Biochemical Oxygen Demand Measurement (BOD)

BIO-ZAW BOD / Toxicity Analysers

The BIO-ZAW series features online analysers for the short-time measurement of the biochemical oxygen demand (BOD) and toxicity assessment. The employed biomass is taken from the plant, making BIO-ZAW a reliable support when assessing the plant’s treatment capacity.

Available in three different housings: Standing with castors as BIO-ZAW-LAB, wall-mounted as BIO-ZAW-PRO or as BIO-ZAW-FIX in a heated stainless steel cabinet for outdoor installation at the site of measurement.


  • Genuine biology
  • Easy handling
  • No reagents required
  • Minimal maintenance
  • Low operating costs
  • Robust design

The BIO-ZAW monitors the oxygen concentration of a sample of biomass in its measurement tank. Bacteria in the sample consume oxygen with their metabolic processes. The observed respiration, the biochemical oxygen demand, is a measure for biological activity. It is one of the most important criterions to determine the performance of a biological treatment step.

Toxic contaminants in the sample water reduce the biological activity and can therefore easily be detected by the measurement of respiration.

No sample preparation is necessary. Sample intake and discharge are performed via a shared tube. A suction basket prevents larger particles from being sucked in, avoiding damage to the analyser.

Wastewater treatment plants