Black & Veatch announced that it has been awarded a contract by the Milwaukee Metropolitan Sewerage District (MMSD) for the rehabilitation of the Inline Storage System (ISS) Pump Station, which dewaters the district’s 500-million-gal deep-tunnel storage system.
Black & Veatch will provide design, procurement and construction-related services for the rehabilitation project.
MMSD’s system is one of the first deep-tunnel systems placed into service in the U.S. to reduce sewer overflows. Since it began operation in 1993, the ISS Pump Station and related tunnel system have prevented more than 64 billion gal of wastewater from polluting Lake Michigan.
“MMSD has been in the forefront in providing deep-tunnel solutions for control of overflows,” said Tom Ratzki, Black & Veatch project director. “The rehabilitation project is further evidence MMSD leads the way in establishing the standard for deep tunnels and pumping stations to control overflows, and we’re delighted to have the opportunity to work with the district on the next generation of deep pump stations.”
The $12-million project will allow MMSD to better manage wet weather-related overflows by improving reliability and increasing capacity of the pump station.
ISS improvements will replace motors and drives with new 5,000-hp induction motors and variable frequency drives; purchase of a new 60-million-gal-per-day (mgd) pump and rebuilding of the three existing 50-mgd pumps; replacement of the heating, ventilating and air-conditioning systems for the pump chamber and surface structure; and miscellaneous piping modifications.
The pump station is 350 ft below ground and must maintain operation throughout the rehabilitation, which creates special challenges. Each pump can be taken out of service for only three to four weeks during dry weather, necessitating special planning provisions for facility design and equipment procurement.
Design of the ISS pump station project is scheduled for completion in January 2010, with construction expected to be completed in December 2011.
Black & Veatch had previously worked with MMSD on design of the award-winning Milwaukee Northwest Side Relief Sewer. That deep tunnel project greatly reduced wet weather overflows and basement backups, earning a Project of the Year Award from the American Public Works Association in 2006. The large, multifunctional tunnel transports and stores wastewater 130 to 180 ft below ground. The relief sewer project also established advanced risk management techniques as critical to success in large-scale underground construction.
