Sunlight disinfection of drinking water

Solarna dezinfekcija (SODIS) je metoda za pročišćavanje vode u kojoj se primjenjuju UVA-zrake kao sredstvo za inaktivaciju bakterija u vodi. Temelji se na korištenju jeftinih i pristupačnih sredstava kao što su PET boce i sunčeva energija. Glavni cilj rada bio je postići smanjenje bakterija u vodi za 4 reda veličine. Eksperimenti su izvođeni ili pomoću sunčevog simulatora koristeći 3 različita UVA-intenziteta, ili u vanjskim uvjetima. Promatran je utjecaj otopljenih organskih tvari i različitih čestica na učinkovitost solarne dezinfekcije. Rezultati su pokazali da su bakterije u prirodnim uzorcima vode otpornije na sunčevo zračenje nego laboratorijski sojevi. Otopljene organske tvari su pojačavale rast bakterija i uzrokovale zamućenje koje je spriječavalo UVA-zrake da u potpunosti prodru kroz uzorak. Od različitih filtar materijala, ispostavilo se da je vata najbolje rješenje za uklanjanje čestica u vodi.Solar water disinfection (SODIS) is a water treatment method that uses UVA irradiation as an instrument for inactivation of bacteria in water. It is based on cheap and easily available tools: PET bottles and sunlight. The main aim of this study was to achieve a log 4 reduction of bacteria. The experiments were either performed with a sun simulator with UVA lamps using 3 different lamp heights to create different UVA intensities or outdoor conditions were applied. Also, influence of dissolved organic substances and different particles on solar disinfection efficiency was observed. The results showed that bacteria in natural water samples were found to be more resistant to sunlight than lab strains. It was also discovered that dissolved organic substances enhanced bacterial growth and produced turbidity which prevented UVA rays to fully penetrate through the sample. From the different filter materials, cotton wool turned out to be the best solution for the reduction of suspended particulate matter