Metagenomic Insight of a Full Scale Eco-Friendly Treatment System of Textile Dye Wastewater Using Bioaugmentation of the Composite Culture CES-1.

Aalfin Emmanuel Santhanarajan,Sung-Cheol Koh,Woo-Jun Sul,Keun-Je Yoo,Hong-Gi Kim,Hoon-Je Seong

doi:10.3390/microorganisms9071503

Aalfin Emmanuel Santhanarajan, Sung-Cheol Koh + Show 4 more

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https://doi.org/10.3390/microorganisms9071503

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Abstract

Effects of bioaugmentation of the composite microbial culture CES-1 on a full scale textile dye wastewater treatment process were investigated in terms of water quality, sludge reduction, dynamics of microbial community structures and their functional genes responsible for degradation of azo dye, and other chemicals. The removal efficiencies for Chemical Oxygen Demand (COD), Total Nitrogen (T-N), Total Phosphorus (T-P), Suspended Solids (SS), and color intensity (96.4%, 78.4, 83.1, 84.4, and 92.0, respectively) 300–531 days after the augmentation were generally improved after bioaugmentation. The denitrification linked to T-N removal appeared to contribute to the concomitant COD removal that triggered a reduction of sludge (up to 22%) in the same period of augmentation. Azo dye and aromatic compound degradation and other downstream pathways were highly metabolically interrelated. Augmentation of CES-1 increased microbial diversity in the later stages of augmentation when a strong microbial community selection of Acinetobacter parvus, Acinetobacter johnsonii, Marinobacter manganoxydans, Verminephrobacter sp., and Arcobacter sp. occurred. Herein, there might be a possibility that the CES-1 augmentation could facilitate the indigenous microbial community successions so that the selected communities made the augmentation successful. The metagenomic analysis turned out to be a reasonable and powerful tool to provide with new insights and useful biomarkers for the complex environmental conditions, such as the full scale dye wastewater treatment system undergoing bioaugmentation.

Highlights

Introduction iationsAzo dyes are one of the oldest synthetic chemicals and are still widely used in textile printing and the food industries
The efficiency of the dye wastewater treatment 67 days before the bioaugmentation of CES-1 was shown in Table 1, which was used as a control for the treatments after the bioaugmentation
The removal efficiencies (%) for Chemical Oxygen Demand (COD), Total Nitrogen (T-N), Total Phosphorus (T-P), suspended solid (SS), and color intensity 50 days after the bioaugmentation were 97.8, 62.6, 95.8, 63.4, and 77.9, showing the increase of COD, T-N, T-P, and color intensity removal efficiencies (%) by 2.9, 14.5, 4.2, and 11.6, respectively. This indicates that the bioaugmentation of CES-1 may be effective in facilitating dye wastewater treatment

Summary

Introduction

Azo dyes are one of the oldest synthetic chemicals and are still widely used in textile printing and the food industries. The textile industry is considered one of the largest water consumers in the world. It is rapidly expanding, and dyes are continuously being upgraded and replaced by superior compounds that have enhanced fastness, stability, brightness, and resistance to natural degradation. Color is the first contaminant to be recognized in the wastewater and has to be removed before discharging into water bodies or on land [2]. The presence of very small amounts of dyes in water (less than 1 ppm for some dyes) is highly visible and affects the aesthetic merit, water transparency, and gas solubility in lakes, rivers, and other water bodies [3]. It is noteworthy that some dyes are highly toxic and mutagenic, Licensee MDPI, Basel, Switzerland

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