for white goods which will
have the effect of pushing the market towards rental rather than
sale. This, Mr Frances said, would be a reversal of the current
trend in the UK. However, industry awareness of this possibility
has led the major rental companies, Thorn and Granada, to join
with manufacturers Whirlpool and Hotpoint in developing products
better suited to rental and refurbishment than existing models.
It has also been an incentive for companies to support CREATE,
as a recognised reprocessor.
The project was cost intensive in its first three
years but is now moving into profit and looking to plough the
profit back into the business. With its objectives of employment
creation, economic viability and environmental improvement, it
is eligible for support from Objective 1, the Single Regeneration
Budget and Welfare-to-Work. Trainees must spend three months on
probation. All study for an NVQ Level 2 in Engineering and spend
a week on placement at a local Ford plant. The training programme
lasts for one year .
Goods are sold from a shop at the plant, the Furniture
Resource Centre shop in Liverpool and two independent second hand
retailers. Guarantees are offered for three months or one year,
depending on the customer's choice. CREATE's call rate for repairs
within guarantee is considered to be comparable to that in other
sectors of the market, at 0.7 - 0.9 per cent, compared to 0.2
per cent in the retail sector. The slightly higher rate reflects
the greater age of the product.
The Hardcore Recycling Initiative
Eric Simms then gave a short presentation on the
Council's Hardcore Recycling Initiative.
Traditionally, construction waste arisings have been
landfilled but, as with the CREATE scheme, private sector awareness
of the probable development of more restrictive legislation has
led to a partnership for their better use.
The Council handles half a million tonnes of construction
wastes per year. A review of the options for managing this waste
was conducted two years ago, since it was perceived that the responsibility
for management of this waste was an increasing strain upon the
Council, exacerbated by the Landfill Tax. The waste is composed
of items such as broken paving and bituminous materials from roads
which are suitable for recycling.
The Council did not consider itself to have either
the expertise or the access to markets which would enable it to
take on a recycling project on its own. It defined its general
aims as: to establish a facility on existing Council land; to
provide a building for the facility in line with planning requirements;
and to find a partner willing and able to pay other costs, accommodate
existing contracts and source markets. Tarmac Quarry Products
Limited was selected as a result of a three stage tender process.
It is estimated that the scheme, which is still in negotiation
between the partners, will provide savings on disposal costs of
about £600,000 per year for the Engineering Services Division.
The purchase of recycled materials produced by the scheme is also
expected to lead to an annual saving of £40,000.
The business risk in the venture rests with the private
company; the council has made no guarantee of materials supply
or of its ability to buy back recycled materials from the project.
However, it is expected that where possible the Council will amend
its specifications to promote the use of the recycled materials.
The facility is to be constructed in April 1998 and commissioned
in late summer.
The sub-committee then travelled to UK Waste Management
Limited's landfill site at Risley, where it was welcomed by Keith
Bury, European Director of UK Waste.
UK Waste landfill site (Risley IV)
The facility is run by UK Waste Management Ltd, a
joint venture company owned by Waste Management International
plc and Wessex Water plc. It is a strategic landfill site for
the North West and already meets the technical conditions which
are expected to be set in the proposed European Directive on Landfill.
The company operates 8 landfill sites in the UK handling 2.5 million
tonnes of waste per year, derived from the industrial and municipal
sectors. The company supports the waste hierarchy and is working
to develop options for recovery and recycling as well as landfill:
it operates a network of Material Recovery Facilities throughout
the UK. While it is perceived that there will remain a need for
landfill in the future, it is expected to be a lesser role than
at present.
