Microbial metabolism regulation on the efficient degradation of aromatic compounds for biochemical treatment process of coal chemical wastewater in pilot scale

doi:10.1016/j.envpol.2023.121872

Environmental Pollution

Volume 331, Part 2, 15 August 2023, 121872

https://doi.org/10.1016/j.envpol.2023.121872 Get rights and content

Highlights

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Inoculation of dominant strains enhanced the diversity of microbial community.
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Various functional strains capable of degrading aromatics were selectively enriched.
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The relative abundance and activity of key enzymes were significantly enhanced.
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The removal rates of different types of aromatics were significantly improved.
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The reduction of biotoxicity indicated the effective removal of feedback inhibition.

Abstract

At present, the common problems of biochemical treatment systems of coal chemical wastewater were the poor system stability and the difficulty in reaching COD discharge standards. Aromatic compounds were the main contributors to COD value. The effective removal of aromatic compounds was an urgent problem in the biochemical treatment systems of coal chemical wastewater. In this study, the dominant microbial strains that could degrade phenol, quinoline, and phenanthrene were isolated respectively and inoculated into the pilot scale biochemical tank of coal chemical wastewater. The regulation effect and mechanism of microbial metabolism on the efficient degradation of aromatic compounds were studied. The results indicated that the various aromatic compounds were significantly removed under the regulation of microbial metabolism, the removal efficiencies of COD, TOC, phenols, benzenes, N-CHs, and PAHs were increased by about 25%, 20%, 33%, 25%, 42%, and 45%, respectively, and their biotoxicity was also drastically reduced. Moreover, the abundance and diversity of microbial community, and the microbial activity were obviously improved, as well as the various functional strains were selectively enriched, suggesting that the regulation system could resist environmental stresses with high substrate concentration and toxicity, which could lead to more enhanced performance for aromatic compounds removal. In addition, the microbial EPS content was significantly increased, implying the formation of microbial hydrophobic cell surfaces, which could improve the bioavailability of aromatic compounds. Furthermore, the enzymatic activity analysis revealed that the relative abundance and activity of key enzymes were all obviously improved. In conclusion, multiple lines of evidence were provided to clarify the regulation mechanism of microbial metabolism on the efficient degradation of aromatic compounds for biochemical treatment process of coal chemical wastewater in pilot scale. The results laid a good foundation for realizing the harmless treatment of coal chemical wastewater.

Graphical abstract

Introduction

The typical characteristic of coal chemical wastewater (CCW) was the large quantity and complex quality, and the chemical oxygen demand (COD) was generally 20,000-30000 mg/L (Liu et al., 2022b). Aromatic compounds were the main contributors of refractory organic pollutants in CCW, accounting for about 50–80% of the COD value in the raw wastewater, among which benzenes, phenols, nitrogen-containing heterocyclic compounds (N-CHs), polycyclic aromatic hydrocarbons (PAHs) were typical representatives (Sun et al., 2021). Aromatic compounds were compounds with benzene ring structure, which had considerable toxicity and carcinogenic mutagenicity (Geng et al., 2020). At present, the poor system operation stability and the difficulty in reaching the standard of effluent were the common problems of CCW biochemical treatment systems at home and abroad, such as Xinjiang Qinghua coal to gas, Inner Mongolia Chifeng coal to fertilizer, and Shenhua Baotou coal to olefin, which seriously affected the harmless treatment of CCW and the sustainable development of coal chemical industry. Especially, the COD value in the effluent exceeded the standard seriously, and more than 90% of it was contributed by aromatic compounds (Yang et al., 2022). Therefore, the effective removal of aromatic compounds was a practical problem that needed to be solved urgently for realizing the harmless treatment of CCW.

