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  Council » Policies and Plans » Rules and regulation » Waikato Regional Plan » Waikato Regional Plan (online version) » 6.4 Guidelines for Assessment » 6.4.1 Guidelines for Assessing Odour

6.4.1 Guidelines for Assessing Odour

6.4.1.1 Matters to be Considered in Determining the Likelihood of Adverse Effects from Resource Consent Applications

In assessing a resource consent application for an existing activity, Waikato Regional Council will consider one or more of the following types of information:

  1. History of complaints regarding the discharge.
  2. Experiences of Waikato Regional Council1 with the discharge and information held by this Council or a territorial authority regarding past compliance.
  3. Information from community consultation undertaken by the discharger.
  4. Information from odour diaries, odour annoyance surveys or other community surveys undertaken by the discharger.
  5. Dynamic dilution olfactometry2 measurements, population annoyance surveys where the population sampled is of sufficient size to provide statistically significant results3 and dispersion modelling* results.
  6. Whether the best practicable option is being applied for the discharge.
  7. Records of emission control improvements undertaken and those improvements proposed for the future.
  8. Past experiences and knowledge of Waikato Regional Council of the odour effects generated form existing sites of a similar nature and scale.
  9. Other information as justified on a case-by-case basis.

 

Advisory Note:

  • The information Waikato Regional Council will require to assess any application under this Plan is set out in Section 8.1.5.

6.4.1.2 Odour Modelling Guideline Values

The following is not a modelling standard and should not be used or quoted as a standard. Waikato Regional Council will use the following as a guide in assessing whether adverse effects are likely to occur for resource consent applications for activities with the potential to discharge significant levels of odour due to the scale and/or nature of the activity.

The odour dispersion modelling guidelines may be used when assessing new activities or be applied to existing activities as appropriate (for example, where options for improvement are being investigated). It is expected that for existing odour discharges other information on which to assess the potential effects will be available, such as community information and Council’s experience. Modelling for new proposals will only be possible where there is a reliable body of information on odour emission rates from the same or very smiliar processes.

Methods of assessment other than those discussed in Section 6.4 of this Plan need to be justified by a resource consent applicant on a case-by-case basis, for example, measurement of individual chemical compounds and comparison to odour thresholds may be appropriate in some circumstances.

The recommended odour modelling guidelines values are summarised in Table 6-6. The values are as recommended by the Ministry for the Environment4. Other values may be able to be justified on a case-by-case basis for specific odour sources if the work has been adequately peer reviewed.



Table 6-6 Recommended Odour Modelling Guidelines (MfE 2003)

Receiving environment sensitivity Concentration Percentile
High (worst case impacts during unstable to semi-unstable conditions) 1 OU/m3 0.1% and 0.5%
High (worst case impacts during neutral to stable conditions) 2 OU/m3 0.1% and 0.5%
Moderate (all conditions) 5 OU/m3 0.1% and 0.5%
Low (all conditions) 5 – 10 OU/m3 0.5%

 

Note:

  • Examples of receiving environments with various sensitivities are provided in Table 2.2 of the MfE Odour Guide.
  • Atmospheric stability has been accounted for in high sensitivity receiving environments. Stability refers to the degree of mixing that occurs.
  • The percentile allows for a small level of exceedence of the predictions to account for worst case meterological conditions, at which adverse effects from odour are unlikely because the conditions occur infrequently.
  • The ‘baseline’ percentile is 0.5%, although 0.1% will also be used to assist in the evaluation of model results depending on the type of source and consistency of emission data. Further discussion of percentile selection is given in the background report5 to the MfE Odour Guide.
  • The concentration components in Table 6-6 already include the peak-to-mean ratio adjustment for all source types, and should be used as design ground level concentrations for one-hour modelling averages.
  • Odour emission concentrations (and rates) used in the dispersion model shall be based on certainty-based forced-choice olfactometry.

 

6.4.1.3 Courses of Action to Assess Odour Complaints for Permitted Activities

In the event of receiving a complaint(s) regarding odour discharges from activities permitted by rules in this Plan, Waikato Regional Council will take the approach outlined in parts a) to e) below, or undertake aspects of this approach, to determine whether or not the odour is objectionable to the extent that it is causing an adverse effect. This approach is distinct from the resource consent approach detailed in Section 6.4.1.4. The approach involves more rapid action and response procedures. For example, the assessment of frequency in a) i) below would substitute use of odour diaries and complaint response with procative inspections by council officers targeted at times when odour is most likely to occur. It also places a greater duty on the discharger to remain within the permitted activity conditions in Section 6.1.8. The criteria that Waikato Regional Council will apply when assessing whether odour is objectionable to the extent that it is causing an adverse effect; and the standard of evidence required for enforcement action, remains the same for both permitted activities and consented activities:

  1. Waikato Regional Council6 will make an assessment of the situation. This assessment will take into account the:
    1. frequency of the odour7
    2. intensity of the odour
    3. duration of the odour
    4. nature of the odour
    5. location of the odour 8
    6. any previous validated odour complaints relating to the same site.

