Owner: Milwaukee Metropolitan Sewerage District
Ballard Marine Construction mobilized a commercial dive team to jet out and then install a 53” custom designed and fabricated aluminum bulkhead. It was designed to fit in three separate adit lines.
Two divers were simultaneously lowered in a man basket down 300ft (92m) in a 10ft (3m) diameter vertical shaft to conduct the diving operations. The bulkhead had been engineered to handle the pressure at 300ft (92m). Divers penetrated 250ft (76m) into a 10ft (3m) pipe. Ballard mobilized and utilized jetting equipment to break up 4’ of material that was then removed by the treatment plant pumps. Topside crew then lowered down the custom built 5,000 lb (2268 kg) aluminum bulk head plug.
Once in the water, the plug was designed for neutral buoyancy. Divers pushed the plug down the pipe and installed it at the pre-designated location to act as a backup for the plants primary cone valve. This allowed the client to replace their pumps when needed. All work was performed in zero visibility, HazMat conditions.
The project was completed in a safe and timely manner.