Simultaneous atrazine degradation andE. coliinactivation by simulated solar photo-Fenton-like process using persulfate

Abstract

This work evaluated the feasibility of a photo-Fenton-like process using persulfate (PS) and ferrous iron (Fe) under simulated solar radiation for degrading the herbicide atrazine (ATZ, 6-Chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and inactivating E. coli. Milli Q water, lake water, and diluted wastewater effluents were spiked both simultaneously and separately with ATZ (4 mg/L) and E. coli (10 CFU/mL), and exposed to treatment. A method for determining the average irradiance throughout the water media in the UV(A+B) range of the Xe lamp emission was developed for bench-scale experiments. These values were used to calculate the UV(A+B) fluences and the solar UV(A+B) energy doses per unit of volume (Q, kJ/L). The obtained kinetic data were presented versus energy dose. Treatment of lake water at near-neutral pH was ineffective via the photo-Fenton-like process, attaining only 20% ATZ removal and 1-log reduction of E. coli. In Milli Q water and wastewater, the complete degradation of ATZ in the absence of bacteria was observed at an average energy dose of 1.5 kJ/L (60 min), while in the presence of cells the degradation efficiency was ∼60%. When ATZ was present, E. coli inactivation was also affected in Milli Q water, with 1.4-log reduction (93%) at a dose of 1.6 kJ/L (60 min), whereas in wastewater complete inactivation was achieved at a lower dose of 1.3 kJ/L (45 min). The energy requirements on a Q basis for simultaneous 90% ATZ removal and 99.99% E. coli inactivation in Milli Q water and wastewater were shown to be less than 10 kJ/L. This suggests the solar/PS/Fe system is promising for simultaneous treatment and disinfection of wastewater effluents.

Assessment of Sulfate Radical-Based Advanced Oxidation Processes for Water and Wastewater Treatment: A Review

“…To the best of our knowledge, only the effectiveness of metallic catalysis, both heterogeneous and homogeneous, for the activation of PMS and PS in order to eliminate microorganisms from water has been analysed. Specifically, iron (in various forms and oxidation states) is the most commonly used transition metal, followed by Co 2+ [35,[119][120][121][122][123][124]. It seems necessary to expand the number of activation methods assessed in order to choose the most effective one for full-scale implementation.…”

“…Most studies in this field are performed over strains of Escherichia coli [13,[121][122][123][124]. This is because this bacterium is recognized as an indicator of faecal contamination in aquatic environments [125], and it is well known in its structure and composition.…”

Inactivation of water pathogens with solar photo-activated persulfate oxidation

“…Persulfate (S2O8 2-, PS), is one via of sulfate radicals (SO4 •− ) generation, characterized by being stable at ambient temperature, having high solubility and non-toxicity [20][21][22]. The redox potential of SO4 •− is between 2.5 and 3.1 V (pH dependent), being near to the hydroxyl radical potential (E 0 = 1.8-2.7 V), which suggests a good behaviour in water treatment [22][23][24][25].…”

Catalytic ozonation by metal ions for municipal wastewater disinfection and simulataneous micropollutants removal

“…Several works on literature demonstrated that metal-catalyzed homogeneous ozonation is efficient in treating wastewater, especially regarding the oxidation of micropollutants [20][21][22] while others are devoted to microorganisms inactivation [23,24]. However, there are few studies describing the microbial inactivation and micropollutants removal simultaneously in WWTP effluent samples [23,25].…”