Längenfeld wastewater treatment plant: Wastewater treatment with low acid capacity

Donau Chemie Water Technology
Natural conditions and flourishing tourism pose ever-increasing challenges for wastewater treatment in the idyllic Ötztal valley. The wastewater treatment plant in Längenfeld in particular had reached its limits and had to be modernized. The low acid capacity of the water in the wastewater treatment plant required specific solutions from DC Wassertechnik.

The wide supply area of the Ötztal wastewater treatment plants


The Ötztal is the longest side valley of the Inn Valley
and consists of the five municipalities of Sautens, Oetz, Umhausen, Längenfeld and Sölden. It is not called "the highlight of Tyrol" for nothing. The Ötztal scores with its overwhelming natural beauty and the variety of attractions as well as the varied vacation program.
The Ötztal Nature Park also includes 67 glaciers, including the largest and longest glaciers in the entire Eastern Alps: Hintereisferner, Großer Vernagtferner, Gurglerferner. With 95 km² of glacier area, the Ötztal Nature Park has a very high glacier percentage of 19% - no other protected area in Austria has such an impressive glacier area percentage.
In addition to the best conditions for skiing and snowboarding, there are other very special highlights here: the breathtaking BIG3 platform and "007 Elements" inside the Gaislachkogl mountain, a cinematic installation from the Bond film "Spectre" and the Timmelsjoch High Alpine Road. The road crossing at 2,474 m has probably been an important connecting axis between the North and South Tyrolean Passeier Valley since the Stone Age. The highest pass crossing in the Eastern Alps offers travelers spectacular views of the high alpine nature - and marks the unique Timmelsjoch experience with six adventure stations.

Längenfeld is known as the "resort in the Ötztal". The Längenfeld thermal spa (Aqua Dome) and the cozy atmosphere of the village offer holidaymakers pure relaxation.

Sustainable wastewater treatment plant for 20,000 population equivalents

Kläranlage Längenfeld - Gemeinde LängenfeldThe Längenfeld wastewater treatment plant has to process the wastewater from the 5,300 residents, businesses, restaurants and hotels and, above all, the Tirol Therme Aqua Dome. The plant is currently dimensioned for 20,000 population equivalents.
The fermentation gases produced from the sewage sludge can be used to heat the sewage treatment plant and building yard, saving up to 40,000 liters of heating oil. All parts of the plant were completely enclosed. This means that the entire sewage treatment plant can be arranged over several levels in a very small area.

The challenge: Längenfeld thermal spa and low acid capacity of the wastewater treatment plant

AQUA DOME - TIROL THERME LÄNGENFELDThe Längenfeld thermal spa requires up to 30% of the plant load and a daily water consumption of up to 500 m3. This means an additional several hundred kilos of salt in the form of sodium bicarbonate, which arrives at the plant every day and has to be processed.
The advantage of the thermal wastewater is the warm discharge temperatures, which means that the aeration tank temperature can be kept constant at 12 degrees in winter. 
  • The wastewater treatment plant is a classic activated sludge plant with upstream denitrification.
  • The sludge produced is statically pre-thickened and then treated anaerobically (in the digestion tower).
  • The sludge is dewatered using a chamber filter press.
  • The entire wastewater treatment plant is enclosed. 
Due to the soft water, there is only a low acid capacity, i.e. this plant requires an increased calcium content to increase/stabilize this acid capacity and the pH value in the activated sludge.

The solution: precipitant mixture and chalk for stable wastewater treatment

Tank farm precipitant - Municipality of LängenfeldIn coordination with the additional addition of chalk and a customized DC Fe/Al mixing product, we achieve a stable floc structure that also increasingly binds filamentous bacteria into the compact floc.

This also results in additional sludge weighting in the biology, improved dewatering and increased growth areas for nitrifiers, which ensure safe and, above all, more stable cleaning operations on the systems.

We have already been able to convince over a dozen customers in this region with this successful combination.

Our Donau Chemie motto for customers: First recognize the cause and then take the right medicine. In this case again a successful combination of DC precipitant mixtures and chalk particles.
Donau Chemie Water Technology
Visit our website to find out more about our state-of-the-art water treatment products and their applications.


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