Solar photo-Fenton at circumneutral pH using Fe(III)-EDDS compared to ozonation for tertiary treatment of urban wastewater: Contaminants of emerging concern removal and toxicity assessment

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

“…), naturally occurring in secondary treated urban wastewater. 104 The inactivation rates were found to be in the following order ozonation (83 mgO 3 /L h)> sunlight/H 2 O 2 (50 mg/L)> SPF (1:1 molar ratio, 0.1 mM of Fe (5.58 mg/L) and 50 mg/L of H 2 O 2 ), for all the target pathogens. SPF with EDDS was also compared to ozonation (i) in the degradation of selected CECs The above discussed results show that ozonation is an effective option for tertiary treatment of urban wastewater but possible additional costs for a post-treatment unit to reduce effluent toxicity and ozonation by-products as well as to improve pathogens inactivation should be evaluated before making the final decision.…”

“…149 Solar driven homogenous AOPs, look an attractive option alternative to ozonation for tertiary treatment of urban wastewater in small WTPs. SPF with EDDS has been compared to ozonation process in the inactivation of pathogens, 104 CECs removal and effect on final toxicity. 105 Sunlight/H 2 O 2 and SPF with EDDS were operated at near neutral pH in RPRs and compared to ozonation process at pilot scale in the inactivation of three pathogens (namely E. coli, Salmonella spp.…”

“…3a), but this technology is quite expensive (the unit cost being estimated as high as 400 € per m 2 ); therefore, cheaper solutions, such as the RPR system (estimated cost 10 € per m 2 ), 140 have been recently investigated for the tertiary treatment of urban wastewater by the SPF process. [103][104][105] Though RPR systems can absorb sunlight less efficiently than CPC reactors, they are characterized by a larger treated volume/surface ratio, and the liquid depth can easily be varied to eventually increase the treatment capacity (Fig. 3b).…”

“…The choice should fall on the chelating agent which results in a fair compromise among process efficiency, treatment scope, investment and management costs. For example, EDDS has proven to be more effective than NTA in the removal of sulfamethoxazole and imidacloprid from real secondary treated urban wastewater104 but less effective than other chelating agents in the inactivation of E. coli and total coliforms106 . Therefore, depending on the scope of the treatment (e.g., CECs removal, bacteria inactivation or both of them) the kinetic can be faster or slower, consequently affecting reactor volume and investment costs.…”

Solar photo-oxidation of recalcitrant industrial wastewater: a review

“…The potent hydroxyl radical, which oxidizes organic molecules in a non-selective manner, can modify the chemical structure of pollutants in this physical-chemical process. With the right process conditions, total mineralization can be achieved, resulting in CO 2 , water, and organic acids (Kowalska et al 2021;Maniakova et al 2021;Ramalho et al 2021).…”