Sustainable design solution for updated rinse water treatment in Katwijk

Drinking water company Dunea supplies drinking water to 1.3 million customers in the region around The Hague. To be able to continue guaranteeing the quality of the drinking water, the company constantly monitors and improves the production process. Witteveen+Bos and Raderadvieswere commissioned to upgrade the wash water treatment installation of the Katwijk water treatment plant and integrate the installation in a historic national monument. A special and challenging project.

In the Katwijk water treatment plant, the existing wash water treatment must be renewed and extended by adding rapid sand filtration and post treatment with UV disinfection. What made this project special was the application of the wash water installation in the old, historic filter building, which has not been used for years. Dunea chose to combine the restoration of this national monument dating from 1912 with recommissioning the building for the function of wash water treatment.

Closed box

Building in this historic filter building created special demands on the project. Because it is a historic building, permission from the local governments’ heritage committee was required for the extension. For the integration of the installation in the historic building, several options were considered. To be able to meet current standards for the safe production of drinking water, it was decided to place the new installation in a closed box in the existing building.

Process steps of rapid filtration and UV disinfection were added to safeguard the wash water functionality of the box-in-box structure. The rapid sand filters remove the last suspended particles and turbidity in the purified water from the settling process which is located outside the building . This makes it possible to improve the UV extinction of the water, reducing energy consumption. During the design phase, the type of filters was discussed. Based on experiences with previous similar projects and installations and sharing knowledge with other drinking water companies, steel pressure filters were chosen.

The new functionalities were incorporated in one of the existing concrete filters of the old building. A new concrete structure was built inside to accommodate the new installation.

Sustainable development principles

During the design process, sustainable design principles were an important consideration when looking for design solutions. Companies in the building sector are increasingly challenged to take responsibility for sustainable solutions. Witteveen+Bos is confident that the projects can help achieve the UN's Sustainable Development Goals. Delivering added value for society is one of the main goals of the projects.

Applying our sustainable development principles reflects this.

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