On 22 January 2026, a first test of high‑pressure water cleaning was carried out in the Superlocal apartment building in Kerkrade, one of the four demo sites in the Interreg ANCHOR project. At this location, concentrated blackwater from vacuum toilets and ground food waste is collected in a vacuum‑based sanitation system operated by Water Authority Limburg. To maintain such a system over time, the vertical indoor blackwater lines occasionally require cleaning to remove precipitation and scaling. This article summarizes why the test was needed, how the procedure was planned, what challenges occurred, and what the outcomes mean for future maintenance.
Why vacuum‑based systems require maintenance
In vacuum sanitation systems, concentrated blackwater is transported from toilets to the vacuum station with minimal dilution. At the Superlocal site, the system also receives food waste from a collective grinder, making the wastewater particularly concentrated. Over time, this can lead to precipitation and scaling inside the polyplast pipes that make up the vertical blackwater lines. These pipes are slid into one another and secured with clamps, which allow for targeted maintenance but also require specialized cleaning methods. To assess whether high‑pressure water cleaning could be used in this type of installation, a controlled test was organized.
Adjustments to the procedure before cleaning
The original plan was to isolate only half of the apartment building by inserting a balloon into the vacuum pipe, allowing cleaning to take place while maintaining vacuum in the newer part of the building. However, this turned out not to be possible. Instead, the vacuum was closed off for the entire building using the valve at the vacuum station operated by Water Authority Limburg. This adjustment required additional communication with residents, who were informed both one week before and again when the plan changed.
Equipment used during the test
The high‑pressure cleaning setup consisted of a rotating, pulsating spray nozzle (ENZ ROTOPULS 01.034BE) attached to a ½‑inch hose. The nozzle used has a water flow rate of 60 liters per second and operates at pressures up to 200 bars. The test was carried out jointly by staff from Water Authority Limburg, the sewer cleaning company Van der Velden and the installation company Ploem, with support from HEEMwonen.
How the test was carried out
The cleaning procedure was planned in multiple steps, beginning with on‑site preparations.
Equipment was brought to the third floor; toilets were flushed several times to clear the pipes, and the vacuum line was closed off through the valve at the vacuum station. Any remaining water in the toilet was removed, after which the toilet was disassembled to provide access to the vertical pipe.
A baseline camera inspection was then performed. The distance meter was set to zero, and images were taken at every meter and at recognizable points. During this inspection, the camera could reach only around 8 meters into the vertical 75 mm pipe.
Before starting the water flow, the high‑pressure nozzle was inserted into the pipe to prevent splashing. However, due to the angle created by the transition from the 50 mm horizontal pipe, through a T‑piece, into the 75 mm vertical pipe, the hose could be inserted only about 0.5 meters. This was the case even without the nozzle attached, and attempts with different nozzles led to the same limitation. Because of this, the planned cleaning pass to 20 meters could not be carried out, and the test ended after documenting the obstruction. Residents were informed after the procedure.
Outcome and next steps
Although the vertical pipes could not be cleaned using high‑pressure water during this test, the results provided important insights. The camera inspection and the attempt to insert the cleaning hose made it clear that the geometry of the pipe layout restricts access for high‑pressure equipment.
Based on these findings, a new plan will be developed to clean the entire building, considering the constraints identified. Further maintenance decisions will be made jointly by HEEMwonen, Water Authority Limburg, Van der Velden, and Ploem.
Parties involved
The test was carried out by staff from Water Authority Limburg (vacuum station operations), Van der Velden (sewer cleaning) and Ploem (installation works), together with HEEMwonen. Their work contributes to the Superlocal demo site’s role in the Interreg ANCHOR project, helping to develop shared knowledge on maintaining vacuum‑based sanitation systems in apartment buildings.
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