Combination of highly efficient microflora to degrade paint spray exhaust gas

Huixia Lan,Heng Zhang,Yanhui Sun,Da Yang,Jianbo Liu,Shixin Qi

doi:10.1038/s41598-020-62972-2

Abstract

Spray paint exhaust gas contains recalcitrant volatile organic compounds (VOCs), such as benzene, toluene and xylene (BTX). Treating BTX with a biofilter often achieves unsatisfactory results because the biofilter lacks efficient microbial community. In this work, three strains for BTX degradation were isolated and identified as Pseudomonas putida, Bacillus cereus and Bacillus subtilis by using 16S rRNA sequencing technology. A consortium of highly efficient microbial community was then constructed on a stable biofilm to treat BTX in a biofilter. A relatively suitable ratio of P. putida, B. cereus and B. subtilis was obtained. An efficiency of over 90% was achieved in the biofilter with VOC concentration of 1000 mg/m3 through inoculation with the microbial community after only 10 days of operation. Thus, fast start-up of the biofilter was realised. Analysis of intermediate products by gas chromatography–mass spectrometry indicated that BTX was degraded into short-chain aldehydes or acids via ring opening reactions.

Highlights

Spray paint exhaust gas contains recalcitrant volatile organic compounds (VOCs), such as benzene, toluene and xylene (BTX)
The indiscriminate discharge of large amounts of paint spray exhaust gas exerts a negative impact on the atmospheric environment[5,6]
Xue et al used a biotrickling filter to treat complex odorous gas and found that bacteria play a greater role than fungi and actinomycetes do in degrading VOCs18

Summary

Introduction

Spray paint exhaust gas contains recalcitrant volatile organic compounds (VOCs), such as benzene, toluene and xylene (BTX). A consortium of highly efficient microbial community was constructed on a stable biofilm to treat BTX in a biofilter. Efficient technologies should be developed to treat paint spray exhaust gas and address its effects. A removal efficiency of higher than 98% was achieved by Bacillus firmus when the concentration of ketone (acetone and methyl ethyl ketone) and benzene in paint spray exhaust gas was lower than 3000 mg/m3 13. Lu et al used Pseudomonas, Kocuria, Arthrobacter and Bacillus to treat exhaust gases containing formaldehyde (0–6.5 mg/m3), benzene (2.2–46.7 mg/m3), toluene (0.5–28.2 mg/m3) and xylene (4.1–59 mg/m3), and a maximum removal rate of 93% and stable treatment effects were obtained during continuous operation[19]. The constructed microbial community shortened the biofilm-forming time accelerated the biofilter start-up and contributed to a stable operation, proving the operational flexibility of the biofilter

Methods

Results

Conclusion