    An adverse effect may be deemed to have occurred or to be occurring from one incident of a significant enough intensity, or duration or offensiveness; or from frequent incidents of lesser intensity or offensiveness; or a combination of these.

  2. In the event that the discharger or complainant(s) dispute Waikato Regional Council’s assessment of the odour problem or the problem is ongoing, Council9, if it so deems neccesary and the dissatisfied party or parties is/are prepared to share costs with Waikato Regional Council, further assessment10 by an independent expert will be undertaken.
  3. If through the assessments made in a) and/or b) it is agreed that a discharge of odour that is objectionable to the extent that it caused or is causing an adverse effect has occurred and is likely to reoccur, Waikato Regional Council will require the discharger to identify and implement an appropriate solution to control the adverse effect.
  4. In the event that an incident or incidents of odour is/are deemed to be objectionable to the extent that there is/are adverse effects and where agreement can not be reached under b) and c) of this section, Waikato Regional Council will take the following approach:
    1. Waikato Regional Council will inform the discharger that action is required to avoid, remedy or mitigate the adverse effects from the discharge. Waikato Regional Council will outline a timeline for the discharger to undertake and complete that work. This may be formalised through the use of abatement notices
    2. If the discharge of odour continues to cause an adverse effect and timeframes are not met, then enforcement proceedings may be initiated. Waikato Regional Council may also require the discharger to apply for resource consent under the relevant rule in this Plan.
  5. For the avoidance of doubt, if through the assessments made in a) it is determined that an incident resulted in an adverse effect, Waikato Regional Council may take enforcement action, irrespective of the processes in a) and/or b), even if the incident was a ‘one-off’.

6.4.1.4 Courses of Action to Assess Odour Complaints for Activities that hold a Resource Consent

In the event of receiving complaint(s) regarding odour from activities that hold a resource consent, Waikato Regional Council will take the approach outlined in parts a) to g) below, or undertake aspects of this approach to determine whether or not the odour is objectionable to the extent that it has caused or is causing an adverse effect:

  1. Waikato Regional Council11 will make an assessment of the situation. This assessment will take into account the:
    1. frequency of the odour
    2. intensity of the odour
    3. duration of the odour
    4. nature of the odour
    5. location of the odour12
    6. any previous validated odour complaints relating to the same site.

    An adverse effect may be deemed to have occurred or to be occurring from one incident of a significant enough intensity, duration or offensiveness; or from frequent incidents of lesser intensity or offensiveness; or a combination of these.

  2. In the event that the discharger or complainant(s) dispute Waikato Regional Council’s assessment of odour problem, or the problem is ongoing, then further assessments will be made by this Council13.
  3. If through the assessments made in b) it is agreed that a discharge of odour that is objectionable to the extent that it caused or is causing an adverse effect has occurred or is likely to recur, Waikato Regional Council will encourage the discharger to identify and implement appropriate solutions to control the adverse effect.
  4. Waikato Regional Council may request that the discharger keep a complaint register and that the discharger respond to complaints to identify the sources or causes of the odour that is having the adverse effect.
  5. Waikato Regional Council may request people living and working in the area to keep a diary that notes the details of any occurrence of odour and the effect it is having on them.
  6. Waikato Regional Council may carry out or commission a public survey or field investigation to determine the extent and impact of the odour.
  7. The discharger may be required to further investigate the significance of the problem using dynamic dilution olfactometry14 and dispersion modelling.

6.4.1.5 Courses of Action – Community Triggered Response

Where complaint(s) concerning odour discharges from consented activities are deemed to be justified (in Section 6.4.1.4), and where there is an established working relationship between discharger and the local community, a community triggered response to compliance could be undertaken as follows:

  1. The complainant could go directly to the discharger to lodge a complaint.
  2. The discharger could respond to complaints to identify the sources or causes of the odour that is resulting in the adverse effect.
  3. Through forums such as community working parties or liaison groups, the complainant and/or community, and the discharger can decide on whatever action is necessary to avoid, remedy or mitigate the adverse effect of the odour discharge.

6.4.1.6 Courses of Action for Considering Enforcement Regarding Adverse Effects from Odour for Consented Activities

In the event that complaint(s) concerning adverse effects from odour are deemed to be justified in Section 6.4.1.4, and where agreement cannot be reached under Section 6.4.1.5, and/or the discharger has not complied with condition(s) on the resource consent, Waikato Regional Council will normally take the following approach:

  1. The discharger will be asked to take whatever action is necessary to avoid, remedy or mitigate the adverse effects from the discharge. Waikato Regional Council will outline or negotiate with the discharger a timeline to undertake and complete that work.
  2. If the odour discharge continues to be objectionable to the extent that it is having an adverse effect and/or timeframes are not met, then enforcement proceedings may be initiated.
  3. For the avoidance of doubt, if it is determined that an incident resulted in an adverse effect, Waikato Regional Council may take enforcement action, irrespective of the process in a) and/or b), even if the incident was a “one-off”.

