WATER TREATMENT PLANT – PROCESS FLOW CHART

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.