ISO 20468-4:2021 水再利用システムの処理技術の性能評価のためのガイドライン — Part 4: UV消毒 | ページ 6

3.1.1

biodosimetry

procedure of measuring the UV reduction equivalent dose (3.1.7) of a specific microorganism in a UV unit and a comparing the results to the known UV dose-response curve of this microorganism determined by bioassay (typically collimated beam methods)

3.1.2

challenge microorganism

microorganism used for a biodosimetry (3.1.1)

Note 1 to entry: Common challenge microorganisms include Bacteriophages MS2, Qβ and T1UV as well as Bacillus subtilis spores

3.1.3

computational fluid dynamics-intensity

simulation method to model a UV unit by performing a combination of computational fluid dynamics (CFD) and optical analysis

3.1.4

lamp protection component

apparatus for protecting the light source, including a lamp protection sleeve, tube or other component

Note 1 to entry: Lamp protection sleeve – the quartz tube or thimble that surrounds and protects the UV lamp. The exterior is in direct contact with the water being treated

3.1.5

low pressure lamp

mercury-vapour lamp that operates at an internal pressure of 0,13 Pa to 1,3 Pa (2 × 10^-5 psi to 2 × 10^‑4 psi) and electrical input of 0,5 watts per centimetre (W/cm)

Note 1 to entry: This results in essentially monochromatic light output at 253,7 nm.

3.1.6

medium pressure lamp

mercury-vapour lamp that operate at an internal pressure of 13 kPa to 1,300 kPa (2 psi to 200 psi) and electrical output of 50 W/cm to 300 W/cm

Note 1 to entry: This results in a polychromatic (or broad spectrum) light output at multiple wavelengths, generally between 200 nm to 400 nm.

3.1.7

reduction equivalent dose

dose of UV in a given device which is determined by biodosimetry (3.1.1)

Note 1 to entry: See “UV dose” and “biodosimetry”.

Note 2 to entry: This UV dose is determined by measuring the inactivation of a challenge microorganism after exposure to UV light in a UV unit and comparing the results to the known UV dose response curve of the same challenge organism determined via Bench scale collimated beam testing.

3.1.8

UV dose

UV fluence

amount of UV energy given as the time integral of the fluence rate or irradiance (W/m²)

Note 1 to entry: This is given in units of mJ/cm² or J/m².

3.1.9

UV irradiance

UV fluence rate

UV intensity

UV output emitted from a given light source and entering a unit area of the irradiated surface. The value is typically given in W/m² or mW/cm²

Note 1 to entry: The terms UV irradiance, fluence rate or intensity are often used to mean the same thing.

Note 2 to entry: For details, refer to Bolton and Linden 2003.

3.1.10

UV intensity sensor

UV irradiance (3.1.9) meter or radiometer instrument to measure UV irradiance (3.1.9)

3.1.11

UV transmittance

fraction of photons in the UV spectrum transmitted through a material such as water or quartz

Note 1 to entry: It is preferable that an online UVT sensor be installed and used to verify UVT.

Note 2 to entry: The wavelength of the UVT (unit %) should be specified, often using a path-length of 1 cm. The measurement is calibrated compared to ultra-pure water (ISO 3696 grade 1 or equivalent).

Note 3 to entry: UVT is related to the UV absorbance (A) by the following equation (for a 1- cm path length): % UVT = 100 × 10^-A .