Response of the nitrification sludge to oxytetracycline and operating the nitrifying reactor for oxytetracycline wastewater treatment

Abstract

The nitrify-based technology has already been regarded as an economical and efficient strategy to remove nitrogen. This study investigated different oxytetracycline (OTC) concentrations inhibited the nitrifying process of an aerobic wastewater treatment system in short-term shocks. The stability of ammonia nitrogen removal had declined trend and demonstrated nitrite accumulation when the concentration of oxytetracycline was 0,1,2,5,10,20mg/L, respectively. And the ammonia oxidation reaction time decreased from 240 min to 120 min. Mixed liquid suspended solids (MLSS) decreased by 50.69%, 48.53%, 74.28%, 65.03%, and 72.97%, respectively. Compared to control OTC (0 mg/L), S-PN decreased from 2.256 mg·gVSS-1 to 0.016 mg·gVSS-1, 0.294 mg·gVSS-1, 0.094 mg·gVSS-1, 0.649 mg·gVSS-1, 0.349 mg·gVSS-1. Total EPS decreased from 7.795 mg·gVSS-1 by 17.00%, 32.91%, 45.09%, 43.04%, and 29.57%, respectively. High-throughput sequencing analyses showed that Proteobacteria and Bacteroidetes were the most phylum. The relative abundance of Nitrospira decreased as the OTC concentration increased, while that of Comamonas increased.