OHA Drinking Water Services
Contact Report Details |
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PWS ID: | OR41 00953 | ||
PWS Name: | WILLAMINA, CITY OF | ||
Who Was Contacted and Phone: | Matt Griffith (503) 437-7003 | ||
Contact Date: | 04/17/2007 | ||
Contacted By: | POTTS, JOHN (DWP) | ||
Contact Method/Location: | Field | ||
Assistance Type: | CIRCUIT RIDER ASSISTANCE | ||
Reasons: | Operations N/A |
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Details: | SUMMARY: Filter bed depth measurements DETAILS: Matt Griffith (MG) requested help to determine depth of anthracite coal (AC) and sand in filter beds of the package treatment plant. He thought there may be some media loss since filters have been online over 8 years wihout any media added. AC media is available in bags stored at treatment plant. Filter plans show a dual media filter bed. They also purchased a new Hach 1720 E turbidimeter to install for CFE measuring as per DWP requirement (they had only IFE units). It was not measuring due to vacuum problems with point of measurement (the downtube on the common header pipe header to contact chamber). I measured the depth of filter 1 and found 16 inches of AC on top of the sand layer. Media was fluffy and loose with no mudballs. Top of filter media was approx. 4 inches below surface wash spray arm. MG dug into filter 2 and found 18 inches of AC media on top of sand layer. Media was also loose and free of mudballs, similar to filter 1. They add a polymer to plant- appears that dosage and backwash are adequate since no mudballs present. Filter box dimensions were 9 ft. by 8 ft. for surface area of 72 sq ft. I showed MG how to determine how much media to add to bring filter 1 up to the 18 inch depth design spec. Spray arms on both filters also had plugged or broken spray nozzles. MG plans on repairing those in the future. I looked at CFE turbidimeter connection and suggested he move pick-up site to another location and install a small clear plastic common header for both filters and have the pick-up point there to measure both filter effluent. This would require DWP approval. I contacted Kari Salis- this method was not approved. I told MG to contact her and work out another method as their options were limited due to plant construction regarding pipe access. ACTION NEEDED: None, unless requested by PWS. |