Biochemical Engineering Journal

A quantitative analytical method to determine the dead cell ratio of bacteria (death ratio) in sludge was developed for evaluating technologies and determining a sufficient amount of ozone for the sludge ozone process. The method with SYTO9 and propidium iodide as staining agents for live and dead cells, respectively, was optimized. The death ratio developed in this study could successfully predict the reduction ratio of the excess sludge in the sludge ozone process with different ozone dosages. Consequently, the death ratio was proven to be a suitable indicator for excess sludge reduction.

The dead cell ratio of bacteria in sludge flocs as an indicator of sludge reduction in sludge ozone process