好氧微生物基团内的基质分布与NH_4^+的硝化特点分析

Research on characteristic of matter distribution and nitrification in the aerobic microbical mass

废水生物处理的微生物基团是以生物膜或悬浮絮体存在于体系内的,其中所含有的大量种群复杂的微生物与基质在微生物基团的分布密切相关.采用微小电极技术测定了微生物基团内DO浓度、NH+4-N浓度的变化特点.结果表明:DO在微生物基团内的扩散深度在一定范围内随体系DO浓度增加而增加;微生物基团内硝化作用发生的范围与DO扩散深度直接相关;过高的DO浓度,由于受传质阻力的影响,其在微生物基团内的扩散深度并不会持续增加;体系DO高于2mg/L以上时的硝化效果基本接近.因此,生物硝化系统内DO为2mg/L时,既可满足硝化要求又可节约能量.

Microbial mass is a kind of biofilm or suspended activated sludge and is prototypes of highly stratified microbial communities, which are able to simultaneously perform numerous processes relevant for biological wastewater treatment. Microelectrodes for O(2) and NH^+4 were combined to examine the characteristics of DO and NH^+4 distribution in a microbial mass. Microprofiles showed that O(2 ) consumption and NH^+4 oxidization were restricted to the upper 50～150μm of biomass. The vertical distribution of NH^+4-oxidization process is very similar to that of O(2) diffusion. Moreover, the result also showed that an increase of O(2) concentration in the bulk water, in the low range of DO concentration, resulted in an increase of O(2 ) diffusion depth .But the depth of O(2) diffusion can't increase more than 150μm because of the diffusion resistance and the limited force of diffusion. The nitrification characteristic, which is under the condition of DO≥2 mg/L, is very similar to that of DO≤2 mg/L. Thus, DO=2 mg/L in biological nitrification system is not only meet the need of NH^+4-oxidization demand, but also meet the need of energy saving.