Wastewater
The City of Bremerton is located in Kitsap County, Washington; approximately 15 miles west of Seattle, across the Puget Sound. Waters of Puget Sound form a combination of embayments and channels in the Bremerton area with the principal embayments being Sinclair Inlet and Dyes Inlet. Puget Sound waters enter the embayments through Port Orchard Bay and Rich Passage. The Port Washington Narrows bisects the City and connects Sinclair Inlet to Dyes Inlet. The city area east of the Port Washington Narrows is referred to as East Bremerton.
Bremerton's sewage system provides sewer service to approximately 37,000 people. The wastewater collection system serves City residents as well as nearby areas in unincorporated Kitsap County. In addition, the City has contracted to receive and treat wastewater from the Puget Sound Naval Shipyard (PSNS), other Navy facilities, and Kitsap County Sewer District No. 1.
The City of Bremerton's wastewater collection system consists of 188 miles of combined and sanitary sewer mains, 14 combined sewer overflow outfalls, 35 liftstations, approximately 16 miles of force mains, 6 odor control stations, 6 flow monitoring stations (for billing purposes) and 2 composite sampling stations. The city has 1 wastewater treatment plant with an average annual flow of 7.6 mgd and a hydraulic peak capacity of 32 mgd, which has seen flow in excess of 38 mgd. Treated effluent from the wastewater treatment plant discharges into the Sinclair inlet.
The older portions of the Bremerton sewer system were constructed as combined sewers (sewers that collect both stormwater and wastewater) which was a common and accepted practice at the time. The sewers originally discharged to the receiving waters without treatment and consequently there was no need to construct separate systems. Thankfully the practice of constructing combined sewers has been prohibited for many years. The current sewer construction practice is to install separate sanitary and storm sewers.
Small sections of stormwater collection systems have been constructed in drainage basins that are all combined sewers or a mix of both and have resulted in partial separation. If a stormwater outfall was not available for the separated stormwater to use then the separated flow was redirected back into the combined storm/sanitary sewer. The capital investment, made in these basins provided partial separation and abandonment of Overflow 5, as well as setting the stage for future separation projects. These final projects will not require the capital investment that would have been required, at todays cost, had the first projects not been completed.
When sewage treatment was first provided in 1946, pipelines were constructed to intercept the combined sewers. Regulating structures were installed at each point of interception to regulate the amount of combined sewage conveyed to the various wastewater liftstations and finally to the wastewater treatment plant. The excess combined sewage overflowed directly to the receiving waters (Combined Sewer Overflow). The regulators were designed to convey all combined sewage to the treatment plant during dry weather, small rainfalls and the first flush of large storm events. Subsequent system improvements have significantly reduced CSO frequency and magnitude.
A major component of Bremerton's sewer system is the Cross-town Conveyance System (Cross-town Pipeline). This system conveys wastewater from all East Bremerton, and the Warren, Callow, Pacific, Phinney Bay and Anderson Cove drainage basins to the wastewater treatment plant. Approximately 85% of the flow to the wastewater treatment plant are conveyed via the Cross-town Conveyance System and most of the associated drainage basins that discharge to this system have combined sewers. Wastewater is pumped into the Cross-town Pipeline through liftstations CE-1 (8,500 gpm), CE-4 (2,030 gpm), CE-6 (1,200 gpm), WB-3 (6,700 gpm) and WB 1 & 2 (1,100 gpm), which belong to Kitsap County. The overall design capacity of the crosstown pipeline is 21,240 plus gallons per minute or 30.58 million gallons per day.
There are 14 permitted CSO outfalls in the Bremerton sewer system, the locations and characteristics are shown on the CSO Site Map. To date we have abandoned many CSO structures including O/F 1B, 5, 7B, 13B, 14, 15 and three structures at O/F 17 (manhole P5, P97 & R81) as well as several cross-connections and misconnected sewer services. As the CSO Reduction and Stormwater Separation Projects are completed several more sites will be abandoned. The overall project goal is to meet the State regulation that limits the City to "no more than 1 CSO event per year per outfall." The current separation and collection system improvement projects will be completed by the year 2011.
