Figure 4-20: Typical Solar Detoxification System
In this process, vacuum extraction is used to remove contaminants from
soils. After condensation, contaminants are mixed with a semiconductor catalyst such
(e.g., titanium dioxide), and fed through a reactor which is illuminated by sunlight.
Ultraviolet light activates the catalyst, which results in the formation of reactive
chemicals known as "radicals". These radicals are powerful oxidizers that break
down the contaminants into non-toxic by-products such as carbon dioxide and water.
advantage of solar detoxification over conventional treatment processes such as those
using granular activated carbon or air stripping is that it completely destroys the toxic
compounds in the water instead of simply removing or displacing them. The solar process
also has no atmospheric emissions.
The target contaminant group for solar detoxification is VOCs, SVOCs,
solvents, pesticides, and dyes. The process may also remove some heavy metals from water.
Factors that may limit the applicability and effectiveness of solar
- It can only be effectively used during the daytime with normal intensity of sunlight.
- Biological fouling or physical fouling with suspended solids or precipitated irons would
limit its effectiveness.
A detailed discussion of data elements is provided in Subsection 2.2.1 (Data Requirements for Soil, Sediment,
DOE has demonstrated the use of solar energy to remediate contaminated
soil at pilot scale. The process has been successfully tested by decontaminating ground
water at a former naval air facility. A 4-month field test was conducted on the grounds of
Lawrence Livermore National Laboratory (LLNL). The ground water contamination there dates
back to World War II, when the facility was a naval air base. Trichloroethylene (TCE) and
other volatile organic compounds that were used to clean engine parts now contaminate the
ground water. The field test was a huge success, proving the detoxification process works.
The process brought the contaminants to levels well below the 5 parts per billion (ppb)
SERDP, 1993. Solar
Detoxification of Explosives in Water, Technology Information Profile
by EnviroSense and SERDP for DOE. Reference No. 890.
USAEC, 1997. "Solar Detoxification of Soil" in Innovative
Technology Demonstration, Evaluation and Transfer Activities, FY 96 Annual Report, Report
No. SFIM-AEC-ET-CR-97013, pp. 99-100.
Points of Contact:
General FRTR Agency Contacts
Technology Specific Web Sites:
Government Web Sites
Non Government Web Sites
A list of vendors offering Ex
Situ Physical/Chemical Soil Treatment is available from the Vendor Information System
for Innovative Treatment Technologies (VISITT)
developed by U.S. Environmental Protection Agency (EPA).
Health and Safety: