Assessment of a pilot solar V-trough reactor for solar water disinfection

Abstract

Rural and isolated communities of low-income countries suffer the lack of access to safe drinking water.

Harvested rainwater (HRW) is becoming an alternative source of freshwater in many areas of the world.

Nevertheless, its quality usually doesn’t meet drinking water standards, posing a health risk for human consumption.

Solar water disinfection – SODIS – is a low-cost household intervention used to disinfect water. In this

work, we investigate a new solar photoreactor based on V-trough mirrors as alternative to the most used

Compound Parabolic Collector (CPC) geometry at pilot scale (54 and 32 L per batch), with the aim of reducing

costs and reactor surface’s footprint. An experimental assessment of two key parameters as water recirculation

and mirror geometry was carried out. For this study several water-pathogens commonly found in HRW were

used, Escherichia coli, Enterococcus faecalis, Salmonella enteritidis and Pseudomonas aeruginosa. Best results were

obtained with the V-trough reactor in static condition, where>5-LRV (log-reduction value) for all bacteria

tested were reached with a solar-UVA dose of 254 kJ m−2 (90 min). At this operational condition, a total volume

of 162 L (3 batches) of water were treated in one full sunny day in Spain (300 min of effective treatment time). A

comparison between CPC and V-trough mirrors resulted in similar disinfection efficiencies even if the actinometric

results showed that CPC collects 1.58 times more photon flux than the V-trough in the solar-UVA region.

These results show the great performance of the V-trough mirror for this application, which is cheaper to produce

than CPC and permits treating higher amounts (66% more) of water for the same collector area and same

treatment time.