In treating simulation coking wastewater in upflow blanket filter(UBF)

addition of NaNO3 in water for simulating backflow of nitrification liquid results in simultaneous methanogenesis and denitrification

along with COD removal rate 94%

and NO3--N removal efficiency 99%.In denitrification dynamics research of the sludge at the bottom of the UBF

double-substrates Monod model was adopted to fit the test data obtained under conditions of nitrite accumulation

NO3--N+0.6NO2--N as the electronic acceptor of denitrification.The results show that there is a good correlation between the fitting curve and the experimental measurement.Then differential model based on Monod model was used to fit the change in the concentration of NO3--N and NO2--N respectively

relevant parameters obtained were as follows:The maximum specific degradation rate and half-saturation constant are 1.13 d-1 and 2.0 mg·L-1 for NO3--N

and 0.66 d-1 and 2.5 mg·L-1for NO2--N.The half-saturation constant of organic substrate based upon NO3--N and NO2--N are 90.8 mg·L-1 and 96.8 mg·L-1.