New water treatment eyed

The Lake Oswego Review, Jul 8, 2010

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In June a panel of national experts in water treatment and public health recommended that the cities of Tigard and Lake Oswego pursue conventional drinking water treatment plus ozone to best meet their future water treatment needs.

The findings were presented at an open house on June 24 at the West End Building.

The recommendation is part of the first phase of planning for an expansion of the city’s water supply through a water partnership with Tigard. The two communities signed an agreement in 2008 to feed long-term water demand, nearly doubling the water drawn from the Clackamas River under Lake Oswego’s water rights and costing nearly $200 million in system upgrades. Tigard ratepayers shoulder a greater burden of those costs, while Lake Oswego citizens will pay about $82 million, said Joel Komarek, the city’s engineering director.

The city of Lake Oswego, which is the managing agency, has contracted with Brown and Caldwell to provide program management, permitting and construction management until the expansion is complete. The contract must be renewed annually.

Experts, assembled by Brown and Caldwell, reached a final recommendation for a new water treatment after three full days of workshops, which included meeting with program staff and a citizen sounding board. Initially 18 different water treatment technologies were examined for social, environmental and economic benefits.

The recommendation validated a 2007 engineering report that conventional treatment meets water quality requirements. The panel recommended ozone in addition, because it is capable of addressing emerging concerns about currently unregulated contaminants. The panel determined that adding ozone as an additional treatment barrier would best protect public health in the long term. Ozone would proactively ensure the best taste year round and would reduce the amount of chlorine used for disinfection, among other benefits.

Additional work will determine costs for this portion of the overall project costs before each city council is asked to confirm the recommendation. However, of the alternatives examined, this treatment recommendation was considered mid-range in terms of cost.

Next, project management team will unveil a capital improvement plan late this year that will confirm size, type, location and updated costs and cost allocations of water supply facilities as conceived in a 2007 engineering report.

The cities plan on beginning the system upgrades in the 2012-2013 fiscal year.