A new approach to toxicity determination by respirometry

Respirometry, as used in wastewater treatment, is the measurement and interpretation of the respiration rate of microorganisms in activated sludge. The respiration rate is the amount of the oxygen per unit of volume and time that is consumed by the microorganisms. For a long time respirometry has been recognized as a valuable basis for controlling the activated sludge process. The reason for this is that respiration rate is directly linked to two important biochemical processes that must be controlled in a wastewater treatment plant: biomass growth and substrate consumption. This paper shows different experiments to quantify toxic or inhibitory effects as determined by the toxicity protocol for respirometry. The protocol used was based on the utilization of the respiration of activated sludge to measure and quantify toxic effects of compounds. Our purpose was for both the protection and treatment ability determination of wastewater plants, depending on the problems (e.g. pollution), needs of customers and possibilities for biodegradation of the tested products.