Dutch-Anglo iron and steel producer Corus installed a biological wastewater treatment plant that was put into operation at their major production facility in IJmuiden , the Netherlands . Following the first year of operation serious problems were encountered. The most probable cause was toxic components in one of the wastewater flows that dramatically decreased the removal efficiency of the plant within a short period of time.
After the process was re-established it was decided that there should be better control of influent composition and sludge health. Since it was not known which particular components in the influent could cause inhibition or toxicity additional chemical analysis was not useful. So it was decided that controlling bacterial performance by regularly analysing the possible effects of the different wastewater flows on the biomass would give the extra information needed to prevent toxic or inhibiting shocks.