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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 00149 | ||
| PWS Name: | BROOKINGS, CITY OF | ||
| Who Was Contacted: | Mark Haglund | ||
| Contact Phone: | 541-412-0424 (Email address hidden) | ||
| Contact Date: | 03/12/2019 | ||
| Contacted By: | PARRY, BETSY (DWP) | ||
| Contact Method/Location: | Phone | ||
| Assistance Type: | VIOLATION RESPONSE | ||
| Reasons: | GWR |
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| Details: | Intermittent problems with their chlorination system continued in February. See 2/13/19 contact report re: January events. In February, there were 5 separate days when the chlorine level at the compliance location dropped below their 0.2 mg/l minimum for GWR 4-log inactivation. An attachment to the February treatment report stated that the chlorine level monitored after the disinfection chamber (the 3+ mile long transmission line from the intake to the plant) was below the minimum for more than 4 hours during 4 of those 5 days, which constitutes a treatment technique violation. To try to address the problem, last week the staff replaced a control valve in their chlorination system, and a trouble-shooter is arriving from Portland to look at their system this week. In the past, there was no recurring problem in keeping the chlorine level > 0.2 mg/L at the compliance location, whether or not the pumps were running at the time. It is worth noting that the water is also post-chlorinated before running through a 60,000 gal reservoir at the plant, which may mitigate the disinfection risk to consumers. However, quick estimates using the worst case scenario with the 60k gal tank only yielded 3.7 additional minutes of contact time there, which wasn't enough to meet the disinfection standard for every day in February. April 5 update: On March 21, Jacobs provided chart recorder images for the February days in question. This detailed data showed that the residual at the approved monitoring location was never below the minimum for a span of 4 hours. The longest stretch was <40 minutes. The DWS compliance staff’s decision was that - because this data was provided weeks after the report due date and after their decision-making point – the Feb. treatment technique violation will stand. However, they waived the public notice requirement given that the delayed data shows the public was not put at risk. |
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| Associated Violations: | Viol #, - : - |
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