Metagenomic analysis of MWWTP effluent treated via solar photo-Fenton at neutral pH: Effects upon microbial community, priority pathogens, and antibiotic resistance genes

Abstract

The effectiveness of advanced technologies on eliminating antibiotic resistant bacteria (ARB) and resistance genes (ARGs) from wastewaters have been recently investigated. Solar photo-Fenton has been proven effective in combating ARB and ARGs from Municipal Wastewater Treatment Plant effluent (MWWTPE). However, most of these studies have relied solely on cultivable methods to assess ARB removal. This is the first study to investigate the effect of solar photo-Fenton upon ARB and ARGs in MWWTPE by high throughput metagenomic analysis (16S rDNA sequencing and Whole Genome Sequencing). Treatment efficiency upon priority pathogens and resistome profile were also investigated. Solar photo-Fenton (30 mg L −1 of Fe 2+ intermittent additions and 50 mg L −1 of H 2 O 2 ) reached 76–86% removal of main phyla present in MWWTPE. An increase in Proteobacteria abundance was observed after solar photo-Fenton and controls in which H 2 O 2 was present as an oxidant (Fenton, H 2 O 2 only, solar/H 2 O 2 ). Hence, tolerance mechanisms presented by this group should be further assessed. Solar photo-Fenton achieved complete removal of high priority Staphylococcus and Enterococcus , as well as Klebsiella pneumoniae and Pseudomonas aeruginosa . Substantial reduction of intrinsically multi-drug resistant bacteria was detected. Solar photo-Fenton removed nearly 60% of ARGs associated with sulfonamides, macrolides, and tetracyclines, and complete removal of ARGs related to β-lactams and fluoroquinolones. These results indicate the potential of using solar-enhanced photo-Fenton to limit the spread of antimicrobial resistance, especially in developing tropical countries.

Solar photo-oxidation of recalcitrant industrial wastewater: a review

“…H 2 O 2 did not influence the breakdown of agrochemical wastewater using photo-Fenton at low concentrations (10-50 mmol/L), while the effects clearly increased at larger concentrations of H 2 O 2 , such as 500 mmol/L (Nogueira et al 2012). Many researchers discovered that increasing the amount of iron salt in the solution increased the rate of contaminant degradation until it reached the optimum dose, after which the rate of degradation decreased (Miralles-Cuevas et al 2021;Soriano-Molina et al 2021c;Vilela et al 2021).…”

“…Although homogeneous photo-Fenton has a high mineralization efficiency under ideal conditions, it has some drawbacks. The main disadvantage is developing a substantial amount of ferric-hydroxide sludge at pH values above 4.0, which negatively impacts the environment and waste management (Vilela et al 2021;Xin et al 2021). Furthermore, catalyst renewal is impractical, and a significant proportion of catalytic metal is lost in the sludge.…”

“…Ayodele et al used a phosphoric acid modified kaolin clay supported ferric-oxalate catalyst to perform photo-Fenton for phenol degradation (Ayodele et al 2012). Many researchers relate the decrease in degradation efficiency at higher concentrations to the consumption of Fenton chemicals before the degradation is finished (Subramanian and Prakash 2021;Vilela et al 2021;Yang et al 2021a).…”

Addressing main challenges in the tertiary treatment of urban wastewater: are homogeneous photodriven AOPs the answer?

“…When the same research group investigated the effect of SPF (using the same experimental apparatus and H 2 O 2 and Fe 2+ doses) on the removal of several ARGs in real wastewater, the observed total removal for β-lactams and fluoroquinolones ARGs after 240 min treatment was in the range of 55-61%. 116 4.2 UV/hydrogen peroxide 25 When the process was operated under sunlight, the effect in terms of CECs degradation (CBZ, flumequine (FLU), and thiabendazole (TBZ), 100 μg L −1 each) in secondary-treated urban wastewater was found to be pollutant-specific and followed the order FLU > TBZ > CBZ (94%, 50%, and 12% after 90 min treatment, cumulative energy (Q UV ) = 4.6 kJ L −1 ). 117 Taking into account that a small amount of iron naturally occurs in water and wastewater, the addition of H 2 O 2 in the presence of sunlight can also promote a photo-Fenton reaction, improving the radical formation and the subsequent CECs removal.…”

“…When the same research group investigated the effect of SPF (using the same experimental apparatus and H 2 O 2 and Fe 2+ doses) on the removal of several ARGs in real wastewater, the observed total removal for β-lactams and fluoroquinolones ARGs after 240 min treatment was in the range of 55–61%. 116…”