The challenge

The wastewater treatment plant used to comprise up to seven rotary piston blowers. Process-related increases in pressure were, however, causing single unit failures with rising frequency. In addition, the relatively high share of industrial wastewater of up to 75% led to large load fluctuations within a few hours. These fluctuations require a rapid response in terms of air supply.

The project

Following an assessment of a range of technological solutions, the treatment plant of Sögel decided to acquire turbocompressors. The decision was partly made on account of recommendations by a neighbouring municipality, which has already been operating Sulzer’s turbocompressors for some years.

Customer with HST turbocompressor

Due to our very positive experience with the first four aggregates, we decided to order this most recent one without obtaining an extended warranty.

Operations Manager at the Sögel wastewater treatment plant

The solution

The supply of oxygen to the aeration tanks 1, 2, 4 and 5 of the treatment plant is now handled by five centrally controlled turbocompressors. While 1-3 units are running during normal operation, additional turbocompressors can be switched on during peak load times to meet considerable increases in the polluting load.

The turbocompressors operate nearly maintenance-free, only replacement of filters is needed. The earlier rotary piston blowers required checking of oil levels and belt tension on a daily basis, replacing filters, oil and bearings by internal and external specialists, and demounting and dismantling of units to enable maintenance.

Customer benefits

Reduction in maintenance costs: According to a conservative estimate by the operator, the conversion to Sulzer equipment translates into yearly savings of 10,000 euros in maintenance costs.

Reduced energy consumption: By converting to turbocompressors, installing new aeration units and optimising the controls, the specific energy consumption of the wastewater treatment plant has been reduced by more than 50% in the past six years. More than 80% of this reduction is due to the installed turbocompressors.

Lower heat build-up, lower noise levels, less vibration.

Product specification

Turbocompressor type ABS HST2500-1-H-4

Airflow range 1'000 - 3'700 Nm3/h
Pressure rise 60-85 kPa
Input power 83 kW
Power supply 380 V-690 V
Input frequency 50 / 60 Hz
Protection class IP33D
Thermal protection PT100
  • HST™ turbocompressor
    The modern and silent HST™ turbocompressor features an advanced design with proven magnetic bearing technology and a high-speed motor driven through a built-in frequency converter.
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