UV-A activation of peroxymonosulfate for the removal of micropollutants from secondary treated wastewater

Abstract

The occurrence of micropollutants (MPs) in the aquatic environment poses a threat for the environment and the human health. The application of advanced oxidation processes based in sulphate radicals (SR-AOPs) to eliminate these contaminants has attracted attention in recent years. In this work, the simultaneous degradation of 20 multi-class MPs (classified into 5 main categories, namely antibiotics, beta-blockers, other pharmaceuticals, pesticides, and herbicides) was evaluated for the first time in secondary treated wastewater, by activating peroxymonosulfate (PMS) by UV-A radiation, without any pH adjustment or iron addition. The optimal PMS concentration to remove the spiked target MPs (100 μg L -1 ) from wastewater was 0.1 mM, leading to an average degradation of 80% after 60 min, with most of the elimination occurring during the first 5 min. Synergies between radiation and the oxidant were demonstrated and quantified, with an average extent of synergy of 69.1%. The optimized treatment was then tested using non-spiked wastewater, in which 12 out of the 20 target contaminants were detected. Among these, 7 were degraded at some extent, varying from 10.7% (acetamiprid) to 94.4% (ofloxacin), the lower removals being attributed to the quite inferior ratio of MPs to natural organic matter. Phytotoxicity tests carried out with the wastewater before and after photo-activated PMS oxidation revealed a decrease in the toxicity and that the plants were able to grow in the presence of the treated water.Therefore, despite the low degradation rates obtained for some MPs, the treatment effectively reduces the toxicity of the matrix, making the water safer for reuse.

Treatment of Winery Wastewater by Combined Almond Skin Coagulant and Sulfate Radicals: Assessment of HSO5− Activators

“…However, in this work, it was observed that the application of a UV-A reactor achieved higher mineralization than the UV-C reactor. The activation of PMS with UV-A radiation was shown to be effective in the removal of micropollutants from the wastewater [67] and in the removal of organic carbon from WW [46], which is in agreement with the results obtained in this work. Although the photolysis of PMS is negligible with UV-A radiation [68], the application of Co 2+ appears to be the contributing factor that increased the efficiency of the reaction and higher mineralization of the organic carbon.…”

Spirulina-based carbon bio-sorbent for the efficient removal of metoprolol, diclofenac and other micropollutants from wastewater

“…Wastewater (WW) samples were collected from the secondary treatment tanks of an UWWTP located in northern Portugal. The characterization of this WW has already been reported in previous studies of our group [48,49]. The WW was filtered through 1.2 μm glass-fiber filters (47 mm GF/C, Whatman™, Maidstone, United Kingdom) to remove suspended solids and then frozen until usage.…”

Performance of the solar/peroxymonosulfate process in (waste)water treatment: abatement of micropollutants, roles of reactive oxygen species, and formation of disinfection by-products

“…21 However, few studies simultaneously identified ROS generated during solar/PMS treatment and evaluated their contributions to organic pollutant removal. 31,32 In terms of practical application in water and wastewater treatment, the economic cost and optimal oxidant consumption have not been well documented. In addition, little work has been conducted to investigate toxicity of disinfection byproducts (DBPs) formed using solar/PMS as a pretreatment prior to final disinfection.…”