Study of Operational Factors Affecting Versatile Implementation of Ferricyanide- Mediated Rapid-Assay for Biochemical Oxygen Demand

BONETTO, M. C.; SACCO, N.; CORTÓN, EDUARDO

Lisboa

Congreso; 7th Ibero-American Congress on Sensors-IBERSENSOR 2010; 2010

Ibersensors

BOD5 test is used to determine organic pollution in natural waters and the total degradable organic load in wastewaters. A ferricyanide-mediated rapid BOD approach has been reported to overcome the oxygen solubility in water limitation that contributes to long incubation time (5 days) in the standard BOD test (BOD5), internationally employed as a water quality parameter. But still themethod has its drawbacks when is required to produce useful information in-situ.The results obtained using an environmental bacterial strain (Klebsiella pneumoniae) that reduces ferricyanide in non de-aerated and de-aerated conditions, are exposed here. We demonstrate that in the assayed conditions, the normally employed procedure to eliminate oxygen (nitrogen bubbling) produce negligible differences compared with the non-bubbled samples, so thefact previously proposed that oxygen is a ferricyanide competitor does not seem to happen.We also report here that the use of formaldehyde enables the comparison of a number of measurements done sequentially, avoiding the use of centrifugation methods to stop the microbial mediated ferricyanide reduction, as previously used for other authors. These results provide new and simple ways for future practical implementation of rapid BOD methods based at ferricyanide and other mediators, which will improve and facilitate active intervention in environmental monitoring.