Enhancing the Performance of Solar Water Disinfection with Potassium Persulfat: Laboratory Study with Enterococcus faecalis

Background & Aims of the Study: The safe drinking water providing is one of the most crucial objections in these centenaries. Bacterial water contamination and high rate of morbidity and mortality is crucial health threat. Efficiency of potassium persulfat (KPS) associated solar disinfection as a novel water disinfection technology was evaluated in batch scale experiments, using Ent. faecalis (ATTCC 29212). Material and Methods: This research is a descriptive and experimental study which done on Tehran city, Iran. Ent. faecalis (ATTCC 29212) was provided in standard form from reference laboratory. Desired bacterial density in water was prepared by Mc Farland method. Water specimens were exhibited with solar radiations from 10 a.m to 16 p.m of Tehran local time. All experiments were conducted into 1.5 L volume of Damavand bottled water. Non-injured bacteria cells were detected by plating onto Bile Esculin azide agar media. Turbid water samples were provided by spiking of sterile slurry. Contact time (1-6 h), turbidity (30-200 NTU), KPS concentration (0.1, 0.7, 1.5 and 2 mMol/l), Ent. faecalis density(1000 and 1500 cell/ml) and UV intensity  were independent and disinfection efficiency was a dependent variable, respectively. Results: Intensity of UVA solar irradiation varied from 3770 to 6263.3 µW/Cm2, with the highest value was measured on 13.30 p.m. In single SODIS and 1 hour contact time, increasing of bacterial closeness from 1000 to 1500 cell/ml implied disinfection performance decreasing in which, the vital bacteria was 10 and 20 cell/ml, respectively; but beyond of this contact time, a complete disinfection was occurred. Disinfection of Ent. faecalis was achieved within 2 h with single solar irradiation but KPS associated solar disinfection with applied dosage of KPS provide completely disinfection in 1 h in which the process efficiency was not influenced by increasing of bacterial density and turbidity up to 200 NTU. Conclusion: Association of KPS with SODIS enhancing water disinfection which can be used in remote area and emergency status.