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OHA Drinking Water Services
Contact Report Details |
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| PWS ID: | OR41 01361 | ||
| PWS Name: | RAINBOW ROCK SERVICE ASSOCIATION | ||
| Who Was Contacted and Phone: | Don Bryant (541) 469-6113 | ||
| Contact Date: | 03/15/2007 | ||
| Contacted By: | STRASSNER, BOB (DWP) | ||
| Contact Method/Location: | Office | ||
| Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
| Reasons: | N/A N/A |
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| Details: | SUMMARY: Turbidity Profiles DETAILS: The plant is treating raw water pumped from an unnamed spring source at a rate of 20 gpm. Raw water NTUs over this filter runs previous 7 hrs averaged 2.0 NTUs. The system is minimally occupied this time of year requiring the treatment plant to be operational every three to four days to sustain storage volume. In preparation for the Turbidity Profile included a baseline of the settled water NTUs was established. The samples were taken from the top of the filter, at the location where the profile samples would be drawn. A siphon was started using a garden hose placing the intake just at the point on the surface of the filter where the backwash water would rise and spill into the wastewater trough to waste during the backwash cycle. The continuous flow was directed to the lab sink where the baseline settled NTU was measured at 0.68 NTUs. Sampling was begun at one minute intervals upon initiation of the backwash cycle. The dual media filter has 17.5 sq ft of surface area and typically filters water at 0.83 gpm sq ft. Backwash is normally determined by the operator based on headloss. The plant does have an auto shut down on high NTUs. The plants backwash is fully automated by timers with the operator able to configure the timers according to the condition of the filter. Don indicated he had been working on the backwash process the previous week and had significantly shortened the process due to the current raw water quality and treated water demands. The backwash cycle was completed in approximately 6 minutes. The plant has no provision for a surface wash but is equipped for a filter to waste process by design that was never completed on start up. The Effluent NTU meter began receiving filtered sample upon completion of the backwash cycle ACTION NEEDED: Repeat Profile under longer | ||