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4.4 Storage and handling of slaughterhouse by-products
4.4.1 Blood
Teil 3 Seite 4-19
The blood produced by the bleeding of the slaughtered animals must be collected as ex-
tensively as possible and thus kept away from the wastewater. Prerequisites for this are
technical implements which facilitate a sufficiently long bleeding period and a complete
collection of the blood. As a rule, blood collector cutters are built along the bleeding lines.
Together with guiding or squirting tins.
In order to prevent the soiling of the slaughtering blood, in many industrial slaughter-
houses the haemorrhage blood is extracted with a hollow knife and immediately led into
cooled collecting containers. The blood collected thus can be used, for instance, for the
production of blood plasma. The residual blood converging in the blood gutters, however,
is collected mainly in tanks and delivered to carcass disposal plants.
The extensive retention of blood is still by far the most important operational prevention
measure in slaughterhouses, and it leads to a major alleviation of the municipal and com-
pany-owned biological wastewater treatment plants.
Provided that the blood has been retained according to the rules of avoidance technol-
ogy, one has to calculate with unavoidable dripping blood losses is at most 0,5 l per pig
and 2 l per cattle. This blood, the BOD5 must be assumed to be at least 160.000 mg/l,
does in any case get into the process water, and despite its relatively low amount it still is
equivalent to 2 or 8 population equivalents, respectively (related to 40 g BOD5/E×d).
4.4.2 Fats
The fat contained in the wastewater from slaughterhouses is produced mainly in the
evisceration units and during the processing of the hides. Any reduction of the pollutant
loads can only be achieved through a careful and extensive retention of the bowel con-
tents, of the fat sludge, and of the bowel slime.
It is necessary to treat the fat-containing production wastewater in sufficiently dimen-
sioned fat separators or comparable implements. In order to improve their effect, it is ad-
visable to install them at locations with increased fat production, that is especially at the
discharges from the evisceration units. The retained fat can be delivered, for instance, to
carcass disposal plants or be used for the production of technical fats.
4.4.2.1 Fat sluge collector (AT3535005)
Description