Abstract:

Denitrification is a key step in sewage denitrification. Adding denitrifying microbial agents is an effective method to improve the removal efficiency of total nitrogen. In this experiment, Pseudomonas aeruginosa F5 (F5 in short hereafter) was harvested from the anaerobic/anoxic tank of an A²/O process in a municipal sewage treatment plant. A culture medium based on actual domestic sewage was prepared to cultivate F5, and the optimal dosage of key nutrients were determined through orthogonal experiments. The optimum dosage of beef extract, K₂SO₄ and MgSO₄·7H₂O were 5.0 g/L, 6.7 mg/L and 5.0 mg/L, respectively. In order to verify the feasibility of denitrification, F5 was added continuously to a pilot-scale (50 m³) A²/O reactor at a ratio of 1∶10000 (V_inoculant/V_{daily sewage}). The addition of F5 increased the total nitrogen removal rate by 19.6%—24.0%. For further improving denitrification efficiency, two mutant strains A75 and A82 were obtained after mutagenizing F5 by atmospheric and room-temperature plasma method (ARTP). The results showed that the total nitrogen removal rate increased by 14.5%—16.2% and 16.8%—18.0%, respectively, by adding A75 and A82 compared with F5. This research provides a reliable and theoretical basis for sewage treatment plants to improve denitrification capability.

Key words: denitrifying bacteria, total nitrogen, A²/O, ARTP, microbial agents

摘要：

反硝化是污水脱氮的关键步骤。投加反硝化微生物菌剂是提升总氮去除效率的有效方法。本实验从城市污水处理厂A²/O工艺厌氧池和缺氧池获取活性污泥并筛选出Pseudomonas aeruginosa F5（以下简称F5）。构建以实际生活污水为基础的培养基培养F5，通过正交试验的方式确定关键营养物质的最适投加量。研究发现，牛肉膏、K₂SO₄和MgSO₄·7H₂O的最适投加量分别为5.0 g/L、6.7 mg/L和5.0 mg/L。为验证F5作为反硝化微生物菌剂的可行性，在50 m³ A²/O中试反应器中以1∶10000（V_菌剂/V_{日处理污水}）比例连续投加F5，总氮去除率提升了19.6% ~ 24.0%。为进一步提高反硝化微生物菌剂的效能，采用常压室温等离子体育种法诱变F5后获得两株诱变菌株A75和A82。结果表明，A75和A82的总氮去除率较F5分别提高了14.5% ~ 16.2%和16.8% ~ 18.0%。该研究为污水处理厂提升氮排放标准提供了可靠的理论依据。

关键词: 反硝化细菌, 总氮, A²/O, 常压室温等离子体育种法, 微生物菌剂