A pump station and a 9-million-gallon combined sewer overflow (CSO) basin are being constructed in Southwest Detroit, MI, in order to eliminate sewer overflows during heavy rain events in the area. L. D'Agostini & Sons, Inc./Lakeshore Engineering Services, Inc. Joint Venture is the general contractor. The work is being done for the Detroit Water and Sewerage Department (DWSD). The $154-million project began in the fall of 2007 and it will be completed in the summer of 2011.
The combined storm and sanitary sewer water will be pumped from the pump station. The project includes six 72-inch pumps and two 54-inch pumps that discharge the water into 72-inch and 54-inch steel pipes. The water will then be treated and proceed through a series of screens to remove solids. The water is then stored in the CSO basin. As the rain event ends and the water flow is reduced, the water is released into the sewer and sent to the treatment plant. The work is part of a Michigan Department of Environmental Quality (MDEQ) effort to clean the Rouge River.
"The pump station was constructed 70 feet into the ground. We used a slurry wall construction to build it. This was done for hydraulic reasons," Gino D'Agostini Jr., project manager for L. D'Agostini & Sons, Inc., said.
The CSO basin and pump station are concrete. An aboveground building is steel, brick and concrete block.
Crews worked 24-hour shifts when rock grouting and slurry wall work was being performed in order to speedup the work.
"We had an artesian water issue that we had to curtail. There were some steps we had to perform to take care of that. We had to grout the rock from the surface elevation, and then we had to install dewatering pumps to reduce the artesian head. Then we built the slurry wall and excavated inside of it," Gino D'Agostini Jr. said.
Equipment for the project was selected based on the work that needs to be completed. "We look at what we have to do and we choose the size of equipment to do that work. The cranes were selected because of the weights we have to lift on the project," Gino D'Agostini Jr. said. L. D'Agostini & Sons has a 150-ton Link-Belt LS518 on the project. Other equipment includes a 110-ton Link-Belt crawler crane provided by Connelly Crane Rental Corporation, of Detroit, and Barton Malow Concrete's 75-ton Grove RT875 and 40-ton Grove RT600 cranes.
Subcontractors for the project include Barton Malow Concrete, of Oak Park, MI; De-Cal, Inc., of Warren, MI (mechanical); Shaw Electric, of Livonia, MI; and K&S Piling (pile driving). The engineering firm for the project is CDM, of Detroit.