298 94 307/02 Untersuchungen zum Stand der Umsetzung des ...

Teil 3 Seite 8-38
In order to reduce the loads and their varying, there is a number of measures available
for the work processes, the production process, and the processing of the products. Par-
ticular mention should be made of:
- Careful relaxation of the sterilisation implements in order to avoid that solids and fat
are dragged along. In this respect, an automatic valve control provides more operation
safety than the manual valve operation. It is recommendable to install sufficiently di-
mensioned separators into the exhaust vapour pipelines, in order to boost the recov-
ery of precious substances.
- Prevention of an excessive thermal load during the drying process. For instance, with
the pH-value there can result differences of up to 3 units; these are the higher, the
higher the thermal load is. Excessive pH-values not only increase the contents of free
ammonia, they also have a lasting negative effect on the fat separation of the prelimi-
nary wastewater treatment.
- Checking of the possibilities to leave the process water of the unclean and the clean
side in the processing.
- Installation of larger mixing and equalisation tanks and additional safety tanks coupled
to the plant, which in cases of operation failures can accept highly loaded wastewater
and can be slowly emptied.
- Prevention of the input of salt brines from the hide and fur conservation through dry
disposal and re-use of some parts.
- Prevention of product losses (e.g. animal meal and fat).
- Doing without chlorine-precipitating chemicals.
- Restriction of chemicals for disinfection and drinking water processing to the neces-
sary degree. Any dosage of chemicals should be controlled automatically. Peak dis-
charges of the disinfection solution into the wastewater treatment plant must by all
means by avoided.
- Return of residues from chemicals and auxiliary agents residues to the respective
suppliers.
8.2.5.2.1
Example plants
Fat cleaning (Kurztechniken C.)
Corporate clarification plant of the Kraftisried animal carcass disposal plant, 87647
Unterthingau
Corporate clarification plant of the East Bavarian Meat Flour Association,94447 Plattling
Corporate clarification plant of the Eiweiß- und Fettverwertung GmbH & Co, 49191
Belm-Icker, Germany
Clarification plant of the Union for Animal Carcass Disposal (Zweckverband für Tierkör-
perbeseitigung) Lenz, 01561 Lenz, Germany