The denitrifier death rate function has been extended to include a threshold for two different rates. Two new parameters have been introduced: DMic_DeathCDormancy and DMic_DormancyThreshold, representing the rate coefficient during the entire range of microbial biomass and the threshold from which the rate will be determined by the previous rate coefficient DMic_DeathRateCoef. New default values (0.01) are assigned to the previous DMIC_DeathRateCoef. Note that the new model will not be able to reproduce the previous by using the default values. However, by setting the DMic_DormancyThreshold to 0 and DMic_DeathCDormancy to 0. and previous default value of 0.09 to DMIC_DeathRateCoef the old model will be valid.