man in blue with helmet

Edition 03/2019

Article and compact news

Our AERZEN customer journal "AERZEN" will provide you with detailed information at regular intervals about our company, our products and application solutions.


Wastewater treatment: Blown up into the mountain

In Zermatt, the wastewater treatment plant is hidden inside the Alpine massif

To accommodate it, extensive caverns were created inside the Alpine massif itself, following major excavation work which took five years to complete. Since then, Zermatt, also known as a “tourist magnet” at the foot of the Matterhorn in the Swiss canton of Valais, has been cleaning its wastewater subterraneously, behind closed doors. Inside the caverns, AERZEN blower technology provides adequate ventilation of the filter lines and activation.

Not much to see: the Zermatt wastewater treatment plant clings to the Alpine massif unobtrusively. Behind the door, state-of-the-art process technology is revealed.

Zermatt lies in a narrow valley, called the Mattertal. “The wastewater enters the treatment plant from both sides of the valley,” says Beni Zenhäusern, Production Manager. The street that runs in front of the entrance portal to the ARA Zermatt therefore has an underground cellar. The computer system and the sand-grease collector are installed here. “A pumping station delivers the pre-treated wastewater 11 meters upwards, before it is separated into two identical treatment lines.”

Zermatt is a phenomenon in wastewater technology. This place has only 5,600 inhabitants. However, the treatment plant has a capacity of 76,000 population equivalents (EEC). Some background to this: During the peak season in winter and summer, dirt loads arrive that reach a chemical oxygen demand (COD) of 60,000 for complete degradation. A COD value of 60,000 EEC corresponds to that of a medium-sized city. The high freight volume and the enormous COD value for wastewater treatment can be explained by the discharge gastronomy.

Energy-optimised and standardised blower technology

The Zermatt wastewater treatment plant has two treatment lines. They are located opposite one another and are equipped with exactly the same technology. Here is one of the two machine rooms, equipped with positive displacement blowers made by AERZEN.

Biology lies further inside the Alpine massif. The two basins of denitrification are connected in a Y-shape to two filter lines, which are functionally part of nitrification. Five filter cassettes form one filter line. Each cassette has 48 hollow fibre units. For the necessary oxygen supply, ARA Zermatt uses identical AERZEN Delta Blower machinery in two blower rooms. Five positive displacement blowers, type GM 50 L (max. 90 kW, 3.300 m³/h, max. 700 mbar) are installed. These fifth generation blowers from AERZEN are energy-optimised and deliver up to 50 standard cubic meters per minute with an engine power of 45 kW. A special feature of the design was that Zermatt lies more than 1,600 metres above sea level. This has a corresponding effect on the density of the air sucked in. The significant temperature differences between winter and summer also pose a challenge.

Two positive displacement blowers, type Delta Blower, ventilate the sand collector.

From each of the two machine rooms, two Delta Blowers supply the nitrification with sufficient oxygen. Two more Delta Blowers are assigned to the diaphragm filter. “The hollow fibres must always stay in motion during operation. We do this with air,” Zenhäusern notes. The remaining fifth blower is mainly assigned to the filter as a reserve, but can also be used for nitrification via a corresponding slide valve position. This design, with identical machinery, makes the power distribution of the blower air flexible, and, as a result of standardisation, reduces the cost of spare parts.

ARA Zermatt works closely with Aerzen Switzerland on service and maintenance issues with regard to operational safety. Michael Schüpbach, the head of the Service Centre in Frauenfeld, south of Lake Constance, has drawn up a revision plan for all blower packages for the wastewater treatment team.

The hollow fibre diaphragms filter the water. The openings are so small that even bacteria cannot pass through them.

Diaphragm filters are also important in connection with operational reliability and long-term availability. After ammonium nitrate degradation, they separate the activated sludge from the biologically purified water. The water is sucked through the diaphragm into the interior of the hollow fibres by vacuum. The pressure difference is generated by a rotary piston pump. The air from the blowers acts as continuous coarse ventilation. This is necessary to keep the diaphragms moving, as the diaphragm openings only measure 0.04 micrometers, which is too small for bacteria. Therefore, the diaphragms would clog immediately if the air-water flow fails.

