Impact of Salinity on Denitrification Kinetics for Landfill Leachate Treatment

In order to determine the mathematical kinetic parameters and provide theoretical reference for the high ammonia nitrogen wastewater treatment under salt-affected conditions, bactch tests were perfomed by using the activated sludge take from a SBR reactor with good performance of short cut nitrification-denitrification.Resultsshow that the rate of denitrification will be decrease if salt fluctuations beyond the normal circumstance of microbiology growth and the influence will be more obvious as the initial NO₂^--N concentration increasing. The system's maximum denitrifying rate(expressed by N) reached 16.28 mg/(gVSS·h) at 10 g/L salt and initial NO₂^--N concentration for 100 mg/L. The denitrification kinetics characteristics of the activated sludge fit Andrews model at different salt levels. It is suggested that an increase or reduce in salt concentration will make the maximum specific nitrite reduction rate μ_max and the saturation constant K_s decrease and the inhibition constant Kⁱ increase. When salt concentration is 10 g/L,the maximum specific nitrite reduction rate μ_max (expvessed by NO₂^--N),the saturation constant K_s and the inhibition constant K_i are 22.57 mg NO₂^--N/(gVSS·h),20.71 mg/L and 613.32 mg/L,respectively.