Fe(0)-活性炭强化短程反硝化脱氮及影响因素

为减少生物短程反硝化对外碳源的依赖,研究了无机环境下Fe(0)-活性炭强化短程反硝化的脱氮效果,并探究了不同铁碳比及初始pH值对系统脱氮效果及N+2O释放的影响.结果表明Fe(0)-活性炭可强化生物短程反硝化,将亚硝氮去除率由7.4%提高到31.1%.当m(铁)∶m(碳)由2∶1降至1∶1和1∶2时,反硝化速率与亚硝氮去除率均呈现先升后降的趋势,m(铁)∶m(碳)为1∶1时达到最大,分别为5.58 mg·(g·h)~(-1)与41.1%,且此时N+2O的释放量较小,为0.10 mg.当pH值由6.0升至9.0的过程中,反硝化速率由7.39 mg·(g·h)~(-1)下降至5.96 mg·(g·h)~(-1),N+2O的释放量由0.19 mg下降至0.12 mg.以上结果表明,在m(铁)∶m(碳)为1∶1和pH为弱酸性的条件下,Fe(0)-活性炭能强化短程反硝化获得较好的脱氮效果,但低pH值会增加N+2O的释放量.

Enhanced Short-cut Denitrification by Fe(0)-activated Carbon and Its Influencing Factors

In order to reduce the carbon source for biological short-cut denitrification, Fe⁽⁰⁾-activated carbon was used to enhance nitrogen removal in the absence of organic carbon, and the influences of the Fe/C mass ratio and initial pH value on the nitrogen removal efficiency were explored. The results showed that the nitrite removal efficiency increased from 7.4% to 31.1% when the Fe⁽⁰⁾-activated carbon was used to enhance short-cut denitrification. When the Fe/C mass ratio was reduced from 2:1 to 1:1 and 1:2, both the denitrification rate and nitrite removal efficiency first increased and then decreased. At a Fe/C mass ratio of 1:1, a maximum denitrification rate of 5.58 mg·(g·h)^-1 and a maximum nitrite removal efficiency of 41.1% were achieved, respectively, and 0.1 mg of nitrous oxide was emitted. When the pH value was increased from 6.0 to 9.0, the denitrification rate decreased from 7.39 to 5.96 mg·(g·h)^-1, and the nitrous oxide emission decreased from 0.19 to 0.12 mg. Therefore, a higher nitrogen removal efficiency could be achieved by Fe⁽⁰⁾-activated at a Fe/C mass ratio of 1:1 and pH value of 6.0. However, more nitrous oxide would be emitted at a low pH value.