Andrew Vosper, Manager of the Risley facility, provided
a history of the site. The landfill is now in its fourth stage,
with earlier stages in the process of restoration. The site is
based on 65 ha of farmland alongside the M62. The farmland is
classified as grades 3b/4 for soil quality. The site opened in
January 1994 and was the first site of its size to be approved
at the planning stage without appeals. During the planning phase
(1992-93) three main issues were assessed: the potential impact
on surface waters; the potential impact on groundwaters; and traffic
impacts on the local community. The land on which the facility
was created is poorly drained, and the raising of the land by
waste disposal presented a risk of flooding. This was addressed
by the establishment of a balancing pond capable of storing a
one-in-fifty year storm (approximately 23,000 cubic metres). Water
is stored in the pond, allowing solids to settle and its quality
to be tested before discharge into the adjacent Silverlane Brook.
The geology of the area is triassic sandstone containing
a significant regional aquifer. The aquifer is pumped for the
public water supply and therefore in need of protection. Overlying
the sandstone are thick deposits of clay which are used by the
company in engineering the site's composite lining system, designed
to contain leachate and gas. Approximately £1.3 - £1.5
million is spent each year on engineering to create new cells
and restore previous cells; about £6 million per year is
spent on maintenance; capital investment costs were about £20
million.
During establishment of a new cell independent quality
assurance auditors are employed to measure performance against
specifications. For example, moisture content of the clay is measured
with a view to the achievement of low permeability. All data is
analysed at the end of the contract and approved by the Environment
Agency prior to acceptance of waste for infilling.
Each cell is lined first with recompacted clay, then
with a geo-membrane made of High Density Polyethylene (HDPE).
The membrane is welded together and tested both destructively
and non-destructively. On top of the membrane lies a geo-textile
layer, followed by a layer of stones: these not only help to protect
the membrane from sharp objects in the waste which might tear
or pierce the plastic, but also act as a drainage blanket for
any liquids leaching out of the waste. The company believes the
controlled collection of such leachates to be crucial in minimising
the environmental impact of the activity: contaminating waters
are collected by pumps and risers as they drain out of the cell,
and treated.
Before any waste can be accepted, the company has
to be satisfied that it conforms to the licensing requirements
for the site including the duty of care and Special Waste Regulations.
The customer inquiry process includes the inspection and sampling
of any special wastes and prior notification is required for all
deliveries. Wastes which cannot be accepted include empty 45-gallon
drums and gas canisters; others, such as aerosols, require special
treatment (see below). Each delivery is given an authorisation
number once approved, which is included in inventories of the
site; in this way the company can at any time trace a particular
load, although it has never experienced a need for excavation
of previous cells at Risley. Under the conditions of its licence,
the company can accept up to 25 per cent of its wastes from special
and difficult waste streams. These wastes include powders and
liquids from the chemical industry, contaminated packaging, restaurant
wastes, and petro-chemical sludges from the petroleum industry
in Ellesmere Port. All are buried within 15 minutes of discharge
into the cell. Where wastes are brought to the site in drums the
content of each drum is certified before disposal; a 'quarantine'
area has been set aside for wastes which are considered to need
in-depth investigation. The company works closely with the client
and the Environment Agency to determine an appropriate treatment
for difficult wastes, since landfill will often provide the least
environmentally damaging option. Three to three and a half thousand
tonnes of waste are put into the landfill each day; in most cases,
the source of the waste is in the Greater Manchester area, Warrington
or Widnes.
An aerosol shredding operation is used for industrial-sized
quantities of aerosols. While the number of aerosols within municipal
waste is small and the potential hazard dispersed over a large
area in the landfill, large-scale disposals of aerosols pose a
threat of combustion, as well as a risk of contamination by leaching
of liquids. Use of the shredder eliminates the risk of combustion,
and liquids are collected for treatment. The capability for biological
treatment of leachate on site is sufficient at present. Both the
content of the leachate and the quality of water around the site
are monitored. Certain of the liquids extracted from aerosols
can be used to suppress unpleasant odours from the site. The company
does not accept CFC propellants for treatment.
Phases I and II of the site are being restored. Permission
was granted for restoration to be of grassland with peripheral
tree planting, but the number of trees has since been increased,
to 110,000 over a decade, partly in conjunction with the Mersey
Forest scheme. Species of trees are mainly indigenous to the North
West. Sheep are allowed to graze on the area and assist with fertilisation
of the soil. Some meadow planting is also taking place.
