Kaneohe-Kailua Regional Wastewater Treatment Plant, Facilities Plan, Tunnel Influent Pump Station (TIPS)

BC was responsible for the delivery of the design of a 45 mgd pump station, headworks facility, and supporting facilities. The four-level, below-grade pump station is constructed within the Kailua tunnel shaft, and is designed with dual drywells and wetwells to enhance redundancy. The headworks facility includes screening and grit removal processes in an enclosed, acoustically treated building to minimize noise and odor nuisances. BC also designed flow diversion structures for a new 3-mile-long, 10-foot-diameter wastewater tunnel from Kaneohe to Kailua. The wastewater conveyance and storage tunnel connects the existing Kaneohe Wastewater Pretreatment Facility (KWPTF) to the existing Kailua Regional Wastewater Treatment Plant (KRWWTP). Four microtunnels and diversion structures were also designed and constructed to divert flows to the tunnel. Supporting facilities for the tunnel and pump station at KRWWTP and KWPTF include standby generator facilities, a medium-voltage electrical distribution system, multiple odor control systems, a state-of-the-art headworks facility, tunnel appurtenances, and various flow diversion structures. This project also includes several innovative features including a tunnel junction structure with dual vortex drops for flow management, a complex tunnel ventilation and odor control system, a tunnel access crane bay for servicing the tunnel, dual trench-type wetwells and dual drywells for pumping redundancy, a unique shallow pump station built into the TIPS shaft wall to handle dry weather flows from Kailua, and an inventive screenings/grit conveyance system to reduce odors and maintenance.