Field Office Compliance - Assistance

Assistance ID - 67037
Des Moines Water Works - 310338211
9966 Maffitt Lake Dr Cumming, IA 50061
Dallas County

FO 5

Report
File Name File Type File Date Note
Comments
2/17/2014 From: Bunton, Jennifer [DNR] Sent: Friday, February 14, 2014 4:13 PM To: Gastineau, Janet [DNR]; Moles, Diane [DNR] Cc: Lynam, Anne [DNR] Subject: RE: Question on IFE reporting Janet, Diane and I checked the rules and the IESWTR guidance manual for turbidity. It is confusing, because they interchangeably use the terms “after the first four hours” and “at the first four hours”. Finally, I found what we were looking for in a training manual we have from AWWA. I attached the relevant slides from the training. They show pretty clearly that the 0.5 NTU trigger applies when two consecutive 15-minute readings occur any time after the first four hours of operation following backwash or other offline time. Note that this four hour grace period only applies to the 0.5 NTU trigger; not the 1.0 or 2.0 NTU triggers. To sum it up, I believe Mike’s interpretation was correct. Regarding the question they had this morning on lowering the LRV for Saylorville, the one thing that could impact is the CT. As long as they are getting 2.5 LRV, and then 0.5 log credit for Giardia through disinfection, they should be okay. With regard to CT, have you verified that they’re getting 0.5 log? In checking with Anne, we have not sent them a permit to tell them they need the 0.5 log, but I know that I have talked with Mike about that in the past. From: Gastineau, Janet [DNR] Sent: Friday, February 14, 2014 1:32 PM To: Moles, Diane [DNR] Cc: Bunton, Jennifer [DNR]; Lynam, Anne [DNR] Subject: Question on IFE reporting Maybe Jennifer or Anne has already approached you about this…during our meeting with DMWW this morning Mike asked about the MOR that asks for “highest consecutive NTU results @ 4 hours after start up or backwash.” Are these four readings a) at the end of the four hours and 15 minutes later or b) the two highest consecutive readings during the entire filter run, but starting after the 4 hour period? I have always taken it to be at the end of hour hours take a reading and then 15 minutes later take another and that is what is reported. However, something about the way the surface water turbidity requirements are worded in the permit attachment leads Mike to think it could be the two highest consecutive readings during the filter run time with the clock starting at the end of the first four hours of continuous filter operation. Can you clear this up based on your access to guidance materials? JANET GASTINEAU
2/14/2014 Topics covered included: • Saylorville high CFE turbidity August 2013 and 4-log removal discussion for membranes • Treatment technique violation at Fleur for CFE turbidity December 2013 (to be issued 2/7/2014) • IFE filter profiles from December 12-13, 2014 • IFE turbidimeter programming (setpoints, failure alarms, data integrity, etc.) • CFE turbidimeter location for monitoring • Written decision making protocol/standard operating procedures for operations staff established by DRC • UST inspection responses (Fleur, McMullen, LP Moon) JANET GASTINEAU
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