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

Abstract

The search for alternative water sources is pushing to the reuse of treated water coming from municipal wastewater treatment plants. However, this requires that tightened standards be fulfilled. Among them is the microbiological safety of reused water. Although chlorination is the mostly applied disinfection system, it presents several disadvantages, such as the high doses required and the possibility of formation of dangerous by-products. Moreover, the threat of antibiotic resistance genes (ARGs) spread throughout poorly treated water is requiring the implementation of more efficient disinfection systems. Ozone and photo assisted disinfection technologies are being given special attention to reach treated water with higher quality. Still, much must be done to optimize the processes so that cost-effective systems may be obtained. This review paper gives a critical overview on the application of ozone and photo-based disinfection systems, bearing in mind their advantages and disadvantages when applied to water and municipal wastewater. Also, the possibility of integrated disinfection systems is considered.

Removal of Enteric Pathogens from Real Wastewater Using Single and Catalytic Ozonation

“…In that previous case, the maximum value of 0.16 mgO 3 /L corresponding to 30 s of treatment was required to achieve total E. coli depletion [26]. The presence of real wastewater and its constituents such as organic matter and ionic species affects significantly the disinfection treatment [20,25,32], which will entail a higher ozone dose required for an effective disinfection. The initial E. coli concentration determined to be in the secondary municipal wastewater was of about 4 log which is not significantly different from the load tested with the spiked ultrapure water [26].…”

SARS-CoV-2 in environmental perspective: Occurrence, persistence, surveillance, inactivation and challenges

“…The free residual chlorine (0.5 mg/L from Cl − or 2.19 mg/L from ClO 2 ) ensured near complete inactivation of SARS-CoV-1 in wastewater [51] . However, the requirement of high doses of Cl − and the possibility of formation of disinfection by-products (DBPs) warrants its usage [171] , [172] . PAA is considered as an alternative to the chlorination process, wherein the H 2 O 2 and acetic acid (CH 3 COOH) generates reactive hydroxyl radicals [173] , [174] .…”

“…Excess dosages may lead to the formation of residual by-products. Inactivates upto 99% of viruses [51] , [69] , [71] , [189] , [171] , [172] , [173] , [174] , [175] , [176] , [177] , [178] , [179] , [180] , [181] , [182] , [184] , [185] , [186] Filtration methods Slow sand and Ceramic Ultra-filtration Nano-filtration Reverse osmosis Membrane Allows separation through a usage of physical barrier from water. Remove virus and bacteriophages upto 0.001 m size [6] , [71] , [172] , [191] Advanced oxidation Photocatalysis Ozone-based Oxidation Cold plasma Fenton reagent Photo- Fenton Electro Fenton Ultrasound Wet-Air Oxidation Technology Supercritical Wet-Air Oxidation Technology (SCWO) Nano-catalyst based advanced oxidation process Rapid release of high reactive species (OH* radicals) that oxidizes or destroys enteric viruses and nucleic acids, cell membrane/ capsid of bacteriophages without the release of byproducts.…”

“… Remove virus and bacteriophages upto 0.001 m size [6] , [71] , [172] , [191] Advanced oxidation Photocatalysis Ozone-based Oxidation Cold plasma Fenton reagent Photo- Fenton Electro Fenton Ultrasound Wet-Air Oxidation Technology Supercritical Wet-Air Oxidation Technology (SCWO) Nano-catalyst based advanced oxidation process Rapid release of high reactive species (OH* radicals) that oxidizes or destroys enteric viruses and nucleic acids, cell membrane/ capsid of bacteriophages without the release of byproducts. Inactivates enveloped viruses upto 99.99％ [6] , [142] , [159] , [171] , [193] , [195] , [214] , [237] , [238] , [198] , [199] , [200] , [201] , [202] , [203] , [204] , [205] , [206] , [217] , [218] , [219] , [220] Other Processes Stabilization/algal ponds Constructed wetland and water bodies Synergic functions of sunlight Bacteriophages also gets inactivated [188] , [190] …”

Investigation of the Effects of Radio Frequency Water Treatment on Some Characteristics of Growth in Pepper (<i>Capsicum annuum</i>) Plants

“…Electromagnetic radiation, particularly radiation emitted from routers, affects all living systems and influences cells, tissues and organs in several ways [9] [10] [11]. They affect, for example, mammals [12]- [17], fruit flies [18], ticks [19] amphibians [20] [21] [22], ants [23], birds [24], honey bees [25] [26] [27] and protozoa [28] [29].…”