The company has a "Good Neighbour" policy
encompassing site access for visits, quarterly liaison meetings
with the local community, conservation projects and educational
initiatives. There are on average seven visits to the site by
schools each year. Information on the site's operation and water
quality is in the public domain and a monthly report is made to
the Environment Agency, which has the responsibility for monitoring
the company's performance. The establishment of the Environment
Agency has led to greater flexibility in waste regulation,
but the company has noted some inconsistency in regulation
across the country. The company supports the Agency's move to
a risk based approach to inspection as a more effective use of
its resources.
At present rates of filling, the site will be operational
for another seven years. However, the company is seeking to reduce
inputs of waste and to implement alternative waste management
options such as composting and biopiles for the treatment of contaminated
soils. The main barrier to long-term expansion of the site is
topology: as Risley is a low lying area, increasing expansion
much above ground level would heighten the visual impact unacceptably.
The company has been allowed to deepen some excavations as it
is perceived that the use of the HDPE membrane (which is guaranteed
by the manufacturer for 50 years) prevents possible contamination
of ground water. The site was one of the first in the country
to undertake a Regulation 15 assessment to determine the risk
of the site to groundwater.
The standards to which the site operates are high.
Mr Vosper explained that the company, which is partly American-owned,
places great emphasis on high quality standards because of its
awareness of liability cases in the USA. The primary duty of site
operatives is to ensure the licence and regulatory requirements
are not breached. The operational procedures are all codified
in a management system which is an integral component of the site's
ISO 14001 Environmental Management accreditation.
Landfill - Coach Tour
All ditches drain to the balancing pool in the NE
corner of the site. The entire site is, however, quite flat and
poorly drained. The balancing pond will be extended once the site
is fully utilised. As the site is situated on clay, a very high
level of suspended solids ends up in the ditches and weir boards
and interceptors help to reduce the problem.
To the north of the site, the land has been previously
landfilled. Clay has been used to provide temporary restoration
and the large clay stockpile is exported to old, closed landfill
sites for restoration work and also sold to third parties. The
clay material is also used as intermediate cover on the flanks
of cells but not on the horizontal areas as this would prohibit
removal of the leachate.
The potential problem of vermin is prevented through
the use of falcons and a plastic kite to deter birds, particularly
seagulls. In summer, active parts of the site are sprayed with
pesticides to control flies but it was stressed that no serious
problems have been experienced to date.
The Sub-committee then passed through the weighbridge
which deals with all waste entering the site. All legal documentation
is dealt with at this point. The weighbridge is necessary because
landfill tax and fees are charged on a per tonne basis. After
passing through the weighbridge, the trucks enter the vehicle
inspection facility. A gantry is used to inspect the load and
the site chemist may run checks to ensure that the waste meets
the conditions of the site licence.
Wheel washers are used to clean vehicles leaving
the site - this is especially important because 90 per cent of
the traffic travels to and from the site along the M62. A metalled
road is used throughout the site because it reduces the turnaround
time for vehicles and also minimises maintenance costs for both
the site and the vehicles. It has been estimated that a metalled
road is economical for the site if it lasts for 2-3 years.
The Sub-committee was shown the area where the company
has applied to operate a 'biopile', to deal with hydrocarbon-contaminated
soils. Nearby, steel tanks with concrete aprons are used to stabilise
liquid wastes by mixing them with absorbent materials. This process
was described as a simple and effective method of dealing with
liquid wastes - the site does not take such materials directly
to landfill as the liquid ends up in the leachate very quickly,
which can have a detrimental impact upon the leachate treatment
process..
There are normally between 300 and 350 trucks on
site each day. Waste is dealt with by two large steel wheeled
compactors. Fixed litter screens are used around the active part
of the site along with some mobile screens to allow for changing
wind directions.
