Graphite Resources

The World is changing

Processes

Steam Autoclaving - the future for waste

The days of sending waste to landfill or incineration are numbered. Landfill targets set by government bodies and pressure from environmental agencies throughout the world are setting the agenda for a new form of waste management - steam autoclaving.

Autoclaving uses a pressurised rotating vessel which, through a combination of steam, pressure and agitation, results in the organic fraction of the waste being separated and broken down into a fibre. The fibre will count towards recycling targets, and will be used within product manufacturing or as a renewable fuel source.

Steam autoclaving is classed as a mechanical heat treatment process and is more effective at diverting waste from landfill than many competing mechanical and biological treatment (MBT) processes as the process enables mixed household and commercial waste to be recycled more easily.

A proven process - it is already widely used to sterilise medical waste and equipment, steam autoclaving provides effective results on a large scale i.e. 80 per cent minimum diversion of waste from landfill.

Autoclaving

The process:

  • Graphite Resources' steam autoclaving system is housed in a modern, purpose-built facility which uses steam to sterilise and stabilise household, industrial and commercial wastes in a series of large autoclaves
  • Each autoclave is, in essence, a long wide steel tube that can handle up to 30 tonnes of waste per cycle
  • 'Black bag' waste is fed into an autoclave, either sorted or unsorted, and is evenly distributed throughout each vessel
  • Steam, at a temperature of up to 160 degrees centigrade, is introduced into each autoclave which then rotates for about an hour. It is this rotating action that ensures that all waste is treated and sterilised, and any cellulose material is broken down into fibre flakes known as CellMatt ®
  • An ultra violet odour treatment system ensures that all bacterial smells are destroyed
  • At the end of each cycle, the sterilised material is sent to the screening and segregation plant where it is separated into various materials such as CellMatt ® fibre, glass, plastic, steel, aluminium and other residues

Steam autoclaving explained

Types of waste handled:

  • Graphite Resources' steam autoclaving process can handle 'black bag' municipal solid waste (MSW) and commercial and industrial waste (C&I) - this excludes hazardous and liquid waste
  • During the treatment cycle, different materials deform at different rates and at different temperatures. Tin cans are de-labelled and the paper labels - along with any remaining food residue is broken down into CellMatt ®
  • Aluminium containers are de-lacquered; even aerosol canisters can be safely recycled before being steam cleaned and flattened
  • Plastic is softened and reduced in volume which makes onward recycling easier
  • Containers made from more than one type of plastic - such as the coloured lid and collar on clear drinks bottles, can be separated during the treatment cycle
  • Glass containers are cleaned. Any labels and even food are absorbed into the CellMatt ® fibre. Glass itself is broken due to the physical agitation - meaning it is ready for separation and collection later on in the recycling process

Autoclaving

 

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