Respiration Index Determination: Dynamic And Static Approaches

Forty-five organic matrices of different types and origin were subjected to the test for the determination of biological stability by means of dynamic respirometric measurement (DRI) and static respirometric measurement (SRI). The results obtained from the comparison between the two indexes indicated that the SRI, compared with the DRI, underestimates the consumption of oxygen by the biomasses and consequently their rate of biological stability by a factor equal to 2. From the analysis of the data it is possible to define the biological stability as DRI<1000 mgO2kg−1VSh−1. The DRI data were correlated with the temperatures of the biomasses showing a linear correlation (R2=0.81, p<0.01) only for stable matrices while for nonstable matrices no significant correlation is found.