Inhibition bioassays

Sampling from a inhibition test

Acute effects

An inhibition assay evaluates the effect of different concentrations of a contaminant or a complex wastewater on the bacteria that are responsible for the wastewater treatment.

Our methods

Inhibition of oxygen consumption
The extent of an inhibition effect on the activated sludge microflora is tested by measuring the impact of contaminants on microbial activity or respiration. AnoxKaldnes assesses inhibition according to the accredited method SS-EN ISO 8192-1995B.

 

Inhibition of nitrification
Nitrifiers are critical in biological nutrient removal processes. They oxidize ammonia to nitrite and nitrate, and are an especially sensitive group of microorganisms. AnoxKaldnes examines inhibition of nitrifying microorganisms according to three accredited methods as follows:

 

  1. SS-EN ISO 9509-1995 (accredited).
  2. Nitritox (accredited). The Nitritox protocol was developed at AnoxKaldnes and is based on the determination of nitrite production within an immobilized mixed culture of nitrifiers. Using a defined culture of nitrifiers has been found to be more reproducible than the conventional nitrifier inhibition methods that rely on activated sludge activity.
  3. VKI (Danish Water Quality Institute) screening method (SNV report 4424) (not accredited).