An ROV was launched on an important mission on Thursday, Sept. 29, 2022, when it took a dip inside the Town of Amherst’s water tanks.
Operated by Josh Rodrigues of Innerkip, Ont.-based Greatario Engineered Storage Systems, the remote operated vehicle was conducting a required inspection of the two, 15-metre-tall water tanks located just off Willow Street that each hold 5.8-million litres of water.
The interior tank inspections are required to be conducted every three to five years in order to ensure water quality, corrosion control and the structural integrity of the tanks, explained Aaron Bourgeois, the town’s director of operations.
“While town staff can visually inspect the outside of the reservoirs for damage or other defects, specialized equipment is required to inspect the interior of the tanks,” Bourgeois said.
This is the first inspection of the tanks, which were built in 2017 and commissioned in 2018.
In the past, the town had two options: draining the tank before inspectors could enter it or hiring trained divers to perform the inspection.
“These methods were very expensive, time consuming and required the tanks to be disinfected or refilled,” Bourgeois said. “The use of an ROV for tank inspections significantly decreases the time needed to complete the work of maintaining water storage tanks. ROVs can be quickly deployed and work can be completed safely and efficiently.”
Potable water tank inspections are also crucial for good water maintenance, Bourgeois said.
“Over time, sediment can gather and collect along the bottom of tanks. If in small amounts, sediment has no impact on the quality of the water or on the structural integrity of the storage tank.”
To conduct the inspections, Rodrigues had to climb the tank, pull up the ROV before dropping it into the water via a hatch at the top of the tanks. Because the tanks are fairly large, he estimated it would take two hours per tank to conduct the examination, which examined the tank’s coating, seals and pipes for such things as corrosion.
The inspection is recorded. The results of the inspection will be presented to the town in the near future.
The examination of the tanks is only one part of the ongoing effort by the town to ensure the town’s water supply remains the best east of the Rockies. Other steps include swabbing the water mains, flushing the water lines and weekly sampling of the water.