A hydrographic dye study of effluent from the Lighthouse Point Water Reclamation Facility in Blaine, Washington, was conducted in November 2012. Six cages filled with oysters were deployed at various locations (stations) along the anticipated path of the effluent to correlate the dye concentrations found at the cages with the indicator bacteria and viral findings in the oysters. Sampling was also conducted at the plant to assess bacteria and virus removal efficiencies through the treatment process. The study objectives were to: (1) determine the bacterial and viral conditions in the influent and effluent and removal efficiencies for a WWTP using membrane filtration (2) determine the bacterial and viral conditions that could arise in receiving waters under a short term lapse in treatment at the WWTP; (3) provide guidance to the Washington Department of Health (WA DOH) regarding the WWTP closure zone based on dilution of effluent (4) research the dilution level needed to achieve reduction in viruses to ensure the safety of shellfish harvested near WWTPs as part of FDA’s dilution guidance The proposed presentation addresses the session theme based on the following features: (1) A description of tools and methodology currently used by FDA to assess risk from wastewater outfalls to commercial shellfish growing areas, including development of an GIS application for mapping dye plumes in real time, (2) Current efforts by FDA to develop an easily quantifiable viral indicator (MS2 Coliphage) and how this indicator correlates with presence of viral pathogens such as Adenovirus and Norovirus in oysters, (3) Evaluation fecal coliform bacteria indicator to assess public health risk from viral pathogens with wastewater plants employing membrane filtration treatment, and (4) Since Blaine sits on the border between the US and Canada, the case study also highlights transborder pollution issues
