Natural Mineral Water: A Challenge for Filtration Technology

Bergische Waldquelle mineral water was rated “Excellent” by ÖKO-Test magazine

In November 2017, the German ÖKO-Test magazine reviewed 21 mineral waters producers suitable for use in the preparation of baby food. The magazine gave Bergische Waldquelle’s glass bottle product an "Excellent" rating.

In other words, the product doesn’t just taste good, but also meets the highest quality requirements—something that Donaldson filtration technology helps achieve.

The "Haaner Felsenquelle" portfolio includes more than 80 beverages, from mineral water to isotonic soft drinks. Since 1909, Haaner Felsenquelle mineral water has been bottled in Haan/Germany (Image 1). Today, seven springs at depths between 140 and 345 meters provide the company’s natural mineral water, which has very balanced levels of mineralization.

In Germany, only a few processes are allowed to be used in the treatment of the water, e.g. the addition and removal of carbon dioxide and the separation of the iron and manganese, which is done using gentle ventilation and/or filtration. Mineral water such as Haaner Felsenquelle is officially recognized as "natural mineral water" because it meets the legal requirement to be labeled as such. This type of official recognition is unique in Germany, as no other food has this certification in the country.

“We ourselves conduct a large number of individual tests in our own laboratory, with tests also conducted by the authorities and independent laboratories, to ensure compliance with the strict specifications. This is a constant challenge for the integrity of the processes in our plant. In this situation, the filtration technology makes a decisive contribution,” explains Lukas Schellenberg, Production Manager at Haaner Felsenquelle, who observes: “Although I can only estimate the number of individual filters, there are certainly more than one hundred." (Image 2) 

Solution

Use of high-purity compressed air with special monitoring

Although the 8-bar process air is produced by two oil-free screw compressors, it must still be cleaned by compressed air filters and an activated carbon adsorber after drying. This ensures that it is better than class 1 according to DIN ISO 8573-1:2010., which implies a residual oil content of less than 0.01 mg/m³ and a particle density of less than 0.1 mg/m³. The PET bottling machine has the capacity to process 13,000 bottles per hour and is supplied with 30 bar compressed air by a piston compressor; which, like the screw compressors, is oil-free. To ensure the air has a high level of purity, special high-pressure filters and a P-SRF sterile filter are used to eliminate contamination with bacteria and particles during the blowing process.

Schellenberg explains, "The entire treatment of compressed air is under our special observation. The priority here is to ensure compliance with particle retention and sterility requirements as well as the energy consumption of the two 30 kW compressors. It is not negligibly influenced by the differential pressure of the filters."

Maintain natural properties and purity

"The special nature of our region, the 'Bergisches Land', plays a big part in the quality of our natural mineral waters. They are pure by nature. Our task as a mineral spring business is to make sure these natural properties and the purity are preserved during bottling and processing."

The entire production is based on this guideline of the Haaner Felsenquelle. Working closely with Donaldson's filtration specialists, the filtration specifications for each application are selected. Here, practical knowledge and continuous tests in our own laboratory meet the latest technology in filtration technology with the LifeTec depth and membrane filter elements. (Image 3)

LifeTec filters (Image 4) differ from previous filter constructions due to a much more stable polypropylene filter liner. The liner’s rhombus-shaped structure not only optimizes the static, but also improves the flow conditions.

The success of this series of liquid filters, approved for direct food contact according to Regulation EC 1935/2004 and Code of Federal Regulations Title 21, is based on the state-of-the-art clean-room manufacturing concept in Donaldson’s Haan/Germany manufacturing plant. The largely digitized and customized production allows for high production quantities, as well as lot size 1, and creates short delivery times.

Sterile filters take performance to new level, with longer filter service life

The service life of compressed air filters when used in highly sensitive areas of mineral water bottling (e.g. the PET process) is also very important to Haaner Felsenquelle.

The P-SRF C and SRF V depth filters can be used as vent filters to equalize pressure when managing the water tanks, concentrate and sugar tanks. These pleated stainless-steel filters are characterized by a particularly high material resistance and service life. P-SRF V is available in sizes between 5" and 30”, with various connections.

The retention efficiency for 0.2 micron bacteria and 0.02 micron phages/viruses achieves 99.99999995%. For nanoscale contaminations of 0.003 micron, it reaches 99.999999991%. The P-SRF V is ozone- and VPHP-resistant, tolerates aerosolized CIP chemicals and can be used in temperatures up to 200° C / 392° F.

Service and fast delivery times

The service portfolio of Donaldson is also robust. Services offered include differential pressure measurement for customer elements, integrity testing for depth filters (DOP test) and quantitative and qualitative particle analysis (0.8 – 120 micron) for liquids. Regeneration of stainless-steel filter elements with differential pressure measurement is also offered before and after cleaning.

Lukas Schellenberg has appreciated the advantage of fast filter delivery: "Fast access to filter elements is an important factor, despite the long service life of the filters, which we control by measuring differential pressure." This is a view that is shared by Senior Manager Helmut Römer, who highlights: "Working with a filtration technology company whose portfolio covers all production areas of a mineral spring company is proving beneficial."