SSO Minimization at the Milwaukee Metropolitan Sewerage District

Black & Veatch recently completed a study for the Milwaukee Metropolitan Sewerage District (MMSD) to help minimize Sanitary Sewer Overflows (SSOs) in their collection system. The study addressed reliability and capacity issues at MMSD's deep tunnel pump station at the Jones Island Water Reclamation Facility (JIWRF). The study recommended replacement of the pump station's existing wound rotor motors and liquid rheostat drives with larger induction motors and variable frequency drives, and rehabilitation of the existing pumps. The study also include replacement of existing HVAC equipment, and modification of the existing pump control strategy and equipment installation for eliminating problems associated with pump backspin during pump shutdown. To address capacity concerns, three alternatives for expanding the existing pump station were evaluated: 1) expansion of the existing cavern, 2) addition of a new separate cavern close by, and 3) addition of a new separate cavern at a different location at the JIWRF.