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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 01509 | ||
| PWS Name: | DEAN MINARD WATER DISTRICT | ||
| Who Was Contacted: | Richard Anslow | ||
| Contact Phone: | 541-824-0036 | ||
| Contact Date: | 09/22/2021 | ||
| Contacted By: | CIVIL WEST ENGINEERS, INC (DWP) | ||
| Contact Method/Location: | Field | ||
| Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
| Details: | Background/Problem Identification: Casey Lyon reached out to Civil West on September 22nd, 2021 and said that the City of Coquille and a small purchasing system of Coquille, Dean Minard, recently exceeded the disinfection by products (DBP) MCL for TTHM’s. The City of Coquille provides conventionally treated water to 1,963 connections drawn from the Coquille River during the dry season and Rink Creak during the wet season. Assistance Provided: A site visit to the City of Coquille the water system suppling Dean Minard with their water on October 19th, 2021. From the information gathered, we provided operational mitigation measures that may help to reduce DBP levels for the water district by implementing the following recommendations at the City of Coquille, we provided coordination and communication between the two-water system during the support effort. Water supplier recommendations: •Eliminate pre-chlorination •Adjust overall chlorination residual to provide just enough residual to meet CT and maintain the required residual in distribution •Inject pH control (soda ash) post-clearwell versus pre-clearwell to allow a lower pH in the disinfection segment (clearwell) •Start a flushing program throughout the distribution system •Reduce contact time within the reservoir tanks as much as possible while maintaining sufficient storage to provide fire-suppression Follow-Up Actions Needed: The circuit rider is available to assist further as needed. |
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