Solar light (hv) and H2O2/hv photo-disinfection of natural alkaline water (pH 8.6) in a compound parabolic collector at different day periods in Sahelian region

Abstract

The photo-disinfection of natural alkaline surface water (pH 8.6±0.3) for drinking purposes was carried out under solar radiation treatments. The enteric bacteria studied were the wild total coliforms/Escherichia coli (10 4 CFU/ml) and Salmonella spp. (10 4 CFU/ml) naturally present in the water. The photo-disinfection of a 25-l water sample was carried out in a solar compound parabolic collector (CPC) in the absence and in the presence of hydrogen peroxide (H 2 O 2 ). The addition of H 2 O 2 (10 mg/L) to the sample water was sufficient to enhance the photo-disinfection and ensure an irreversible lethal action on the wild enteric bacteria contents of the sample. The inactivation kinetic of the system was significantly enhanced compared to the one carried out without H 2 O 2 addition. The effect of the solar radiation parameters on the efficiency of the photo-disinfection were assessed. The pH has increased during the treatment in all the photodisinfection processes (hv and H 2 O 2 /hv). The Salmonella spp strain has shown the best effective inactivate time in alkaline water than the one recorded under acidic or near-neutral conditions. The evolution of some physico-chemical parameters of the water (turbidity, NO 2 − , NO 3 − , NH 4 + , HPO 4 2− , and bicarbonate (HCO 3 − )) was monitored during the treatment. Finally, the possible mechanistic process involved during the enteric bacteria inactivation was suggested.

Wastewater Treatment by Advanced Oxidation Process and Their Worldwide Research Trends

“…The action mechanism of microorganism inactivation by UV differs from the pathogen inactivation by UV/H 2 O 2 . When both WW disinfection techniques are compared, the treatment times are shorter when the combined process is applied [53]. Another type of UV radiation is UV-C, which has been demonstrated to be more effective than UVA/TiO 2 or UV/sono-chemical treatments since it has a great disinfectant power, obtaining an inactivation reduction of 6-log in 10 min of treatment time.…”

Addition of Hydrogen Peroxide to Groundwater with Natural Iron Induces Water Disinfection by Photo‐Fenton at Circumneutral pH and other Photochemical Events

“…All disinfection studies performed using photo‐Fenton processes with 10 mg H 2 O 2 L −1 have been monitored so far with the standard plate count (SPC) method to quantify the microorganisms . However, SPC is known to only consider cell culturability, neglecting the risk associated with persistence of bacterial viability.…”

“…These processes are inhibited by phosphate, sulfate, fluoride, bromide, chloride, carbonate and bicarbonate ions, depending on their concentrations. Inhibition by these species may be due to precipitation of iron, scavenging of or coordination to dissolve Fe +3 toward forming a less reactive complex . To the best of our knowledge, no study to date has reported on how the presence of anions might affect bacterial cell inactivation by photo‐Fenton at circumneutral pH process in natural well waters.…”