Valmet Dry Solids Measurement - Valmet DS

Valmet Dry Solids Measurement (Valmet DS) for dried wastewater sludge (dry cake), is installed after the dewatering machine at municipal wastewater treatment plants. Accurate measurement of biosolids provides significant savings in polymer dosage, energy, and dewatered solids transportation.

A unique solution for dry cake measurement

Valmet Dry Solids Measurement (Valmet DS) utilizes microwave technology, requiring no special certification or safety procedures, to make a stable and accurate solids measurement for dewatering control in wastewater treatment. Valmet DS extracts a continuous sample from the falling cake flow after a centrifuge or screw press and measures the solid content before returning the sample back to the process.


  • 100% safe microwave technology
  • Up to 25% less polymer usage
  • Minimized transportation costs of dry cake
  • Optimized polymer dosage and torque of the centrifuge
  • Reduced fuel consumption at combustion plant
  • Optimization of total solids (TS) value of dry cake
  • Better oversight of dewatering and process efficiency


Continuous measurements bring cost savings for wastewater management

Feedback control using the accurate dry solids measurement provided by Valmet DS can fully optimize polymer dosage and provide energy savings through better torque control of the centrifuge. Maximizing drying efficiency to a target dry cake solids content can provide additional savings with reduced transportation costs and improved power boiler combustion.

  • Reliable screw based sampling
  • Cake solids range up to 35 %
  • Built-in calibration routine
  • Industrial Internet remote access

In addition to full remote access of Valmet DS functions, measurement data, alarms and diagnostics via the Industrial Internet, the Valmet DS Ethernet connection can be used for local control with a laptop or tablet computer during commissioning.


Valmet DS is typically located in the downfall section of the dry cake. A sample retrieval screw feeds a return screw which compresses and pushes the sample
through the microwave sensor chamber before being returned to the process.

The Valmet DS measurement is based on multivariable microwave resonance, compensated for variations in material temperature and calibrated during commissioning with samples taken from the screw and oven dried.




Superior solids measurements solutions for wastewater – test the ROI tool calculator


Sensor material Ceramics / Body Aisi 317L
Measuring range Up to 35 % solids
Material measured

Municipal dried wastewater (sewage) cake

Temperature range +0...65 °C
Repeatability 0.01 %
Resolution 0.001 %
Mill system interface 4...20 mA, Ethernet

24 VDC (measuring electronics)
3 phase AC (sample screws) *

IP-classification IP65

Customer success stories

VandCenter Syd is aiming higher with an optimized process

VandCenter Syd is aiming higher with an optimized process

VandCenter Syd, one of Denmark's largest and oldest water companies, installed Valmet Dry Solids Measurement (Valmet DS) to obtain fast and credible measurement signal for the dry matter percentage on the outlet of the decanter.

Clean Water Services maximizes efficiency with continuous data

Clean Water Services maximizes efficiency with continuous data

Clean Water Services in Oregon, USA, wanted to maximize the efficiency by using the most modern instruments. Now Valmet's wastewater measurements offer continuous data of sludge solids for operator.

Valmet goes underground to help treat wastewater

Valmet goes underground to help treat wastewater

The Kakolanmäki wastewater treatment plant has been operating in the southern Finnish city of Turku since the beginning of 2009. Since the plant is built underground it has a more constant and higher temperature than surface facilities, a distinct advantage for treatment conditions.

Valmet wastewater solutions save energy and chemicals

Valmet wastewater solutions save energy and chemicals

Tampere Water recently installed several Valmet total solids measurement devices and a sludge dewatering control package at its Viinikanlahti wastewater treatment plant in Tampere, Finland.