Standardization
On the basis of several European research projects Germany and Austria decided to establish a common standard for the use of UV in drinking water. Since the beginning of the official start 1997 Switzerland and the Netherlands were following as well. At the moment the standard is subject to CEN and could be expected that the standard will be valid all over Europe in a couple of years. The standard includes the following parameters: • Proof of capability to deliver sufficient UV dose: UV dose of 400 J/m2 which is equivalent to the reduction of 4 decades on water relevant pathogens including photoreactivation
Biodosimetric validation: Collimated beam based biodosimetric verification of 400 J/m2 with spores of B. subtilis
Definition of sensor performance and construction: Sensor should have more than 90% Selectivity at 254 nm
Calibration of sensor and collimated beam: Uridine actinometrie
Definition of UV system construction types: Same Geometry, Same Lamps, Relation of minimum
and maximum flow 1:20
Definition of water qualities with respect to the ability to be disinfected with UV: Fe 0.03 mg/l, Mn 0.02 mg/l, Turbidity 0.3 TE/F
(not UV specific)
The maximum test capacity for one system is 19 MGD. The standards are focused on low pressure at the moment. Medium pressure is tolerated in Germany but neglected in Austria. Both sides agreed to work on a specific medium pressure certification process with special reference on sensor and by-product formation. The standards are setting the core of an official certification
process from the water authorities in these countries. The main point of that certification includes the determination of minimum sensor signals representing 400 J/m2. This gives the indication of the actual disinfection performance of each system during operation (online) and makes the disinfection process transparent.
US Outlook
In the US the interest and focus on UV-disinfection of people in the water field increases tremendously. At the moment the EPA is working on a regulation for the use of UV in drinking water. This is based on two facts:
- Health risks have to be minimized due to the substitution of chlorine
- Evidence for ability of UV to eliminate Cryptosporidium parvum on a high effective level
The new use of UV in drinking water requires standardization of the technology and the process in the US as well.
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Drinking Water
