Integrated compressor system helps a regional wastewater plant

When pump manufacturer Robuschi tested its ROBOX energy WS 65 magnet screw compressor in a civil wastewater treatment plant in the province of Trento, Italy, the new technology performed beyond the client’s expectations.

Located in the comune of Dimaro, the plant presented an unusual challenge. While all other treatment plants in the area feature canonical 4.5 m-deep oxidation tanks, the Dimaro tanks are 7 m deep. In addition, the plant is located about 800 m above sea level, resulting in a significantly lower atmospheric pressure compared to other sites.

When Robuschi introduced a low-pressure ROBOX screw compressor with a conventional motor, the compressor was able not only to replace one of the existing ROBOX lobe evolutions, but actually met the entire plant’s requirements on its own. The owners and managers of the plant were delighted with the results, going on to purchase a Robuschi ROBOX energy WS 65 compressor in July 2016.

The configuration of ROBOX energy — which integrates both the inverter and the electric dashboard internally — allows for an easy and effortless installation process. It is a versatile machine, featuring Smart Process Control that analyses process data and modifies the product’s operation to match the varying oxygen supply required throughout the day.

“Water requirements are not constant: there are peak periods followed by various falls and rises,” explained Giovanni Stancher, production warehouse manager of Provincia Autonoma di Trento wastewater treatment plants. “It’s the machine’s job to maintain a constant oxygen level according to the value set. This feature, made possible by the integrated inverter, prevents the on-off alternation that would decrease plant efficiency. In addition, it prevents peaks in oxygen flow, thus improving the quality of the wastewater treatment. The advanced ROBOX technology therefore simultaneously saves energy and optimises the quantity of oxygen, with zero waste.”

Now the plant’s main machine, ROBOX energy runs alongside the traditional ROBOX screw compressor unit, which acts to compensate for any marked load increases during the summer tourist season or at other times of high demand. The traditional unit also operates as a spare machine if the main compressor needs inspections, maintenance or repairs.

“This way we have a complete system comprising just two units that can work either together or in rotation while also giving us maximum flexibility,” said Stancher. The new compressor system therefore delivers lower running costs, fewer problems and greater savings.