PLASMA ARC
One of the most exciting innovations in waste to energy, this involves a plasma arc which ionises waste to create syngas and slag. Air Products is constructing a plant on Teesside using Altern NRG technology; while in Canada, Plasco is operating a full-scale 50,000-tonne plant transforming municipal waste into syngas.
The challenge with plasma arc is high parasitic loads, making it an expensive approach to waste management.
However, at Stopford Projects Dr Ben Herbert says the group is working on a small plasma demonstration plant with a major utility and power generator. The new plant is using a new process utilising microwave to generate heat, creating a far lower parasitic load, with lower operating and capital expenditure.
SEWAGE MINING
Sewage waste is a rich source of energy and materials, especially high in fats. When not properly managed it can mean clogged sewers – remember the infamous London fatberg – and high-cost cleaning. Removing this waste to generate new products could prove the future of waste management.
The development of bioplastics and other plant-based materials could have a dramatic impact on industrial reliance on petrochemicals
Ostara has developed a process that takes 80 to 90 per cent of phosphorus and nitrogen out of waste water, removing contaminants and developing a secondary product – an effective non-water soluble fertiliser. The company is already operating a plant for Thames Water, as well as five in the United States and one in Canada.
Isreael’s Applied CleanTech has developed a sewage mining system, which picks out and recycles useful fibres from raw urban and industrial waste water, increasing the efficiency of treatment plants and reducing the amount of unwanted sludge and the cost of waste water treatment by 20 to 30 per cent.
BIOPLASTICS
The development of bioplastics and other plant-based materials could have a dramatic impact on industrial reliance on petrochemicals, being not just biodegradable but compostable. It could also address waste by-products in the supply chain.
Biome Bioplastics, for example, develops its products and materials from potato starch, a by-product of the wallpaper paste industry. According to director Paul Mines, the company has already developed a plant-based material for biodegradable coffee pods, offering one of the first sustainable packaging alternatives in the single-serve market.
“We’ve had traction in high-value, relatively niche sectors, like coffee pods, disposable razors, even tree protectors for horticulture,” he says.
While the cost of bioplastics is currently two to three times that of oil-derived plastics, Mr Mines expects to see rapid developments in industrial biotechnology. He says: “I can see a path where we can make cheaper bioplastics, probably within three to four years.”
In conclusion, Allan Barton, Arup’s director and global leader, resources and waste management, advises: “There are two basic approaches to take. If the waste is organic, then cycle as nature intended by burning or composting. If it’s inorganic, then cycle it around and around the supply chain. We need to look at the waste stream as a source of materials to refine, just as petrochemical companies refine oil.”
