Integrierte Vermeidung und Verminderung der Umweltverschmutzung

Chapter 3
LIQUID WASTE
IN
VOLUME/WEIGHT
3.5 - 8.5 m 3 /t of raw
material a
POLLUTING
LOAD
COMPOSITION
Total waste water f :
* BOD5 : 140 - 7000 mg/l
* TSS: 60 - 3000 mg/l
2 m 3 /t h : COD 6000 - 12000 mg/l
TKN 300 mg/l
7.4 m 3 /t i : COD 4650 mg/l
WASTE
WATER
Cleaning water/
Fluming water a
Blanching
water
Waste water
Waste water
(caustic)
Canning/Sealing
Sterilisation/Cooling
FRUIT AND VEGETABLES
PROCESSING AND
PRESERVATION
Pre-conditioning
Washing/Fluming
Sorting
Trimming/Peeling
Blanching g
170 January 2006 RHC/EIPPCB/FDM_BREF_FINAL
Cooling
Peeling d
Coring e
Slicing & Dicing
Drying
Stem, dust, leaves, stalks,
rotten raw material
Stems, leaves, stalks, etc.,
rotten material c
Freezing
SOLID WASTE/
BY-PRODUCT
Frying h Spent oil
Stalks, leaves, seeds e
% SOLID
WASTE IN
WEIGHT
1 - 30 b
0.07
TOTAL: 5 - 30
a Large quantities of water are used for processing fruit and vegetables, specially in cleaning operations. Very variable depending on the raw material and the type of process.
b There is a large difference of solid waste percentage depending on the type of vegetable or fruit, from 1 % in cranberries to 20 % in broccoli or carrots.
c Removal of rotten and injured fruits and vegetables by mechanical methods such as sieves and perforated plates. For the removal of very rotten fruits, salty solutions are used
(brine density graders).
d Removal of peel. Different methods are used depending on the peel thickness, toughness and final’s product demand: mechanical, thermal (steam) and chemical (NaOH)
in case of potatoes it is steam peeling and takes place before blanching.
e Sometimes is necessary to do it mechanically (cherries) for seeds and kernels removal.
f Average total wastewater is around 3.7 m3 /U (unit of production), with average values of BOD5 of 5 kg/U and TSS 0.5 kg/U.
g Some products are not blanched such as preserved onions.
h For fried potatoes production. The wastewater from washing, steam peeling and blanching are sent to the WWTP and 5 l/t of anaerobic sludge is generated and incinerated.
i For the production of preserved potatoes and carrots (data from Finnish companies).
Figure 3.8: Type and amount of wastes produced in fruit and vegetable processing and
preservation
[134, AWARENET, 2002]
Some reported figures for producing fruit and vegetable juices are shown in Figure 3.9.