ISO 20468-4-2021 pdf download

ISO 20468-4-2021 pdf download.Guidelines for performance evaluation of treatment technologies for water reuse systems一 Part 4: UV Disinfection. 5.2 UV unit A UV unit has simple components including irradiation chamber, a light source, an automatic cleaning system and a UV intensity sensor. A specific LW unit may need one or more UV intensity sensor and one or more irradiation chamber and light source, depending on the specifics of the application. UV units may be categorized into closed and open systems, based on the configuration of UV units in the irradiation chamber. The closed system has a LIV unit, comprised of UV lamps and their sleeves, placed in the closed vessel flow chamber. Meanwhile, the open system has a Liv unit immersed in an open channel or chamber with gravity flow and water level control device. LIV systems can also consist of non-contact unit designs with LIV lamps suspended outside a transparent conduit that carries the wastewater. — light source A light source for LIV disinfection should have a germicidal emission at wavelengths appropriate to the task, often at the wavelength of 253,7 nni or a combination of wavelengths between 200-385 nm. Options include low-pressure mercury lamps, medium-pressure mercury lamps, excimer lamps, pulsed-Xenon lamps, and ultraviolet light emitting diodes. The light source should be housed in a lamp protection component. — cleaning system A cleaning system Is the device having a wiper driven by electric power supply, hydraulic power supply or pressurized air, or ultrasonic wave. etc. Options include a mechanical wiper consisting of a brush, ring or a mechanical chemical wiper consisting of a chamber with rings filled with a washing liquid. — LIV intensity sensor A LIV intensity sensor is installed to measure the LIV irradiance in the irradiation chamber so that the irradiance can be tracked and it can be determined whether the required dose has been provided. — ballast A ballast is installed when using a LIV lamp as a light source. Ballasts provide the power that the lamp converts to LIV photons (energy). 5.3 Influent water quality monitoring devices A UV transmittance monitor can be used to feed data to the system controller to adjust the power of the lamp to assure that the required dose is provided. To check whether or not the water quality of the influent has changed from the design conditions, water quality monitors including a LIV transmittance monitor, a turbidity meter...