From: Andy Peters

Sent: Thu Sep 17 08:02:17 2020

To: Gerald Fisher; Ryan Hepler

Subject: FW: Ash tastes in water

Importance: Normal

Attachments: image003.jpg;

Gentleman, FYI, Mr. Starner took the time to respond about ash/taste in the water from our questions yesterday.

Thanks,

Andy

From: Steve Starner <SStarner@Silverton.or.us>

Sent: Thursday, September 17, 2020 8:00 AM

To: Andy Peters <apeters@cityofmolalla.com>

Cc: Petra Schuetz <PSchuetz@Silverton.or.us>; Christy Wurster <CWurster@Silverton.or.us>

Subject: RE: Ash tastes in water

Good Morning, Andy.

We are not receiving taste issues here, at least that I am aware of. However, just as the ash started to fall, our chlorine residual went away. We attempted to troubleshoot piping failure, valves, pump performance. Then did some bench tests to confirm a significant chlorine demand from dissolved organics introduced by charcoal/ash. We switched from our on-site generated sodium hypochlorite 0.8%, to carboys of 12.0% solution. Our treated water color went from 0.1 units to 12.0 units. Color is a secondary contaminant, not recommended to exceed 15.0 units, and not enforced by OHA. So, we have gotten calls regarding chlorine odor (our first user residual is 0.88 mg/l), and concerns about the light yellow color in the water.

Taste and odor are difficult to manage because (like color) they are subjective and not regulatory. My only suggestion to control taste and odor is to add more carbon to the top layer of the filters. You might run this by Chantel or James at the Drinking Water Program, 971-599-0293, for additional suggestions.