OHA Drinking Water Services
Contact Report Details |
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PWS ID: | OR41 05592 | ||
PWS Name: | BOB BELLONI RANCH | ||
Who Was Contacted: | Greg Duskin | ||
Contact Phone: | 541-269-0321 | ||
Contact Date: | 09/29/2022 | ||
Contacted By: | CIVIL WEST ENGINEERS, INC (DWP) | ||
Contact Method/Location: | Field | ||
Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
Details: | Background/Problem Identification: Kent Downs of OHA reached out on behalf of Ty Crosby at the Bob Belloni Ranch requesting assistance with an ongoing DBP problem. Assistance Provided: The circuit rider made a site visit and identified the following issues related to the elevated DBPs: 1. The surface water intake needs extensive work. We recommend rehabilitating the dam structure to both raise and slow the impounded water. The infiltration well structure needs to either be outright replaced or rehabilitated at a minimum. Cleaning out the interior of the infiltration well should be the first step. The intake pump also should be properly installed in a casing in the well media. 2. The system may benefit from slowing down (or resizing) the raw water pump to both avoid stirring up sediment in the intake well and to aid in flocculation/sedimentation in the flocculation chamber in the treatment building. 3. The system is currently pre-chlorinating RAW water to nearly 1.0 mg/L to avoid biofouling of the media filter. We strongly recommend lowering this dose as much as possible to mitigate the formation of DBPs. 4. The system is also post-chlorinating to meet 4-log virus inactivation. We recommend that the residual be kept at a minimum on this chlorinator as well. The system currently has 148 minutes of contact time and would only need to meet an absolute worst cast CT of 8. This would only require a trace amount of chlorine to meet CT, smaller than the 0.20 mg/L required at the distribution entry point. We recommend maintaining 0.20 mg/L at first user, and detectable residual in distribution. Follow-Up Actions Needed: The circuit rider can provide further follow-up assistance if needed. |