The evaluation of bacterial-augmented floating treatment wetlands for concomitant removal of phenol and chromium from contaminated water.

Contamination of aquatic ecosystems with organic and inorganic contaminants is a global threat due to their hazardous effects on the environment and human health. Floating treatment wetland (FTW) technology is a cost-effective and sustainable alternative to existing treatment approaches. It consists of a buoyant mat in which wetland plants can grow and develop their roots in a suspended manner and can be implemented to treat stormwater, municipal wastewater, and industrial effluents. Here we explored the potential of bacterial-augmented FTWs for the concurrent remediation of phenol and hexavalent chromium (Cr6+) contaminated water and evaluated treated water toxicity using Triticum aestivum L. (wheat) as a test plant. The FTWs carrying Phragmites australis L. (common reed) were inoculated with a consortium of four bacterial strains (Burkholderia phytofirmans PsJN, Acinetobacter lwofii ACRH76, Pseudomonas aeruginosa PJRS20, Bacillus sp. PJRS25) and evaluated for their potential to simultaneously remove phenol and chromium (Cr) from contaminated water. Results revealed that the FTWs efficiently improved water quality by removing phenol (86%) and Cr (80%), with combined use of P. australis and bacterial consortium after 50 days. The phytotoxicity assay demonstrated that the germination of wheat seed (96%) was significantly higher where bacterial-augmented FTWs treated water was used compared to untreated water. This pilot-scale study highlights that the combined application of wetland plants and bacterial consortium in FTWs is a promising approach for concomitant abatement of phenol and Cr from contaminated water, especially for developing countries like Pakistan where the application of advanced and expensive technologies is limited.

This pilot-scale research provides new interventions and information required for establishing a large-scale remediation framework for the effective, sustainable and eco-friendly remediation of phenol and Cr co-contaminated aquatic ecosystems, using bacterial augmented floating wetlands technology (FTWs).

Exploring the potential of bacterial-augmented floating treatment wetlands for the remediation of detergent-contaminated water.

Due to industrialization and urbanization, the use of detergents inadvertently led to contamination of aquatic environments, thus posing potential threat to aquatic organisms and human health. One of the main components of detergents is linear alkylbenzene sulfonate (LAS), which can cause toxic effects on living organisms, particularly aquatic life in the environment. In this study, floating treatment wetlands (FTWs) mesocosms were developed and augmented with LAS-degrading bacteria. The plant species, Brachiaria mutica (Para grass), was vegetated to establish FTWs and bacterial consortium (1:1:1:1) of Pseudomonas aeruginosa strain PJRS20, Bacillus sp. BRRH60, Acinetobacter sp. strain CYRH21, and Burkholderia phytofirmans Ps.JN was augmented (free or immobilized) in these mesocosms. Results revealed that the FTWs removed LAS from the contaminated water and their augmentation with bacteria slightly increased LAS removal during course of the experiment. Maximum reduction in LAS concentration (94%), chemical oxygen demand (91%), biochemical oxygen demand (93%), and total organic carbon (91%) was observed in the contaminated water having FTWs augmented with bacterial consortium immobilized on polystyrene sheet. This study highlights that the FTWs supported with immobilized bacteria on polystyrene sheets can provide an eco-friendly and sustainable solution for the remediation of LAS-bearing water, especially for developing countries like Pakistan.

This pilot-scale study provided insights to resolve the detergent-contaminated wastewater issue, using floating treatment wetlands (FTWs) augmented with bacteria. The FTWs augmented with bacteria immobilized on a polystyrene sheet and vegetated with Brachiaria mutica led to high degradation of LAS, a toxic compound of detergent, from the contaminated water.

Improved remediation of amoxicillin-contaminated water by floating treatment wetlands intensified with biochar, nutrients, aeration, and antibiotic-degrading bacteria.

Residual antibiotics have become emerging contaminants of concern for their adverse impact on the ecosystem. Additionally, their accumulation in the environment is increasing antibiotic resistance among pathogens. This study assessed the impact of intensification of biochar, nutrients, aeration, and bacteria (BNAB) on the remediation potential of floating treatment wetlands (FTWs) to treat amoxicillin (AMX)-contaminated water. The FTWs were developed with saplings of Vetiveria zizanioides and intensified with biochar (1.5%), nutrients (25 mgL-1 N, 25 mgL-1 P, 20 mg L1 K), aeration (7 mg L-1), and AMX-degrading bacteria. The results showed that all the amendments enhanced the AMX degradation, while the maximum reduction in COD (89%), BOD (88%), TOC (87%), and AMX (97%) was shown by the combined application of all the amendments. The combined application also enhanced plant growth and persistence of the inoculated bacteria in the water, roots, and shoots. This approach can be employed for the low-cost, environment-friendly treatment, and recycling of antibiotic-contaminated wastewater, where BNAB intensification can further improve the bioremediation efficiency of FTWs in the case of heavily polluted waters.

Vetiver grass floating treatment wetlands (FTWs) removed 83% amoxicillin.Intensification of floating treatment wetlands enhanced amoxicillin removal to 97%.Intensified-FTW removed COD, BOD, and TOC by 89%, 88%, and 87%, respectively.Potential of Intensified-FTW for bioremediation of highly polluted water is shown.