SMDSA WID Working Group Position Paper – November 2002
SMDSA Waste Incineration Directive Working Group
Position Statement
The SMDSA is the recognised trade association for the clinical waste management
industry of England and Wales. SMDSA members operate all bar 3 of the
commercial clinical waste incinerators in the UK. These incinerators dispose of in
excess of 100,000 tonnes of clinical waste, which is equivalent to the entire clinical
waste arising from the NHS.
In response to DEFRA’s request for input from the SMDSA a Waste Incineration
Directive “working group” was established and this document summarises its views.
This document addresses the impact that the implementation of the Waste
Incineration Directive 2000/76/EC will have on the clinical waste disposal industry. It
highlights particular requirements in the Directive that will be difficult or impossible
to achieve, or which will have a major impact on the market sector. It also provides
pragmatic solutions.
The Clinical Waste Sector
The disposal of clinical waste is a very specialist market sector with intimate links to
both the National Health Service and Private Health sector. A large proportion of the
clinical waste produced in the UK carries a significant risk of infection, and requires
disposal in dedicated clinical waste incinerators or other types of plant designed to
destroy all types of pathogens. There are no alternative disposal routes for certain
types of infectious or sensitive clinical waste, so that any loss of capacity whether
short term or medium term would result in major disruption to the NHS as recognised
by the NHS in their recent report on developing a strategy for waste management
(produced by the Purchasing and Supplies Agency).
Virtually all existing clinical waste incinerators in the UK were designed and
constructed in the early to middle 1990’s as a direct result of the implementation of
the Environmental Protection Act 1990 [EPA.1990], consequently they were all
commissioned into service less than 10 years ago. Since then they have undergone a
significant amount of upgrading to meet the demands of revised guidance notes and
changes to legislation, these changes include PG5/1/92, PG5/1/95 and the Hazardous
Waste Incineration Directive.
Following the EPA of 1990, a number of large listed companies invested quite heavily
in the industry, but in the last 5 years they have distanced themselves from the market
place due to much higher than expected investment requirements brought about by
legislation and consequently inadequate return on investment. In addition to the
financial impacts the new legislation carried, there was real concern within the
industry that significant inconsistency in terms of policy interpretation,
implementation and enforcement was evident and this increased the ‘risk’ of staying
in the market. Most of the ‘ large corporates ‘ exited the sector leaving relatively
small private companies in their place. In the last 5 years we have continued to see
considerable inconsistency being applied within the industry and this is reflected in
the continued poor financial performance of most companies.
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SMDSA WID Working Group Position Paper – November 2002
At the present time there is a fine balance between clinical waste arisings and
available incineration capacity, we believe this will be so for at least the next 5 years.
The introduction of WID, given present guidance details means all operators will be
obliged to meet the new emission and ash quality standards by the 28th December
2005. If the implementation of the Directive remains unchanged it will soon force
operators to consider whether they should upgrade or decommission their plants
within the timeframe given. Those operators who have plants that cannot be viably
upgraded will be forced to permanently close them down despite the fact that they are
all less than 10 years old. Other plants will be taken out of commission for periods of
between 1-3 months. Both options will potentially lead to a loss of capacity in
2003/2004/2005 and some of that will be permanent. Building replacement
incinerators is not a viable proposition at this time and new capacity will not be
forthcoming in time to meet the shortfall.
For plants that might be capable of upgrade the time frame presently given in the
WID suggest that all CW incineration plants would need to have completed
design/design fix/equipment procure/contract award/construct and commission
between now and the set target date of Dec 2005. This programme is, in our opinion
unrealistic.
Capacity shortage impacts in the CW industry cannot realistically be viewed the same
way as say municipal waste incinerators [MWI] because these plants can more easily
divert their waste arisings direct to landfill as an alternative disposal route during
downtime.
Impact on the Environment
On the whole, clinical waste incinerators are well managed and provide an essential
service to the local hospitals and community. It is worth recalling that during the year
2000 petrol strike we were placed on the emergency list for fuel because it became
apparent that clinical waste was reaching unhealthy levels after only 48 hours of
limited collections.
It is also important to note that CWI plants are small in comparison to the much larger
MWIs. As such, the volume of atmospheric emissions from a typical plant is
approximately one hundredth of the emissions from the larger MWI, and dispersion
modelling of current emissions at CWI plants show that they have no significant
effect on the local environment. We do not believe the WID takes this factor fully into
account. For clinical waste plants, there are three specific technical issues that cause
the major concerns.
1. Emission Limits
The WID proposes to set emission limits significantly lower than those currently set
for existing CWIs, albeit based on averages and percentiles rather than absolute
values. Advances in flue gas cleaning techniques over the past few years mean that
while most of the proposed limits can be met, the proposed limit for Hydrogen
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SMDSA WID Working Group Position Paper – November 2002
Chloride - a daily average of 10 mg/M3 - remains a major problem. HCl levels in raw
flue gas have risen steadily since most CWIs were designed, and can vary
significantly over short periods. These effects are linked to the increased use of
disposables, particularly plastics in the waste.
CWIs were originally designed to meet the PG 5/1 (92) standard of 100 mg/M3 HCl,
