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Teil 3 Seite 1-14
The amount of steam used for the production of blood meal is approx. 150 kg/t; it does
not contribute considerably to the blood-water amount or the exhaust vapours from the
drying process.
The cleaning water from the unclean side must be fed into a unit for thermal disinfection
and there kept hot at a temperature of 100°C for at least 30 minutes, or be treated to-
gether with the raw material. The latter option, however, refers only to the process water
from raw material moulds and the rinsing off of animal matter.
The thermal treatment is as a rule done discontinuously. This means that the wastewater
part-stream is led into a closed container via an equalisation tank or via a sufficiently large
pumping swamp. The heating is done in this container. Thus, the wastewater part-stream
occurs flood-like at a high temperature. The cooling is done directly by adding fresh water
or indirectly. The discharge temperature should not exceed 30 °C.
Prior to the treatment in the thermal stage, frequently the solids are separated by sedi-
mentation tanks, sieves, fat separators with sludge catcher, or by floatation plants.
Through these implements, this wastewater part-stream can considerably be unloaded,
because solids are retained and because the reload from solid substances in the thermal
treatment is prevented.
1.4.2.3 Soil
1.4.2.4 Energy
The main bulk of energy in the meat meal production is consumed in the production step
„drying“. There, about 2/3 of the entire energy demand of a plant are consumed.
1.4.2.5 Odour
The raw material of the meat meal industry is increasingly subjected to biological decay
due to heat influx (also depending on the seasonal) and through longer storage periods.
This decay leads to the production of extremely odorous degradation products. The major
ones of these are:
• Hydrogen sulphide
• Ammonia
• Aldehydes
• Lower fatty acids
• Merkaptanes and sulphides
Together, they increase the odour intensity. Odour units (GE) of 80.000-800.000 GE/kg
of raw material can occur. The average value is given as 250.000 GE/kg of raw material.
Odour emissions occur during