Integrierte Vermeidung und Verminderung der Umweltverschmutzung

Chapter 2
In principle, many different methods of transport are possible for material and liquid flows.
Some examples of transport systems commonly used include perforated trays connected to an
unbroken conveyor or loop, moving horizontally or vertically; screw conveyors which transport
the solid material in a countercurrent flow vertically or upwards under an incline slope, the
screws are perforated to obtain a uniform flow of liquid and finally, an unbroken perforated belt
where the solvent is circulated under pump action and sprayed on top of the solid material.
2.1.3.2 Deionisation (C.2)
2.1.3.2.1 Objective
Deionisation or ion exchange is used to remove unwanted organic and/or inorganic constituents
from water and food products. See also electrodialysis in Section 2.1.3.6.
2.1.3.2.2 Field of application
In the dairy industry, deionisation is applied in whey processing. For the application of whey
solids in human food and in baby food, low levels of mineral constituents are required.
Deionisation is also widely used in the FDM sector for the treatment of boiler feed-water for
power and steam generation and for the production of deionised process water. Deionisation is
also applied to remove minor ionised organic substances.
2.1.3.2.3 Description of techniques, methods and equipment
Deionisation is normally carried out by passing the product through a column containing ion
exchange resin beads. The beads contain a large number of active sites which are capable of
holding a wide variety of metals, non-metal inorganic molecules and ionised organic
constituents. The columns are operated batch wise and need to be regenerated when the beads
are exhausted or saturated. This is normally carried out by treatment of the columns and beads
with a variety of chemicals which remove the impurities and regenerate the active sites.
2.1.3.3 Fining (C.3)
2.1.3.3.1 Objective
Fining is the process of clarifying liquids, i.e. removing suspended particles which give the
liquid a cloudy appearance.
2.1.3.3.2 Field of application
The production of sparkling wines and beer.
2.1.3.3.3 Description of techniques, methods and equipment
The fining agent introduced causes the minute hazy particles to flocculate and precipitate out of
solution. These particles are proteins, polyosides, polyphenols, ferrous or cupreous complexes.
For the fining action to take place, the electrical charges between the fining agent and the
particles must be opposed, which means that it is necessary to carefully choose the fining agent
depending on the effect sought. The nature and the dose of the fining agent can be determined
by laboratory tests. Moreover, some other treatments can be technically classed as examples of
the fining process, such as iron elimination with potassium ferrocyanide.
The fining agents used can be divided into two major groups; organic and mineral fining agents.
Some organic fining agents are gelatine, ichthyocolla, egg albumin, blood albumin, algein,
caseins and caseinates. Some mineral fining agents are bentonites, silica gel and oenological
tannins.
18 January 2006 RHC/EIPPCB/FDM_BREF_FINAL