Veolia Rye House Energy Recovery Facility Air Quality Impact Assessment

Air Quality Impact Assessment Required to demonstrate that the impact of emissions to air from the facility is acceptable Primarily considers the effect on local air quality, and deposition to ground at sensitive ecological receptors. The air quality impact assessment outputs are used in the following ways: As information to be used in compiling the Environmental Statement (ES) to accompany the planning application to the Waste Planning Authority (Air Quality and Ecology chapters). As part of the Impact Assessment carried out to form part of the Environmental Permit application to the Environment Agency.

Approach to the Assessment Builds on work originally carried out for the Fieldes Lock facility. Uses much of the baseline information collected for Fieldes Lock, with updates where necessary. Will consider the impact of emissions to air from: The facility itself (the main stacks and diesel generators). The effect of changes to road traffic flows on ‘receptors’ near to the designated access route to the site. The cumulative effects of the operation of the nearby Rye House Power Station and Trent Developments Facility

Pollutants Considered by the Assessment Emissions limits from the EFW Facility are set for a number of pollutants within the Industrial Emissions Directive (IED): Oxides of nitrogen Particulate matter (PM10 and PM2.5) Sulphur Dioxide, hydrogen chloride, hydrogen fluoride, ammonia Volatile organic carbon (VOC) A range of industrial metals Dioxins and furans, PAHs and PCBs The primary pollutants of concern emitted from road traffic: Particulate matter.

Computer Dispersion Modelling The modelling needed to account for: The position of sensitive receptor locations. The height of the stacks - needs to balance the need for effective dispersion against other constraints such as visual impact, cost and engineering feasibility. Variation in meteorological conditions (5 years of data were used). Queueing traffic on local roads during peak periods.

Terrain Effects The proposed facility is situated within the Lee Valley.The effect of any change in ground height on dispersion was therefore considered within the modelling. In conjunction with the use of representative met data from Stansted, the model has therefore accounted for the effect of local terrain on the dispersion of stack emissions.

Preliminary Model Outputs The results at sensitive human receptor locations are presented as: The process contribution (PC), or the change made by the operation of the facility, which is also expressed as a percentage of the air quality standard. As a Predicted Environmental Concentration (PEC), which includes the contribution from existing and possible future emission sources elsewhere in the local area. This value can be directly compared with the relevant air quality standard The change in pollutant concentrations and deposition rates to ground are predicted at sensitive ecological sites, in order to inform the ecological assessment.

Consideration of Stack Height A range of heights for the main stacks was considered in order to justify the preferred release height of 86.75 m as appropriate. At heights below 65 m, the incremental improvement in dispersion with height is more pronounced. Above this, the incremental benefit of further increases in the stack height become less effective in reducing the PC to ground-level concentrations. Overall, preliminary model results indicate that the use of a 86.75 m stack would be capable of mitigating both the short-term and long-term impacts of the modelled emissions of all pollutants, such that no significant adverse effects would occur at any receptor.

Preliminary Model Outputs The results will also be presented visually as a series of pollutant contour plots. This plot shows the impact emissions from the facility stacks on annual mean nitrogen dioxide concentrations.

Many Thanks