Investigating the microbial inactivation efficiency of a 25 L batch solar disinfection (SODIS) reactor enhanced with a compound parabolic collector (CPC) for household use

BACKGROUND: A simple point-of-use solar disinfection (SODIS) reactor was designed to treat 25 L of water and was constructed from a methacrylate tube placed along the linear focus of a compound parabolic concentrator (CPC) and mounted at 37◦ inclination. Experiments were carried out over a 7 month period by seeding a 106 CFU mL−1 concentration of Escherichia coli K-12 in 25 L of well water or turbid water to mimic field conditions and determine the microbial effectiveness of the reactor.RESULTS: During periods of strong sunlight, complete inactivation of bacteria occurred in under 6 h, even with water temperatures 50 ◦ C. No regrowth of bacteria occurred within 24 h and 48 h following solar disinfection. The construction cost of this prototype reactor was approximately US$200 but with an expected lifetime of 10 years, the running cost of the reactor is expected to be US$0.002 L−1.CONCLUSION: This study confirms that significant water disinfection can be achieved using a low cost CPC-enhanced 25 L batch SODIS reactor.