HMIP lays down markers in BPEO assessment plans

Companies regulated under integrated pollution control (IPC) will have to provide detailed, costed justifications of their choice of process and abatement equipment under draft guidelines published by HM Inspectorate of Pollution (HMIP).1 The methodology is less rigid than an earlier proposal, and now takes some account of solid wastes. But its requirement on firms to prepare a transparent evaluation of the environmental impact of a range of process options will demand a massive improvement in the quality of IPC applications.

Applicants for authorisation under IPC face two fundamental requirements. They must assess the environmental consequences of releases from their processes. And they must show that their activities represent the "best available techniques not entailing excessive cost" (BATNEEC) - and also the "best practicable environmental option" (BPEO) where releases go to more than one environmental medium.

However, ENDS' recent study of the implementation of IPC showed that, in practice, very few companies have met these requirements (ENDS Report 227, pp 3-4 ). HMIP says that there has been a marked improvement with recent applications for existing chemicals processes, but many operators still appear not to have considered alternative processes or to have provided cost data to support claims that a particular option would entail "excessive cost".

Last summer, HMIP attempted to tackle the problem with outline proposals for a "BPEO Index" (ENDS Report 222, pp 16-19 ). Its plan was to require firms to evaluate the environmental impact of various process options. The option with the lowest impact would be the "best environmental option" (BEO) - and any proposal to deviate from this would need full justification, normally on the grounds of excessive cost.

Many observers felt that the strictly numerical basis of this original formula failed to acknowledge gaps and uncertainties in the science of environmental impact. The concern was heightened by the exclusion of solid waste from the Index, even though with some processes it may be one of the most significant environmental issues.

HMIP's revised proposal is less rigid. It stresses that the procedure "should not be used in a mechanistic way", and that the final justification for the process choice "should weigh all relevant factors based on expert judgement".

The result, says HMIP, will be an "audit trail" which will allow BATNEEC to be determined in a "structured, transparent and consistent manner". The draft says that the system "should be followed for all applications received under IPC" and the assessments placed on the public register to allow "independent public scrutiny". But it then muddies the water - because of "site-specific circumstances", it says, the methodology should not be seen as prescriptive.

Despite HMIP's attempts to portray the proposal as one of its contributions to the Government's deregulation drive, in practice it will mean considerably more work for most operators - if only because for the first time they will be forced to address their legal duties under IPC. The assumption must be that HMIP may be happy to apply a degree of proportionality by exempting smaller or less polluting processes from the full requirements of the assessment procedure.

In an effort to ease the process, HMIP has commissioned consultants DNV to study the feasibility of setting up a consortium of regulators, operators and environmental groups. This would prepare a toolkit of standard mathematical models and supporting data bases to be placed in the public domain, potentially offering a "template" for applicants to follow.

The final guidance is expected in the autumn. Key features of the consultation paper are as follows:

  • Preliminary assessment: The base case is taken as being the existing level of releases from an existing plant. Operators of a new process should consider unabated release levels from a "basic facility".

    All releases, including those of non-prescribed substances, should be identified irrespective of their magnitude, and the concentration, emission rate and estimated annual load provided. For discharges to sewer, allowance should be made for the typical removal rate of a particular pollutant during sewage treatment.

  • Identification of significant releases: The next stage is to assess the predicted long-term concentration of each substance in the environment, taking account of background levels. If this remains below a specified "action level", then HMIP says that the release can be considered insignificant.

    Some environmentalists are unhappy with this concept. They point out that IPC's principal goals are to prevent or minimise releases of prescribed substances. The use of action levels may, they say, reward "dilute and disperse" techniques or favour developments in unpolluted areas.

    HMIP also faces a major headache in defining action levels below which the environmental consequences of a release are "negligible". The draft suggests that provisional levels could be set at 10% of statutory environmental quality standards (EQSs) or World Health Organization guidelines, or at 1% of HMIP-derived "environmental assessment levels" (EALs).

  • Interim environmental assessment levels (EALs): One of the biggest problems with HMIP's initial proposals was that formal EQSs have been set for relatively few substances. Ultimately, the assessment system would require EQSs or EALs for a range of different environmental receptors to be derived on a consistent basis.

    HMIP intends to carry out further research in an attempt to derive meaningful standards to protect sensitive ecosystems. In the meantime, it has attempted to plug the gap with a wide-ranging set of interim EALs, expressed as concentrations in air and water and as maximum rates of deposition of pollutants on land. These are based primarily on human health criteria taken from a mixture of national and international guidelines on environmental and occupational exposure.

