Estimation of (C/N) ratio for microbial denitrification

Elemental balances of microbial growth have been applied to calculate (C/N) ratio in a denitrification process. The correlation between biomass yield coefficient and degree of reduction has been used to estimate the critical (C/N) ratio. It has been shown that when the degree of reduction of the substrate is lower than 4.67, the critical value of (COD/N) is almost constant and equals 7.6 g O2 g(-1) N. The batch cultures of denitrifying bacteria Ervinia sp. on glucose, sodium acetate and methanol have been used to verify theoretical relations. The results of experiments generally agree with theoretical considerations.