Solids sensor

Optimizing the use of polymer in solid / liquid separation


In many areas of industrial, municipal sewage, and dewatering technology, the use of polymeric flocculants to accelerate the solid / liquid separation has been established as the state of the art method. Dewatering equipment like decanters and belt filter presses are completely dependent on the use of these products. The effectiveness of clarification or dewatering processes is highly dependent on the optimal use of the flocculants. Since even continuously accumulating suspensions and slurries may change with respect of their solids content, the optimization of polymer dosage is often difficult. Manual adjustments of the dosing quantity according to the sludge parameters is only possible only at longer time intervals and thus leading to a variation between overdosing and possibly underdosing These variations lead to an interruption in the production or dewatering process.

Use of automated measurement and control technology

07 Messsonde

Solids sensor with automatic cleaning by  wiper

The technical solution of the problem above offered by HeGo Biotec GmbH is based on a continuous measurement of solids in the inlet for the clarification or dewatering process. The measurement technology uses a scattered light measurement in the invisible infrared spectral range. A parallel evaluation of different stray light signals ensures color-independent measurement of the solids content. Even with extreme color changes of the mud or the background medium, this technique guarantees stable readings. Clean measurement windows are a prerequisite for high-precision optical measurement methods. The testing probes for suspended solids are outfitted with an automatic wiper cleaning system which reliably prevents the soiling of the measuring windows. The monitoring unit has an LCD screen which displays the real-time measured values. The data storage capabilities allows the evaluation of previous measurement results up to three months at a recording density of one sample per ten minutes. The measured concentration of solids in the suspension is analyzed and, via frequency converter, a dosing pump is directly controlled to ensure a proportional polymer dosage.

Example of use

  • Solids measurement and optimizing flocculant dosing in municipal sewage systems in the inflow of thickening and dewatering equipment for primary, secondary and mixed sludges
  • Solids measurement in the field of water purification of gravel, sand, rock and Kaolin works in inflow of thickening and dewatering equipment for optimizing the flocculant dosing and prevention of production downtime




Advantages at a glance

  • Optimizing the flocculant dosing combines material reduction with higher reliability.
  • Direct conversion of acquired measurements via frequency guarantees a dosage of polymeric flocculant proportional to solids content.
  • Using a scattered light measurement method ensures exact determination of solids content, even with severe color changes in the suspension.
  • Lab-tested automatic wiper cleaning ensures clean measuring window and therefore accurate readings.
  • The display and evaluation unit allows constant verification of the current measured value as well as an evaluation of previous measurements.