SBR法短程硝化处理纤维素乙醇废水的中试研究

Pilot-scale study on treatment of cellulosic ethanol production wastewater with shortcut nitrification by SBR

针对纤维素产乙醇废水高有机物、高氨氮、难降解的特点,运用短程硝化反硝化脱氮工艺,基于序批式活性污泥反应器(SBR)的调试运行,研究反应器运行方式对COD去除和脱氮效能的影响,为日后纤维素乙醇废水处理的工程化提供借鉴。结果表明:通过控制DO(0.5 mg·L^(-1))、p H(7.6~8.5)和投加碳源等条件,可实现亚硝酸盐氮的积累和转化,最终三氮去除率稳定在70%以上;通过投加不同碳源对比实验,发现乙酸钠作为反硝化外加碳源比葡萄糖具有更高的效率;厌氧工艺处理过的纤维素乙醇废水经短程硝化反硝化工艺处理后,COD去除率维持在20%上下,表明废水可生化性极低,已不适应生物法处理,须利用化学氧化法才能进一步去除;通过周期实验,发现硝化阶段碱度过量对短程硝化进程影响并不明显,相反充足的碱度是保证硝化反应进行的必要条件。

After anaerobic treatment,cellulosic ethanol biorefinery wastewatercan still havea high chemical oxygen demand（ COD）,high ammonia nitrogen levels,and large amounts of recalcitrant compounds. In view of these characteristics,a shortcut nitrification process was used to treat the wastewater in a sequencing batch reactor（ SBR） in order to provide reference data for a full-scale study. Results showed thatthe removal rate of all three kinds of nitrogen（ NH4^＋-N,NO2^--N,and NO3^--N） could bemaintained at more than 70% by controlling the dissolved oxygen（ DO）（ 0. 5 mg·L^-1）,p H（ 7. 6 to 8. 5）,and carbon source in the shortcut nitrification and denitrification process. Sodium acetate wasa higher efficiencycarbon source than glucose for denitrification,as shown through comparison tests. The shortcut nitrification and denitrification process could remove about 20% of the COD. Theeffluent of the SBR was poor in terms of biodegradability; therefore,an advanced oxidation process might be a better choice for further COD removal. The excess carbonate alkalinityconcentrations had no apparent adverseimpact on the shortcut nitrification process in cycle experiments,buta sufficientcarbonate alkalinityconcentration was important for keeping the nitrification process running smoothly.