Green gallery

The ET2005 exhibition and conference, to be held at the National Exhibition Centre from 24-26 May, showcases the latest in environmental technologies and services, as Stuart Nathan reports.

New technologies for reducing emissions, cleaning up land and water, and improving the efficiency of processes will be sharing the stage with seminars on the latest developments in legislation and standards at ET2005. The show is co-located with the National Energy Management Exhibition and International Clean-Up (ICU). The shows form a forum for the environmental sector.

Water treatment is high on the agenda at ET. Among the new technologies on display is the gravity aerator, developed by Wirral-based Newton Industrial Group — a device which, claims Newton managing director John Howarth, could save energy equivalent to the output of 60 wind turbines.

The aerator introduces air into wastewater so that it can be treated using the activated sludge process, the system used by most sewage works to degrade organic molecules in waste. Currently, the water is aerated by pumping it into a shallow fountain, or by bubbling air through treatment tanks. Both solutions use large amounts of energy to power the pumps. By contrast, the gravity aerator forces the water over a gravity-fed waterfall, producing the same effect with much less energy.

‘Our system could have a very positive environmental impact,’ explains Howarth. ‘I estimate that if every UK sewage works used it, the 180MW energy savings would be the same as 60 modern wind turbines, or a small nuclear power station. It would also stop 600 000tpa of unwanted carbon dioxide from being released into the atmosphere from power generation.’

The key to the system is the shape of the surface over which the water falls. After being pumped to 50cm above the surface of the treatment tank, the water passes over a steel plate with a gradually increasing gradient, which maximises the amount of air entrained into the surface of the flowing liquid. As the water enters the tank, the entrained air forms gas bubbles that are forced downwards by the fast-flowing water. As they sink, some 90% of the oxygen in the bubbles is dissolved into the water. A demonstration version of the unit can be seen on Envirolink Northwest’s stand, C44.

Also concerned with water treatment is Southern Water Scientific Services, but the company’s stand at ET2005, E50, is showcasing its expertise in contaminated land remediation. The company is awaiting MCERTS certification to test for the presence of five different metals in contaminated land, making it one of only three laboratories in the country certified to handle five or more metals. The company is also due to be certified to classify hazardous wastes by the summer.

‘This addition to our portfolio of services will undoubtedly provide an invaluable and potential money saving service to producers of waste, and extends our already strong offer to the contaminated land sector,’ says laboratory commercial team manager Rob Fuller.

Attention is also focusing on the upcoming WEEE (waste electrical and electronic equipment) Directive, which is due to be implemented in the UK this year. Stewart Ward of DARP Environmental Consultancy, says that the UK needs to put infrastructure in place as soon as possible to deal with WEEE.

The consequences of failure would be a loss of revenue, he says, as waste is exported for treatment and recycling abroad. ‘We need a network of central collection points where consumers can take their used electronic equipment,’ he says. ‘People will not want to return each item to a manufacturer’s dedicated return centre.’ DARP believes that ‘demanufacturing’ — removal of glass, ferrous and non-ferrous metals, including precious metals — from electrical and electronic equipment, could become a major industry in the UK.

WEEE is the subject of a conference at the ET Show, one of a series hosted by photocopier maker Kyocera Mita. The ‘Green Card’ conference will feature speakers from companies such as Toyota and Barclays, discussing practical solutions to WEEE problems and presenting case studies of how real-life problems were overcome.