Decontamination of water by combined solar advanced oxidation processes and biotreatment - Solar Energy Sciences and Engineering Applications - page 381

ions producing hydroxyl radicals. When UV/visible radiation is added, it is called
photo-Fenton, which is a catalytic process. Fe 3 + (and related species and organic com-
plexes) absorbs solar photons as a function of its absorptivity. This must be taken into
consideration when the optimal photoreactor load is calculated as a function of light-
path length. After long experimentation with different photoreactors under sunlight at
the Plataforma Solar de Almería (PSA) in Spain, the optimal concentration proposed
is 0.2-0.5 mM of iron depending on photoreactor diameter (Malato et al., 2009).
Under the “SOLARDETOX'' project (Solar Detoxification Technology for the
Treatment of Industrial Non-Biodegradable Persistent Chlorinated Water Contam-
inants, Brite Euram III Program, 1997-2000, BRPR-CT97-0424), a European
consortium coordinated by the PSA was formed for the development and marketing of
solar detoxification of recalcitrant water contaminants. The main goal of the project
was to develop a commercial non-concentrating solar detoxification system using the
compound parabolic collector technology (CPC). A full-size demonstration plant for
field demonstration was constructed at Hidrocen facilities (Madrid, Spain). The same
collectors have also been used to treat paper mill effluents in Brazil and Germany,
and paper mill effluents, surfactants, and textile dyes in Spain (Malato et al., 2007).
In 2004, a new CPC plant was installed in the context of a project for the collec-
tion and recycling of plastic pesticide bottles using advanced oxidation process (AOP)
driven by solar energy funded by the European LIFE-ENVIRONMENT programme.
This plant, which is now in routine operation, has a total collector surface of 150 m 2
and photo-reactor volume of 1.06 m 3 . More recently, in a new step forward, solar
photo-Fenton and aerobic biological processes have been combined, in a 100 m 2 CPC
solar photo-Fenton reactor and an aerobic biological treatment plant based on a 1 m 3
immobilized-biomass activated sludge reactor (Figure 12.2.3). The overall efficiency
Figure 12.2.3 Solar photo-Fenton plant with 100m 2 of CPC.