|
|
| Introduction :: Data Search Options :: Water System Search :: DWS Home :: DWS Rules |
OHA Drinking Water Services
Contact Report Details |
|||
| PWS ID: | OR41 01174 | ||
| PWS Name: | BUELL-RED PRAIRIE WD | ||
| Who Was Contacted: | Scott Cure | ||
| Contact Phone: | 503-843-2885 (Email address hidden) | ||
| Contact Date: | 08/18/2022 | ||
| Contacted By: | BAIRD, GREGG (DWP) | ||
| Contact Method/Location: | Phone | ||
| Assistance Type: | MONITORING | ||
| Reasons: | Cyanotoxins |
||
| Details: | Contact report 1 of 2: DEQ notified OHA 8/11 that the routine raw water sample collected Mon. 8/8 for cyanotoxins analysis had a preliminary detection of microcystins at 0.32 ug/L, however the sample was visibly irregular (under the microscope there was a considerable amount of inorganic/crystalline material observed), had a lower-than-expected pH of 3.9, and had a measurable free chlorine residual. Upon reanalysis, the microcystins were measured at 0.21 ug/L and the dupe at 0.19 ug/L which is below the level requiring increase raw/finished water monitoring. After discussions between OHA and DEQ regarding possible causes of the sample irregularities and validity of the sample, a site visit was made 8/16 to inspect the raw water sample tap and see if a cause for the sample anomalies could be identified. Raw sample tap appeared to be prior to any treatment, polymer injection point is about 6 feet downstream of raw tap, operator indicated standard practice is to run tap 30 minutes prior to collecting sample. Based on these observations and under the theory that polymer may be able to reach the raw sample tap under certain conditions, a recommendation was made to the operator to 1) make sure the treatment plant/dissolved air flotation unit were running, and 2) run sample tap for shorter duration (1-2 minutes) prior to sampling. Another raw water sample was collected by the operator this same date under these recommended operating conditions to see if the issue would be resolved. DEQ notified OHA the 8/16 raw sample had a pH in the normal range of 7, however there was a measurable free chlorine residual in the range of 0.1 to 0.9 ppm. While the pH issue seems to be resolved, there is still no explanation for the sample containing a chlorine residual as there is no chlorine injection point prior to the sample tap (continued on next contact report). | ||