    Striking omissions from the list of EALs are maximum deposition rates for sulphur and nitrogen oxides. One of the most interesting aspects of last summer's proposal was the potential to relate "critical load" exceedances for long-range acid deposition back to individual plants. However, the issue has been shelved because HMIP feels that it is too difficult to disentangle the effects of numerous distant sources - and the new draft makes no mention at all of acidification.

  • Selection of practicable process techniques: The paper proposes that a range of primary processes or abatement techniques should be identified which are capable of meeting the level of control indicated in IPC process guidance notes.

    Any process option which causes a statutory EQS - or even a non-statutory EAL - to be exceeded "is considered unacceptable and an alternative process or abatement option should be sought". It is far from clear what will happen if background levels or other sources are already causing exceedances of the EQS or EAL. However, HMIP expects most environmental concentrations to fall in the "tolerable" zone, between the EQS/EAL and the action level.

    No guidance is offered on the expected scope of the technology review. The National Society for Clean Air is concerned that the draft focuses on technical fixes and outputs from the process, and may not encourage firms to look at more fundamental factors such as choice of raw material or fuel.

    HMIP recognises that for existing processes the range of options "may be constrained by plant specific conditions, such as the nature of the existing process, site layout or planning requirements". But it says that at this stage "the only economic consideration is that the options should be viable" - whatever that means.

  • Assessment of longer-term environmental effects: HMIP has stuck with the broad principle of last summer's BPEO Index, under which a numerical value is assigned to the environmental impact of each release from a process option. Values for all releases and all media are then added to give an index of the total environmental impact of that option.

    However, several crucial details have changed - including the title of the Index. The initial BPEO Index proposal required only "significant" releases to be evaluated. However, the new Integrated Environmental Index (IEI) appears to include all releases.

    The method for evaluating the environmental impact of each pollutant has also changed. The first version was based on the ratio of the predicted environmental concentration, expressed as an annual average, to the EQS/EAL. Background levels were therefore included.

    However, the IEI uses the ratio of the plant contribution to the EQS/EAL. HMIP had initially argued that background levels had to be included to relate the Index to environmental harm. But it now says that "at a particular location the ambient pollution concentrations and nature of the receiving medium will effectively be the same for all process options."

  • Assessment of other factors: A range of other effects cannot easily be incorporated in the IEI, but should also be evaluated, the paper says. HMIP has offered a list of short-term exposure limits, and a screening procedure should be used to see if these could be exceeded.

    The global warming potential of emissions from each process option should also be assessed. However, the draft does not make clear whether emissions arising from off-site power generation should be included.

    Similarly, the potential of VOC releases to add to photochemical ozone formation should be addressed, though here there is uncertainty over the weighting factors for each chemical.

    The final, and perhaps most significant, assessment is of the relative hazard potential of waste arisings - which had been excluded from the initial proposals. HMIP plans to adapt a scheme developed by a Government/industry Working Group on Priority Setting and Risk Assessment in 1991, which scores materials by their toxicity, potential for bioaccumulation, degradation in soil and water, solubility and volatility. However, HMIP says that "no absolute quantitative meaning should be applied to these scores".

  • Ranking of options: HMIP's "over-riding principle" is that if the operator's preferred option corresponds to the BEO then no further justification is required.

    In most cases, HMIP expects that the greatest weight will be attached to the index of long-term effects - and that the option with the lowest index will represent the BEO. However, the "other" environmental factors must also be weighed and could be used to modify the final ranking of process options. HMIP says that this is a matter for "professional judgement" - but that a clear, written justification for the decision should be presented on the public register.

  • Inclusion of cost data: Use of an option other than the BEO must, the paper says, be justified by its "cost-effectiveness...in terms of pollution reduction or prevention". As before, HMIP expects that "break points" may be identified beyond which further reductions could only be achieved at a much greater incremental cost.

    HMIP expects annualized costs to be prepared for the plant's forecast operating life. This immediately raises the question: to what extent will it be prepared to bring forward closure or replacement of old plant? It is also unclear how the BPEO assessment procedure will relate to the process guidance notes' deadlines for upgrading existing processes - though HMIP is showing signs of dropping the deadlines altogether (see pp 37-38 ).

    The draft requires detailed capital and operating cost estimates to be supplied and justified by the operator. To date, virtually no IPC applicants have provided even the crudest financial data. Industry is likely to respond to the new demands with a deluge of confidentiality claims which may threaten the promised transparency of the assessment procedure. However, the draft does not mention the issue, and it is unclear how HMIP would treat such claims.

    Even when the BPEO has been identified, it may not necessarily represent BATNEEC - in some cases, an inspector may need to consider wider factors such as operator competence when determining an application.

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