The liaison meeting that I chair, on Tuesday night received a presentation on plant safety from the manager of Sita’s incinerator on Tees Side.  He covered aspects of plant design, licensing and operation.

Quite a convincing performance by a manager with a chemical engineering background.  As we have been told before, the combustion process is closely controled with the burner pre-heated to a temperature where dioxins are destroyed before any waste is placed on the grate.  During continuous operation the pollutants that are created are monitored continuously and if they exceed licensed levels corrective action is taken.  The limits for the pollutants are set by the EEC based on small fractions of levels known to be harmful to human life.  Pollutant “spikes” do occur and the main method of control appears to be through mixing of the waste before combustion to try to ensure that large concentrations of matter such as sulphur-rich or very wet material do not occur.

The plant is of course built to standards such as those for boiler systems that have evolved over many years.  Controls and monitoring systems are duplex redundant so failure of one set does not produce disaster.  Electrical supplies for fans, the grate, the control system etc.  are derived from the grid, the site turbine and alternator and from backup diesel generators.  This all sounds good but the problem is often unknown links between systems that makes them not truly independent.

A useful meeting which was unfortunately a bit low on local members.