man in blue with helmet

Edition 02/2017

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.


In the aeration tank, the turbo provides ventilation

Robust in operation: at Emsbüren, the AERZEN turbo saves quite a lot of energy

At Emsbüren wastewater treatment plant, Wasserverband Lingener Land invested in new blower technology for the aeration tank. In comparison with the old assembly, the turbo blower made by AERZEN saves between 100 and 200 kilowatt hours every day. Modernisation of wastewater treatment plants in order to reduce their energy consumption benefits the entire population.

Emsbüren wastewater treatment plant
In the biology, designed for a population equivalent of 16,000, the aerobic and anaerobic phases for nitrogen composition alternate cyclically.

Wasserverband Lingener Land has four wastewater treatment plants in the towns of Lengerich, Freren, Spelle and Emsbüren. About 35,000 citizens in nearly 12,000 households are connected. With a capacity of 16,000 population equivalents, Emsbüren wastewater treatment plant is the biggest, and in the course of its modernisation, it was equipped with a turbo blower made by AERZEN. The compact unit supplies the aeration tank cyclically with oxygen for the oxidation of ammonium to nitrate. This had been preceded, in 2015, by equipping the basin, which has a depth of six metres, with modern fine-bubble diffusers made in Austria. According to the estimation of Hermann Schräer, a local skilled worker, the energy savings at the wastewater treatment plant, which amount to around 30 per cent in overall operation, are mainly due to the new aeration concept. 

Modernisation with great effectiveness

“In the purification process, we are now working so productively that we could take one of our two aeration tanks out of operation,” says Schräer. And this increase in effectiveness directly improves resource efficiency- for example, only one submersible mixer has to be used, instead of two. “The agitator only has a power of 3 kW, but that is three kilowatts saved over a long operating period,” adds Schräer. After all, the agitators are working around the clock, as in Emsbüren the biology is not aerated in different zones of a basin but intermittently in one basin. This has a diameter of 24 metres and a capacity of 2,500 cubic metres. The Aerzen Turbo blower TB 50-0.8S, with its electrical motor power of 42 kW and a maximum speed of 42,000 rpm, supplies a volume flow of up to 2,000 cubic metres per hour. The turbo blower installed beside the aeration basin in a compact building has to reach in its performance class a differential pressure of up to 800 millibar. This value is sufficient as the maximum back pressure at the ground of the biology, with a water depth of six metres, is 600 millimetres. As the air supply is provided only a few metres away from the basin, the efficiency increases once again. Shorter pipings reduce friction losses, thus resulting in a lower flow resistance in the system.

Energetically optimised turbo

Aerzen turbo blower TB 50-0.8S
Short line at Emsbüren: the Aerzen turbo
blower TB 50-0.8S is installed in a small, soundproof room directly beside the aeration tank.

The cyclic reduction of the nitrogen bound in ammonium and nitrate compounds makes it necessary that aerated and nonaerated phases alternate as far as time is concerned. At present, the daily operation comprises nine aeration cycles. The capacity of the turbo blower is controlled within the redox curve via the current actual value of the oxygen saturation in the water. “For the nitrification phase, an oxygen concentration of 2 mg/l has proved to be successful. If this value has been achieved the PLC reduces the capacity of the turbo,” explains Schräer. If the wastewater plant blew in more air and increased the oxygen concentration to about 3 mg/l, on the one hand this would mean wasted money, and on the other hand the time required for the anaerobic nitrate removal would increase. At Emsbüren, they operate on the basis that a wastewater treatment plant will usually observe a COD value of 70 mg/l, but their average value is 40 mg/l. Therefore, Schräer assesses the available technology as “a very good solution, particularly for small wastewater treatment plants. ”During an aeration cycle, first of all the turbo blower starts operating for a few minutes at 100 per cent capacity, to set the wastewater in the basin in motion. For the remaining time, the plant runs energetically optimised at about 60 per cent of the maximum capacity. At present, the time span of the aerobic and anaerobic phases is fixed at approximately two hours. During the night, and with less inflow, longer periods apply and the considerably lower air requirement is covered by a small positive displacement blower. At Wasserverband Lingener Land (WVLL), the turbo blower is the heart of the biology “and is running very well,” says the skilled worker. In comparison with the replaced technology (an older turbo blower), the operation is extremely safe and energy efficient. The Aerzen Turbo type TB 50-0.8S starts with a power of 42 kW and then reduces to 23 kW. As improved energy efficiency always involves the correct design for the necessary air requirement, the blower capacity has been designed exactly for this basin. The old blower, manufactured in 2001, had been dimensioned generously and had a connection capacity of more than 70 kW - too much for the aeration system of 2,500 cubic metres and its basin with a depth of six metres and a diameter of 24 metres. While magnetic bearings involve an extremely complex regulation and monitoring of the function, the Aerzen Turbos work with a simple and effective air foil bearing. A specialist in blower and compressor technology uses as a maintenancefree friction partner a 2-pot coating. One of these materials is polytetrafluorethylene. PTFE is a thermoplastic, which, due to its very low coefficient of friction, is used as a non-stick coating.


