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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00279 | ||
| PWS Name: | ESTACADA, CITY OF | ||
| Who Was Contacted and Phone: | Dave Stone (503) 630-8270 | ||
| Contact Date: | 02/13/2013 | ||
| Contacted By: | FARRELLY, PETER (DWP) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | OTHER REGULATORY - REGULATORY ASSISTANCE | ||
| Reasons: | Operations SWTR |
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| Details: | SUMMARY: Taking down CW1 for painting - recalculate CT for one month DETAILS: Dave called Pete to ask how to meet CT requirements once he takes Estacadas Clearwell #1 (built in 2000, 150,000 gallon tank) down for painting (and curing, etc.) Pete sent Dave an Excel file that calculates different temperatures and pHs generally seen in late winter that he may encounter. But raising the residual to 1.8 ppm will satisfy most conditions. While the 2002 Tracer Study on file did not isolate CW2 for a test, by inference DWP determined the contact time was greater in the half-sized tank. Dave will also try to keep the water level above 14.8 feet in the 17 foot 75,000 gallon standpipe, Clearwell 2. There is also 400 feet of 10" pipe between the first user and CW2. At 600 gpm this only adds 2-3 minutes of contact time. The pipe only holds 1,630 gallons. ACTION NEEDED: Dave needs to assure no major changes in pH or temperature in the next month, and to use the Excel spreadsheet to help determine appropriate chlorine dosing while CW1 is down. |
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