Technology - Source separation/ MBT

MBT or Mechanical Biological Treatment is a large scale process which involves two main treatments:

  • Mechanical – Involves shredding, screening and metal extraction. These processes result in the separation of oversized, inert, recyclables and biodegradable waste fractions.
  • Biological – Biodegradable fraction is broken down by microbial activity within a controlled environment

MBT treatments fall into two general types of processes:

  • Splitting Process. This is mechanical separation prior to biological treatment, which separates out the residual waste into recyclable and biodegradable fractions. Typically this process would involve shredding the residual waste, followed by magnetic extraction of ferrous metal and then screening into two sizes. Large size fraction then goes to incineration or landfill, and the small waste fraction (100mm-150mm) can be composted or biodigested. Further screening of contaminants such as plastics is normally required.
  • Dry Stabilisation Process. This is Biological treatment prior to mechanical separation, where the entire mixed waste is composted in an enclosed air-controlled plant. Materials separation takes place after the composting, and the stabilised biodegradable fraction of about 10% can be used as landfill cover. The remainder of the stabilised waste is converted to RDF (Refuse Derived Fuel).

What you should look out for with MBT

MBT deals with mixed waste with no obligation on householders to source separate their waste. This is convenient at first sight, but detaches the public from direct involvement in re-cycling or responsibility for their own waste. This in turn removes public pressure on manufacturers and retailers to reduce packaging and may lead to the continuation of current large increases in waste per household.

Non Source-separated biodegradable waste from MBT cannot be classed as high quality compost, and therefore is very unlikely to be of sufficient quality for agricultural or horticultural use, making it into another waste stream instead of a useful bio-fertiliser.

Source separated biowaste becomes a valuable source of hygienic bio-fertiliser, and if processed through Biodigestion, a source of Renewable Energy.

What seems like an easy overall solution can, in the long term, prove very costly.

Useful Links:

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Non Source-separated biodegradable waste from MBT cannot be classed as high quality compost or bio-fertiliser

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Collection of mixed bag waste detaches the public and retailers from direct involvement in re-cycling or responsibility for their own waste

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The Landfill Allowance Trading Scheme (LATS) creates big income earning opportunities for Waste Authorities who have access to Biodigestion plant facilities. I can explain

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With Value Engineering, Biodigestion Plants can usually be built at far lower cost and at less risk than with big constructors with juicy middleman margins. Ask me how this works.

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Independent Biodigestion plants can be built quickly to handle biodegradable waste. You could solve your LATS problems at no risk. Ask me how