Approaches to Practical Sewer Pipe Inspection Technology Using Drones, Based on Public-Private-Academic Partnership

Yokohama City’s sewer pipeline facility has an extension of about 11,900 km (about 600,000 spans), about 530,000 manholes, and about 1.4 million inlets and laterals, about 2.7 trillion yen in existing investment (about 70% of existing all investment) and has a huge stock among sewerage facilities.The length of the pipeline that has passed the standard service life of 50 years now is about 800 km (7%), and it is expected that it will become about 2,800 km (24%) in 10 years and about 7,900 km (67%) in 20 years, as the aging will progress rapidly in the future.If the sewer pipeline becomes aging and deteriorates, there is a possibility of causing serious danger to a third party due to a collapse of a road or the like. Also, in order to realize a sustainable sewerage project in our country, the inspection of pipeline was mandated by the revision of the sewerage law in 2015.Therefore, in Yokohama City, we aimed at low cost and the improvement of safety in the pipe inspection targeting the pipes of middle and large caliber, 800 mm or more, which the planned inspection had not been conducted so far, and in order to establish the method not confined to the conventional method, we focused on the drone which has been drawing much attention recently and started the effort to establish the pipeline inspection technology, so we report its outline.