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Westbury incinerator - should we be worried about pollution?

September 11, 2017 11:48 AM

When Lafarge was operating in Westbury there were concerns about potential pollution from the chimney affecting the health of the population. Now similar questions are being asked about the Northacre incinerator.

Here's a message from Friends of the Earth:


"In 2015 Wiltshire Council gave planning consent in principle for the building of a "Renewable Energy Plant" (incinerator with electricity generation) at Northacre, Westbury. This waste disposal plant will burn mixed Wiltshire waste (paper, cardboard, food waste and mixed plastics) which have been converted into a pelletised "fuel" at the adjacent Hills Waste plant in Westbury. The Westbury "Renewable Energy Plant" is awaiting construction.

Once the current Wiltshire contracts for the burning of ... household waste expire (in the incinerator at Slough and incinerators on the Continent) then one must presume that the Northacre plant will be built, and Westbury will have an operational incinerator (renewable energy plant) serving all of Wiltshire.

The problems with this reality are as we pointed out to Wiltshire Council and the Environment Agency at the time of planning consent in principle in 2015. We explain these below.

Whilst emissions to atmosphere from incinerators are now carefully regulated, and meet tough emission standards, they still emit small particles of dust (soot). Such particles are measured in microns (millionth of a metre). Particles of 10 microns in diameter and down to particles of 2.5 microns are captured by the stack filters. However once the particles fall below 2.5 microns in diameter (not visible to the human eye at this size) the filters are no longer efficient in capturing them; and, the smaller the particle becomes the less efficient the filters become in capturing them. Thus virtually no particles below 1 micron in size are captured.

This is where the problem begins.

Firstly, incinerators emit large volumes of these tiny particles (2.5 microns or less). These particles are, on the outside coating of the particle, contaminated by metals and other chemical compounds present either in the original waste or not destroyed perfectly during the incineration process. This makes these tiny particles "toxic" - potentially injurious to health if they enter the human body.

Next, these tiny particles are so small that they easily penetrate deep into the lung, evading the lung's bronchial filters due to their smallness of size. Once inside the lung they are readily absorbed into the blood stream. If their composition were solely carbon, this would be fairly inconsequential. However, if toxically contaminated, this process can lead to injury to health (primarily pulmonary and cardiovascular).

Normally these tiny particles, once emitted from the incinerator stack, would be readily dispersed into the surrounding air - the dilution effect - and rendered effectively harmless in exposure terms. However the occurrence of this depends on the incinerator stack being correctly located for local meteorological and topographical conditions, and being of sufficient height to encourage good dispersion.

In the case of the Northacre plant, the environmental statement submitted in 2015 stated that there would be ground pluming events i.e. occasions when the emissions from the stack would not go upwards but come onto the ground. The environmental statement said that it could not predict the frequency of these grounding events, nor their location, nor their duration.

Thus when operational the town of Westbury, and surrounding areas, could experience toxic plume grounding events of unknown frequency and duration. Thus there would be a risk of injury to public health.

Despite this fact, planning permission in principle was given by Wiltshire Council.

Now that Wiltshire Council is revising its waste management operations, due to become operational next year, we ask you to re-examine this matter of how the Northacre plant at Westbury will operate, and to seek independent evaluation of the risk to public health from the forecasted plume grounding events."