Nitrogen Removal from Micro-Polluted Reservoir Water by Indigenous Aerobic Denitrifiers

International Journal of Molecular Sciences

Shi-Yu Di¹  Lin Guo¹  Zi-Zhen Zhou¹  Ting-Lin Huang¹  Na Zhou¹  Shi-Lei Zhou¹  Hai-Han Zhang¹ 

[1] School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China;

关键词: aerobic denitrifiers;    aerobic denitrification;    nitrogen removal;    source water;   

DOI  :  10.3390/ijms16048008

来源: DOAJ

【 摘 要 】

Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20–26 °C and a dissolved oxygen concentration of 3–7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/Land that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each withno nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimentaland control systems ranged from 2.8 × 104 to 2 × 107 cfu/mL and from 7.75 × 103 to5.5 × 105 cfu/mL, respectively. The permanganate index in the experimental andcontrol systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems.

【 授权许可】

Unknown