Field Office Compliance - Assistance

Assistance ID - 32604
Osceola Water Works - 310338248
2320 WEST CLAY STREET Osceola, IA 50213
Clarke County

FO 5

Report
File Name File Type File Date Note
Comments
4/26/2011 From: Gastineau, Janet [DNR] Sent: Tuesday, April 26, 2011 7:54 AM To: Bunton, Jennifer [DNR]; Veerabhadrappa, Taroon [DNR] Subject: RE: Osceola CT The operator called me yesterday to let me know he has been working on this since I alerted him last week. He worked with his engineer to understand how the automation calculates CT. Turns out the pH meter needed calibrating and with the inaccurate pH readings this was providing inaccurate calculations in the programming. They have an SOP now for calibrating the meter. He said the ratio has already started to increase. I’ll continue to keep an eye on it, but wanted to let you know what he found out. JANET GASTINEAU
4/18/2011 From: Gastineau, Janet [DNR] Sent: Monday, April 18, 2011 1:45 PM To: 'OSCEOLAWATER DEPARTMENT' Subject: CT information The very end of chapter 43 has minimum CT values for 99.9 percent inactivation based on free chlorine residual, pH and temperature of the water. Years ago your system probably did a disinfection profile and the programming for the MOR is probably based on a combination of this profile and the appropriate table. I would start at 43.9(2) at http://www.legis.state.ia.us/aspx/ACODOCS/DOCS/567.43.pdf CT is calculated depending on your chlorine concentration, contact time, temperature and pH of the water. Like TOC removal, you are considering if the chlorine concentration and time achieved compare well with the minimum requirements for CT from the tables. Time has to do with flow rate through storage, volume of storage, and time between chlorine injection and the first customer. CT actually stands for concentration of chlorine x time of contact. Step 1: Determine CT required using the correct CT Table. Step 2: Calculate CT achieved using the formula. Step 3: Compare CT achieved to CT required. • If CTacheived > CTrequired, then you will have met your disinfection requirement. • If not, you must take the appropriate actions to ensure CT Disinfection requirements are met. Like I mentioned, this is probably all in the programming, but I would begin to look into what can be changed to increase the ratio. I hope this helps. If I hear something further from the water supply engineers on this subject, I’ll let you know. JANET GASTINEAU
4/18/2011 Brandon called back and said the MOR is automatically populated. Automatic system set up the program. He called his engineer to discuss but hasn't heard back. I told him I would send him some information to start evaluating what can be done to raise the CT achieved to more easily meet the CT required. He said the south filter media was changed in 2010 and the north four filter media will be changed in 2011. He is hoping this helps with the TOC removal, which we also talked about hovering around 1.0 at least RAA. JANET GASTINEAU
4/18/2011 Last six months of TOC removal: 0.85 10/2010 0.94 1.16 1.00 1.18 0.98 03/2011 JANET GASTINEAU
4/18/2011 I called Brandon and let him know this is something I wanted to talk about--I was only able to leave a message. JANET GASTINEAU
4/18/2011 From: Gastineau, Janet [DNR] Sent: Monday, April 18, 2011 1:01 PM To: Bunton, Jennifer [DNR]; Veerabhadrappa, Taroon [DNR] Subject: Osceola CT The last three months the minimum CT ratio has been a 1.0 and TOC removal is just a little above 1.0. I didn’t want it to go on too long without letting you know. I know Jennifer has worked with them on some filter issues. I’ll be contacting the operator to get his ideas. Thanks. JANET GASTINEAU
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