The interest in on-line water quality monitors has increased significantly in the last years, because of the need for rapid, reliable and continuous monitoring. This has resulted in the introduction of new monitors which can provide (near) real-time information on water quality. They can be used for continuous river water quality control as well as for drinking water protection against intentional contamination. Still no universal monitor is yet available which is able to protect against all kinds of threats. The combination of complementary systems into a single integrated monitoring platform would greatly enhance the applicability of real time monitoring devices. Such a combination should be found in the complementary information derived from a chemical analytical technique and from an effect monitor (biomonitor). Where a chemical analytical monitoring system identifies and quantifies specific water contaminants, biomonitoring gives an indication of the total quality, including the effects of unknown toxic substances.
This combination was found in using the TOXcontrol, a biological toxicity monitor using luminescent bacteria, and the scan spectroyserTM, a submersible UV-VIS spectrophotometer probe, to evaluate drinking water safety. This combination allows for the verification of alarm signals from one instrument with the signal of the other, reducing false alarm rates. Experiments were performed in a laboratory setting and in a field test. It is concluded that the combination of the UV-VIS spectrophotometer and the toxicity biomonitor comprises a monitoring system with a high added value being capable of detecting a broad range of contaminants at low concentrations.