New Brightwater plant in King County, Wash., combines efficient treatment with odor control technologies that make the plant a good neighbor.
After more than a decade of planning and about five years of construction, the 36 mgd (design) Brightwater Treatment Plant began operating in September 2011. It was the largest capital improvement in the history of King County, Wash., and the largest expansion of the regional wastewater system since the two original plants were built in the 1960s. “It’s a really significant project, and one we’re really proud of,” says communication specialist Annie Kolb-Nelson. The final $1.85 billion cost includes an on-site environmental education/ community center and over 70 acres of public open space and restored habitat. The treatment plant includes a technologically advanced odor control system to address King County’s commitment to odor-free operation. While Brightwater can make a claim to be one of the world’s largest membrane bioreactor plants, a plant under construction in Dubai, due to come online in a year or two, will be larger. Still, it was a major project for the county Wastewater Treatment Division. Brightwater joins the West Point plant in Seattle and the South plant in Renton in serving a total of 1.5 million people in 34 cities and sewer districts in King County and parts of Snohomish and Pierce Counties in the Seattle area. Brightwater itself will serve about 189,000 people in northern King and southern Snohomish Counties. King County and their engineering consultant team of CH2M HILL and Brown and Caldwell, selected the ZeeWeed hollowfiber membrane bioreactor (MBR) from GE Water & Process Technologies. It combines clarification, aeration, and filtration in a single process, saving capital and operating costs. “Hollow-fiber ultrafiltration is very applicable to wastewater treatment because the microscopic particles have biological components like viruses and bacteria,” explains plant manager Ron Kohler. “The membranes filter out pollutants to the bacterial level, achieving high-quality water suitable for landscape irrigation and reducing pollutant loading into Puget Sound substantially compared to conventional secondary treatment. We get very low turbidity and zero coliform.” Plant operator Angelo Archuleta, who has been working in wastewater plants for about 20 years, adds, “The dynamics of an MBR are very interesting and different.”