Solar disinfection of contaminated water: a comparison of three small-scale reactors

This paper compares three different collector shapes for the disinfection of water heavily contaminated with Escherichia coli (K-12). Tests were carried out in real sunlight using laboratory scale reactors to determine the performance of different reflector profiles. The reactors were constructed using Pyrex tubing and aluminium reflectors of compound parabolic, parabolic and V-groove profiles. Results have shown that the compound parabolic reflector promoted a more successful inactivation of E. coli than the parabolic and V-groove profiles. Tests were also carried out to assess the improvement to disinfection which could be achieved using TiO₂ coated Pyrex rods fixed within the reactors. This technique, however, yielded a slight enhancement in the compound parabolic reactor but no benefit to overall disinfection performance in either the parabolic or V-groove reactors.These results show that the use of UV sunlight to disinfect contaminated drinking water in a full-scale continuous flow solar reactor is both promising and an appropriate technology for developing countries but that the inclusion of a fixed photocatalyst within the reactor tubes has yet to prove any significant improvement.