Testing the Performance of Doped Copper Photocatalyst in Disinfection of E. Coli in Drinking Water

Approximately 1.1 billion people in the world lack access to safe drinking water and most of them are forced to rely on supplies that are microbiologically unsafe. Consumption of contaminated water causes about two million deaths a year, mostly children under the age of five mostly due to poor sanitation and lack of good hygiene. In addition, there are around 4 billion cases of waterborne diarrheal diseases such as typhoid, hepatitis, polio and cholera.

Due to the global water safety challenges, scientists have been forced to come up with methods through which microbiologically unsafe water can be treated to avail safe water to the populations lacking access to treated water. Some of the methods include: chlorination, boiling of water and filtration. Anyway, though all these methods achieve their goals, it is important to note that they are very expensive to set up and maintain, hence the need for a cheaper alternative known as SODIS.

Solar disinfection (SODIS), a point-of-use water treatment method that uses UV radiation in sunlight to inactivate pathogenic organisms, was discovered by Professor Aftim Acra in the early 1980’s. Because SODIS relies largely on weather conditions, its efficiency varies greatly. The purpose of this study was to improve the performance of SODIS using copper doped photo catalyst. The specific objectives were to test the presence of photocatalyst in Nairobi River, Kirichwa river and Ruai wastewater treatment plant; to investigate the mechanism of inactivation; and lastly to investigate the effect of E. Coli concentration on inactivation efficiency.

The results revealed variable concentrations of E. Coli in the three water sources with Ruai leading the level of contamination. Experiments to investigate the mechanism of iancativation revealed that solar photocatalysis is the main cause of E. Coli inactivation compared to sola radiation alone or the toxicity of copper. In addition, studies on photo catalytic technique for disinfection demonstrate this process to have potential for widespread application in point of use water purification processes.

Key words: Photocalysis; E. coli, SODIS, Point of use water purification

Documentation :