MBT (Mechanical Biological Treatment) is a
wide ranging term that describes a range of waste
treatment technologies that, when combined, can
be used to treat residual municipal solid waste.
MBT is defined as a process that “partially processes
mixed household waste by mechanically removing
some parts of the waste and biologically treating
others, so that the residual fraction is smaller and
more suitable for a number of possible uses”.
MBT in itself does not result in the final treatment
of residual waste. The outputs from an MBT process
are typically in a form that may require further
treatment to make them suitable for an end use.
Alternatively they have been treated to a standard
that makes them suitable for disposal. For this reason,
MBT can be considered a pre-treatment process.
our challenge,
our opportunity,
our future,
have your say
The mechanical element of the treatment
method refers to a range of sorting, separation
and size reduction equipment that can be
employed to recover various recyclable elements
from the residual waste and prepare it for further
treatment. The complexity of the mechanical
treatment generally determines the degree of
sophistication of the MBT processes. This reflects
the ability of the process to recover materials that
can be recycled or have monetary value, such as
recoverable metals.
The mechanical process generally
separates out the material that has
a high paper, card and plastics content
that is, in most cases, used as a fuel
in thermal treatment facilities.
The advantages and disadvantages
of mechanical biological treatment
are outlined as follows;
It can vary from a simple shredding
and trommelling (sieving) process
to a complicated system incorporating
shredding, trommelling, magnetic
extraction, electrical separation,
near infra red separation, optical
separation, ballistic separation etc.
• MBT combines proven technologies that are in use worldwide
These treatment methods can be applied
singularly or in combination where the
output from the anaerobic digestion
phase can be further treated by the
aerobic composting process.
The biological treatment process
produces a stabilised organic material
that is either landfilled or used as a
compost, depending on its quality
and compliance with regulations.
• Reduces the amount of waste that goes through the biological treatment process
• Can remove additional recyclable materials from the residual waste
• Produces materials that can be used
as energy sources
• Reduces biodegradability of organic material if it goes to landfill
• Low capital costs compared to other residual waste treatment methods
• Not a final treatment process
• Markets for outputs may be limited
•Significant volumes of stabilised
residue may have to be disposed
of at landfill sites
• Potentially higher operational costs compared to other residual treatment methods
• Lower long term cost certainty compared to some other options
Printed on recycled stock Ref 106021
The biological treatment of waste
converts the remaining organic material
into a more stable material. It is either an
aerobic or anaerobic process - i.e. it uses
microbes that perform in the presence or
absence of oxygen. The aerobic treatment
of the organic material is typically a
composting process that produces a
stabilised organic material. The anaerobic
treatment produces methane gas that
can be utilised in electricity generation.