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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 95390 | ||
| PWS Name: | OSU ROWING CENTER | ||
| Who Was Contacted and Phone: | Scotty Hammerquist (541) 754-9211 | ||
| Contact Date: | 10/09/2012 | ||
| Contacted By: | MACPHERSON, JAMES (REGION 2) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | OTHER REGULATORY - REGULATORY ASSISTANCE | ||
| Reasons: | GWR None |
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| Details: | SUMMARY: 4-log disinfection questions DETAILS: Would a design that keeps the system pressurized be acceptable? Yes, as long as adequate CT is met. Discussed CT as a function of disinfectant concentration, contact time, and temperature. If using chlorine as a disinfectant, 0.2 mg/L and 30 minutes of contact time at 15 C would provide a CT of 6 (4-log inactivation) though the most conservative CT is 12 (water just above freezing). For CT of 12, if the peak hourly demand flow was 10 gpm and the chlorine concentration was 1.0 mg/L, then a contact chamber with perfect mixing would need to be 120 gallons. Discussed less than perfect mixing. Also discussed UV and that it currently doesnt have treatment credit for 4-log virus inactivation in Oregon. ACTION NEEDED: none | ||