The city of Milwaukee launched a project to replace approximately 46% of the 70,000 lead lateral water ser- vice lines in the city, including 18 miles of water mains. The initiative was spurred by tests showing children’s elevated lead blood levels reaching 4.6%.
The primary cause was the lead water service lines going into buildings, such as homes, schools and daycare facilities. In 2017, the city began replacing sections of lead service lines, from the cast iron water mains in the streets to the curb stops at property lines. In 2018, the city decided it could expedite the process by purchasing its own hydro excavation equipment.
After examining equipment options, the city purchased a Vacall AllExcavate hydro excavator with a 12-yard debris body mounted on a freightliner truck chassis, from Serwe Implement.
The service line replacement process typically involves digging down 12 to 15 ft, removing soil, rocks and other material to expose the lead line, then clearing the area where the new copper line can be installed.
“The vacuum system is very powerful because of its design,” said Nathan Berk, sales manager for Serwe. “It has an 8-in. tube with a positive displacement vacuum pump and an air flow system that’s far better than other machines.”
An option that was added to the AllExcavate machine has paid off in terms of productivity dividends. A high dump option makes it easier to raise and tilt the body to empty debris into roll-off containers the city placed around town. The debris tank can be raised 76 in. above ground level, then shifted back horizontally 21 in. beyond the rear bumper using remote control. The debris tank can be tilted and dumped over the walls of containers without spillage or the need to travel to dumping stations.
“The vacuum system is powerful because of its design,” Berk said. “It has an 8-in. tube with a positive displacement vacuum pump and an efficient air flow system.”
The AllExcavate machine is taken off the line replacement work to occasionally handle repair jobs, like digging around utility lines and foundations. The machine also is equipped with optional heated cabinetry that encloses the boiler, warming the water for hydro excavation when temperatures drop below freezing.