Innovative Use of Cable-Guided Drones to Inspect Sewer Traps as Part of the Haliotis2 Project
2 July 2026In the spring of 2026, the teams responsible for operating Haliotis2 used specialized drones to conduct nighttime inspections of four “siphons” in the main collector—the branch connections of these large-diameter underground pipes, which allow wastewater to flow through the city by passing beneath each of the natural stormwater valleys and thus reach the wastewater treatment plant. This operation is part of the routine maintenance of the wastewater treatment plant and the networks that feed it, carried out in parallel with the Haliotis2 renovation and modernization project.
What this solution achieved: It identified and quantified sediment and grease deposits in these siphons, which can accumulate at these specific points and potentially obstruct the flow of effluent. These interventions can be carried out during normal operations without causing any disruption to local residents.
Why this is important: Deposits and grease can reduce water flow and cause incidents. Detecting them early allows us to take action before they become problematic and, above all, to optimize cleaning operations to minimize the impact on nearby residents.
This is also an opportunity to remind everyone that we can all help ensure that sewer systems function normally and optimally by making sure not to flush wipes down our drains, by avoiding pouring oils and fats down our kitchen sinks and bathroom sinks, and by ensuring that grease traps for food service professionals are properly sized and maintained. In this way, each of us, in our own small way, can play a vital role in the well-being of the community.