 

Explanation and Principal Reasons for Adopting Sections 6.4.1.1 to 6.4.1.6
Section 6.4.1.1 provides a guideline for the course of action that Waikato Regional Council can take when assessing a resource consent application for an existing activity (this includes a consent renewal or review of an existing activity which has not previously held consent). The list provided is not hierarchical. Not all of the approaches outlined will necessarily be relevant in an assessment. The Ministry for the Environment, Good Practice Guide for Assessing and Managing Odour in New Zealand (2003), rates odour assessment techniques as having a high, medium or low ranking depending on the situation. The MfE Odour Guide should be referred to if the reader is unsure as to which techniques are most appropriate for a given situation.

Section 6.4.1.1 part a) indicates that Waikato Regional Council will consider the history of complaints received by the regional community regarding the discharge. Complaints can be used as an indicator of past performance from the site.

Section 6.4.1.1 parts b) and h) rely on information held by Waikato Regional Council and past experiences of Council Officers regarding any adverse effects caused by the discharge. In situations where new activities are proposed, this Council will draw on experience and knowledge gained from existing sites of a similar nature or scale.

The provisions in parts c) and d) accommodate consideration of community feedback and experience with the discharge. Community feedback need not be restricted to complaints, there are many techniques available to dischargers to gauge whether or not the community considers the odour to be objectionable to the extent that it is causing an adverse effect. Methods include odour diaries and community opinion or odour annoyance surveys. Refer to the Ministry for the Environment Good Practice Guide and Air Quality Technical Report Number 24 for more information. A report by Lincoln Environmental (1997) also provides useful background reading on survey design15.

Section 6.4.1.1 part e) provides for two further techniques for quantifying and assessing the potential adverse effects from odour discharges. Dynamic dilution olfactometry is a method that can be used for measuring odour concentration16. Dispersion modelling can be used to estimate the effects of changes in air contaminants discharged into the atmosphere. Models can predict how changes in processes and controls will affect air quality and can improve understanding of complex air quality issues. It is important to use them properly with regard to their limits, and with consideration of the uncertainty of their outputs17.

Section 6.4.1.1 part f) provides for an assessment based on a best practicable option approach. Policy 4 in Chapter 6.1 outlines where Waikato Regional Council considers best practicable option is preferable over an air quality management approach. Section 6.4.1.1 part g) assesses whether the principles of continuous improvement have been, or could be, adopted by the discharger.

Section 6.4.1.1 part i) allows Council to consider any other information where it can be justified as being relevant to the assessment.

Section 6.4.1.2 part 1 provides dispersion modelling guideline values that will be used by Waikato Regional Council when considering resource consent applications. The guidelines have been provided in this Plan in recognition of the need for criteria on which to make decisions in a consistent manner, which in turn provides certainty to resource users in the Region. Waikato Regional Council wishes to provide certainty and consistency in approach when assessing resource consent applications regarding odour by providing modelling guidelines in the Plan and aligning the values with the MfE Odour Guide. It should be noted that the guidelines are not modelling standards and should not be used or quoted as such.

The odour modelling guidelines should be applied to applications for any activity that is of a scale or nature that has the potential to discharge significant levels of odour. For new activities the operations should be designed to meet the guideline values in this Plan or other values justified on a case-by-case basis, for example guidelines developed for specific industries. However, modelling for new proposals will only be possible where there is a reliable body of information on odour emission rates from the same or very similar processes.

For exisiting actitivies it may be more appropriate to assess an application using the provisions in Section 6.4.1.1 rather than to use modelling as a primary assessment tool.

The steps listed in Section 6.4.1.3 provide a checklist for Waikato Regional Council to follow when addressing complaints regarding odour for permitted activities. It should be noted that this checklist is not hierarchical. Not all of the approaches outlined may be relevant in the assessment of effects for a given activity. The differences between this procedure and the procedure given in Section 6.4.1.4 are to allow Council to respond faster to odour complaints from permitted activities. This method is intended to avoid a long drawn out process in rectifying issues with permitted activities that do not comply with the standard conditions for permitted activities set out in Section 6.1.8.

Section 6.4.1.3 part a) provides the criteria for assessment that should be used by a council officer. Consideration of each separate factor in part a) i) to vi) is important when making an assessment as to whether or not the odour is objectionable to the extent that it is causing an adverse effect. Due to the more rapid response required, by necessity the duration of assessment will be curtailed. More frequent officer inspections may replace the use of extensive odour diary systems. There will often be times where it will be appropriate for an officer with delegated authority to assess the odour event, particularly if the event occurs a large distance from Waikato Regional Council offices. In cases such as this, territorial authority officers can play an important role.

