OHA Drinking Water Services
Contact Report Details
|PWS ID:||OR41 00213|
|PWS Name:||COQUILLE, CITY OF|
|Who Was Contacted:||Ray Doan|
|Contacted By:||CIVIL WEST ENGINEERS, INC (DWP)|
|Assistance Type:||CIRCUIT RIDER ASSISTANCE|
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.
A site visit to the water system was made on October 19th, 2021. From the information gathered, the following operational mitigation measures may help to reduce DBP levels at the City of Coquille:
•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.