Removal of Nitrate by Bacteria by Absorption Well Method in Wastewater Treatment Plants

Nitrate is one of the pollutants in wastewater that its removal and reduction from wastewater is essential to reduce pollution and prevent damage to the life of living organisms. One way to remove nitrate is by biological removal by bacteria. Depending on their enzymatic power, these bacteria convert nitrate to nitrite and eventually to molecular nitrogen. The aim of this study was to investigate the effects of bacterial uptake to remove nitrate, by creating anaerobic respiration conditions of aeration unit with high SRT, during hydraulic maintenance from ۱۲ to ۷۲ hours, in lahijan wastewater treatment plant of Pseudomonas bacteria was and analyzed. The findings show a decrease in COD and BOD by more than ۹۷%, respectively, and nitrogen and phosphorus removal efficiency up ۹۶% and ۹۲%. Among all the bacteria separated in the current study, the Pseudomonas with a rate of ۴۴.۲% and Alacaligenes with a rate of ۳۳.۵% and Enterobacter with a rate of ۳۰.۸% and Shigella ۳۱.۷% were identified as the dominant species. The results of the current study showed that the advantages of the use of mentioned method would lead to the removal of the organic matters and nutrients, and activity of denitrifying bacteria, besides a significant reduction in algae growth. According to the results of the analysis by the T-Test, with two independent groups and in the significance level of ۵% there is a significant different between the aerobic and anoxic groups in terms of NH۴-N and NO۲-N and NO۳-N.