Section 6.4.1.3 part b) provides for the assessment of odourous events by other council officers or by an independent expert. This will be particularly appropriate if the discharger or complainant(s) dispute the first assessment undertaken as part of a), or if the problem is ongoing. If this is the case and the dissatisfied party or parties are prepared to share costs with Waikato Regional Council, then Council, if it deems necessary will undertake a further assessment by an independent expert.

If it is agreed by the discharger and Council that a discharge of odour that is objectionable to the extent that it has caused or is causing an adverse effect has occurred through the assessments made in parts a) and b), then Section 6.4.1.3 part c) provides for a problem solving approach in the first instance. Waikato Regional Council will encourage the discharger to identify and implement solutions to the problem; the responsibility rests with the discharger to avoid, remedy or mitigate the adverse effect.

Section 6.4.1.3 parts d) and e) outline the options available to Waikato Regional Council if through the process from a) to c), the event caused an adverse effect but no agreement has been reached. Waikato Regional Council may request that the discharger undertake measures to avoid, remedy or mitigate the adverse effects of the discharge and/or undertake enforcement procedures against the discharger. Waikato Regional Council may also require the discharger to seek a resource consent for the activity.

The steps listed in Section 6.4.1.4 provide a checklist for Waikato Regional Council to follow when addressing complaints regarding odour for activities that hold a resource consent. It should be noted that this checklist is not hierarchical. Not all of the approaches outlined may be relevant in the assessment of effects for a given activity.

Section 6.4.1.4 part a) provides the criteria for assessment that should be used by a council officer. Consideration of each separate factor in part a) i) to vi) is important when making an assessment as to whether or not the discharge is objectionable to the extent that it is causing an adverse effect. There will often be times where it will be appropriate for an officer with delegated authority to assess the odour event, particularly if the event occurs a large distance from Waikato Regional Council offices. In cases such as this, territorial authority officers can play an important role.

Section 6.4.1.4 part b) provides for the assessment of odourous events by other Council Officers or by an independent expert. This will be particularly appropriate if the discharger or complainants(s) dispute the first assessment undertaken as part of a), or if the problem is ongoing.

Section 6.4.1.4 parts d) and e) outline the actions that may be requested of the discharger or the community. This may involve Waikato Regional Council requesting the discharger to keep a complaint register and/or requesting people living and working in the area to keep a diary noting the details of any odour and the effect it is having on them.

Under Section 6.4.1.4 part f) Waikato Regional Council could carry out, or commission, a public survey of effects. There are many techniques for public surveying. The technique chosen needs to be carefully developed and the right questions asked in order to produce useful and credible information18. Waikato Regional Council could also carry out field investigations to determine the extent and impact of the discharge. As with community surveys, there are many techniques that can be undertaken for field investigations and again the technique chosen needs to be carefully developed19.

Section 6.4.1.4 part g) outlines a further approach if the approaches in parts a) to f) cannot be achieved. The discharger could be required to undertake an odour assessment using dynamic dilution olfactometry and/or be required to use dispersion modelling techniques to investigate means of avoiding, remedying or mitigating adverse effects caused from the discharge of odour.

The provisions in Section 6.4.1.5 parts a), b) and c) recognise that some dischargers have a well-established relationship with the local community, and have open channels of communication. The community-triggered response is a valid management approach to address adverse effects from odour and already occurs within some communities within the Region. This approach reduces the need for Waikato Regional Council involvement where there are complaints, although it does not rule out involvement from this Council if the problem cannot be solved between the parties.

Notwithstanding Council’s ability to take enforcement action at an early stage in certain circumstances, the provisions in Sections 6.4.1.3 to 6.4.1.5 reflect Waikato Regional Council’s commitment to a problem solving approach with the community and dischargers and also indicates this Council’s desire to see dischargers address their adverse effects in a proactive manner. Where problems still occur Waikato Regional Council will need to consider enforcement action.

Guidance is provided on when to initiate enforcement action in Section 6.4.1.6 parts a), b) and c). Decisions on enforcement will need to be made on a case-by-case basis but account will be taken of:

  1. the success of the measures undertaken under Sections 6.4.1.3, 6.4.1.4 and/or 6.4.1.5 parts a) and b),
  2. the commitment of the discharger to rectifying the problem,
  3. the commitment of the discharger entering into consultation with the affected community,
  4. the extent of the adverse effect and the degree to which it was predictable and preventable.

The amount of time given to the discharger to investigate and implement control options before enforcement proceedings are initiated would be dependent on the complexity of the problem, the costs involved, the level of community concern and the degree of adverse effect.

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