There are better ways of disposing of waste than simply dumping it in a waste disposal chute and transporting it to landfill. Josephine Smit looks at two technologies that have been applied in Scandinavia that are now being trialled in the UK

Waste collection at Wembley City

If you’ve ever thrown a sweet wrapper into a bin in Barcelona or Sweden’s examplar community Hammarby Sjostad, then you’ve started it on a journey through a network of underground pipes that handles the city centre’s refuse. The technology behind Barcelona’s waste handling is now coming to the UK with such major developments as Wembley and King’s Cross Central planning to install it.

At Wembley City, Quintain Estates & Development is creating a scheme with thousands of homes, office and commercial space. The people using all of those buildings will be generating a vast quantity of rubbish, and this is how the developer plans to deal with it.

  • What particular challenges does the Wembley scheme pose from the point of view of waste handling and collection?

The consented section of the 90 acre Wembley City development will contain 4,500 homes, 1 million ft2 of retail and leisure, a four-star hotel and around 1 million ft2 of commercial space. In addition to its 10,000 residents, it will also attract crowds of up to 90,000 on match days. This means that many different types of waste will be created and the amounts will vary significantly from day to day.

Provision of traditional waste management systems would place considerable strain on E E the transport system. If you assume that every block of homes would need up to five refuse and recycling collections a week, combined with the retail and commercial space it’s easy to see how this would add up to 30 refuse lorry collections every working day. And this is only the area of the development for which the developer has outline consent.

  • Why did the developer decide to use the Envac system?

Quintain says: “We are committed to creating a flagship development in terms of social and environmental sustainability at Wembley. The entire scheme will achieve the BREEAM standard of ‘very good’; renewable energy technologies will be used and a strategic approach is being taken to elements such as lighting and mechanical & electrical engineering to drive down energy use across the 90 acre site.

“Waste is an obvious area where a significant reduction in energy use could be achieved for generations in the form of reducing road-based waste collection and providing residents with an easy way to recycle.”

  • What is the Envac technology?

It is a Swedish vacuum system which transports waste through underground pipes at speeds of up to 70km per hour. Waste is thrown into indoor or outdoor bins. A refuse bag can be temporarily stored in a chute, then released into the system and sucked through the pipe network to a collection centre.

  • What about recyclable waste – will that go through the Envac pipe system?

The Envac system operates through a valve system to carry the four waste streams independently: cardboard, organic, other recyclables and general waste. Typically, twice a day these valves are opened in sequence so that the waste streams remain uncontaminated. All waste travels down the same pipe network to the collection station, where it is channelled into the appropriate container.

  • Are homes connected to the system – and if so, how will that work?

Residents will access Envac within the courtyard of their apartment building, where four separate inlet points will segregate the waste.

  • Will litter bins in public areas be connected to the system?

A decision has yet to be taken.

  • Where will the waste go?

Wembley City will have its own waste collection centre.

  • What does the technology cost?

Typical “capital” costs for an installation on a new build scheme are in the region of £1,000 per home, with a further 25% cost for infrastructure works.

  • What are the advantages of the system?

It eliminates noise and smells and saves on labour.

Waste to power on the Isle of Wight

If you are holidaying in the Isle of Wight over the summer, then why not pop into its newest attraction? The island is home to the UK’s first waste to energy – or gasification plant, and will have a visitor centre explaining its principles. The Isle of Wight is obviously short on space for landfill and much of its waste is currently taken off the island and transported via road to Lincolnshire. The financial and environmental costs of that make it a natural candidate to trial turning waste into energy with this £8m plant.

Isle of Wight council chose technology from Energos, part of Ener-G, which is investing £4m in the project. The technology has already been applied at locations in Norway and Germany. The plant is scheduled to be operational in May, and its progress is being closely watched by the public sector.

What is gasification?
Gasification converts waste to gas in a two-stage thermal treatment process. Waste is shredded and metals are removed before it is fed into the chamber. Resulting heat energy is used to produce steam, which is then used to generate electricity.

How much waste will the system take?
Isle of Wight Council’s resource recovery facility will handle 60,000 tonnes of waste, but only half of that will be used to generate electricity. The facility, which is operated by Biffa subsidiary Island Waste Services also handles recycling.

How much energy will the plant generate?
The plant can generate 2.3MW of electricity, enough to power 2,000 homes. Electricity is currently imported from the mainland.

Does the process result in any ‘waste’ of its own?
The process does produce ash in the form of bottom ash and fly ash. The bottom ash is inert and so can go to landfill on the island where it will be used as daily cover. The fly ash will be sent off the island, treated and disposed of.

How did this project come about?
The project is part of Defra’s New Technology Demonstrator Programme, which promotes innovative ways of reducing biodegradable waste sent to landfill. Defra is providing £2.7m to meet 35% of the £8m cost of developing and operating the facility in its first year.

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