In California, any ultraviolet (UV) disinfection system used as a part of
wastewater reclamation treatment process must be capable of producing a UV dose
with the same germicidal effectiveness as a UV dose of 140 milliwatt seconds per
square centimeter (mWs/cm2 ) obtained by the low-pressure, UV light with a
wavelength of 254 nanometers (nm). The equivalent UV dose must be delivered at a
wastewater transmittance of 55 percent, measured at the wavelength of 254 nm. In
addition to the low-pressure low-intensity systems which are approved for
wastewater reclamation in California, other technologies such as low-pressure
high-intensity, medium-pressure high-intensity, and pulsed UV systems are being
proposed for use in wastewater reclamation. There are significant differences
among these technologies. The low-pressure systems are monochromatic, and the
majority of emissions are produced at a germicidal wavelength of 254 nm. For
medium-pressure systems, the lamps are polychromatic. Since the germicidal
effectiveness of the UV wavelength varies in the range of 200 to 300 nm, the
estimation of the germicidal efficiency of the medium-pressure UV lamp output
requires factoring in the germicidal effectiveness of each wavelength. For pulsed
UV systems, the dose estimation must also take into consideration the impact of
pulse frequency on disinfection. In addition, there are differences in lamp arc
length, power input, reactor configuration, and dose calculation methods used by
UV system manufacturers. Establishing the differences among the technologies and
manufactured systems required developing a test protocol that
compared these technologies against a standard method. A proposed protocol has
been developed. The results from laboratory and field tests of a medium-pressure,
high-intensity pilot unit are used to assess the protocol. The results reported
herein represent the first field test of the proposed protocol. Includes 5 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 470 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 01/01/2000 |
