OHA Drinking Water Services
Contact Report Details |
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PWS ID: | OR41 00670 | ||
PWS Name: | PORT ORFORD, CITY OF | ||
Who Was Contacted: | James Parmenter | ||
Contact Phone: | 541-269-0732 (Email address hidden) | ||
Contact Date: | 11/20/2018 | ||
Contacted By: | PARRY, BETSY (DWP) | ||
Contact Method/Location: | |||
Assistance Type: | OTHER REGULATORY - Adjust contact minutes in SWTRs | ||
Reasons: | SWTR |
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Details: | Today I informed the water system staff (Terrie Richards and Duane Eckhoff) that the number of contact minutes on their monthly treatment reports could be raised to 37.5 based on the following. Dyer Engineers (James Parmenter) conducted a tracer study on 9-11-2018 which added the second (non-baffled) contact tank. Two identical tanks had been installed at the treatment plant way back when, but they had only been using the tank with the baffles up to now. Before the Sept study, the second tank was put online, with the plumbing arranged so that one tank would overflow from the top into the other, so that one tank would retain its full volume at all times. Adding the 2nd tank is an interim measure, not the final solution that would assure adequate contact time at all times and all seasons at their target chlorine level. But the few additional minutes gained by this second tank should keep them in compliance through the lower water temperatures this winter, along with increasing the chlorine level. They plan to make other changes next summer to add more contact time (possibly a buried contact loop). Because this was an interim tracer study (between the "before" study in April 20178, and the "after" to be conducted following changes in late 2019), I approved the new minutes based only the completed tracer study worksheet rather than a full report. I also had several conversations with James Parmenter to assure that it all made sense. The second (non-baffled) tank only added 7.5 minutes to the total contact time. |