The challenge

During the past years, because of successive extensions of the dairy production sites, the size of the wastewater treatment plant has grown significantly. Initially, a set of roots blowers were providing air to the biological tanks. These roots blowers were later replaced by more efficient screw compressors. The performance of the new machines, however, proved to be rather disappointing and moreover, their maintenance was expensive. When the latest extension of the IWWTP was recently decided, the client looked for additional compressors, which would not only respond to the technical specifications, but also give complete satisfaction in the long term.

Dairy plant wastewater treatment hst turbocompressor
The two HST 20-6000-1-190s in the compressor room

The solution

Sulzer tailored a package of two HST 20-6000-1-190 turbocompressors and one master control unit (MCU) to match the customer’s requirements exactly. A complete set of pipework accessories for the new compressor room was also supplied. In addition, Sulzer gave recommendations for the most proper application of the equipment, e.g. for the ducting of the motor cooling air outlets, which reduces the temperature in the compressor room and is beneficial for the process air. Finally, the optimal design of the installation helped save a lot of energy.

The performances of the HST turbocompressors have exceeded the client’s expectations with significant energy savings, little maintenance, and a low noise level. Furthermore, the top-quality service from Sulzer is greatly appreciated.

Business Development Manager

Dairy plant wastewater treatment hst turbocompressor control unit
The master control unit in the compressor room

Customer benefit

The two HST 20-6000 turbocompressors offer a truly outstanding wire-to-air efficiency. They interface with the upper level control system through the MCU. This MCU selects the most economical compressor combination (one or two running – duty points in the best efficiency zone) to keep the pressure within tight limits whatever air flow is needed.

The two HST 20-6000 are extremely silent, which means a better working environment. The noise level in the compressor room is remarkably low (max. 73 dBA).

The HST uses digitally controlled magnetic bearings, which cause no mechanical friction or wear. The maintenance of the machine mainly consists of the regular replacement of inlet filters.

During the past three years, the operational costs have been minimal, with low energy consumption, no shutdowns, and very small service and maintenance expenses.

Today, the client is extremely satisfied with the Sulzer equipment and collaboration. The customer actually considers further HSTs for the future expansion of the wastewater treatment plant.

Product specification

Two turbocompressors HST 20-6000-1-190

Airflow range 2'000 to 7'000 Nm3/h
Pressure rise 70 kPa
Input power 190 kW
Max. current (400 V) 309 A
Power supply 380 – 690 V
Input frequency 50 – 60 Hz
Max. noise level 73 dBA
  • 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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