Project Overview

SOLWATER Project was approved by the European Commission in 2001 and the activities have been initiated in November 2002. The project has a duration of 36 months.

SOLWATER Project main objective, and expected project result, is the development of a fully autonomous system to the disinfection and elimination of trace organic contaminants in household drinking water in rural areas of developing countries, without any chemical addition and with the only use of energy from sunlight. The proposed technology would be based on the photocatalytic generation, by using sunlight, of hydroxyl radicals and singlet oxygen species to, respectively, detoxify and disinfect contaminated drinking water. Titanium dioxide photocatalytic process will be used to hydroxyl radical generation and Ru(II) polypyridyl complexes will be used to singlet oxygen production. A small photovoltaic cell would provide the energy to continuously pump the water throught the reactors. Where convenient, the proposed device could be easily adapted to only detoxification or disinfection applications. This general objective is expected to be achieved by the successful obtainment of the following scientific and technological partial objectives.

Scientific objectives:

  1. Assessment of persistent residual effect of Ru(II) singlet oxygen process over specific selected bacterial colonies, such as Etreptococcus faecalis, coliforms, Escherichia coli, Mycobacterium Tuberculosis and Vibrio Cholerae.
  2. Determination of combined photo-killing effect of hydroxyl and singlet oxygen radicals (generated by the previously mentioned processes) over the same target micro-organisms.
  3. Assessment of titanium dioxide photocatalytic degradation efficiency at ppm/ppb level, using selected target hazardous water contaminants: pesticides, chlorinated compounds, etc.
  4. Determination of combined effect of hydroxyl and single oxygen radicals (generated by the previously mentioned processes) over degradation of the same organic contaminants, at trace level.

Technological objectives:

  1. Development of an efficient solar photocatalytic reactor to hydroxyl radicals generation, by supported titanium dioxide systems, to organic contaminants degradation.
  2. Development of an efficient solar photocatalytic reactor to singlet oxygen radicals generation, based on polymer-supported sensitizers, to bacterial disinfection.
  3. Development of the most yearly efficient optic for sunlight caption adequate to the local latitude and the useful wavelength of light related with the photocatalytic/photosensitizing processes to be used. This optic would be based on static Compound Parabolic Concentrators (CPCs).
  4. Development of a low-cost and robust static solar collector with long-term reliability to integrate previous reactors, optic and hydraulic systems (it must be noticed that low-cost is not a primarily objective of this proposal; if final system fulfil efficiency expectatives, cost reduction would be addressed at later stages by project Consortium).