亚硝酸盐对厌氧产酸耦合反硝化工艺的影响

以木薯酒精废水为碳源，通过批次实验研究了亚硝酸盐对厌氧产酸耦合反硝化系统的影响。结果表明，投加600 mg·L^-1 后的最终产酸量与空白反应器相差不大，但是投加相同浓度亚硝酸盐后产酸受到严重抑 制，最终产酸量仅为空白反应器的1.8%。而硝酸盐还原过程中厌氧产酸受到抑制可能是由于反硝化中间产物亚硝酸盐的存在，低投加量的亚硝酸盐即可对厌氧产酸产生强烈的抑制作用并具有持续性，且对各产酸组分的影响作用：正丁酸>丙酸>乙酸。随着 的降低，亚硝酸盐的还原率由74.9%降低至22.2%。当游离亚硝酸（free nitrous acid， FNA）浓度为0.05 mg·L^-1以上时，亚硝酸盐还原几乎被完全抑制（90%以上）。此外，随着 的增加，反硝化所占的比例逐渐减小，而DNRA过程（dissimilatory nitrate reduction to ammonium，异化硝酸盐还原为铵）逐渐占优势。

Effects of nitrite on integrated process of denitrification with anaerobic acidogenesis

The effects of nitrite on integrated process of denitrification with anaerobic acidification were conducted in a batch reactor using cassava stillage (CS) as substrate. The results showed that the final volatile fatty acids(VFA) production of anaerobic reactor was similar for with and without adding nitrate (600 mg·L^-1 ), but severe inhibiton of acidogenesis took place after adding the same amount of nitrite and the final VFA production was only 1.8% of that of the blank reactor. The decrease of anaerobic acid production in the nitrate reduction process was mainly due to the presence of nitrite. A small amount of nitrite could strongly suppress anaerobic acidogenesis, and the effects of nitrite on VFA composition was n-butyric>propionic>acetic acid. With decrease of ratio, nitrite reduction rate decreased from 74.9% to 22.2%, and was suppressed almost completely (>90%) at the concentration free nitrous acid (FNA) above 0.05 mg·L^-1. Furthermore, with increase of ratio the proportion of denitrification decrease gradually in nitrite reduction, while dissimilatory nitrate reduction to ammonium (DNRA) process became dominant gradually.