Good end results when Ekeby treatment plant built a new sludge treatment facility

Eskilstuna Strängnäs Energi och Miljö needed to build a new sludge treatment facility. In 2017, FVB was tasked with project management and programming for the automation part.

The project as a whole includes a building, two sludge presses and a storage silo for sludge. Besides managing the process for sludge dewatering, FVB also managed HVAC, heating and ventilation.

The process itself can be described as follows: the retted sludge is pumped up from a pool and flocculant is added before it is fed into sludge presses that dewater the sludge. The sludge is collected in a tank that holds 200 cubic meters, which corresponds to between 150 and 175 tons of sludge, depending on its dry content. There is a loading unit for trucks under the tank where each truck takes about 10 tons of sludge, which is then taken to a landfill.

Extensive project

Peter Eklund has led the project at FVB.

“For our part, it is been about making sure the process and its controls are working. Several contractors have been involved in the project, as it includes construction, HVAC, process and automation. There are many people and machines on site at the same time,” says Peter.

A number of challenges have also arisen. The building is 25 meters high so a lot of time-consuming installations to handle the assembly were carried out with aerial work platforms and scaffolding.

A fair amount of planning was also required to do the programming and signal checking, after which the objects were ready to be finalized.

“To meet the needs for regulating, controlling, checking and alerting, a lot of logic has to be built into the program,” says Peter, who feels satisfied with the project.

Great cooperation

Lina Norling, the client at Eskilstuna Strängnäs Energi og Miljö, is also satisfied.

“This has been a big project, both in terms of time and cost,” says Lina.

“Our cooperation with FVB has worked very well. Being responsible for functionality means being a key player in every step. The end result was great.”

“The facility has been operating since the end of 2017, and we haven’t had to make any major changes. There have only been minor adjustments that the operating staff have come up with after commissioning,” Lina concludes.

For more information:
Peter Eklund, 021-81 80 64


  • Siemens S7-300 PLC with distributed IO for controlling processes, HVAC and heating.
  • Each process section has a Siemens 12 inch Comfort panel for local operation.
  • Profibus communication to nine ABB frequency converters for motor control.
  • Signal exchange of process values for regulation between two existing control systems was also part of the project.
  • Control for PLC is programmed in Siemens TIA Portal.
  • HMI process images were designed and animated in the iFix SCADA master system for central monitoring of alarms and history.

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