Application of calorimetric measurements for biokinetic characterisation of nitrifying population in activated sludge.

A preliminary investigation is described on the application of calorimetry as a sensitive technique to evaluate nitrifying activity in activated sludge. Calorimetric profiles (thermograms) related to heat dissipation due to biological nitrification reactions (ammonia or nitrite consumption) have been interpreted. Correlations between calorimetric data and the main process variables, i.

Calorimetric investigation of anaerobic digestion: Biomass adaptation and temperature effect.

A high-resolution bench-scale calorimeter (Bio-RC1), specially suited for microbiological studies, has been used to investigate the response of an anaerobic granular sludge to repetitive glucose additions at various temperatures. Through the analysis of heat-evolution profiles resulting from substrate degradation, significant biological events have been identified: the feeble net heat uptake related to aceticlastic methanogenesis has been evaluated, and the detrimental effect of a nutrient deficiency, which led up to 75% decrease in heat production rate, has been detected. After several glucose pulses under non-limiting nutrient conditions, a reliable and reproducible reference thermal response, which is an important condition for the application of calorimetric measurements to detect inhibitory effects, was finally obtained.

Calorimetry: a tool for assessing microbial activity under aerobic and anoxic conditions.

For many years, calorimetric measurements have been used for understanding, modelling, controlling, and optimising chemical reactions. Calorimetry could be as well utilised to investigate biological processes, which however, involve very small amount of heat and therefore require very sensitive instruments. For this purpose, a Mettler Toledo RCI (Reaction calorimeter) was modified, changing both hardware and software, increasing its resolution up to 5 10m W/l.