In total, underground biology has a filter area of 32,500 square metres. This is roughly the size of 4.5 soccer pitches, and it all happens in the smallest of spaces. Adding up the hollow fibres, their total length of around 5,000 kilometres would stretch from Zermatt to Dubai. “We make a living from tourism,” says Beni Zenhäusern. For this, the town has invested in a wastewater treatment plant which has ten times more capacity than the population actually needs. In addition, there are the strict wastewater regulations. Whereas in Switzerland the limit value is 0.8 mg. phosphate per litre, in Zermatt it is only 0.5 mg due to the receiving water. In view of these constraints, the wastewater treatment plant in Zermatt exclusively uses technology which meets the highest demands on availability. AERZEN holds the position of manufacturer and partner at the same time - in addition to providing pure technology, the company also passes on its know-how over the entire life cycle.

Compact news

AERZEN is World Market Leader

AERZEN is World Market Leader

Big thumbs-up from Wirtschaftswoche: In a study, the renowned German business magazine has found out that AERZEN is the world market leader 2020 in the field of “Positive Displacement Blowers and Screw Compressors”.

The economist Prof. Christoph Müller, from the University of St. Gallen in Switzerland, has developed a robust assessment procedure for the magazine, on the basis of which he draws up a list of world market leaders every year.

Wirtschaftswoche published a tabular overview of the 450 companies with turnover and sectors in which they dominate in a special issue dated 14 October 2019.

“Star of Product” for AERZEN Delta Hybrid

Aerzen China received the award “Star of Product” for the rotary lobe compressor Delta Hybrid at the 14th International Water Conference in Qingdao, China. The event took place from 25 to 28 June 2019. A total of 20 companies were nominated for the award. AERZEN won due to the outstanding performance, reliability and economical energy consumption of the Delta Hybrid. Lang Weiguo, Sales Director Aerzen China, accepted the award on behalf of the company. Tony Chien, Sales Manager Aerzen China for the water industry, gave a lecture on energy savings and new developments in blowers for wastewater treatment.

Aerzen China participated for the second time in the water conference in Qingdao and has already confirmed its participation for the next year. More than 2,500 participants showed great interest in the company’s energy-saving solutions and products. The China Association for Science and Technology and the Qingdao Municipal People’s Government are the hosts of the event.

Aerzen Turbo Korea successfully validated for US-American CTPAT programme

Aerzen Turbo Korea successfully validated for US-American CTPAT programme

Thanks to the successful re-validation of Aerzen Turbo Korea as a foreign supplier, Aerzen USA can continue its participation in the CTPAT programme. CTPAT, which is the Customs Trade Partnership Against Terrorism, is intended to strengthen international supply chains and improve border security in the United States. Every four years the re-validation of a supplier abroad becomes necessary, in this case Aerzen Turbo Korea. Aerzen USA has been participating in this programme since 2016, which brings considerable advantages for the import of goods. For example, CTPAT members are subject to fewer customs inspections and waiting times at the border for the import of products are reduced.

Craig Russell leads the Middle East and Africa

At the beginning of September 2019, Craig Russell took over as Managing Director of Aerzen Gulf and Head of the Middle East & Africa. Born in Scotland, he will lead the AERZEN Group in the Middle East and Africa from Dubai and sees great potential in the region: “Taking over responsibility for the Middle East and Africa is a privilege for me,” says Russell. “The emerging markets generally offer us numerous opportunities, and this region is definitely already very successful. I support many of the initiatives that have already been launched, such as the expansion into East and West Africa and the development of local production.”

Russell has lived with his wife and two children in Dubai for many years, where he initially worked for American and Japanese family businesses in the food processing and packaging industries and later was responsible for the restructuring and sale of engineering companies.

New Head of Supply Process Gas

Walter Reiter has taken over the global management of Supply Process Gas at AERZEN and succeeds Pierre Noack. Reiter has over 30 years of experience in management positions in German plant and mechanical engineering companies.

New Head of After-Sales

Björn Heuer took over the management of After-Sales from Bernd Brakemeier on September 1, 2019. With more than 25 years of professional experience, including time as service engineer and product manager for Delta Blower and Delta Hybrid, he has extensive practical experience as well as in-depth product and application knowledge. For the past five years he has been responsible for the After-Sales Field Service division.