Over the last three decades, bioremediation has been proven to be the most effective way to degrade various pollutants due to the low-cost, high-performance and environmentally friendly (Zhou et al., 2022a). In the treatment system of CCW, the biochemical treatment system was the core structure to realize the effective treatment of CCW (Shi et al., 2022). However, it was regrettable that the effluent from the biochemical treatment system was often accompanied by a large number of refractory organics, which made it difficult for the COD value to reach the standard. In order to achieve the standard discharge of CCW, bioaugmentation and metabolic regulation were often used in practical engineering (Fang et al., 2013). At present, the methods of enhancing the degradation of aromatic compounds in actual CCW treatment plants mainly focused on the addition of growth mechanisms (e.g. methanol, sodium acetate, etc) and the addition of a certain proportion of domestic sewage, whose main function was to improve the microbial biomass in the system, which could promote the removal of pollutants. However, the increase in biomass did not mean an increase of the amount and activity of key enzymes in the metabolism of refractory organic substances. As a result, the concentration of COD in wastewater was often reduced, and refractory organic matter still existed in large quantities (Shi et al., 2022). In fact, crucial roles for metabolic regulation were the regulations of microbial physiological response and enzyme activity. It has been reported that high biodiversity and selective enrichment of various dominant microbial strains in biochemical ponds could improve the ability of microorganisms to resist adverse environment (Wu et al., 2018a). In addition, the microbial extracellular polymeric substances (EPS) carried a large number of aromatic structures and unsaturated fatty chains that interact with aromatic ring molecules, and EPS also contained a large number of functional groups related to binding aromatic compounds, which would be beneficial to the improvement of the bioavailability of aromatic compounds (Liu et al., 2022a). Additionally, the essence of microbial metabolism of organic matter was the production and action mechanism of key enzymes. Therefore, whether the induced expression and activity improvement of key enzymes could be achieved through microbial metabolic regulation was crucial to promote the effective degradation of aromatic compounds (Luo et al., 2019). At present, there were few reports on the regulation characteristics and mechanisms of microbial metabolism for efficient degradation of aromatic compounds in pilot-scale complex systems based on microbial physiological response level and enzyme activity level.

In this study, the dominant microbial strains capable of degrading phenols, N-CHs, and PAHs were isolated, respectively, and inoculated into a pilot scale biochemical tank of coal chemical wastewater. The following issues were mainly discussed: (1) the regulation effect of microbial metabolism in the biochemical treatment process of coal chemical wastewater; (2) the regulation mechanism of microbial metabolism on the efficient degradation of aromatic compounds for biochemical treatment process of coal chemical wastewater in pilot scale.

Section snippets

Isolation and identification of dominant microbial strains

The isolation of dominant microbial strains was performed in the minimal salt medium (MSM) with phenol (300 mg/L), quinoline (300 mg/L), and phenanthrene (30 mg/L). The concentrations of 300 mg/L phenol, 300 mg/L quinoline, and 30 mg/L phenanthrene were selected in experiment because of the contents of different aromatic compounds in actual CCW and the tolerance concentration of microorganisms to different aromatic compounds. 20 mL of activated sludge from an ordinary municipal sewage treatment

Metabolic characteristics of aromatic compounds by dominant microbial strains

In this study, ordinary municipal activated sludge was used as the bacterial source, and phenol, quinoline, and phenanthrene were used as the only carbon source for isolating the dominant microbial strains capable of degrading phenol, quinoline, and phenanthrene respectively. The analysis of their 16S rRNA gene revealed the highest sequence identity with the Pseudomonas nitroreducens strain VITWW2 (99%), Rhodococcus biphenylivorans strain TG9 (99%), and the Burkholderia sp strain (99%),

Conclusion

In this study, various dominant microbial strains screened were inoculated into the pilot-scale actual CCW biochemical treatment tank. The regulation effect and mechanism of microbial metabolism on the efficient degradation of aromatic compounds were studied. The results showed that the diversity and abundance of microbial community, and the microbial activity were significantly improved, as well as the various functional strains were selectively enriched in the regulation group inoculated with

Credit author contribution

Xingshe Liu: Investigation, Visualization, Methodology, Conceptualization, Supervision, Writing – review & editing. Yongjun Liu: Funding acquisition, Investigation, Visualization, Supervision, Writing – review & editing. Hui Tang: Investigation, Writing – review & editing. Aining Zhang: Writing – review & editing. Zhe Liu: Visualization, Investigation, Writing – review & editing. Zhihua Li: Investigation, Writing – review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 51978559), and Shaanxi Provincial Key R & D Program (No. 2019ZDLSF05-06).

References (50)

Y.C. Chang et al.
Whole-genome sequence of Aquamicrobium sp. strain SK-2, a polychlorinated biphenyl-utilizing bacterium isolated from sewage sludge
Genome Announc.
(2015)
F. Fang et al.
Bioaugmentation of biological contact oxidation reactor (BCOR) with phenol-degrading bacteria for coal gasification wastewater (CGW) treatment
Bioresour. Technol.
(2013)
S. Geng et al.
Microbial diversity and co-occurrence patterns in deep soils contaminated by polycyclic aromatic hydrocarbons (PAHs)
Ecotoxicol. Environ. Saf.
(2020)
P. Isaac et al.
Differential expression of the catabolic nahAc gene and its effect on PAH degradation in Pseudomonas strains isolated from contaminated Patagonian coasts
Int. Biodeterior. Biodegrad.
(2015)
N. Liu et al.
Enhanced biodegradation of chlorobenzene via combined Fe³⁺ and Zn²⁺ based on rhamnolipid solubilisation
J. Environ. Sci.
(2021)
X. Liu et al.
Metabolic fates and response strategies of microorganisms to aromatic compounds with different structures
Bioresour. Technol.
(2022)
Y. Liu et al.
Pyridine degradation characteristics of a newly isolated bacterial strain and its application with a novel reactor for the further treatment in pyridine wastewater
Process Biochem.
(2020)
Z. Liu et al.
Role of cycle duration on the formation of quinoline-degraded aerobic granules in the aspect of sludge characteristics, extracellular polymeric substances and microbial communities
Environ. Res.
(2023)
J.A. Lopez-Gonzalez et al.
Dynamics of bacterial microbiota during lignocellulosic waste composting: studies upon its structure, functionality and biodiversity
Bioresour. Technol.
(2015)
C. Lu et al.
A PAH-degrading bacterial community enriched with contaminated agricultural soil and its utility for microbial bioremediation
Environ. Pollut.
(2019)

