氨氮和硫酸盐对谷氨酸厌氧生物降解性能的抑制及机理

采用连续运行1119d的上流式厌氧污泥床（UASB）反应器，研究了最佳有机负荷条件下氨氮和硫酸盐对模拟废水中谷氨酸降解性能的抑制作用.结果表明，有机负荷为8.0g COD/（L·d）时，COD去除率达到最高值为（97.94±0.28）%.逐步提高进水氨氮浓度，起初对谷氨酸降解性能的影响不大；但升到2000mg/L时COD去除率和甲烷产率明显降低，继续升至4000mg/L时即达到半抑制状态.逐步提高进水硫酸盐浓度至4000mg/L，甲烷产率和溶液中游离硫化氢（FS）浓度分别呈现一直下降和升高趋势，但COD去除率均能维持在90%以上.进水中的氨氮和硫酸盐分别因离解平衡和生物还原作用形成游离氨（FAN）和FS，进而抑制了产甲烷菌的活性；前者因FAN扩散到细胞内部破坏质子平衡从而过多消耗ATP，后者还因硫酸盐还原菌的增殖存在底物竞争抑制作用.

Inhibition and process mechanism of ammonia nitrogen and sulfate on anaerobic degradation of glutamate

To investigate the effect of ammonia nitrogen and sulfate in the influent on anaerobic degradation of glutamate under the optimal organic loading rate, a lab-scale up-flow anaerobic sludge blanket (UASB) reactor was continuously operated for 1119 days. The results showed that the maximal COD removal efficiency as high as (97.94±0.28)% was obtained at an organic loading rate of 8.0g COD/(L·d). When step-wise increasing the ammonia nitrogen concentration in the influent, the UASB reactor a small fluctuation on glutamate removal efficiency under low ammonia nitrogen concentrations (<1000mg/L), subsequently appeared a distinct decline in the COD removal and methane yield at 2000mg/L, and then the half-inhibitory concentration of ammonia nitrogen exhibited at 4000mg/L. When step-wise increasing sulfate concentration in the influent from 200mg/L to 4000mg/L, methane yield and free sulfide (FS) concentration in the mixture fallen into increasing and decreasing trends, respectively; but the COD removal efficiencies were generally in a high level (>90%). Both the ammonia nitrogen and sulfate in the influent could inhibit the glutamate degradation activity of methane-producing archaea (MPA) through dissociation equilibrium and biological reduction, respectively. Besides, FAN could freely diffuse into microbial cells resulting in proton imbalance and then excessive ATP consumption in the former. In contrast, substrate competitive inhibition was existed as for the reproduction of sulfate-reducing bacteria in the latter.