Balfour Beatty served as the general contractor for the Sunnyside Wastewater Treatment Facility, which involved the construction of a new 5 MGD treatment plant discharging to Puget Sound. The plant is upgradeable to 10 MGD.
The project included: 1,750-LF of 30-inch effluent pipeline and out fall diffuser, the new Vernon Road Diversion sewer connection, the new Lift Station No. 20 and associated gravity sewers and force main.
Additional construction work at the plant included influent screening, washer compactors, flow measurement, grit removal, primary clarifiers, a gravity thickener, primary effluent screening, aeration basins, membrane bioreactor basins, hollow fiber membrane filtration equipment, process air blowers, membrane air blowers, chemical feed systems, mixed liquor pumps, compressed air system, non-potable water system, and UV disinfection system, anaerobic digesters, a digested sludge storage tank, sludge thickening and dewatering centrifuges, digester and plant heating equipment, sludge pumps and sludge conveyance system, odor control biofilter system, a generator building, a diesel fuel storage and dispensing facility and an administration building with laboratory.
The SCADA system at Sunnyside is set up for monitoring and control from any of three control rooms at the plant. All of the subsystems have monitoring available through SCADA, and nearly all of the subsystems are able to be controlled through SCADA. The exceptions are in the few cases where the designer determined it wiser to require the plant operators to physically go to the process in order to make a control change, rather than make a change remotely.
The plant heating system uses gas generated from the digester tanks to run two boilers which provide heat to the buildings on site. The system can be supplemented by gas from the local utility if needed. Also, the plant draws its process water from its own effluent thus reducing the amount of potable water that must be drawn from the community supply. The overall site layout utilizes the natural changes in grade in order to gravity feed as many of the processes as possible, thus reducing the amount of energy required to pump wastewater around the site.
Balfour Beatty was responsible for concrete, trench excavation and backfill, surveying, site improvements for the installation of the new lift station, including sheet piling, excavation and backfill, setting vaults and manholes and SWPPP controls. Balfour Beatty also furnished and installed the following specialty equipment: grit removal systems, influent and effluent band screens, primary clarifier mechanisms, gravity thickener, mechanical mixer, centrifuges, sludge screw conveyor, digester sludge covers, UV disinfection system, composite sampler, laboratory water system and the owner-furnished membrane system.
Balfour Beatty’s team worked closely with the owner and design team prior to receiving the notice to proceed to reduce the overall cost of the project by over $5 Million. Originally the contract documents did not have a value engineering clause. However, through mutually agreeable terms during the redesign, Balfour Beatty offered significantly more than 50% shared savings.