J. Luo et al.

Simultaneous removal of aromatic pollutants and nitrate at high concentrations by hypersaline denitrification:Long-term continuous experiments investigation

Water Res.

(2022)

J. Luo et al.

Integrated approach to enhance the anaerobic biodegradation of benz[alpha]anthracene: a high-molecule-weight polycyclic aromatic hydrocarbon in sludge by simultaneously improving the bioavailability and microbial activity

J. Hazard Mater.

(2019)

W. Ma et al.

Biotoxicity assessment and toxicity mechanism on coal gasification wastewater (CGW): a comparative analysis of effluent from different treatment processes

Sci. Total Environ.

(2018)

C. Muangchinda et al.

16S metagenomic analysis reveals adaptability of a mixed-PAH-degrading consortium isolated from crude oil-contaminated seawater to changing environmental conditions

J. Hazard Mater.

(2018)

M.A. Musumeci et al.

Substrate specificities of aromatic ring-hydroxylating oxygenases of an uncultured gammaproteobacterium from chronically-polluted subantarctic sediments

Int. Biodeterior. Biodegrad.

(2019)

C. Ou et al.

Coupling of iron shavings into the anaerobic system for enhanced 2,4-dinitroanisole reduction in wastewater

Water Res.

(2016)

N. Panigrahy et al.

A comprehensive review on eco-toxicity and biodegradation of phenolics: recent progress and future outlook

Environ. Technol. Innov.

(2022)

S. Shahryari et al.

High phenol degradation capacity of a newly characterized Acinetobacter sp. SA01: bacterial cell viability and membrane impairment in respect to the phenol toxicity

Ecotoxicol. Environ. Saf.

(2018)

J. Shi et al.

Review on treatment technologies of coal gasification wastewater in China

J. Clean. Prod.

(2022)

J. Shi et al.

Enhanced anaerobic degradation of nitrogen heterocyclic compounds with methanol, sodium citrate, chlorella, spirulina, and carboxymethylcellulose as co-metabolic substances

J. Hazard Mater.

(2020)

S.R. Subashchandrabose et al.

Biodegradation of high-molecular weight PAHs by Rhodococcus wratislaviensis strain 9: overexpression of amidohydrolase induced by pyrene and BaP

Sci. Total Environ.

(2019)

Y. Sun et al.

Current advances in coal chemical wastewater treatment technology

B. Wang et al.

Effect of mixed soil microbiomes on pyrene removal and the response of the soil microorganisms

Sci. Total Environ.

(2018)

F. Wang et al.

Characterization of a phenanthrene-degrading microbial consortium enriched from petrochemical contaminated environment

Int. Biodeterior. Biodegrad.

(2016)

P. Wang et al.

A high-efficiency phenanthrene-degrading Diaphorobacter sp. isolated from PAH-contaminated river sediment

Sci. Total Environ.

(2020)

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Microbial metabolism regulation on the efficient degradation of aromatic compounds for biochemical treatment process of coal chemical wastewater in pilot scale☆

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Isolation and identification of dominant microbial strains

Metabolic characteristics of aromatic compounds by dominant microbial strains

Conclusion

Credit author contribution

Declaration of competing interest

Acknowledgements

Genome Announc.

Bioresour. Technol.

Ecotoxicol. Environ. Saf.

Int. Biodeterior. Biodegrad.

J. Environ. Sci.

Bioresour. Technol.

Process Biochem.

Environ. Res.

Bioresour. Technol.

Environ. Pollut.

Water Res.

J. Hazard Mater.

Sci. Total Environ.

J. Hazard Mater.

Int. Biodeterior. Biodegrad.

Water Res.

Environ. Technol. Innov.

Ecotoxicol. Environ. Saf.

J. Clean. Prod.

J. Hazard Mater.

Sci. Total Environ.

Sci. Total Environ.

Int. Biodeterior. Biodegrad.

Sci. Total Environ.