Evaluation of the Performance of a Solar Photocatalytic Reactor to Disinfect Water in Field Tests

ARAUJO, P.; NAVNTOFT, C.; APELLA M. C.; BLESA, M. A.

Granada

Conferencia; IV Internacional Conference Interfaces Against Pollution, IAP 2006; 2006

International Group on Interfaces Against Pollution

A recirculation solar reactor (SOLWATER) that uses heterogeneous photocatalysis and photosensitization was tested in a shanty house in the Province of Tucumán, Argentina. The present communication describes the main characteristics of the reactor and the results of the tests carried out. To evaluate the capability of the reactor to disinfect water, the concentration of four types of bacteria present in the water was followed as a function of the irradiation time and meteorological conditions. The chosen organisms were total coliforms, fecal coliforms, Enterococcus faecalis and Pseudomonas aeruginosa. The evaluation of the evolution of bacterial concentrations leads to the following conclusions: (a)    Neither time nor accumulated total energy defines per se the rate of bacterial destruction. Both factors must be taken into account. Also very important is the ratio (time under irradiation) / (total experiment time) (in the SOLWATER reactor, this ratio is ca 0.2. Finally, the recirculation rate, defining the cycling frequency, is also of importance. (b)   The variability of the results is larger than that observed in laboratory tests using collection strains of one given bacterium. (c)    Fecal coliforms can be removed totally in sunny days, after 4-6 h irradiation. (d)   Total coliforms and Ent. faecalis are largely removed, although in some experiments the count after 6 h irradiation time is not zero. (e)     Pseudomonas aeruginosa is apparently protected by the other strains, and/or by the starvation conditions of the experiments. This conclusions lead to a positive evaluation of the feasibility to build larger reactors for water disinfection, but also indicate the need to solve the observed effect of bacterial consortiums.