Presentation Abstract

The Hammersley Inlet Growing Area has experienced several clusters of norovirus-like illness in recent years. This presentation will describe a recent study to help evaluate how likely the Shelton WWTP is a potential source of viral loading to the growing area. A hydrographic dye study of the WWTP effluent was conducted by injecting dye at the WWTP at a continuous rate over a full tidal cycle (approximately 24 hours) to approximate steady state concentrations. Sampling of wastewater was also done to evaluate microbial removal across the treatment train. Sentinel shellfish cages are also deployed to measure bioaccumulation of microbial indicators. Plume tracking was conducted for 5 days to determine the extent of excursion of dye as well as the overall dilution of wastewater effluent. The goals of the study are: • Determine the steady state dilution, travel time and dilution of effluent that would be discharged during a failure of the Shelton WWTP over the first ebbing tide and subsequent tides; • Quantify MSC removal efficiency of Shelton WWTP under different operational conditions; • Examine MSC loadings from WWTP under different operational conditions and relate those to MSC levels in shellfish tissue. Deployed shellfish are replenished for microbial analysis every few weeks during the study period. Overall, this study will assist WADOH and FDA in the understanding of the accumulation of bacterial and viral indicators and pathogens in shellfish at various dilutions with respect to a wastewater effluent discharge and the operational performance of the WWTP. .

Session Title

Restoring Shellfish Harvesting Beaches in the Transboundary Salish Sea

Keywords

Hammersley Inlet, Dye study, Norovirus, Shellfish

Conference Track

SSE1: Habitat Restoration and Protection

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE1-265

Start Date

5-4-2018 11:15 AM

End Date

5-4-2018 11:30 AM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 5th, 11:15 AM Apr 5th, 11:30 AM

Dye and microbial study in response to outbreak of norovirus-like illnesses from consumption of shellfish from Hammersley Inlet, Washington

The Hammersley Inlet Growing Area has experienced several clusters of norovirus-like illness in recent years. This presentation will describe a recent study to help evaluate how likely the Shelton WWTP is a potential source of viral loading to the growing area. A hydrographic dye study of the WWTP effluent was conducted by injecting dye at the WWTP at a continuous rate over a full tidal cycle (approximately 24 hours) to approximate steady state concentrations. Sampling of wastewater was also done to evaluate microbial removal across the treatment train. Sentinel shellfish cages are also deployed to measure bioaccumulation of microbial indicators. Plume tracking was conducted for 5 days to determine the extent of excursion of dye as well as the overall dilution of wastewater effluent. The goals of the study are: • Determine the steady state dilution, travel time and dilution of effluent that would be discharged during a failure of the Shelton WWTP over the first ebbing tide and subsequent tides; • Quantify MSC removal efficiency of Shelton WWTP under different operational conditions; • Examine MSC loadings from WWTP under different operational conditions and relate those to MSC levels in shellfish tissue. Deployed shellfish are replenished for microbial analysis every few weeks during the study period. Overall, this study will assist WADOH and FDA in the understanding of the accumulation of bacterial and viral indicators and pathogens in shellfish at various dilutions with respect to a wastewater effluent discharge and the operational performance of the WWTP. .