Integrierte Vermeidung und Verminderung der Umweltverschmutzung

Filleting of herring Filleting of cod
Parameter Average
(kg/m 3 Range
) (kg/m 3 Concentration
) (kg/m 3 Load
) (kg/t fish)
BOD7 10000 5000 – 20000 600 – 1300 8 – 19
Fat 12000 2500 – 16000 50 – 70 0.3 – 1.4
Dry matter 20000 5000 – 28000
Protein 6000
Total nitrogen 100 – 600 0.3 – 3.1
Suspended solids 1.6 – 11.3
Water consumption (m 3 /t) 5
Table 3.17: Waste water from fish filleting
[134, AWARENET, 2002]
Chapter 3
In precooking, water is re-used several times and recovery can be made. About 3 – 4 g oil/kg
fatty fish, protein and pieces of fish are released into the water with oil forming a layer on the
surface. If the fish is made in brine, there is a high salt concentration in the waste water. Skin is
removed from some species, such as mackerel, with the help of a warm caustic bath. Waste
water is consequently alkaline and is treated by neutralisation.
The waste water contains blood, flesh, guts, soluble protein and waste material and is high in
BOD, COD, TSS, FOG, and phosphates, as well as detergents and other cleaning agents.
Waste water production rates and characteristics depend highly on the production lines. Data for
Germany are presented in Table 3.18.
Production
Waste water
production
(m 3 /t)
SS
(mg/l)
BOD5
(mg/l)
Fats*
(mg/l)
Herring 17 – 40 220 – 1520 2300 – 4000 190 – 450
Fresh fish About 8 170 – 3650 1000 – 6250 46 – 2500
Smoking of fish About 8 14 – 845 1000 – 1700 24 – 180
Salting of salmon About 35
Deep frozen fish 2 – 15
Thawing 0 – 70 30 – 1800 4 – 46
*expressed as petrolether extract
Table 3.18: Typical waste water production rates and characteristics for fish processing in
Germany
[27, ATV, 2000]
3.3.2.3 Solid output
The solid wastes generated during fish processing range between 20 – 60 % of the catch,
comprising skin, guts, bones, heads, cephalopods, feathers and shells. For example, when the
fish quality is poor, soft fillets can get caught in the skinning knife. This decreases the yield and
increases the production of by-products and waste.
Part of the waste water and almost all of the solid output may be used for different purposes.
Fatty acids and flavours may be recovered from cooking water. Rejected fish are used in animal
feed or for production of fish-meal and fish-oil and used afterwards in foodstuff, animal feed
and coatings.
RHC/EIPPCB/FDM_BREF_FINAL January 2006 157