The target: reducing energy demand and lowering CO2 emissions

In order to reduce energy demand and CO2 emissions, the Roskow wastewater treatment plant carried out extensive construction work between 2021 and 2023. “A lot has changed structurally in these three years,” says Thomas Hantke, Technical Director of the WAH: “We have completely modernised the machine technology, the construction technology and the E/I&C and process control technology. The plant is now up to date in terms of energy efficiency. This results in a number of positive effects regarding energy consumption, CO2
emissions and costs.”

Energy optimisation of aeration technology: key to higher energy efficiency

A central component of this was the energy optimisation of the aeration technology in two aeration tanks. By switching to highly efficient turbo technology from AERZEN and new aerators, the Roskow wastewater treatment plant was able to reduce its energy demand in 2023 by around 330,000 kWh compared to 2022, saving 177 t of CO2. In addition, a digestion plant including an associated CHP plant and upstream pre-treatment was installed in a separate construction phase, which has an annual output of 660,000 kWh. This will save a further 354 t of CO2 per year.

Turbo blowers replace old compressor station

Biological treatment is at the heart of every wastewater treatment plant, but it is also the biggest consumer of electricity and therefore costs. Previously, rotary lobe compressors and Delta Blower positive displacement blowers (two GM 25 S) supplied the microorganisms in aeration tanks 1 and 2 with oxygen. These have now been replaced with five turbo blowers: one AT 50 and one AT 100 per tank and one AT 150 as a central reserve. “The Havelland Water and Wastewater Association has always used AERZEN technology on its wastewater treatment plants. We are well looked after there and feel that we are in good hands. The machines are reliable and the services are outstanding,” says Thomas Hantke, who is delighted with the excellent cooperation. With regard to the turbos, he adds: “We are very happy that the Turbos are so compact. This is very beneficial for our limited installation capacities. They are also service-friendly. An oil change is not necessary. This makes work easier for our operating staff. The brand loyalty also has advantages in terms of spare parts stocks, standardisation, control technology, operation and maintenance.”

The Aerzen Turbo is unbeatable in terms of energy

The Turbo blowers of the G5plus series which are now in operation at the Roskow wastewater treatment plant, are among the most compact and efficient turbos in their
class and are currently unbeatable in terms of energy efficiency: compared to conventional turbo technology, their energy efficiency is up to 10% higher. Compared to
displacement machines such as positive displacement blowers, savings of up to 30% can even be achieved. This can be accomplished by highly efficient individual components,
such as the extremely powerful and energy-saving permanent magnet motor, which meets the future requirements of the IE5 classification (Ultra Premium Efficiency) thanks to the particularly aerodynamic design with turbo impeller and spiral casing and the innovative multilevel VFD technology with up to 90% less power loss in the motor compared to conventional converter technology. “Aerzen turbos stand for maximum energy efficiency, absolute reliability, reduced maintenance costs and low life cycle costs, making them an ideal solution for supplying oxygen of the aeration,” emphasises Sales Engineer Christian Meyer from AERZEN. Minimum machine footprint Thanks to the air foil bearing with double coating, Aerzen turbos offer an extended bearing service life of up to 80,000 operating hours regardless of start-stop cycles and are virtually maintenance free. The only thing that needs to be done is to change the filter regularly. The reduced dimensions warrant a minimum machine footprint - ideal when space is limited. AERZEN manufactures and develops all of its products via in-house production. This means that all components can be perfectly matched with each other and ideally adapted to the operating process.
This guarantees maximum reliability, operational reliability and cost-effectiveness.

50% higher oxygen input thanks to state-of-the-art aeration

The aeration elements were also modernised as part of the renewal of the blowers. Instead of candle diffusers, large-format aerators ensure that the air provided by the
AERZEN packages reaches the pool. At the same time, the configuration was optimised and the area increased from 60 m² to 160 m². 50% more oxygen can now be
entered with the same amount of air. This enables enormous energy savings. Thanks to the new technologies - blowers and aeration elements - as well as the construction of a pre-treatment and digested sludge plant, the tank volume could be reduced: instead of three, only two aeration tanks are needed. The third basin, which had its own compressor station with a further three machines, was taken out of permanent  operation and serves as a buffer basin.