which was reduced to 30 mg/M3 as PG 5/1 (95) was implemented. The plants
authorised in June 2000 to comply with the Hazardous Waste Incineration Directive
standard for co-incinerators were required to meet a daily average limit of 25 mg/M3.
All of these reduced levels were met by increasing the quantities of Calcium
Hydroxide (lime) used to neutralise the HCl, and by fitting lime recirculation systems.
However, recent work carried out by SMDSA members has demonstrated that such
modifications cannot meet the proposed limit with any degree of consistency.
The current HCl emission limits are achieved by operating baghouses with a
stoichiometric ratio of 3: 1 (lime: HCl). This is a wasteful system, as it produces a
large quantity of a highly alkaline waste product (spent lime) which has to be
consigned for disposal as special waste, to one of the few landfill sites licensed to
accept hazardous waste. Research work indicates that the theoretical stoichiometric
ratio that would be required to meet the proposed 10mg/m3 limit for HCL is 6:1 or
even 10:1. However, simply adding more lime with all the environmental disbenefit
of quarrying transportation and disposal is still unlikely to give the required outcome.
It has been calculated that if a stoichiometric ratio of 6:1 is adopted by the sector, an
additional 1,200 tonnes of lime will be used (and will require disposal), to remove the
extra 5 tonnes of HCl needed to meet the new limit.
An alternative form of flue gas cleaning is the use of ceramic filters, usually used with
Sodium Bicarbonate as the neutralising reagent. Some CWI operators installed such
systems during the early 1990s, but suffered severe operational problems as well as
problems in achieving emission limits, and most replaced their ceramic filter systems
with baghouse/lime systems now regarded as the best available technology.
It is clear that there is no single-stage flue gas cleaning system capable of achieving
the 10 mg/M3 limit for HCl proposed by the WID. Anyone designing a new CWI at
the present time would need to opt for a two-stage or multi-stage flue gas cleaning
system to achieve the limit, with one of the stages possibly being a wet scrubber. It is
not possible to retro-fit a multi-stage system at most existing CWIs due to space
constraints, inherent design characteristics, and planning consent factors
Paragraph 20 of the introduction to the WID contains the following statement:
“ There may be grounds to provide for specified exemptions to the emission limit
values for some pollutants during a specified time limit and subject to specific
conditions “
SMDSA believes that such a statement allows the Regulators to make use of this
mechanism to make a specified exemption for the HCl limit set for existing clinical
waste incinerators. Such an exemption would be given in recognition of the problems
detailed above and the lack of an implementable Best Available Technique to achieve
the proposed limit.
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SMDSA WID Working Group Position Paper – November 2002
Ash Quality
Clinical waste incinerators are designed with a Secondary Chamber operating at a
minimum temperature of 1000 degrees Centigrade, to provide at least 2 seconds
residence time under oxygen rich conditions. This temperature, higher than the 850
degrees Centigrade required by the WID, is required to provide complete destruction
of harmful pathogens and also the small quantities of Prescription Only Medicines
(particularly cytotoxic drugs) present in the waste. The WID now proposes a limit of
3% TOC in the ash, a measure of ash quality that the present generation of CWIs were
never designed to meet. We feel it would be much more appropriate to measure ash
quality from a CWI by a biological test that demonstrates the effectiveness of
pathogen destruction. There is a precedent to this, namely the use of a culture of
specific micro-organisms to demonstrate the effectiveness of disinfection by an
autoclave, and we believe this test could easily be adapted for CW incinerators under
2 tonnes/hour.
The consultation paper on the implementation of the WID, recently circulated by
DEFRA, proposed a derogation from the 3% TOC requirement for non-traditional
plants such as pyrolysis plants and cyclone incinerators. The only clinical waste
pyrolysis plant in the UK would meet the terms of the derogation, which makes a
distinction between elemental carbon and organic carbon. This appears to be a
reasonable solution that recognises that the carbon in ash limit is not a sensible
measure of the effectiveness of the process. Similarly a derogation should be given for
CWIs, and a biological test based on that used for autoclaves should be used.
It is noted that Autoclave and Microwave CW technologies produce no mass
reduction and a biodegradable end product. CWI produce an 80% reduction in mass
and an inert waste. If the incineration process ensures sterilised waste and reduces
landfill tonnage, why regulate on a TOC testing regime?
2. Abnormal Operating Conditions
Article 13 of the WID states that an operator should close down operations if
continuous monitors break down for 4 hours continuously, or more than 60 hours in a
year. We believe this requirement does not reflect the reliability or sensitivity of such
instruments, nor their current state of development. We have not found it possible to
source a supplier of continuous monitors who would guarantee the reliability of their
instruments to this degree, indeed most are reluctant to agree to anything less than 24
hour response to breakdowns. We consider that the implementation of this
requirement should be delayed and only be applied after a number of manufacturers
and suppliers have successfully demonstrated that all instruments are capable of
complying with the article. They should also be fully capable and prepared to offer
operators a back-up contract that complies with the ‘repair timeframes’ stated in the
WID. If this requirement is enacted without alteration it would severely impact
capacity due to increased levels of downtime. In our experience Regulators would
then be placed in a situation whereby they would tell operators to continue operations
until the fault was repaired.
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SMDSA WID Working Group Position Paper – November 2002
The Environment Agency will already be aware of the poor confidence levels
surrounding the M certification process; there is clear evidence that some instruments
certified using this method are not always as sensitive or reliable as they are deemed
to be.
To summarise,

