Technology for Upgrading the Tailwater of Municipal Sewage Treatment Plants: The Efficacy and Mechanism of Microbial Coupling for Nitrogen and Carbon Removal

Yinan Zhang,Jiafeng Ding,Kexin Yang,Xueping Ye,Hangjun Zhang,Yuxin Fang,Shihuan Lu

doi:10.3390/w13202850

Yinan Zhang, Jiafeng Ding + Show 5 more

Open Access

https://doi.org/10.3390/w13202850

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Abstract

The efficient removal of carbon (COD) and nitrogen (NH3-N) is vital to improving tailwater from municipal wastewater treatment plants. In this study, denitrification and decarburization bacteria with stable removal efficiencies were introduced into a membrane bioreactor (MBR) for 45 days of field experiments in a QJ Wastewater Treatment Plant (Hangzhou, China) to enhance carbon and nitrogen removal. After adding the decarbonization microorganisms into the denitrification reactor, COD removal increased from 31.2% to 80.2%, while compared to the same MBR with only denitrification microorganisms, the removal efficiency of NH3-N was greatly increased from 76.8% to 98.6%. The results of microbial analysis showed that the cooccurrence of Proteobacteria and Bacillus with high abundance and diverse bacteria, such as Chloroflexi, with autotrophic decarburization functions might account for the synchronous high removal efficiency for NH3-N and COD. This technology could provide a reference for industrial-scale wastewater treatment with the goal of simultaneous nitrogen and carbon removal.

Highlights

IntroductionSince 2013, China has successively promulgated a number of laws and regulations to solve a series of environmental problems, including water pollution, and set clear standards for the emissions of nutrients, such as carbon and nitrogen, in terms of water quality management
The results show that the dominant genera of microorganisms in the microbial samples were different, and most of the dominant genera belonged to Proteobacteria
We used the denitrification and decarburization bacteria selected in our previous experiment as the inoculum for an membrane bioreactor (MBR); when decarburization microorganisms were added to the MBR reactor containing only denitrification microorganisms, the reactor obtained better carbon removal capacity, but the original denitrification effect was increased, and the chemical oxygen demand (COD) removal efficiency increased to 80.9%

Summary

Introduction

Since 2013, China has successively promulgated a number of laws and regulations to solve a series of environmental problems, including water pollution, and set clear standards for the emissions of nutrients, such as carbon and nitrogen, in terms of water quality management. Zhejiang Province has a well-developed river network, and as water consumption has gradually increased with rapid economic development, water pollution in this area has become increasingly serious. Zhejiang Province was the first province in China to propose “five water treatments” and has been improving the management model to enhance the quality of the aquatic environment to a certain extent in recent years. There is only one municipal sewage treatment plant in each city of Zhejiang Province, and all tailwater is discharged into natural water bodies directly after reaching the standards. To ensure the ecological safety of receiving water bodies, there is currently an important demand for technology and equipment that enable denitrification and decarbonization

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