Steiner (1987) summarises known large, high-rate
anaerobic systems installed in slaughterhouse wastewater-
treatment systems (Table 6). The current
status of these units is unknown and there are few
published data for them.
In comparison to their popularity for treating
wastewater from many agro-processing industries
(i.e. brewing, potato processing, etc.), the application
of high-rate anaerobic systems toslaughterhouse wastewater has encountered significant
problems. These include (Stebor et al., 1990):
(i) The high fat, oil and grease concentrations in
the wastewater causing severe problems, due
to their insolubility, which slows the rate of
degradation, and its tendency to form scums
and coat surfaces. High suspended solids concentrations
in the feed adversely affects
UASB, fluidised-bed and fixed-media anaerobic
processes. Recent studies have shown that
the form of pollutants (i.e. suspended, colloidal
or soluble) in the influent wastewater
greatly affects the performance of high-rate
anaerobic systems (Sayed & de Zeeuw, 1988).
(ii) The BOD concentration in the feed is relatively
low for successful operation of high-rate
anaerobic processes, which operate better at
BOD5 concentrations of 10 000 mg/1 or more.
This requires high hydraulic throughput