AN ACTIVATED SLUDGE-BASED BIOSENSOR FOR RAPID IC(50) ESTIMATION AND ONLINE TOXICITY MONITORING

The RODTOX (Rapid Oxygen Demand and TOXicity tester). an activated slu dge-based respirographic biosensor, is a device for on-line monitoring of the short-term biochemical oxygen demand (stBOD) and potential tox icity of incoming wastewater on the basis of on-line interpretation of respirograms resulting from pulse additions of either calibration sub strate or sample. The principle of toxicity detection is based on the comparison of calibration respirograms before and after receiving a po tential toxicant. In this paper, the results of the RODTOX as an on-li ne toxicity monitor are presented. In addition, a simple and fast proc edure to estimate the IC50 of a toxicant has been developed. and its v alidity and good repeatability demonstrated. The performance of this p rocedure is compared with that of the Microtox test.