In regard to air quality statements in the booklet, please define “there will also not be a significant odour impact?”
Further to discussion with Powys Council Council’s Environmental Health Officer (“EHO”) and following a site visit to a similar Installation in Kidderminster it was confirmed by the EHO that “there were no unpleasant odours detectable at the site boundary” and “a qualitative assessment [of odour] would be acceptable”. In accordance with the Institute of Air Quality Management (“IAQM”) Odour Guidance (2018) an estimation of the effect of odour has been undertaken considering the risk of odour exposure and receptor sensitivity.
The nearest sensitive receptor (Cefn Cottage) is 182m north of the Installation (downwind). Under calm conditions, odour would remain within the site boundary due to the nature of the quarry void, however, during turbulent conditions odour would be moved away from the Installation and would gradually dissipate. When considering the wind roses for the numerical weather prediction data the winds are generally from the south west, which is in keeping with local knowledge of the site where the wind in known to funnel up the valley. Thus the nearest downwind receptor Cefn Cottage, would have the most effective odour pathway, whilst all other receptors to the north and north east would have a less effective odour pathway. It is considered that due to the topography of the location of the Installation, i.e. it is situated within the quarry void, it would require turbulent conditions for any potential odour to be dispersed beyond the site boundary, consequently the pathway effectiveness is considered moderate. Receptors located upwind are considered to have an ineffective pathway.
The Installation has been designed in accordance with best available techniques (“BAT”) to ensure that there is no odour beyond the site boundary, consequently the magnitude of the odour release is considered to be small.
Therefore, impact descriptors contained within the IAQM Odour Guidance, for a moderately effective pathway, with a small odour potential, the risk of odour exposure at the nearest sensitive receptor is considered Negligible Risk.
The final step in the assessment is to consider the sensitivity of the receptors. The majority of the receptors in the vicinity of the site are considered high sensitivity receptors, as they are predominantly residential, receptors are considered to expect a high level of amenity and are expected to the present, if not continuously, but certainly for a large period of time.
Consequently, based on the negligible risk of odour exposure and the high receptor sensitivity, the likely magnitude of odour effect at the nearest sensitive receptor location is classed as having a negligible effect in accordance with the IAQM Odour Guidance.
Professional judgment is then used to determine if this is “significant” or “not significant”. This is based on a number of factors such as the Magnitude of Impact, Geographic Extent, Frequency, Duration etc. (all of which are defined in each of the relevant EIA Chapters). For odour, operations are undertaken within the confines of the waste reception hall. The waste reception hall will be kept under negative pressure with extracted air used as combustion air to destroy any odour causing compounds. Fast acting roller shutter doors will be installed to the waste reception hall and will remain closed when not in use. The mitigation is incorporated into the design of the building and the operational procedures. Consequently, it is considered that there will be no significant impact from the tipping or storage of waste.