Cleaning drones keep sewers operational so humans don’t have to.
poorly maintained sewers can lead to serious consequences; however, conducting regular inspections can be a long, costly, and risky process. The proposal is to use underground drones for waste cleaning.
On the morning of December 24, 2016, residents of a home in Fraser, Michigan, heard a strange "pop" sound coming from their walls. At first, they attributed it to the melting snow sliding off the roof, but they soon realized the truth: the noise was caused by bricks being expelled as their house slowly sank into a sinkhole. Authorities evacuated the home and nearby residences while assessing the situation, determining that the cause was a collapsed sewer interceptor, which endangered several houses and a long stretch of the busy 15 Mile Road.
Vince Astorino, operations director of the Macomb County Public Works Office, commented on the significant impact this had on the community. "An 11-foot diameter sewer line, approximately 70 feet deep, experienced a failure that drastically reduced the flow of wastewater. This section of the pipeline is near the main drainage of our system, to which about 800,000 residents are connected," he explained. Thanks to the swift action of Astorino and his team, bypass systems were established to prevent wastewater from backing up into residents' homes. Ultimately, only one house, the one where the noise was heard, had to be demolished, although it took nine months to replace the 4,000 feet of faulty pipe. The direct cost to taxpayers amounted to almost $75 million, excluding additional expenses for nearby residents and businesses due to the disruption.
To avoid similar tragedies in the future, it is crucial to conduct regular inspections of sewer lines, looking for cracks that, if neglected, may allow soil to enter and cause the pipes to collapse. However, inspecting sewers can be a slow, expensive, and dangerous process, as pipes are often dark, narrow, and frequently filled with gases. This is where drones come in, designed to operate in confined spaces. A new generation of drones is being used to carry out these inspections more efficiently and safely.
The Elios 3 drone, made by the Swiss company Flyability, is a popular choice for sewer inspections. This device, featuring a modular design and elements such as a protective cage, a sturdy structure, powerful lighting, and a 4K camera, can navigate through dark pipes while generating a 3D model of the environment. Eloise McMinn Mitchell, communications manager at Flyability, noted that the company has experienced significant sales growth due to the capabilities and efficiency of the Elios 3 compared to human-led inspections. "To inspect a section of sewer beneath a road, you need at least four people and to divert traffic in several places. With the drone, only two people are required, and no one has to enter the pipe," she added.
As of May 2024, to optimize its inspection process, Macomb County adopted a technological approach that combines an Asio X drone, manufactured by rival Flybotix, with software called SewerAI. This advancement had a total cost of around $100,000. Previously, the county spent one million dollars on inspections every three years.
The Asio X, with a diameter of about 16 inches and equipped with powerful lights and a high-definition camera, can capture clear video of the sewer system and navigate nearly all pipe sizes. Astorino described the difference from the previous method as "radical." Instead of analyzing data in the field, the information captured by the drone is sent to SewerAI, where artificial intelligence is used to automatically detect defects.
A series of tests have been conducted to compare the capabilities of SewerAI with the work of manual inspectors, and the results have shown that the software consistently outperformed in accuracy and efficiency. Inspections that used to take months can now be accomplished in 10 days, and most are reported within 24 hours. Macomb has become a pioneer in this field by being the first county in Michigan to implement this combination of drones and artificial intelligence software and has received recognition for its innovation.
Astorino states that his team is always looking for ways to further modernize operations, remaining open to technological advances that may emerge in a rapidly evolving field.