Solar photocatalytic disinfection of agricultural pathogenic fungi (Curvularia sp.) in real urban wastewater

Abstract

The interest in developing alternative water disinfection methods that increase the access to irrigation water free of pathogens for agricultural purposes is increasing in the last decades. Advanced Oxidation Processes (AOPs) have been demonstrated to be very efficient for the abatement of several kind of pathogens in contaminated water. The purpose of the current study was to evaluate and compare the capability of several solar AOPs for the inactivation of resistant spores of agricultural fungi. Solar photoassisted HO, solar photo-Fenton at acid and near-neutral pH, and solar heterogeneous photocatalysis using TiO with and without HO, have been studied for the inactivation of spores of Curvularia sp., a phytopathogenic fungi worldwide found in soils and crops. Different concentrations of reagents and catalysts were evaluated at bench scale (solar vessel reactors, 200mL) and at pilot plant scale (solar Compound Parabolic Collector-CPC reactor, 20L) under natural solar radiation using distilled water (DW) and real secondary effluents (SE) from a municipal wastewater treatment plant. Inactivation order of Curvularia sp. in distilled water was determined, i.e. TiO/HO/sunlight (100/50mgL)>HO/sunlight (40mgL)>TiO/sunlight (100mgL)>photo-Fenton with 5/10mgL of Fe/HO at pH3 and near-neutral pH. For the case of SE, at near neutral pH, the most efficient solar process was HO/Solar (60mgL); nevertheless, the best Curvularia sp. inactivation rate was obtained with photo-Fenton (10/20mgL of Fe/HO) requiring a previous water adicification to pH3, within 300 and 210min of solar treatment, respectively. These results show the efficiency of solar AOPs as a feasible option for the inactivation of resistant pathogens in water for crops irrigation, even in the presence of organic matter (average Dissolved Organic Carbon (DOC): 24mgL), and open a window for future wastewater reclamation and irrigation use.

In vitro Antifungal Susceptibility of Agents for Superficial Phaeohyphomycosis

“…1,16 Specifically for the genus Curvularia, the treatment of choice is not yet fully established. According to Aguas et al 18 the use of AMB, miconazole (MCZ), CTC, TRB and ITC present satisfactory results. In parallel, studies demonstrate that therapy with ITC and TRB has been effective in cases of Tinea nigra caused by H. werneckii.…”

Ozone and Photocatalytic Processes for Pathogens Removal from Water: A Review

“…A developing alternative that can be considered as an effective low-cost disinfection process is the use of semiconductors as catalysts to promote photo-disinfection. After the successful application of TiO 2 -Pt for the inactivation of Lactobacillus acidophilus, Saccharomyces cerevisiae, and E. coli [117], a growing interest was put on photocatalytic disinfection [35,38,40,[118][119][120].…”

“…This "residual disinfecting effect" was also observed [42] when UV-LED lamp was used for irradiation of TiO2. The explanation Based on the satisfactory results, the solar photocatalytic disinfection (SPC-DIS) started to develop and focus on more resistant microorganisms, like: Cryptosporidium parvum [119,127,128], Bacillus subtilis [118], protozoa [118], photogenic fungi ( [38,118], and MS2 [129]. However, according to Lonnen et al [101], SPC-DIS was ineffective against the cyst stage of Acanthamoeba polyphaga.…”

“…Although it has to be mentioned that solar water disinfection (SODIS) as well as photocatalytic disinfection are developing very well lately [33][34][35][36][37]. However, potential to use sunlight [37][38][39][40] or low cost LED lamps [29,[41][42][43] to initiate the disinfection process in the presence of catalyst seems to give the biggest advantage over other methods. Moreover, photocatalytic disinfection leads to inactivation of viruses, bacteria, and its spores and protozoa maintaining residual disinfectant effect [22,36,42].…”

Comparison of Different Bacteria Inactivation by a Novel Continuous-Flow Ultrasound/Chlorination Water Treatment System in a Pilot Scale

“…Since the 1970s, various advanced water treatment technologies have emerged, e.g., ozonation, ultraviolet (UV) irradiation, photo-catalytic disinfection, and cavitation disinfection [6][7][8][9]. At present, some water treatment plants have already introduced new disinfection technologies.…”