From:                                         Tom Giese [TomGiese@KennedyJenks.com]

Sent:                                           Tuesday, September 09, 2008 2:18 PM

To:                                               James Kelly

Cc:                                               Chris Kelsey

Subject:                                     RE: Discharge to Wetland

 

Jim,

My responses:

1)     You could design for up to 4.0 MGD, as this will be the rated maximum Class A reclaimed water production with the addition of the future 4th UV reactor.  With the initially installed 3 reactors, the capacity will be 2.0 MGD of Class A reclaimed water (such that you would have to discharge to the river when plant flows exceed 2.0 MGD, which will require some additional control logic, actuated valves, etc.).  It’s possible you could even get by with Class B reclaimed water, in which case the capacity would be even higher.

2)     You could design for lower capacity, though there won’t be much storage in the WWTP.  It would require reprogramming of the MBR system to allow surging of water level in the tanks and may adversely impact the process if surging occurs frequently.  However, if the WWTP was producing more than was needed, you could only pump what is required and let the rest overflow to the headbox and discharge through the outfall.  Again, this will require some additional control logic, actuated valves, etc.

3)     We looked at wetlands discharge for Pierce County not long ago and Ecology did not seem to have any significant issues with the concept.  It is highly likely that you may end up with a second compliance point related to the wetlands.

4)     We’ve arranged our design not to exclude this.  The routing of the discharge line will not be simple, due to crossings of 48”, 36” and 24” pipelines among others, but should be achievable.  It may require the discharge line running above grade along side the BNR tank.

Tom Giese

From: James Kelly [mailto:jkelly@ci.arlington.wa.us]
Sent: Tuesday, September 09, 2008 1:39 PM
To: Tom Giese
Cc: Chris Kelsey
Subject: Discharge to Wetland

 

Tom –

 

The wetland delineation, geotech, and survey are complete for the City’s Stormwater Wetland; We are beginning to work with the Stormwater Wetland design.  As you know, it is our intention to have the effluent from the Reclaimed Water Facility discharge into the wetland during peak summer months to mitigate temperature and DO impacts to the Stillaguamish River.  Some questions:

 

1.    In designing the wetland hydraulic capacity, what should we design for – the Daily Max month of 4.0 MGD?

2.    Could we design lower hydraulic capacity and have surge storage within the BNR and MBR?

3.    How do you think DOE will accept our proposal to discharge Reclaimed Water into a stormwater wetland to mitigate temperature and DO impacts?

4.    As we move closer to determining where the discharge point to the wetland will be, we might come back and ask K-J to design the discharge line from the two 15 hp pumps to the WWTP boundary (and controls)……please keep this in mind as you think of an alignment.  

 

Thank you-

 

 

 

James X. Kelly, PE | Utilities Manager

City of Arlington | Utilities Division

154 West Cox Ave.

Arlington, WA 98223

Phn:  360-403-3505

Fax:  360-435-7944