|Features||Underground installation in concrete tanks|
|Biological wastewater treatment|
|Balancing of fluctuating wastewater loads|
|Treatment Modules||ClearFox® FBBR with primary sedimentation|
|Sedimentation tank and secondary sedimentation|
|pH value adjustment|
|COD||1500 mg/l||150 mg/l|
|BOD||400 mg/l||40 mg/l|
In 2012, a young man founded a brewery in western Germany. Sales went well, so the existing capacities quickly became too small. While he rented space in other breweries, he continued to expand his site near the Dutch border. In the process, a wastewater treatment plant for a brewery was to be built on the company’s premises to purify the produced wastewater.
The amount of waste water produced daily is about 150 PE, which mainly comes from two sources: most of it consists of waste water from the brewing process, a smaller part is the sanitary wastewater of the employees. Therefore, the wastewater is not only characterised by an increased COD and BOD5, it also contains solids such as malt residues, hop residues and yeast cultures.
The brewing process requires a great deal of hygiene and cleanliness. It is therefore necessary to clean all utensils, tubs, and kettles immediately after use. This creates a very large wastewater load. Although breweries are constantly trying to minimise their water footprint, even economical cleaning processes require about 3.5 litres of cleaning water per litre of beer.
The brewing process is divided into three phases: The brewing day, where the basic substance of the beer is obtained, the maturing phase, where the alcohol is produced, and the storage phase, where the beer develops its full flavour. All in all, this process takes about five to six weeks. 90 percent of the wastewater is produced on the brewing day. This means that the wastewater flow is very irregular, which the wastewater treatment plant for a brewery must compensate for.
To treat the wastewater to the desired discharge quality, the ClearFox® team offered the brewery four underground concrete tanks in which the entire wastewater treatment solution is installed. The first tank is a primary clarifier with sludge storage. The second tank is a collecting tank in which coarse solids such as malt residues can settle. In the third tank, biological wastewater treatment takes place using ClearFox® FBBR technology. Secondary sedimentation with pH adjustment takes place in the fourth tank.
The first two tanks serve to balance the fluctuating wastewater inflows. Since the mixing and equalisation tank is aerated, initial biological treatment already takes place there. The fixed-bed reactor consists of a growth material for microorganisms that reliably purify the wastewater biologically. Since the wastewater is still slightly acidic even after biological treatment, pH adjustment in the last tank is a necessary step to achieve the desired discharge values.
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