FNA对NO_2~-为电子受体反硝化的抑制动力学研究

为考察实际污水生物脱氮过程游离亚硝酸(free nitrite acid,FNA)对以NO2-为电子受体反硝化的抑制动力学,采用"2级UASB-A/O耦合工艺"处理城市生活垃圾渗滤液.在实现稳定短程脱氮(130 d运行)的前提下,以A/O反应器内具有良好短程生物脱氮特性的污泥,在不同ρ(NO2--N)和pH梯度下进行反硝化批次试验,基于大量试验数据确立反硝化抑制动力学模型,并通过函数拟合确定不同pH下以NO2-为电子受体的反硝化抑制动力学模型常数.在恒温且恒定pH条件下,ρ(NO2--N)与比反硝化速率rSS之间的变化曲线符合Andrews抑制动力学模型;不同pH条件下,最大比反硝化速率Rmax和半饱合常数KS差别较大,pH=8.0下的Rmax和KS最大,分别为17.8 mg/(g.h)和6.40 mg/L;当pH=6.5～8.0时,抑制常数KI随pH的升高而显著增大,而相应的ρ(FNA)(0.177～0.225 mg/L)属于同一数量级,从动力学角度验证了FNA为真正的抑制剂.

Inhibition Kinetics of FNA to Denitritation Using Nitrite as Electron Acceptors

A lab-scale two-stage UASB-A/O combined process for treating the real municipal waste leachate is used to investigate the inhibition kinetics of free nitrite acid(FNA) to denitritation using nitrite as electron acceptors in wastewater.Under the premise of achieving short-cut nitrification-denitrification stably(running 130 days),a number of denitrification batch tests are carried out in different concentrations of NO-2-N and under different pH gradient with sludge,which is from an A/O reactor and has good biological short-cut denitrification nitrogen removal efficiency.A denitritation inhibition kinetics model is established based on a large number of experiments and the Nitrous denitrification inhibition kinetic constants under different pH are deduced by function match.The relationship curves of NO-2-N concentration and specific rate of denitrification match the Andrews inhibition kinetics model well at constant temperature and pH conditions.The maximum specific denitrification rate Rmax and half-saturation constant KS significantly vary at different pH,Rmax and KS being 17.8 mg/(g·h) and 6.40 mg/L under pH 8.0,respectively.When pH is in the range of 6.5-8.0,the inhibition constant KI significantly increases with the increase of pH.However,the corresponding value of ρ(FNA)(0.177-0.225 mg/L) remains the same level of magnitude,which proves that FNA is the true inhibitor from the view of kinetics point.