Hi Tina, Mark -
Here are the answers to David’s questions a few emails below. Mine are in RED, with Jason’s being in GREEN.
Let me know any thoughts before we forward the answers on to DEQ this week.
Jennifer Cline, P.E.
City of Molalla
Public Works Director
O: 503.759.0218
F: 503.829.3676
"From: Jason Clifford [mailto:jclifford@cityofmolalla.com]
Sent: Friday, May 22, 2015 12:25 PM
To: Jennifer Cline
Subject: RE: Molalla SSO follow-up questions.
From: Jennifer Cline [mailto:jcline@cityofmolalla.com]
Sent: Friday, May 22, 2015 12:00 PM
To: Christine Hein; Mark Strandberg; Jason Clifford
Cc: J.W. Ring; Phillip Bender; Dan Huff
Subject: FW: Molalla SSO follow-up questions.
My comments are below in RED
Hi Jason – please reply to all and with any additional, missing, or clarification comments to mine. I believe there are 11x17 copies I/S was using when looking at our system. If you bring them to City Hall I can scan them.
Jennifer Cline, P.E.
City of Molalla
Public Works Director
O: 503.759.0218
F: 503.829.3676
From: COLE David [mailto:COLE.David@deq.state.or.us]
Sent: Friday, May 22, 2015 11:12 AM
To: 'Jennifer Cline'; Dan Huff; Jason Clifford; 'jehredt@cityofmolalla.com'; Mark Strandberg
Cc: YELTON-BRAM Tiffany; MRAZIK Steve; PINNEY Mike; HYNSON Mark; COLE David
Subject: Molalla SSO follow-up questions.
Hello All. First I want to thank you for taking the time to meet with Tiffany and me earlier this week to discuss the recent SSO. After considering the information you provided, we have the following additional questions:
- 1. At the time when Industrial Systems, Inc. installed the SCADA system, did they recommend also installing separate, back-up alarms for the pumps that failed when the SCADA system went down? At the time when Industrial Systems (I/S) quoted the City for the SCADA system upgrade in 2014, no recommendations were provided in the quote to update the communication hardware at the plant (i.e. replacing existing Ethernet Switches, cabling and testing). See attached 2014 SCADA Upgrade quote. No they did not. That was Jake’s and my idea. Industrial Systems tied the transfer pumps and alarms together so when the pumps turned off, so did the alarms.
- 2. What are Industrial Systems’ recommendations for maintaining and checking the SCADA system? Since it was installed, have you followed the recommendations, and if so, can you produce documentation to show that you followed them? Since the 2014 SCADA system update, to my knowledge I/S has not provided a preventative maintenance plan or recommendations for the WWTP system. It has been discussed that the City will be working to create an SOP to address this exact concern.
- 3. When the wastewater treatment plant operators are on-call over weekends and nights, how often is the SCADA system checked, either remotely or in person, for proper operation? Does the plant Operations and Maintenance manual specify who is to perform these night and weekend checks, and how often to perform the checks? Jake or myself take the city laptop home every night. It is checked when there is an alarm at the WWTP. It is per the discretion of the operator how often SCADA is checked. There is no O&M manual that will specify who and how often SCADA is checked.
- 4. Regarding the SCADA improvements: Please collect as-built plans and other engineering documents regarding this project (engineer’s reports, plans, specifications, manufacturer’s cut sheets, etc.) for DEQ review. Please contact us when they are collected and ready for our review. The City has the original 11x17 plans that we will make available. To my knowledge, no diagrams were provided to the City for the software upgrades or programming changes. New Network Block Diagram for current quoted upgrades will not be available until complete. See attached IS Ethernet Upgrades attachment.
- 5. What is the operational water level elevation in the aeration basins? Jason? What is the usual freeboard? 2-ft. Minimum 1 foot of freeboard at almost every WWTP. I keep it at 10’ with 2’ of freeboard.
- 6. Did the SCADA outage affect influent flow measurements? Yes, as the influent backed up into the headworks and created bi-directional flows, the flow transducer in place could not accurately measure flows and recorded inaccurate readings. If not, what was the influent volume measured over the period of the outage? The influent measured would have stayed the same; approximately 1.0-1.2 mgd since there was little to no rainfall.
- 7. Per schedule B of your permit, Chlorine use and dose is measured daily. How is this done if no one is on site to do it? Jason? Cl2 dose is controlled by myself dependent on Cl2 residual. The dose could vary daily. Our permit states river discharge Cl2 residual is not to be greater than 0.07ppm monthly average. Daily maximum Cl2 residual cannot exceed 0.17ppm. We are not currently discharging or irrigating. We are not chlorinating effluent. Per summer discharge, we are required to take a Cl2 residual at the site where we are irrigating. We are not required to take a Cl2 residual at the WWTP when we irrigate. There is an inline Cl2 meter that measures residual daily. That measurement is printed out daily along with the pounds of chlorine tablets in the chlorinator.