208 Environmental Biotechnology
a sizeable and sustainable outlet. Suffice it to say that any such marketing
operation requires significant assurances to the customer in terms of the mate-
rial’s quality, safety and value and moves are afoot to establish more widely
agreed and accepted criteria. To this end, developments like the application of
specific oxygen uptake rate (SOUR) testing as a means of objectively assess-
ing microbial activity within the composting matrix may have a wider role
to play.
Another area of concern often expressed is that of pathogen persistence, which
leads many to view the need for sanitisation as synonymous with sterilisation,
which, of course, it is not. The health risks potentially associated with biowaste
processing to both workers and end-users has been well documented elsewhere
and it is not our intention to restate that work here. However, what is less
widely appreciated, and is more directly relevant to our central theme, is that
particularly for large-scale applications a balanced and thriving community of
micro-organisms is one of the most valuable contributions a good biowaste-
derived soil amendment can make to poor soils. Removing pathogens, weed
seeds and spores from biologically processed waste, while not producing a sterile
wasteland, remains one of the key balancing acts of biowaste treatment.
Ironically, it is the expansion of biotechnology in areas beyond the development
of better systems for immediate biowaste treatment which is likely to have major
implications for waste management. For any processing technology, there is clear
advantage in having a relatively pure input material and this has led to much
discussion over the years regarding the respective benefits of separation on site
against householder segregation. The latter approach has itself led to the plastic
bags in which the biowaste so segregated becoming something of a nuisance at
central treatment facilities, typically needing to be opened and removed, which
is a labour-intensive operation at such a large scale. The increasing use of truly
biodegradable plastics has already started to have an impact on the situation,
especially at composting plants, since bags which will themselves decompose
significantly reduce the amount of work involved.
If the predicted widespread use of cheap bioplastics, grown as alternative crops
in transgenic plants, becomes a reality in the future, then this may itself have
repercussions for the amount of material requiring biological treatment. Plastics
account for around 8–10% of the developed world’s waste stream and while
reducing the demand for finite oil resources for the production of polymers
has much to recommend it, one inevitable consequence will be to increase the
amount of expressly biodegradable material in refuse. With growing numbers
of countries looking to increase biowaste diversion, even allowing for effec-
tive recycling initiatives and attempts at waste minimisation, biotechnology may
play an even larger part in the approaches to integrated waste management of
the future.