societe Biomass Stress Index - BSI™

The Biomass Stress Index is a unique feature of LuminUltra's Total Control test kit line. Because of the precision and accuracy built into our test kits, we are able to measure the true tATP™ and dATP™, providing not only a precise measure of living biomass quantity via cATP™, but also a measure of relative biomass population health through BSI™.

There is no conventional equivalent available to measure biomass health - this measurable characteristic is available only through LuminUltra! The series of figures below explains how BSI is determined:

The BSI is calculated from tATP and dATP as a ratio:

BSI (%) = dATP/tATP

Hence, the higher the dATP content of the sample relative to the tATP, the higher the BSI. High BSI values are related to stressful situations - for example, the addition of a biocide such as chlorine will impose a stress on the biomass and cause the BSI to rise. Other stresses, such as oxygen depravation, toxicity, or nutrient deficiencies will also produce high BSI values. In general, BSI is a 'general alarm' of the water or wastewater process, where a change in BSI signals a change in biomass quality, for better or worse.