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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00202 | ||
| PWS Name: | COLTON WATER DISTRICT | ||
| Who Was Contacted and Phone: | Pete Dostert (503) 824-2500 | ||
| Contact Date: | 10/15/2009 | ||
| Contacted By: | POTTS, JOHN (DWP) | ||
| Contact Method/Location: | Field | ||
| Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
| Reasons: | N/A N/A |
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| Details: | SUMMARY: Tracer Study DETAILS: PWS and Water District have entered into a Bilateral Compliance Agreement that requires the District to conduct a CT study to determine chlorine contact time prior to the first user. The tracer study must be completed before 9/30/09. The Water District received an extension to 10/7/09 to complete the study as the chlorine dosage increase preliminary study was not completed before 9/30/09. I met with Pete to conduct the CT study on 10/7/09. A demand flow of 450 gpm was used consistently throughout the study. A hydrant was opened downstream from the first user and the flow measured at the reservoir effluent meter. A free chlorine residual of 0.65 mgl was measured consistently at the first user and used as the base line for the study. The chlorine dosage was increased to 2.15 mgl for the study as measured prior to the clearwell. Chlorine residual were measured at the first user, dosing sample tap and effluent meter sample tap. Preliminary evaluation of the data indicates an estimated chlorine contact time of 50 minutes from dosage to the first user. I reviewed the data and initiated preparation of the report. A final report will be completed in early November. ACTION NEEDED: Complete CT study report and sent to all parties. | ||