CPC photoreactor

Water Disinfection by Sunlight and Ti02 Using a CPC Photoreactor... 

Fig. 17.7 Inactivation of E. coli by sunlight in a CPC photoreactor. The insert contains the UV (continuous line) and total (dashed line) solar irradiation measured during the period of the experiment. 25th (a) and 26th (b) September 2003, in Lausanne, Switzerland. Dark control for samples that corresponds to 0, 1, 2, and 3h of the illumination exposure. Conditions VT0T = 35 L, recirculation rate = 20.5 L min-1, illumination time = 3 h (a) and 5 h (b), natural pH. Type of water LLW. The bars show the SD of four samples...

In a study on the photodegradation of lincomycin Augugliaro et al. [40] reported the use of a hybrid system consisting of a solar photoreactor with the catalyst suspended coupled with a membrane module. The photo-oxidation experiments were performed in a batch solar photoreactor at pilot plant scale by using compound parabolic collectors (CPC), installed at the Plataforma Solar of Almeria . 

Rincdn, A.G., and Pulgarin C. (2007c) Absence of E. coli regrowth after Fe3+ and Ti02 solar photoassisted disinfection of water in CPC solar photoreactor. Catal. Today. 124,204-214. 

As discussed previously, several solar photoreactor geometries can be reduced to cylindrical glass tubes externally illuminated by different types of reflectors, like parabolic troughs, CPC, V-grooves, or without reflector, directly illuminated by the sun. In this section the general solution of the PI approximation for this t)q5e of photo reactors is reported. This general solution is applicable to any particular reactor if the flux distribution impinging on the wall of the tubular reaction space is known. 

Although different solar photoreactors have been developed in the last 20 years, each one with its own advantages and limitations, there is still room for new designs and innovative ideas. Nowadays, CPC appear as one of the most promising alternatives among solar photocatalytic reactors. The concepts of nonimaging optics, with its emphasis in efficient energy collection can also be a very useful in future developments. 

Immobilisation of Ti02 on solid supports appears to be an attractive alternative avoiding the separation step in photocatalysis. Immobilisation of titanium dioxide has been adapted to a pilot scale solar photoreactor in a compound parabolic collector (CPC), and shown to be effective on the degradation and mineralisation of phenol and some emergent contaminants in a municipal effluent [57, 76]. 

Fig. 7.3 Main types of photoreactors used for water and wastewater treatment (irradiated by sun or UV lamps) (a) compound parabolic collector (CPC) (b) parabolic trough reactors (PTR) (c) double-skin sheet reactor (DSSR) (d) slurry, wall, fixed bed reactor (e) batch reactor with outer source of irradiation and (f) batch reactor with inner source of irradiation...

Vidal et al. presented the first pilot-plant study about solar photocatalysis for bacterial inactivation. Researchers constructed a new low-cost compound parabolic concentrator (CPC) prototype containing solar collector (Pyrex photoreactor tubes, aluminum reflective surface), flowmeter, pump, sensors (pH, O, T, UV radiation), pipes, fittings, and tanks (PVC). This solar photoreactor has an area of 4.5 m and it was tilted at local latitude to maximize the available solar irradiation. It was observed 5-log reduction for E. coli and Enterococcus faecalis (initial concentration lO -lO" CFU/cm ) after 30 min of solar irradiation (solar UV value 25 W/m )... 

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