A Modern, Sustainable Treatment of Solid Waste in Brittany, France

January 24th, 2009 by Professor Nicholas Day

Decision time is approaching for the treatment of Guernsey’s waste.

A range of approaches can be expected in response to the call for tenders. At one extreme is likely to be the solution adopted by Jersey, for a large mass burn incinerator to handle, at great expense, the great bulk of the waste stream.  More closely attuned to modern developments is the approach taken by our nearby neighbours in Brittany, in the north west of the  Cotes d’Armor.

Along the Cote de Granit Rose, from Paimpol to Lannion, and inland to Guingamp and beyond, 107 communes, with a total population three times that of Guernsey, joined forces some 10 years ago  for the sustainable management of their waste.

From the outset, the underlying strategy was clear. Waste is a resource, from which the maximum value should be extracted. To achieve this, multiple treatment channels would be established, which would adapt and evolve as new technologies emerge.

The main centre is in the Brittany countryside halfway between Pluzunet and Begard, with two subsidiary composting facilities elsewhere. My wife and I visited the centre in mid-November, and were given an afternoon’s tour of the facility.

The main site is on some three hectares, dominated by a large building which houses an incinerator, recycling facilities and a variety of storage areas for recyclables and bottom ash. Next to the site are four hectares of greenhouses.  In 2007, 125,000 tonnes of waste was processed, consisting of all the municipal waste and some 30% of industrial and commercial waste.

So what are the main treatment streams, and what value is extracted?

First, incineration, which has a role to play but not a dominant one. The incinerator can handle 55,000 tonnes per year, that is some 40% of the total waste (the Guernsey equivalent on a population basis would have a capacity of about 20,000 tonnes per year i.e. along the lines of the micro-incinerator proposed by the Waste Disposal People’s Panel), and works to full capacity throughout the year apart from two periods of two weeks when it is closed for maintenance. The energy generated is partly converted to electricity and exported into the local grid (10,500 MWh per year) and partly to heat the neighbouring four hectares of greenhouses, with plans to add an additional four hectares. The greenhouses produce flowers and, to a smaller extent, vegetables. The bottom ash is sold for use as hard core, under strictly regulated conditions, on roads. There are no plans to increase the incineration capacity.  In fact they expect the  amount of household waste incinerated to decrease steadily as the quantity composted or recycled increases, the resulting spare capacity of the incinerator then being used to increase their treatment of industrial waste. The use of the energy from the incinerator directly as heat is not only more efficient than converting it into electricity, it also directly replaces the use of fossil fuels for greenhouse heating, and at about one third the cost.

Second, household waste.  Until recently, about a quarter of household waste was composted at a plant at Pleumeur-Boudou set up in 1983. The resulting compost no longer meets current standards, introduced in 2006 with stringent limits on contamination by heavy metals, plastic, glass etc., so the plant is being replaced.

The new plant, with a capacity of 20,000 tonnes per year, is designed to remove contaminants such as old batteries, other metal objects, glass and plastic and should be brought on stream by the middle of next year. The new plant produces compost that will meet the new standard (NFU44-051) for agricultural use, and should fully meet the requirements of the Brittany vegetable growers association. The amount of household waste composted rather than incinerated will increase as demand for the compost grows, and it is anticipated that in the medium term most household food waste will be treated in this way. The compost will be used mainly in vegetable production.

Third, wood. Nearly 10,000 tonnes of wood are handled yearly at present. None goes into the main incinerator. Clean, untreated wood, e.g. from plant waste, is sold as fuel, either for heating in schools, hospitals etc., or for greenhouse heating. Treated wood at present is chipped and processed into chip-board, although there are plans to build an 8MW incinerator at the Pluzunet centre, with proper treatment of the combustion gases, to heat a further 8 hectares of greenhouses for vegetable production.

In addition to these treatment streams, the organisation runs a household waste recycling scheme. Uptake has increased steadily since its inception, and they are confident of reaching the European target of 50% within a few years.  It also handles nearly 35,000 tonnes of plant waste a year from which wood for fuel is separated. The remaining 30,000 tonnes is composted and the compost sold. As part of their continual experimentation with new treatment streams, they have recently developed, in collaboration with a Brittany engineering firm, a means to compact expanded polystyrene foam into a reusable form.

At the start of 2009, Guernsey, like most of the developed world, faces a future full of uncertainties. The recent turbulence in world markets for fossil fuels and food is a forerunner of larger future shocks, as pressure mounts on the world’s resources.  In addition, Guernsey faces its own problems with a looming budget deficit and several major infrastructure projects in urgent need of attention. Like our Brittany neighbours, we should be focusing on how we can exploit our waste intelligently and be fully open to new technical developments as they emerge. Wood used as fuel, for example, could replace large quantities of imported oil, and together with compost could give a major boost to a renascent growing industry. It could be a grossly expensive misuse of resources for Guernsey to lock itself in to a single ‘solution’  for the next 25 years.

I should like to thank Magalie Quelenn, responsible for communications at Valorys-Smitred, for a highly informative afternoon.

More information is available at their website: www.valorys.smitred.com )

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