SOLAR TREATMENT OF WATER FACILITIES

The facilities of solar detoxification and disinfection unit consist of several solar CPC (compound parabolic collector) pilot plants (Figures 1, 2 and 3), and pilot reactors for biological treatment, ozonation, and nanofiltration for water treatment, an UV-disinfection system and a test facility for photocatalytic production of hydrogen based on solar energy.

Figure 1. CPC photo-reactors (SOLAR prototype).
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Figure 2. Instrumentation in the CPC photo-reactors (a) SOLEX and (b) CADOX.

There are also several CPC prototypes for applications of water disinfection. One of these systems consists of two 50 mm outer diameter borosilicate-glass tubes installed in the reflector focus and mounted on a fixed platform tilted 37º. The illuminated collector surface area is 0.42 m2. The total volume of the system is 14 L and the illuminated volume is 4.7 L. Photo-reactor for solar disinfection ‘FITOSOL’ consists of two components, a CPC solar reactor (4.5 m2 of collector surface,  45 L of irradiated volume, and 60 L total) and a pilot post-treatment plant for photocatalyst recovery (100L). The system is equipped with pH and dissolved oxygen online sensors, connected to a controller for automatic data acquisition. A heating and cooling system was designed and installed in this photo-reactor to maintain the water temperature constant between 15 and 45ºC. Different air injection points have been also added to photo-reactor to increase the oxygen dissolved in the system as well as several sampling points.

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Figure 3. New CPC photo-reactors installed in 2010 for solar water disinfection applications: (a) CPC25, (b) CPC-SODIS and (c) FITOSOL-2.

Along with these pilot-reactors, there are two solar simulators provided with xenon lamps for small-scale photo-chemical water tests in which radiation intensity and temperature can be controlled and monitored.

There are also several solar pyranometers installed for measuring solar global radiation (Kip&Zonen) in different ranges of wavelength (280-400 nm; 300-400 nm; 200-3600 nm and 310-2800 nm) and different orientation, either horizontal or tilted 37º to the horizontal. Registered information is stored in a database for later evaluation. A spectral double channel photometer (Avantes) is also available to monitor solar radiation in the whole solar spectrum.

In addition, a hangar (Figure 4) holds our non-solar pilot facilities for wastewater treatment, which is equipped with a gas distribution system, an UPS (Uninterruptible Power Supply), three-pin plugs, a centralized system of tap and demineralized water and an optical fiber connection.

Figure 4. View of the hangar at Solar Water Treatments group.

The pilot plants installed inside the hangar (Figure 5) are:

  • A 20 L contact column ozone reactor (Figure 5a) for batch operation (ozone production of up to 44 g O3/Nm3 for a gas flow of 0.2 Nm3/h).
  • The nanofiltration (NF) system consists of three NF membranes positions connected to work either ‘in parallel’ or ‘in series’ and ‘cleaning’ mode.
  • A biological pilot plant with a double depuration system. It has an IBR (Immobilised Biomass Reactor) system with a total volume of 60-L, and a SBR (Sequencing Batch Reactor) system (Figure 5b). It can be operated in continuous or in batch mode.
  • A UVC/filtration pilot plant (Figure 5d) for microorganisms’ removal from water prior, with a maximum operation flow rate of 200 L/h. 

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Figure 5. Pilot plants located in the hangar: Ozonation (a), Nanofiltration (b), Biological (c) and disinfection UVC/filtration treatment pilot systems (d).

A large pilot UV plant for UVC treatment of wastewater is also available in these facilities (Figure 6). It consists of three UV-C lamps (max. flow rate 25 m3h-1, 254 nm peak wavelength, 400 Jm-2 max. power) connected in series, with the flexible configurations for single lamp, two or three lamps in recirculating batch mode or continuous flow mode.

Figure 6. UVC pilot plant. Three medium pressure UV lamps (254 nm) inserted in stainless steel frame (left view). Automatic dosing pumps for automatic control of pH and H2O2 addition (right view).

This facilities have also a 1m3/h plant for filtration/flocculation (Figure 7) for raw wastewater pre-treatment operations.

Figure 7. Filtration/flocculation pilot plant for treating raw water.

An experimental 30m2-greenhouse permits crops cultivation under controlled conditions for in-vivo testing of irrigation reuse of treated/untreated wastewater. It is conformed by 4 equal and individual rooms (3×2.5m2) for different tests with controlled temperature, humidity, irrigation and aeration. A polycarbonate cover avoids solar UVA&B radiation (Figure 8).

Figure 8. Cultivation chamber for wastewater crops irrigation reuse at PSA facilities.
Figure 9. View of the updated PSA Unit of Solar Treatment of Water facilities.