Visit to Recovery Facility at Marchwood - TrustNews Dec 11
Have you wondered how your nonrecyclable household is disposed of? Here in Hampshire it goes to one of Veolia’s Energy Recovery Facilities (ERF). Previously household waste was disposed to landfill or incinerated. However landfill space is running out and the old incinerators would not meet EU emission regulations. So with waste levels predicted to continue rising, Hampshire investigated the options available and in 1995 the Hampshire Waste Strategy was adopted which provides a sustainable waste management strategy for all domestic waste in the county.
The strategy is based on waste minimisation; composting of green garden waste; recycling; support for anaerobic digestion; use of recovery technologies including incineration; waste processing facilities with the remaining waste going to landfill. The ERF at Marchwood is one of the waste processing facilities. It produces electrical energy, which it exports to the National Grid, by burning non-recyclable waste. There are two other ERFs, one at Portsmouth and the other at Basingstoke. The three serve the whole of Hampshire.
The ERF was built on the site of the old Marchwood power station. One of the key issues was to ensure that the structure was of a high architectural standard and which fitted well in its surroundings. The result was a 36 metre high aluminium clad dome, 110 metres in diameter, with two 65 metre high chimneys. Another issue was the likely increase in the number of lorries and other vehicles using the roads in the area. In the event, this appears not to be too much of a problem. The works meets the latest legislation regarding environmental impact including emissions, noise and odours.
The works burns the non-recyclable waste and the heat is used to produce steam which is used to generate up to 15MW of electricity which is exported to the National Grid. This is enough energy to meet the demands of up to 22,600 homes.
We were given an introduction by the Manager, Mr Ouseby , who explained the history of the development of the works and how it operated. He answered the many and varied questions from Trust members before showing us around the works which are staffed by a total of 45 people and run 24 hours per day throughout the year. It is highly automated so that on the night shift only 2 staff are needed.
The non-recyclable waste is tipped into a bunker which can store up to 4 days full plant capacity. A grab crane then lifts the waste into a hopper from where it drops onto the fire grate. The ash passes to an ash handling system where ferrous material is recovered for recycling and the remaining ash is also sent for recycling. Hot gasses produced in the combustion chamber pass through a water tubed boiler where they heat the water into steam. A turbo-generator uses the steam to produce electricity for export to the National Grid.
The boiler flue gasses go through extensive cleaning processes to reduce the oxides of nitrogen, to neutralise acid gasses, to remove dioxins and heavy metals and to remove dust particles. The residue from this cleaning process (Air Pollution Control Residue) is disposed of to a licensed site. The discharge through chimneys is continuously monitored and we were told that what goes out of them is probably cleaner than the air in the centre of Southampton and possibly cleaner than the air that enters the boiler. Of all the waste delivered to the site, only 3% ends up in a licensed site, the rest is reused or recovered in the form of energy.
I would like to express our thanks to Veolia and to Mr. Ouseby for his time and his patience in answering our questions and showing us around the very impressive works. Also I would like to thank Keith and Carole Leaman who gave us lunch at their home after the visit.