反硝化微生物菌剂提升A²/O工艺TN去除效果

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.