Mechanical problems that have idled two machines boring a tunnel for the Brightwater sewage-treatment plant won't stop King County from putting the plant into operation as scheduled in 2011, the project manager said.

Mechanical problems that have idled two machines boring a tunnel for the Brightwater sewage-treatment plant won’t stop King County from putting the plant into operation as scheduled in 2011, the project manager said.

Although the plant will open on time, the 13-mile tunnel won’t be ready to carry treated wastewater to Puget Sound. Until the tunnel is completed, water will be sent through existing pipes and dumped into the Sound near the West Point or Renton plant, project manager Gunars Sreibers said Friday.

He said the county and the contractor operating the two stalled boring machines haven’t discussed who will bear the cost of the delay. “I think it’s fair to say there are many millions of dollars that are on the table. Our focus right now is to look at what we need to do to get the machines up and running.”

Repairs will begin next week on a 17 ½-foot-diameter machine 340 feet below ground in Bothell. Several tunnels were drilled from the Maywood Hills Elementary School property to the machine to remove underground water so workers can fix the damaged machine under normal atmospheric pressure, avoiding the need for short shifts followed by decompression.

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The county announced Friday it will seek a permit from Lake Forest Park to drill dewatering wells to the other machine, which is 300 feet below the 19500 block of 53rd Avenue Northeast.

Sreibers said the first machine is expected to go back into service in September or October, the second machine by late fall or early winter.

The $1.8 billion Brightwater plant, under construction on Highway 9 in Snohomish County north of Woodinville, was scheduled for completion in 2010 but the startup date was pushed back to September 2011 before the tunneling machines were damaged.

Vinci/Parsons RCI/Frontier-Kemper, the contractor boring the central portion of the tunnel, laid off more than 120 workers when the tunneling machines were shut down in May and June. The contractor has been working with the German-based manufacturer, Herrenknecht, to repair the rims of the machines and prevent additional damage.

Keith Ervin: 206-464-2105 or kervin@seattletimes.com