The implementation of the WID in its present form will have a major impact on
the CWI sector; a niche sector that requires an element of special consideration
that has been overlooked during the WID preparation stages.

The vast majority of the WID requirements can be met through the careful and
consistent operation of existing plant. However, HCl limits, carbon in ash and
monitoring requirements can not.

Very few if any existing plants could be modified to meet all the WID
requirements. For any that could the cost would be excessive for absolute
minimal, if any, environmental benefit.

Consistent regulation will be important. Imposing significant financial burdens on
some but not all operators would cause the economic collapse of the industry

Available capacity within the sector is very finely balanced meaning that any
reduction in capacity, whether short term or permanent, will have a significant
impact on the NHS and the environment. This impact will far out weigh the
environmental improvements to be gained by the WID as it relates to small CWI
plants

The timeframe available to fully implement the WID is considered to be too short
and this needs to be carefully reviewed.

There are provisions in WID that would allow the very limited derogations
required to ensure the continuity of the service to the NHS.
We hope that DEFRA and the advisory group within the Environment Agency will
give serious consideration to our position statement and meet with us to discuss the
way forward. To date, most operators have been extremely responsive to past
legislative changes and in most cases have been able to implement practical
improvement programmes commensurate with BATNEEC, sensible time scales and
practical regulation guidelines. In many instances over the last 5 years the SMDSA
membership has worked with Regulatory Bodies in an effort to pass on its expertise
when trying to match practical solutions to theoretical requirements. Our concern in
this instance is that failure of all parties to gain a real understanding of the impact of
WID on our small industry will have a serious effect on our customers and the market
sector in general.
SMDSA WID Working group - 19th November 2002
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