Hermann Schräer
Hermann Schräer, skilled worker at Emsbüren

The wastewater treatment plants of WVLL Emsbüren show the energy saving advantages offered by turbo blowers even in relatively small biological basins. Moreover, the robust construction of the turbo series TB makes it possible to end continuous operation and to operate the turbo cyclically instead. Thus, this procedure forms the basis for a simple and effective modernisation of small municipal wastewater treatment plants in the countryside. At Wasserverband Lingener Land they are already planning their next projects.

Compact news


Discovering potential and creating transparency

Load operation in wastewater treatment plants is subject to wide variation. The amount of wastewater to be treated – and its level of pollution –will change depending on region, time of day, day of the week, season, or amount of rainfall – often without warning. With the new AERaudit service, AERZEN measures the air volume requirements of a wastewater treatment plant and shows the individual saving potential. Equipped with a mobile measuring case which includes sensor technology, energy counter and data logger, the AERZEN service team screens the blower station. On site, i.e. at the wastewater treatment plant, all necessary operating data (volume flow, system pressure, temperature, kW-rating) is measured and recorded live for a defined period. The recorded data is then assessed in detail at the offices of AERZEN’s parent company. No weak load or peak load remains undocumented. On this basis, the AERZEN team develops one or more possible solutions customised to the individual plant. The objective is clear: to provide utmost energy efficiency. Customers are provided with a transparent and comprehensive presentation of the load profiles and energy consumption of the blower station. In addition, AERZEN documents an individual solution involving the various machine technologies of the Performance³ portfolio (Blower, Hybrid, Turbo). AERZEN illustrates the potential for saving energy and CO2 in the plant, and the payback periods that can be achieved.


Safety standards for the pneumatic industry: new brochure

A unique selling point of AERZEN products is that our silencers are free of absorption material. Thus, this feature has been included in the leaflet portfolio. The new brochure Safety Standards (A3-121-00) provides information about oil-free operation of AERZEN assemblies, as well as about the increased energy efficiency and lifetime extension of process air systems thanks to AERZEN reactive silencers without absorbent material. Please have a look at this new brochure.

The AERZEN duo in Argentina

New Aerzen subsidiary in Argentina

On 1st May 2017, Aerzen Argentina S.R.L. commenced business operations, headed by Alejandro Knoop, based in the suburb of Vincente Lopez of the Argentine capital Buenos Aires. Cristina Pilz is working for Aerzen Argentina as the office’s administrative assistant. There were two reasons for the foundation of the 49th AERZEN subsidiary: on the one hand, a U.S. company had taken over the AERZEN representative in Argentina, which had been working for us there for 37 years, and this led to the fact that AERZEN products were no longer in focus; on the other hand, the arrival of the new Argentine Government has been accompanied by signs of an economic upswing. An important partner is Germany, as it became clear on the occasion of Angela Merkel’s visit to Buenos Aires on 8th June. Alejandro Knoop was also invited to the gala dinner with the Argentine President Mauricio Macri and the Federal Chancellor – a great honour for him and Aerzen Argentina. In the initial phase, Aerzen Argentina will focus on serving existing customers. The wide distribution of AERZEN machines in many main applications provides a good basis for the successful establishment of this new subsidiary. In 2018, sales and service activities will be extended.


Aerzen U.S.A. opens sales office in Houston

Aerzen USA based in Coatesville, Pennsylvania is on an expansion track: This is evidenced by the recent opening of our American subsidiary’s first regional sales office in Houston, Texas. We will now have the opportunity to support our numerous customers in the Gulf of Mexico region directly and more intensively, while also gaining new customers. There are many important refineries and petrochemical plants on the Gulf coast, where our blowers for pneumatic transportation and our process gas compressors are in operation. “Close cooperation with our customers is the key to our mutual success,” says Tony Morris, Managing Director, Aerzen U.S.A. On 20th April 2017, many customers and business partners celebrated the Open House day of the new office in Houston. Employees mainly in sales, application technology and support work in this building, which is also equipped with a conference and training room.