The WORK of this Contract comprises the rehabilitation of the Pearl Ave and Tacoma Ave PSs, to include the removal and replacement of all pumps and piping to support the goal of eliminating sanitary sewer overflow (SSO) events at each location. The WORK also includes rehabilitation of several structures on the Tacoma Retention Basin site and the construction of a new Tacoma Basin PS (TBPS). Components of this project include, but are not limited to: 1. Pearl Ave PS (Area 2 as defined in the Contract Drawings) • Bypass pumping for Pearl Ave PS for the duration required to complete the extent of the work listed below necessary prior to the new pumps being placed into operation. • Removal of the existing centrifugal pumps and replacement with chopper pumps. • Replacement of all existing piping and valves, including piping penetrations. • Replacement of pump related instrumentation and flow meters. • Replacement of the electrical systems, including variable frequency drives (VFDs) for the pumps. • Removal of existing comminutors and replacement with a channel grinder, including concrete channel modifications. • Minor structural and architectural rehabilitation on the interior and exterior of the PS and effluent channel, including masonry work, crack repair, and painting. • Replacement of the heating, ventilation, and air conditioning (HVAC) systems. • Replacement of the standby generator. • Fencing replacement. • New storm sewer, including two (2) inlets and a manhole for site drainage. 2. Tacoma Ave PS (Area 3 as defined by the Contract Drawings) • Bypass pumping for Tacoma Ave PS for the duration required to complete the extent of the work listed below necessary prior to the new pumps being placed into operation. • Removal of the existing centrifugal pumps and replacement with chopper pumps. • Replacement of all existing piping and valves, including piping penetrations. • Replacement of pump related instrumentation and flow meters. • Installation of a new chopper pump along with corresponding piping, valving, and ancillary systems. • Replacement and increase of the electrical systems, including variable frequency drives (VFDs) for the pumps. • Minor structural and architectural rehabilitation on the interior and exterior of the PS and effluent channel, including masonry work, crack repair, and painting. • Replacement of the heating, ventilation, and air conditioning (HVAC) systems. • Replacement of the standby generator. • Fencing replacement. • Replacement of a segment of the force main, including a new pigging station. • Installation of a force main meter vault 3. Tacoma Overflow Chamber. (Area 4 as described by the Contract Drawings) • Bypass pumping for Tacoma Overflow Chamber for the duration required to complete the extent of the work listed below. • Replacement of the channel grinder with an electrically-powered unit. • Modifications to support the construction of the new Tacoma Basin Pump Station. 4. Tacoma Ave Retention Basin (Area 5 as defined by the Contract Drawings) • Bypass pumping for Tacoma Retention Basin for the duration required to complete the extent of the work listed below. • Replacement and infill of existing skylights. • Fencing replacement. • Structural modifications to raise the existing overflow weir to the SSO. • Plugging the existing 48-inch connection to the Overflow Chamber. • Constructing two new connections to the basin – one 48-inch RCP connection from the TBPS, and one effluent channel from the TBPS. • Replacement of one dewatering pump in the dewatering wet well with a chopper pump. • Removal of the existing grinder. 5. Tacoma Basin PS (Area 6 as defined by the Contract Drawings) • Construction of a new, 20 MGD capacity pump station that allows gravity flow into the bottom half of Retention Basin and then fills the remaining top half of the Retention Basin with pumped flows. • Construction of an above-grade support building, containing the electrical room and associated HVAC equipment. • Utility relocations including the 12-inch dewatering return line and the 36-inch overflow.
