"...Anaerobic Digestion (AD) offers many opportunities
in waste recycling, not just through stabilisation
of active bio-wastes and mineralisation of certain
elements for added value to land, but also by offering
extra income streams through the use of biogas (methane)
for renewable heat and power export.
AD has been used for centuries in industrial applications,
but in the large-scale applications of centralised
AD (CAD), it has come into its element as has been
proven for around 20 years in Germany and Scandinavia,
where a wide variety of appropriate waste streams are
processed and treated in this way. The importance of
recycling organic matter, macro-nutrients as well as
micro-nutrients is as important as reducing carbon
emissions to the atmosphere for agriculture, but also
the other retail and industrial links in the food chains
we all depend on.
This form of biotechnology has huge potential to solve
many of the interconnected issues in the development
of our increasingly dominant human ecosystem. By providing
a continuous flow operation, these CAD facilities can
take a large throughput for a relatively small "footprint" and
therefore have an attractive relative capital cost.
The more recent development of fully integrated CAD
facilities to take in and separate mixed, non-hazardous
wastes (e.g. MSW) through Mechanical Biological Treatment
(MBT) systems offers the opportunity to maximise the
recycling of inert fractions of waste as well as the
recycling of the biogenic resource, whilst providing
heat and power for on-site use and export.
MBT systems can be designed to take a variety of locally
available wastes and use an appropriate "front-end" pre-treatment
system to extract the biogenic fraction (for AD), where
at the end the solid fraction is a valuable compost
material with more stable, balanced and homogeneous
qualities that is free of pathogens and weed seeds...."