Biotechnology and Waste - Environmental Biotechnology: Theory and Application - page 175

of sugars and therefore are carbohydrates, lignin is a polymer of the two amino
acids, phenylalanine and tyrosine. Despite its abundance, its structure is poorly
understood, in part a tribute to the fact that it is extremely resistant to degrada-
tion and therefore presents problems to the analyst. Fortunately for the natural
process of carbon and nitrogen recycling on which our biosphere depends, fungi
degrade lignin and, in addition, some microbes, like those resident in the gut of
termites can perform the same function.
Biowaste makes up a huge percentage of refuse; some 2500 million tonnes
arises each year in the European Union alone (Lemmes, 1998) and this is a
figure which many authorities suggest increases by between 3 and 5% annually.
Although the focus of much of this chapter is firmly centred on the biowaste
component of Municipal Solid Waste (MSW), since this is the kind of waste
which most directly concerns the largest number of people, it is important to be
aware that this does not represent the full picture, by any means. Of these 2500
million tonnes of biowaste, 1000 million is agricultural in origin, 550 million
tonnes consists of garden and forestry waste, 500 million is sewage and 250
million results from the food processing industry, leaving MSW only to make up
the remaining 200 million tonnes. In 2008, the European Commission estimated
that the EU as a whole is producing between 75 and 100 million tonnes of
biowaste annually from food and garden waste alone. Recent moves to accelerate
the production of the long-anticipated draft EU Biowaste Directive - and its
eventual implementation - come as little surprise as a result.
The scale of the problem is clearly large, one study suggesting that an annual
total of between 850 and 1000 kg (total solids) of material suitable for biological
treatment are produced per person (Frostell, 1992). There is general agreement
that biowaste accounts for around a third of the industrialised world's municipal
waste stream and that a further 30% or so is also expressly biodegradable, such
a definition including paper. In the light of this, the fact that the potential for the
development and application of approaches based on biological processing has
not yet been more rigorously or comprehensively explored remains somewhat sur-
prising. Moreover, with society in general increasingly committed to the 'green'
ideals of maximised recycling and the rational utilisation of waste, it is difficult
to see how such goals can realistically ever be expected to be met, without signif-
icant attention being paid to the biowaste issue. In this respect, the writing may
already be on the wall, since the demands of legislation appearing in Europe,
the US and elsewhere has already driven fundamental reappraisals of the way in
which all refuse is regarded. In particular, regulatory changes designed to reduce
the amount of raw biodegradable material destined for landfill must ultimately
come to promote biotechnologies which can treat this material in an effective and
more environmentally acceptable way. While predicting the future is, of course,
notoriously difficult, it seems likely that biological processing will continue to
assume an ever-more central role in future waste management regimes, which
presents both exciting possibilities and some genuine challenges to the industry
itself. However, in order to understand why, it is important to consider the current
difficulties posed by biowaste under traditional disposal routes.