Solar Disinfection Using Zero Valent Iron for Inactivation of Escherichia coli and Total Coliforms in Water Using a Raceway Reactor

Abstract

Contamination from microorganisms is one of the gravest types of water pollution. In 2022, there were 842,000 new cases of gastrointestinal diseases worldwide. The aim of this study was to size, construct, and evaluate a Raceway reactor (28 L total capacity) as a laboratory-scale solar disinfection system for the inactivation of Escherichia coli and total coliforms in water, using Zero Valent Iron (ZVI). For this purpose, a sample of E. coli contaminated potable water was treated with steel wool as a source of ZVI and solar irradiation. Using a 23 factorial design with four central points and a total of 12 trials, the following was investigated: the effect of the Fe0 dose (0.6–1.8 g L−1); it should be noted that both the natural and drinking waters of the study area have iron concentrations of less than 0.1 mg L−1. Depth tests of the treated water in the reactor were carried out at different levels (5, 7 and 9 cm) and with a duration of four to six hours. Therefore, it is concluded that the reactor/ZVI is effective for the disinfection of E. coli and total coliforms at concentrations >2419.6 MPN/100 mL, reaching 99.96% disinfection for both cases; it is also a cost-effective treatment due to its inexpensive inputs.