Environmental Biotechnology - Theory and Application

Biotechnology and Waste 207

Table 8.5 EF analysis results (metals)

Metal mg/l Comments

Cadmium <0.25 Low

Chromium <1Low

Copper <1Low

Lead <1Low

Mercury <0.01 Low

Nickel <1Low

Zinc 2.7 Low

several months, ADAS concluded that the liquor was a ‘useful source of nitrogen
and potash for crop growth’.
Though this method proved itself remarkably efficient in laboratory and inter-
mediate trials, the company for which it was developed subsequently abandoned
further research into biological waste treatment and, consequently, EF has never
been taken to pilot scale. As a result, it is not possible to say how well it
might perform, though for such aerobic processes utilising a completely mixed,
suspended growth regime, even relatively small-scale studies tend to be fair rep-
resentations of full-scale performance. This is particularly relevant to this system,
as the hydrolysed organics are directly assimilated by the resident microbes, rather
than simply accumulating in the process liquor.
In the foreseeable future, it is unlikely that this approach will make the tran-
sition to commercial application, not least as a result of outstanding intellectual
property questions. Nevertheless, it stands as a worthwhile example of how alter-
native technologies can be developed to meet particular needs.

The issue of local circumstance is a recurrent theme throughout the whole of
environmental biotechnology and probably so in waste management as much,
if not more, than in any other aspect. As a consequence, it is highly unlikely
that any one technology will establish itself as the monopoly treatment, which
effectively also guarantees the scope for the further development of existing or
novel minority biotechnologies.

Closing Remarks

Biowaste management cannot solely be about maximising the diversion of biode-
gradable material from landfill; it must seek to maximise the return of materials
thus diverted back into the chain of utility as an equal priority. This is a particular
consideration for those biological treatment processes that result in some kind
of compost or similar product. Though it is beyond the scope of this book to
discuss the issues of marketing and product quality in depth, it must be obvious
that any significant level of biowaste diversion via these approaches demands