Waste water tech for sewage treatment plants

Sewage treatment plants clean up tons of waste water every day. Technical problems or even system failures cannot be tolerated. At every purification stage of your sewage treatment plant, use drive technology that is individually tailored to your requirements, prevents failures, and lowers energy costs.

Bird's eye view of a sewage treatment plant modelT
  • Infeed with screw pump
  • Screening system and wash press feed
  • Screening treatment
  • Sand trap with scraper and grit classifier
  • Primary sedimentation with scraper
  • Aeration tank
  • Final sedimentation with scraper
  • Digestion tower

Infeed with screw pump

Screw pump in sewage treatment plant

As soon as the waste water reaches the sewage treatment plant, it is lifted by the screw pumps in the infeed to sewage treatment plant level. A motor is coupled to the gear unit via a belt for this purpose. The mechanical cleaning begins. In the infeed, the amount of waste water, temperature, pH, and electrical conductivity are measured. In the infeed with screw pump, the drive unit consists of an X-series helical gear unit with motor adapter and AC motor.

Screening system and wash press feed

Screens in sewage treatment plant

First, the waste water in the screening system is coarsely cleaned. All larger solids are removed from the water. This can range from baby wipes, carpet scraps, wedding rings, or even dentures. Screen cleaners then transport the filtered substances for further processing. In the existing screening system, parallel-shaft helical gear units are used in combination with an AC motor. Thanks to their slim design, parallel-shaft helical gear units are used mainly in confined spaces and are optimally suited for long-term operation.

Screening treatment

Wash press

The wash press is generally fed directly through the screen or by a conveyor. A solid shaft screw pushes the screenings into the wash area. Here, fecal matter is removed using a washboard and friction process. Water is subsequently removed from the washed material in the pressing zone. This process step uses parallel-shaft helical gearmotors and helical-bevel gearmotors as well as frequency inverters.

Sand trap with scraper and grit classifier

Sand trap with scraper for sewage treatment plants

In the sand trap, the flow rate of the waste water is reduced so that heavier materials such as gravel, sand, or soil settle. These solids are fed to the grit classifier under pressure. The tangential inflow causes a rotation of the water so that the heavy materials like sand sink into the tip of the funnel. F.. series parallel-shaft helical gear units or helical-bevel gear units from the K.. series are primarily used in the sand trap in combination with an energy-saving motor.

Primary sedimentation with scraper

Primary sedimentation with scraper

Even lighter particles of dirt settle in the primary clarifier because the waste water flows very slowly. To allow the lighter particles to settle, the flow rate of the waste water must be reduced. High-ratio SPIROPLAN® right-angle gear units from the W..9HG series or K series helical-bevel gear units with primary gear units are used.

Aeration tank

Aeration tank in sewage treatment plant

Biological treatment begins in the aeration tank. Here, microorganisms are mixed into the wastewater so that harmful ammonia is converted into pure nitrogen. The tank is aerated to ensure that the bacteria are supplied with sufficient oxygen and keep moving. Air is added via rotating rotors arranged perpendicular to the tank surface. X.e series helical gear units are the preferred choice for driving the surface fans.

Final sedimentation with scraper

Final sedimentation with scraper

By further reducing the flow rate of the waste water stream, sedimentation of the settleable substances takes place: The saturated microorganisms sink to the bottom of the final clarifier. This sludge is pushed together with a slide feed and discharged through a funnel in the middle of the basin. In the final sedimentation high-ratio SPIROPLAN® right-angle gear units from the W..9HG series or K series helical-bevel gear units with primary gear units are used.

Digestion tower

Digestion tower

During waste water treatment, sewage sludge are produced. This sludge forms gas in the digestion tower, which is used for heat production. In order to guarantee an optimal digestion process, the temperature in the digestion tower must be kept at 36 – 37 degrees. The digested sludge is constantly agitated by a mixer. To absorb the forces that occur, FM... or FAM... series helical-bevel gear units in special agitator design are preferably used.

Modernization of a screw pump

Replacing outdated drive technology and installing modern solutions for smooth and sustainable processes in the wastewater treatment plant

With the SEW-EURODRIVE retrofit service, you can bring your outdated screw pump drives back up to speed. Whether gear unit, motor, belt, coupling or frequency inverter - everything is coordinated and from a single source. Watch this video to find out how we modernized the drives of the screw pumps in a large German sewage treatment plant and brought them up to the latest energy standards.

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Living responsibility

Sustainability is a central part of our philosophy. Our drive technology ensures smooth processes in the sewage treatment plant and relies on environmentally friendly solutions.

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