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7.1.1 Rendering
7.1.1.1 Water
Teil 3 Seite 7-3
Generally, the companies in the meat meal production do not belong to the water-
intensive industrial plants in regard to their water demand and thus the wastewater pro-
duction. On the other hand, their wastewater has a high organic load, the pollutant load
being equivalent to approx. 100 PE per ton of raw material.
Unpolluted cooling water and rainfall water are as a rule discharged without treatment.
The following table shows the sizes of the specific wastewater amounts of the single
part-streams.
Table 7-1: Process water and wastewater part-streams in the meat meal industry
Process water and wastewater part-streams spec. process water and waste-
Entire wastewater
1)
water production
m³/t of raw material
0,9-1,6
Exhaust vapour condensates (process water) 1) 0,6-0,7
- of which from the drying 0,4-0,6 (70-95 %)
Blood process water
Exhaust vapour condensates from the feathers proc-
0,4-0,7
essing
Exhaust vapour condensates from the bone processing 0,35-0,5
Cleaning wastewater
- unclean side (sterilisation discharge) 0,1-0,2
ess water
2)
- of which proc-
1
0,05-0,1
- clean side 0,1-0,2
Exhaust air treatment
0,02-0,1
Production water processing ca. 0,01
De-sludging wastewater (Evaporator) ca. 0,02
Cleaning of lorries 0,05-0,2 3)
Domestic wastewater, incl. laundry wastewater 100-200 (l/E*d)
Cooling water with continuous-flow cooling 10-20
1)
2)
3)
TBAs without special processing
from separation and drying
1-5 times washing per week and vehicle
The composition of the process water is shown in Table 7-3.
Table 7-2: Composition of the process water in a TBA without processing of blood, feath-
ers, or bones
Parameter Unit Average value Range
pH-value - 5,7-9,5
Specific conductivity mS/c
m
4,7 2,2-22