OHA Drinking Water Services
Contact Report Details |
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PWS ID: | OR41 00613 | ||
PWS Name: | PENDLETON, CITY OF | ||
Who Was Contacted and Phone: | Bob Patterson (541) 276-1811 | ||
Contact Date: | 12/08/2010 | ||
Contacted By: | GOSS, BILL (DWP) | ||
Contact Method/Location: | Field | ||
Assistance Type: | OTHER REGULATORY - INFORMAL INSPECTION | ||
Reasons: | SWTR N/A |
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Details: | SUMMARY: Inspected IFE Turbidimeters DETAILS: Met with Bob and Tim Smith at the water treatment plant. Inspected the four new Hach 1720E turbidimeters on the individual filter effluent lines. Small pumps are required to move the water from the IFE piping that is under negative pressure to the turbidimeters. The IFE piping pressures at the time of the site visit ranged from -7 to -10 psi. The small pumps cavitate due to the negative pressure, and one failed after operating approximately 10 weeks. Water is pumped from the IFE piping into a degassing chamber that allows entrained air to dissipate. The turbidimeter then draws water from the bottom of the degassing chamber. The pumps need to run 24/7 to keep water flowing through the turbidimeters. Another operational difficulty has been air getting into the turbidimeter lines when a filter train is taken offline for integrity testing or for other reasons. After the filters are returned to operation, the turbidimeters take about 40 minutes to recover and collect accurate data. Data collection is following the recommendations on page 5-16 of the EPA Membrane Filtration Guidance Manual. When a filter train is in production, IFE turbidity readings are taken every 60 seconds, and a running 15 minute average is calculated. A single "snapshot" of the turbidity is also collected every 15 minutes. ACTION NEEDED: PWS will continue to monitor IFE turbidities, document operational challenges. |