基于碳酸氢钠为碳源的氢自养反硝化去除地下水中硝酸盐研究

氢自养反硝化修复地下水中的硝酸盐污染以其清洁、环保又经济而受到广泛重视。利用全自动恒温振荡仪,以NaHCO3为碳源驯化氢自养反硝化细菌,并对影响氢自养反硝化速率的因素进行了研究。结果表明,以NaHCO3作为唯一的无机碳源,不仅可以高效驯化氢自养反硝化细菌,而且可以控制体系的pH值,效果优于单独以CO2或以CO2和NaHCO3共同为碳源的系统;当单独以NaHCO3为碳源时,其浓度为2g·L-1时可以满足氢自养反硝化细菌的生长,并使体系pH保持在8.5±0.2;当初始NO3--N浓度〈135.6mg·L-1时,反硝化速率随着NO3--N浓度的升高而增大,当NO3--N浓度过高时（〉135.6mg·L-1）,会抑制氢自养反硝化的进行;当pH在6.0～9.0时,氢自养反硝化可以进行,但其最适pH为7.0～8.0,而当pH〈6.0或pH〉9.0时,反硝化基本停滞;温度为35℃时反硝化速率最大,为2.83mg·L-·1h-1,当温度为15℃时,有明显的亚硝酸盐积累。

Nitrate Removal from Groundwater by Hydrogen Autotrophic Denitrification Using Bicarbonate as Carbon Source

Hydrogen autotrophic denitrification attracts wide attention since it is clean,environmental friendly and economic.In this study,carbon dioxide and bicarbonate were selected as carbon sources.Tests were performed to compare their effectiveness on denitrification under different conditions.The results showed that bicarbonate as the only inorganic carbon source led to faster acclimation,and the stabilization of pH,which was better than that only with carbon dioxide or carbon dioxide combinated with bicarbonate as carbon sources.The concentration of 2 g·L-1 bicarbonate was sufficient for the growth of denitrifying bacteria if only bicarbonate was added as carbon source.The performance of denitrification increased with higher nitrate load when its concentration was below 135.6 mgN·L-1.But it would inhibited denitrification with higher nitrate load.The nitrate degradation could be achieved when pH ranged from 6.0～9.0,but the best pH was 7.0～8.0.A lower（6.0） or higher（9.0） pH resulted in stagnation of denitrification.The best denitrification efficiency（2.83 mg·L-1 h-1） was achieved with a temperature at 35 ℃.The accumulation of nitrite occurred at 15 ℃.