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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00970 | ||
| PWS Name: | NESKOWIN REG WATER DIST | ||
| Who Was Contacted: | Troy Trute | ||
| Contact Phone: | 503-392-3966 (Email address hidden) | ||
| Contact Date: | 06/08/2022 | ||
| Contacted By: | HOFELD, EVAN (DWP) | ||
| Contact Method/Location: | Phone | ||
| Assistance Type: | OTHER REGULATORY - Discussed LCR sampling and PR for Sodium Bicarbonate | ||
| Reasons: | Lead or Copper |
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| Details: | Troy called to discuss a reduction in lead and copper monitoring and plan to add sodium bicarbonate to augment the existing soda ash corrosion control treatment. Due to the addition of ACH coagulation to improve TOC removal, which lead to a decrease in disinfection byproduct levels, the system was placed on 6-month monitoring for lead and copper at 10 tap sample locations. The increased lead and copper tap sampling was done to assess any impacts the ACH had on corrosion control. The sampling was concluded by the end of 2021 and showed that the lead and copper 90th percentile were both well below action levels and sufficient to qualify for a reduction to once every 3 years at 5 tap sample locations beginning 1/1/22. Bench testing showed that the addition of sodium bicarbonate would help the system increase alkalinity without drastic increases in pH. Although meeting a minimum pH of 7.2 is attainable with soda ash alone, keeping alkalinity above the 23 mg/l minimum level has been difficult. I provided Troy the EPA guidance manual on selecting corrosion control treatment and recommended he contact the SRF technical assistance circuit rider (Civil West) for further assistance. I explained that the change, if implemented, would need to be approved through plan review (fee of $825) and two 6-month demonstration rounds of lead and copper testing at 10 sites would be needed to demonstrate the change to corrosion control treatment did not adversely impact lead or copper levels in the distribution system. | ||