Degrémont-Ozonia reinforces ozone drinking water treatment plants

To comply with new regulations on pathogens and bromate restrictions, Degrémont Technologies-Ozonia will equip the ozone drinking water treatment plants in Joinville and Orly with AQUARAY H20 UV reactors...

PARIS, France, Apr. 21, 2009 -- To comply with new regulations on pathogens and bromate restrictions, Degrémont Technologies-Ozonia will equip the ozone drinking water treatment plants in Joinville and Orly with AQUARAY® H20 UV reactors.

The addition of Degrémont Technologies-Ozonia's AQUARAY® Ultraviolet units will upgrade 2 ozone plants for the city of Paris and bring them to full compliance.

With a capacity to treat 2 x 300 000 m³/day of drinking water, the project is the largest drinking water UV contract in Europe.

Pathogen removal and bromate concentration reduction
Levels of bromate ions in drinking water have recently come under scrutiny. These are commonly formed by the reaction between ozone and bromide ions, which are naturally present in water.

However, the addition of UV disinfection units to ozone treatment plants ensures that only the safest and highest quality of water is delivered, and well under limits imposed by new regulations on pathogens and bromate ions:
• The AQUARAY® H2O UV reactors act as a final barrier in the disinfection process by inactivating pathogenic microorganisms like viruses, bacteria and parasites. UV lights are particularly effective for chlorine-resistant microorganisms such as Cryptosporidium and Giardia, even at low doses.
• UV treated water fully meet the new maximal limits of bromate concentrations, which were lowered to 10 µg/l (from 25 µg/l) in December 2008.

The challenge: retrofitting the plant with UV reactors while maintaining full operation of the existing lines.

Degrémont and Degrémont Technologies-Ozonia were selected not only for the efficiency of their AQUARAY® H20 ultraviolet water disinfection reactors but also because of their long experience and ability to retrofit existing sites while maintaining full operation.

Careful consideration was given to the design and modeling of the UV reactors in order to guarantee compliance with the project's specifications and to the development of an installation plan that would keep the operation of the treatment lines already in place intact.

The project consists of:
• Replacing the regulation valve,
• Adding a shut-off valve,
• Installing the UV reactors in the existing plant while minimizing head loss, after a functional analysis of the filters/UV reactor combination,
• Guarantying a dose of 40 mJ/cm2, under the most unfavorable conditions (maximum flow, minimum transmittance).

After validation of the specific operating conditions at the Orly and Joinville sites by DENARD (Degremont North America Research and Development) , Degrémont Technologies-Ozonia developed highly-advanced hydraulic modeling parameters (based on Computerized Fluid Dynamics (CFD) using "Fluent" software), in order to precisely calculate and quantify the effects of hydraulic disturbances and pressure losses.

This preliminary study demonstrated without a doubt that installation of AQUARAY® H20 UV water disinfection reactors would have no significant impact on the hydraulics of the plant and that given the low pressure losses, they could be easily retrofitted to the main piping system, at the outlet of the activated carbon filters.

The study also established the DN 500 diameter as the most appropriate choice for the plants. The reactor/valve combination guarantees the specified head loss and the performance of the hydraulic regulation.

"The CFD modeling step was crucial and confirmed that our UV reactors could be installed without any negative impact on the activated carbon filters. The technical teams of Eau de Paris and Degrémont greatly contributed to the success of this project through active collaboration" said Vincent Pilmis, Project Manager for Degrémont Technologies-Ozonia.

Degrémont Technologies-Ozonia has a long history and extensive experience with UV and ozone technologies, and supplies both the industrial and municipal sectors. Degrémont Technologies (SUEZ ENVIRONNEMENT) is the worldwide dedicated equipment branch of Degrémont. Within SUEZ ENVIRONNEMENT, Degrémont is the company which specializes in water and wastewater treatment plants.

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