Bacterial Augmented Floating Treatment Wetlands for Efficient Treatment of Synthetic Textile Dye Wastewater

Abstract

Floating treatment wetland (FTW) is an innovative, cost effective and environmentally friendly option for wastewater treatment. The dyes in textile wastewater degrade water quality and pose harmful effects to living organisms. In this study, FTWs, vegetated with Phragmites australis and augmented with specific bacteria, were used to treat dye-enriched synthetic effluent. Three different types of textile wastewater were synthesized by adding three different dyes in tap water separately. The FTWs were augmented with three pollutants degrading and plant growth promoting bacterial strains (i.e., Acinetobacter junii strain NT-15, Rhodococcus sp. strain NT-39, and Pseudomonas indoloxydans strain NT-38). The water samples were analyzed for pH, electrical conductivity (EC), total dissolved solid (TDS), total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), color, bacterial survival and heavy metals (Cr, Ni, Mn, Zn, Pb and Fe). The results indicated that the FTWs removed pollutants and color from the treated water; however, the inoculated bacteria in combination with plants further enhanced the remediation potential of floating wetlands. In FTWs with P. australis and augmented with bacterial inoculum, pH, EC, TDS, TSS, COD, BOD and color of dyes were significantly reduced as compared to only vegetated and non-vegetated floating treatment wetlands without bacterial inoculation. Similarly, the FTWs application successfully removed the heavy metal from the treated dye-enriched wastewater, predominately by FTWs inoculated with bacterial strains. The bacterial augmented vegetated FTWs, in the case of dye 1, reduced the concentration of Cu, Ni, Zn, Fe, Mn and Pb by 75%, 73.3%, 86.9%, 75%, 70% and 76.7%, respectively. Similarly, the bacterial inoculation to plants in the case of dye 2 achieved 77.5% (Cu), 73.3% (Ni), 83.3% (Zn), 77.5% (Fe), 66.7% (Mn) and 73.3% (Pb) removal rates. Likewise in the case of dye 3, which was treated with plants and inoculated bacteria, the metals removal rates were 77.5%, 73.3%, 89.7%, 81.0%, 70% and 65.5% for Cu, Ni, Zn, Fe, Mn and Pb, respectively. The inoculated bacteria showed persistence in water, in roots and in shoots of the inoculated plants. The bacteria also reduced the dye-induced toxicity and promoted plant growth for all three dyes. The overall results suggested that FTW could be a promising technology for the treatment of dye-enriched textile effluent. Further research is needed in this regard before making it commercially applicable.

Selection of Endophytic Strains for Enhanced Bacteria-Assisted Phytoremediation of Organic Pollutants Posing a Public Health Hazard

“…Also, the collective action of endophytic Microbacterium arborescens TYSI04 isolated from shoots of Typha domingensis and Bacillus pumilus PIRI30 obtained from roots of Pistia enhanced textile effluent degradation and toxicity reduction, which was confirmed by significant reductions in chemical oxygen demand-COD (79%), biological oxygen demand-BOD (77%), total dissolved solids-TDS (59%), TSS (27%), and color removal within 72 h when a combination of plants and bacteria was applied [49]. A similar effect was achieved by Nawaz et al [50] with the use of a consortium consisting of PGP strains (i.e., Acinetobacter junii NT-15, Rhodococcus sp. NT-39, endophytic Pseudomonas indoloxydans NT-38), and Phragmites australis for removal of three commonly used acid metal textile dyes containing two sulfo groups: Bemaplex Navy Blue D-RD, Rubine D-B, and Black D-RKP Bezma from water.…”

“…Therefore, the acquisition of such isolates needs to be enhanced through the integration of the community-based approach with biodegradation pathways. However, few studies have implemented this concept to date, and most strains for application in consortia are still chosen in culture-based in vitro assays [19,36,50]. Thus, to improve the selection of candidates for such bacterial communities, omics-based technologies can be applied.…”

Pulsed Discharge Plasma in High-Pressure Environment for Water Pollutant Degradation and Nanoparticle Synthesis

“…Methyl orange is one of the azo dyes that contain a large number of aromatic rings; this dye compound is also a group of chemical compounds that may result in increasing amounts of environmental pollution. Therefore, the removal process for this compound from wastewater has gained great attention [53][54][55][56][57][58][59][60][61][62][63][64]. As shown in Figure 5, the methyl orange compound was successfully decomposed into its derived compounds using the high-voltage discharge plasma treatment with the different types of metal electrodes.…”

Investigating degradation metabolites and underlying pathway of azo dye “Reactive Black 5” in bioaugmented floating treatment wetlands

“…In an earlier study, the bacterial inoculation in constructed wetlands, vegetated with P. australis, signi cantly (ANOVA, p < 0.05) increased the removal of RB5 compared to the non bacterized controls (Riva et al 2019). Plants have great power to degrade pollutants by making symbiotic relations with the dye degrading bacteria (Glick 2010;Nawaz et al 2020;Shahid et al 2020). In such relations, the root system of the plants helps contaminant utilizing microorganisms by providing nutritious compounds and favorable environmental conditions, thus increasing bacterial actions and contaminant breakdown in the root zone (Nie et al 2011;Khan et al 2013a,b;Fahid et al 2020).…”