The Sub-committee was shown the Environmental Compound
Area on the site where the aerosol shredder is sited. Metal recovered
from the cans is sent to Warrington for recycling by Alcan. Liquid
waste is collected in a tank and then either treated at the stabilisation
plant, taken off site or sprayed over the waste to reduce odour
problems in the summer. The Environmental Compound Area is also
used to store quarantined waste. For material which has been rejected,
the Environment Agency is contacted to decide on the best course
of action. It may be removed from site or still discharged at
the Risley site, since single loads can often be absorbed safely
within the larger mass of material.
An Industrial Estate forms the closest neighbour
to the Risley site. Around 600m away from the site is a residential
district. Funds from the landfill tax have been used by UK Waste
to contribute towards setting up a Visitor Centre in a nearby
nature reserve. Sponsorship of other schemes is also being undertaken,
including local educational initiatives and facilities for local
children generally.
The landfill is on the site of an old ammunitions
factory and all the old borehole wells (used to provide water
for the manufacturing process) have been capped and grouted. The
Sub-committee was shown one of the earlier phases (Risley III)
which was closed in 1994 and is now undergoing restoration.
Chris Parry, in charge of the landfill processes
side of UK Waste, told the Sub-committee that a leachate treatment
and gas-to-energy plant is situated on the site of Risley III.
Large balancing tanks are used to receive and blend the leachate.
A biological reactor is then used to treat the leachate in a similar
way to sewage treatment. However, the liquid is around 30-40 times
stronger than ordinary sewage in terms of ammonia content and
Chemical Oxygen Demand. As a result, the process is roughly equivalent
in treatment requirements to those posed by a population of 9,000-10,000
people.
Around 100 gas wells across Risley III vacuum out
the landfill gas, which is then compressed and boosted through
the generator engines to create around 2 MW of electricity. The
quantities of gas received have so far been roughly in line with
predictions from modelling. The generators were purchased from
a colliery in south Wales and are currently expected to last around
20 years on site. They use 600 cubic metres of gas per hour and
are around 20% less efficient than modern equipment. However,
despite their age, the generators are only off-line for around
300 hours each year. Although a reserve flare is available, this
is only used for around 200 hours per year during periods of extended
generator maintenance.
A further scheme is underway to harness gas from
200 wells across Risley IV and it is anticipated that this will
bring a further 6MW of generating capacity. At present, gas from
Risley IV is taken from vertical wells and piped to a flare station.
An odour control system comprising a fine spray is employed along
the metal fence boundary of Risley IV. The system was introduced
voluntarily although UK Waste acknowledged that there had been
an increase in the number of complaints received in recent years.
Gas escaping from the site tends to bring about odour problems
and one way of minimising the problem, prior to installation of
the permanent system, is to harness the landfill gas at an earlier
stage in the process using shallow wells.
Two or three compactors are used every day to help
achieve a target density of 1 tonne/m3. The capacity
of the site is around 7.5 million m3. Good compacting
is also necessary to reduce the problems of waste blowing away.
The Sub-committee observed dry waste being pushed
over the lower layer of "difficult" waste. Leachate
recirculation is practiced and the site is self-sufficient in
the summer months - no further leachate treatment is required.
In winter months, the greater amounts of rainfall mean that around
100-150 m3 of leachate must be treated each day from
Risley IV.
The waste being landfilled contains various materials
which could be recycled such as cardboard and plastics. UK Waste
commented that they had invested in separation equipment for commercial
waste at their MRFs but, with the collapse of the paper market,
the facilities were working well below capacity. With the introduction
of the Packaging Regulations, there were signs of recovery. With
regard to the separation of household waste, UK Waste asserted
that 'dirty' Materials Reclamation Facilities in their experience
were not a viable proposition because of the problems of contamination
experienced with the recovered materials and the corresponding
low commercial value.
Gas monitoring boreholes are used in the site before
landfilling takes place, to provide background information on
methane and CO2 production. This practice enables clear
analysis of the gas production from the landfilled waste. Footpaths
exist around the perimeter of the site and one had to be diverted
when setting up the site. However, as the site is restored over
time, more footpaths and better public access to the site will
be offered.
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