Recommendations for Catastrophic Wastewater System Failures in a Modern Metropolitan Area

In the late 1980s it was discovered that the Pacific Northwest is sited in the Cascadia subduction zone, a fault capable of producing a magnitude 9.0 earthquake, which could result in significant destruction along the almost 700 miles of impact. One likely result of this earthquake would be a catastrophic impact to wastewater systems in the Portland metropolitan area, with anticipated loss of wastewater systems for 6 months-1 year. With approximately 2.3 million residents in the area, this loss poses a significant threat to the public's health in the aftermath of an earthquake of this magnitude. A group of multidisciplinary professionals from the five counties in the area was convened to develop recommendations to assist the public to safely handle their sanitation needs in the absence of a functional wastewater system for an extended period of time. Participants represented the disciplines of public health, emergency management, public works, wastewater treatment, waste hauling, and the Oregon Department of Environmental Quality. The group developed recommendations for the handling of human waste by residents of the Portland metropolitan region following a catastrophic earthquake. In this special report, we review the process, assumptions, and final recommendations for use by the public in a long-term wastewater system failure.