July 14, 2003 News Release Environmental review of four alternatives recommended for Carnation wastewater treatment system King County's Wastewater Treatment Division is recommending an environmental review of four alternative systems to treat and discharge wastewater for the City of Carnation. Carnation has contracted with King County to design, build and operate the system. In August, the county and city will conduct an environmental scoping process for the alternatives. That process will include a public comment period and public meeting to gather comment on environmental issues and alternatives to evaluate in an environmental impact statement, or EIS. "Replacing individual septic tanks with a wastewater treatment plant is an important step toward the long-term viability of Carnation," said City Manager Bill Brandon. "The new treatment system will help us meet the needs of Carnation residents, schools and businesses while protecting public health and the environment." The county and city have identified potential sites for building the treatment plant and discharging highly treated wastewater: two alternative sites for the plant and two alternatives for discharging the highly treated effluent. Both discharge alternatives would work for either of the alternative plant sites: Alternative 1A includes a plant site west of the business district and state Highway 203 on city-owned property at the end of Entwistle Street. It would discharge highly treated wastewater from a new outfall in the Snoqualmie River. Alternative 1B includes the plant site at Entwistle Street. It would discharge highly treated wastewater by filtering it through soil into groundwater. That method is called upland discharge. Alternative 2A includes a plant site in the area now used for concrete fabrication east of the Carnation Fire Station and state Highway 203. It would discharge highly treated wastewater through the new river outfall. Alternative 2B includes the plant site near the fire station. It would use upland discharge to filter highly treated wastewater through soil into groundwater. The proposed river outfall is at Chinook Bend, north of Northeast Carnation Farm Road and southwest of Carnation-Duvall Road Northeast (State Route 203) where the river bends from north to west. A pipeline to the outfall could run north along the Snoqualmie Valley Trail. The outfall would include a partially buried 8-inch-diameter pipe extending to the bottom and middle of the river channel. The proposed study area for upland discharge is southeast of Carnation in unincorporated King County. The study area contains five parcels south and east of the closed Carnation landfill between Northeast 24th and Northeast 20th streets. Ten acres will be needed from one parcel or a combination of the parcels. A pipeline to the site could run south along the Snoqualmie Valley Trail. Treatment plant alternatives "One of the key decisions for the plant design will be the treatment technology," said Christie True, King County's capital improvement manager for wastewater facilities. "Newer advanced-treatment technologies may offer advantages over conventional technologies, but they often cost more." King County has recently tested various new technologies to reclaim wastewater safely and effectively. For the Carnation plant, King County will conduct water quality monitoring and modeling, review technology-based standards, and evaluate expected future standards. The plant must meet or exceed strict water quality standards for discharge or beneficial reuse. "Our main drivers for choosing the treatment system will be cost, the amount of wastewater to be treated, and the level of treatment needed to protect the environment," True said. "Selecting the treatment process will be an important part of the project." When it opens in 2007, the plant will treat from 250,000 to 500,000 gallons of wastewater per day. King County will size the plant to serve the city as defined by Carnation's comprehensive plan and designated urban growth area. King County will need about five acres for the plant. "The state's Growth Management Act requires public facilities to support growth within urban growth areas designated by local jurisdictions," Brandon said. "The Carnation plant will be designed to handle growth only within the limits of our city's comprehensive plan." Treatment discharge alternatives The most cost-effective alternative for discharging highly treated wastewater may be putting it into the Snoqualmie River, True said. King County is now doing water quality monitoring and modeling to determine levels of treatment to meet requirements of the state Department of Ecology and the federal Endangered Species Act. For the upland discharge alternatives, King County would need to find soils that enable the effluent to seep into the ground at sufficient rates to reduce the land needed and protect the quality of groundwater. One value of either discharge alternative is that in the summer, King County could reuse some treated effluent in beneficial ways. The reclaimed water would be treated to such a high level that it is safe for non-drinking water uses like irrigation. The county will evaluate potential uses in the Carnation area, such as irrigating park or agricultural land. Public involvement process "We're working closely with city officials and local residents in a rigorous siting evaluation to identify the best sites for treatment and discharge facilities," True said. "We'll continue to hold public meetings and other opportunities for public comment at all key points in the siting process." One element of the public involvement program has been a citizens advisory committee. Representing a range of interests, the 14-member committee has provided advice and comment on siting criteria and options. Examples of site selection criteria include land-use compatibility, geographic considerations (for example, closeness to planned sewers), technical feasibility, and environmental impacts. After the environmental scoping process in August, the King County Executive is expected to select two or three alternatives for detailed evaluation in the draft EIS. King County will draft the EIS and release it early 2004 for public comment. Comments on the draft EIS will be addressed in the final EIS, scheduled for release next summer. The County Executive, in consultation with the City of Carnation, will then select the final system. System design and permitting is scheduled for 2004-2005. Construction is tentatively scheduled for 2006-2007. For more information For information on the treatment plant, contact King County's Carnation Wastewater Treatment Plant Project Information Line at 206-263-5212 or toll-free at 1-800-325-6165, ext. 35212. Or send an e-mail message to CarnationWWTP@kingcounty.gov, or check the project Web site at http://dnr.metrokc.gov/WTD/carnation/. For information on the local sewage collection system, contact Carnation City Manager Bill Brandon at 425-333-4192 or visit the city's Web site at http://www.ci.carnation.wa.us/. King County's wastewater treatment utility protects public health and water quality by serving 18 cities, 15 sewer districts and more than 1.4 million residents in King, Snohomish and Pierce counties. Related Information Wastewater Treatment Division Facts at a glance about our wastewater system News Releases

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