Journey to the centre of the earth

French writer Jules Verne imagined it in his novel Journey to the Centre of the Earth, but French waste management company Tiru went one step further. It took a small group of journalists on a real journey to the centre of the earth – well, almost.

The trip, which we went on, marked the official opening of the Isséane energy-from-waste (EfW) facility – two-thirds of which is built underground – on a busy thoroughfare alongside the river Seine in Paris. At street level, it looks like a smart factory office block, inconspicuous amid the industrial, commercial and residential buildings and construction sites that are its immediate neighbours.

The cultivation of plants to create a living roof and green walls enhances its visual impact. From the ground, there’s no sign of a stack – Isséane’s twin 5m chimneys are hidden by the perimeter roofline.

The statistics stack up

What does stack up impressively are the statistics. The Isséane integrated waste management centre comprises the incinerator, with its 460,000tpa capacity, and a recycling centre operated by Tiru’s partner, SITA, capable of handling 55,000 tonnes of materials. Isséane operates 24/7 under contract to SYCTOM, the largest public authority responsible for waste disposal in France.

Brought online in December 2007, Isséane is already contributing energy for the Paris region; more than 182,000 inhabitants rely on it for their heating and hot water. It also supplies hospitals, schools, museums and commercial buildings within a 15km radius. This power is generated from the residual waste produced by more than one million residents from five districts to the west of Paris, and 20 nearby towns. By dealing with waste locally, Isséane complies with the proximity principle.

Tucked in for treatment

The 450 trucks a day bringing in the city’s waste discharge their loads underground. Recyclables are sorted, with 75% of the materials and 15% of the bulky items sent to specialised reprocessing industries. Residual waste is sent downstairs where two incineration kilns each process 30.5 tonnes of waste per hour.

Isséane states that one tonne of domestic waste treated at the plant will yield 3.3 tonnes of steam for use in the heating system and for electricity production. It will also create 20kg of scrap metals for recycling, 20kg of bottom ash, 17kg of fly ash and 10.5kg of solid residual waste recovered from the filter system. The bottom ash is transported by inland waterway for further treatment so it can be used to replace

primary construction materials, while the fly ash is sent for disposal.

About two-thirds of the facility is dedicated to advanced emissions controls. An electrostatic precipitator recovers more than 99% of the particles contained in the combustion gases. Flue gases are mixed with bicarbonate and activated carbon before passing through a filter, to absorb the pollutants, and going for treatment within a catalyser. The only emission, Isséane claims, is invisible water vapour.

Nimbyism has not been an issue, according to Isséane spokeswoman Alison Jones. “There is a nimby factor in France, as in the UK. But, for this particular project, the replacement of an old plant – designed in the early 1960s with high stack and white plume – by a state-of-the-art

energy-from-waste facility with a well integrated and discrete architecture, and a reduced nominal capacity, has worked in favour of this project,” she says.

She adds: “The project received the blessing of the environmental minister, Mme Voynet, who was, at that time, from the green party. In addition, SYCTOM had a positive public consultation programme involving the local inhabitants – they set up local residents’ panel very early in the process.”

The residents’ panel will function throughout the facility’s lifetime, ensuring that any adverse effects of the plant’s operation can be brought to immediate attention. The idea of waste being processed and converted into energy so discreetly in the heart of the city producing it is clearly an attractive one. According to our guide, Barthélémey Fourment, the only other facility comparable at the moment is in Monaco.

Power provision

TIRU, through its subsidiary Cyclerval, does have a presence in the UK, where it operates EfW and integrated waste management facilities. Jones says she is unaware of anyone contemplating a plant in the UK.

“In this country, EfW facilities tend to be sited on industrial or waste management areas anyway, so addressing visual impact is less of a concern,” she says.

But she does believe the Isséane approach of integrating high recycling with state-of-the-art incineration and combined heat and power provision might be ideal for the UK.

She says: “With traditional fossil fuel supplies dwindling, the UK urgently needs a long-term, secure and sustainable energy source. Nuclear is highly controversial and alternative wind and wave technologies are still in their infancy – so what can be done now? Part of the answer must lie in adapting the modern and proven heating technology that Europe has in abundance and combine it with a sustainable use of residual waste.”

Mike Gerber is a freelance journalist