...effluent rather than a “sewer-to-tap” endeavor. But the outreach efforts paid off, and now “we have no known opposition,” Markus says. He adds that the water district is considering expanding the plant by another 15 mgd within the next year or so. The plant has the capacity to be expanded eventually to 130 mgd.
In Washington state, King County’s wastewater treatment division is building two plants that will use advanced membrane bioreactor technology (AMBR) rather than a conventional activated sludge system to treat wastewater to levels for reuse in irrigation and other non-potable uses. The result will be “a product that’s usable for irrigation…without having to do additional treatment,” says Christie True, director of the King County wastewater treatment division. “The wastewater will be seven to 10 times cleaner than typical secondary treated wastewater.”
The Orange County project is the world’s “largest indirect potable reuse project of its kind.”
— MIKE MARKUS, ORANGE COUNTY WATER DISTRICT
Construction of the 36-mgd AMBR Brightwater plant in the northern part of the county began in late 2005 and is scheduled to be completed in 2010. According to True, the Brightwater facility, which will eventually be expanded to 54 mgd, is currently the largest application of MBR technology used for municipal wastewater treatment in the world. The Seattle office of Hoffman Construction is the general contractor and construction manager on the project. CH2M Hill Cos., Denver, is lead design engineer. Total project costs, including the plant, an odor-control system, conveyance tunnels and an outfall into Puget Sound, are $1.7 billion.
Advanced membrane bioreactor technology pairs an activated sludge secondary treatment bioreactor with a microfiltration membrane to convert screened sewage into clean effluent in a single process, eliminating the need for separate primary, secondary and advanced treatment tanks. Because the technology takes up 40% less space than conventional settling tanks, odor- control becomes easier to engineer and the design holds the potential to reduce plant footprint, say county officials.
King County is using the same MBR technology at a much smaller, $20-million plant being built in Carnation, Wash. The 0.5-mgd plant will discharge treated water into a wetland that filters into a river. “We could go directly into the river, but it’s much better to go into this wetland and create more habitat” for fish and wildlife, True says. “We’re not just looking at it strictly from a water supply standpoint, but more of a holistic way of looking at it and the whole landscape here.”
True says that County Executive Ron Sims (D) is a strong proponent of recycling water as a tool to prepare for climate change. Under Sims’ leadership, the county developed a climate plan in early 2007 that outlines strategies for mitigating and adapting to the effects of global warming, including water-related impacts.
Sims signed an executive order in June requiring environmental assessments on certain county projects to study the potential impact of greenhouse gases, the first such action by a local government in the country.
The wild card in the number of drinking water and wastewater projects that ultimately will move forward is the amount of funding made available. EPA estimates that more than $277 billion is needed for water infrastructure capital investment over the next 20 years. But Benjamin Grumbles, EPA assistant administrator for water, acknowledges that federal funding alone will not meet these needs.
“We’re not just looking at it strictly from a water supply standpoint.”
— CHRISTIE TRUE, KING COUNTY WASTEWATER TREATMENT DIVISION
In Congress, the House this year approved a $14-billion bill reauthorizing the clean water state revolving fund program through 2011. But the Senate has failed to introduce a comparable bill, and President Bush has threatened a veto if a package were to reach his desk.
Orange County’s Markus says that because federal funding is tight, “more and more, agencies are having to look to themselves to fund” projects largely through local and state grants and programs, as well as partnerships such as the one between Orange County’s water district and sanitation district that funded their water reuse program.
Atlanta Dept. Of Watershed Management
Atlanta�s current tunnel work is part of a comprehensive plan to reduce overflows and already has proved effective.
Grumbles has suggested that states and municipalities develop innovative strategies such as public/private partnerships and new types of bond measures to stretch dollars further. One example of such an approach is in Atlanta where, in 2004, city residents passed a referendum that dedicates a 1¢ sales tax to a water enterprise fund. The referendum is up for renewal in 2008. Without the enterprise fund, rates would increase by nearly 35%, says Atlanta’s Hunter. “It's a fairly easy representation to make to our ratepayers,” he says.
But Hunter is skeptical about EPA’s recommendation to lift caps on private activity bonds, which would provide an incentive for private entities to contribute to projects. “No one’s ever been able to demonstrate that there is a real need to do this,” he says. “It seems to me that we’re going down a trail looking for a solution that’s not necessary.”��