Effect of short-term light irradiation with varying energy densities on the activities of nitrifiers in wastewater

Mingzhu Yang; Shuang Qiu; Lingfeng Wang; Zhipeng Chen; Yanbing Hu; Jianhua Guo; Shijian Ge

doi:10.1016/j.watres.2022.118291

Effect of short-term light irradiation with varying energy densities on the activities of nitrifiers in wastewater

Water Res. 2022 Jun 1:216:118291. doi: 10.1016/j.watres.2022.118291. Epub 2022 Mar 12.

Authors

Mingzhu Yang¹, Shuang Qiu¹, Lingfeng Wang¹, Zhipeng Chen¹, Yanbing Hu¹, Jianhua Guo², Shijian Ge³

Affiliations

¹ Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, Jiangsu 210094, China.
² Australian Center for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
³ Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing, Jiangsu 210094, China. Electronic address: geshijian1221@njust.edu.cn.

PMID: 35313179
DOI: 10.1016/j.watres.2022.118291

Abstract

Microalgal-bacterial consortium (MBC) process has been proposed as an alternative to conventional activated sludge process for nitrogen removal from wastewater. As one of the most influencing parameters, light irradiation effects on microalgae have been extensively investigated. However, light influence on the performance of nitrifiers in activated sludge and its mechanism remains unclear. In this study, the effects of three factors (light irradiation power, irradiation time and sludge concentration) on activities and physiological characteristics of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were systematically studied through both the Design of Experiments driven response surface methodology (RSM) approach and light-nitrification kinetic modeling. Results indicated that light irradiation with the specific light energy density (Es) at 0.0203-0.1571 kJ·mg^-1 VSS (80-160 W/400-1000 μmol·m^-2·s^-1, 2.0-5.0 h and 2750-4250 mg·L^-1) stimulated the relative AOB activities (rAOB) by 120.0%. This was supported by the increased electron transport system activity, key enzyme activity (AMO) , gene expression (amoA) and energy generation (ATP consumption) in the light treatment. Moreover, further Es increasing up to 0.18 kJ·mg^-1 VSS inhibited both AOB and NOB activities. The inhibition was ascribed to the joint light responses of metabolic disorders and lipid peroxidation. The findings enhance our understanding of nitrifiers' physiological responses to short-term light irradiation, and promote the development of MBC as a sustainable approach for wastewater treatment.

Keywords: Ammonia-oxidizing bacteria (AOB); Light irradiation; Microalgal-bacterial consortium (MBC); Nitrifier; Nitritation; Nitrite-oxidizing bacteria (NOB).

MeSH terms

Ammonia / metabolism
Bacteria / metabolism
Betaproteobacteria* / metabolism
Bioreactors / microbiology
Nitrification
Nitrites / metabolism
Oxidation-Reduction
Sewage / microbiology
Wastewater* / microbiology

Substances

Nitrites
Sewage
Waste Water
Ammonia