Introductions
Water is the
major raw materials used in production
of alcoholic and non alcoholic beverages
as such the supply and treatment of
water is a vital importance to the
brewery because the availability of
water affects the quality of product.
Raw Water Supply
The raw water is
sourced form 5 boreholes. The depth of each boreholes is
120m. each pump is connected to the
surface with that flexible riser pipe. From
the borehole analysis, it was
detected
that it contains some ions from dissolved salts. These ions are undesirable for brewing eg
irons, this has an influence on the
flavour and their color of the
beer, it inhibits sacchari fication and given
a hard bitterness. it supports the oxidation of beer ingredient
which leads to hazy beer. Manganese at
higher levels has the same effect as the iron is beer. It also has a negative
influence of foam stability. Also ammonium in raw water is an
indicator for organic contamination and
bears the risk of forming nitrate through partial oxidation reaction. Nitrate
is toxic for yeast as it inhibits its growth and fermentation .
Furthermore, the water is aggressive due to lack of
calcium (CA) when compared to the
carbonate content. As such, these ions/impurities that have adverse effects on
beer production need to be removed as
well as the addition of Ca(OH)2
lime to meet the calcium specifications. This
is basically what is being done in water treatment plant. These plant is designed for the production of two
main water namely; I soft (service) water ii product water
PROCESS FLOW CHART OF THE WATER TREATMENT PLANT
Lime Preparation
Tank
Lime milk
preparation is carried out manually in
the preparation tank here, the white lime is mixed with water to form a
solution, this mixture is stirred with a
stirrer. After through mixing, the lime
milk will be delivered into the lime saturator by the help of a
pump.
Lime Saturator
The lime milk is
pumped into the lime saturator as well
as the raw water. Here the water is saturated with Ca(OH)2 ie increases the calcium
hardness of the water. Also this lime dosing is used to regulated the PH
Oxidation Air
Feeding
The water is
aerated as at flows from the lime saturator to the sand filter. This air
oxidizes some impurities in the water such as iron and manganese. Once oxidized, these chemicals fall out of the
solution and become suspended in the water.
The suspended material is then
removed through sand filtration processes.
Sand Filters
The sand
filter are 3 in number these are enclosed tanks that contain different aggregates
of gravel arranged in different layers. During filtration, water flows form the top through
the filter medium (Gravel) to the bottom of the filter . On the process, the layers
of the
gravel will trap the suspended material both the iron and manganese from the water while the water passes through
pipe to carbon filter . The next stage.
After
filtration, the filter ate will be split
up onto two parallel treatment system in order to obtain
softened water and product
water.
Softened
(Service) Water
To produce water,
50% of the pre-treated water is sorted in the storage tank, on the
on-line to the softened water storage
tank, chlorine dioxide is dosed as disinfectants additive in the return linking line of
the soft water distribution
pumps to obtain a free chlorine level of 0.5mg/l at the point of use.
Use of the soft
water in the company
1.
it
is used as rise water for tanks and beer
lines
2.
it
is use in the washing of the crates and
bottles and also in pasteurization of
the packaged product
3.
it
is used as the general purpose water in
the brewery
Product Water
For production of product water, the remaining 50% of
the pre-treated water will flow through
two carbon filters. At the carbon filter, the colour, odour and taste
are removed from the pretreated water. Then the water flows form
the carbon filter to the product storage tank where it is stored
until when it is needed for distribution.
UV Unit
Before entering
the distribution system form the product water storage tank, the product water
will pass an ultra –violet (UV) unit for disinfections purpose by minimizing
the microbiological load. The (UV) destroys micro organisms by changing their genetic
information. The (UV)unit is installed
after the distribution pumps that distribute the water to the brewery. This
arrangement is so because the product water needed not to stay long after
passing through (UV) unit. A if it does, micro-organisms will start to
grow in it prior to its usage.