Logisticontour no. 25 featured an article about a groundwater survey conducted by Vitens on West-Terschelling using a Logisticon pilot installation.

The groundwater there contains small amounts of methane, most of which is removed via conventional treatment at the treatment plant. This does not yet take place in the anaerobic nanofiltration units, resulting in the connected aeration and degassing tower requiring frequent cleaning. After concluding the survey using the pilot installation, the decision was made to build a membrane degassing unit and a nitrogen skid.

As space is limited, these two new units will be built on platforms above the current nanofiltration units. The membrane degassing unit will operate between the existing nanofiltration and the degassing tower and, like the nitrogen skid, will be fully integrated into the existing treatment line operated by Vitens.

Operating principle

The principle of using membranes for degassing relies on bringing the water to be degassed into close contact with a vacuum and/or stripping gas, with the phases being separated by a hydrophobic membrane. As no nitrogen is present at the plant, the decision was taken to design a nitrogen skid (compressor with nitrogen generator) to produce nitrogen for use as stripping gas.

This smart innovation will improve the operation of the background treatment and the degassing towers will need less maintenance than they do now. This solution will also provide improved and more stable drinking water quality. The project will be delivered in early March.