热解温度对生物炭提升厌氧氨氧化性能的影响

Effect of pyrolysis temperature for biochar on improving nitrogen removal efficiency of Anammox

为探究生物炭对厌氧氨氧化工艺中硝酸盐积累的缓解作用,通过批次实验考察了不同热解温度(300,500,700℃)生物炭对厌氧氨氧化系统脱氮性能的影响.结果表明,300,500,700℃生物炭的添加使体系总氮去除率较空白组分别提升了14.6%、7.1%、3.3%,其主要原因是生物炭作为电子介导体促进了硝酸盐的还原,还原产物亚硝酸盐继续进行厌氧氨氧化反应,进一步减少了11.2%、9.1%、5.8%的剩余氨氮.300℃生物炭表面具有丰富的酚类、醛类和酮类等失电子基团,其供电子能力为2.64mmol e-/g,高于500℃(1.92mmol e-/g)和700℃(1.32mmol e-/g)的生物炭,故其更好地强化了体系中的电子转移.微生物群落和功能蛋白分析表明,生物炭的添加增强了Ca.Kuenenia、Pseudomonas、Thauera等丰度,有利于厌氧氨氧化和反硝化菌的富集,同时,生物炭通过促进NapA(EC:1.9.6.1)和NarG(EC:1.7.5.1)等功能基因的表达,强化了反硝化过程的氮代谢水平.

In order to explore the alleviating effect of biochar on nitrate accumulation in anammox process,the effect of biochar at different pyrolysis temperatures(300,500 and 700℃)on nitrogen removal performance of anammox system was investigated.The results showed that the total nitrogen removal rate was increased by 14.6%,7.1%and 3.3%,respectively,after the addition of 300,500 and 700℃biochar compared with the control group.The main reason was that biochar promoted the reduction of nitrate as an electronic mediator,and the reduction product continued to participate in the anammox reaction to further reduced the residual ammonia nitrogen by 11.2%,9.1%and 5.8%.The surface of biochar at 300℃was rich in electron-losing groups such as phenols,aldehydes and ketones,and its electron-donating capacity was 2.64mmol e-/g,which was higher than 500℃(1.92mmol e-/g)and 700℃(1.32mmol e-/g),so the electron transfer was better strengthened.Microbial community and functional protein analysis showed that the abundance of Ca.Kuenenia,Pseudomonas and Thauera were enhanced by the addition of biochar,which was beneficial to the enrichment of Anammox and denitrifying bacteria.Meanwhile,biochar enhanced nitrogen metabolism during denitrification by promoting the expression of NapA(EC:1.9.6.1)and NarG(EC:1.7.5.1)functional genes.