A part of the computer system for Wrangell’s water treatment plant crashed last week causing some communication problems. The Public Works Department was able to restore some function, but not everything.
Tom Wetor, Wrangell’s Public Works Director, said the system is called SCADA and it is critical to utility infrastructure. It’s basically an alarm system for personnel at the Department. The SCADA system notifies them when something is amiss and they can respond accordingly. Because the computer system crashed, they lost temporary oversight of the plant. If something went wrong no one would be notified to fix it.
Wetor said this type of computer failure could result in a community-wide health and safety issue involving water and sewage.
“This is definitely a big problem for us as we lose control and oversight of necessary planning functions,” he said at Tuesday evening’s Borough Assembly Meeting. “Basically what this means is that if we had a water main break over a weekend we would drain the tanks before we ever even knew about it.”
To prevent a possible situation where the tanks are drained, the department checked the plant every four hours to make sure everything is properly working, even over the weekend. Normally, the SCADA system would monitor the operations.
“Part of the problem was kind of a game of whack-a-mole”
The problem with the system started last Wednesday night and they worked on it until Saturday morning. It took a long time because the 20 year old SCADA computer does not connect to the internet.
When they put in the new programmable logic controller, which is the computer part that crashed, some things came back on and certain things did not.
“Part of the problem was kind of a game of whack-a-mole,” Wetor said. “As soon as we got the turbidity tank levels and influent plant flows back online then we lost the alarm system.”
Wetor said they have the majority of controls working right now, such as Excel automatically logging the data. That data is needed for compliance and oversight.
But the next step in the system is still not working – the graph that compiles the data from Excel is not working. The department is waiting for spare parts to arrive that will fix it.
Wetor said that once the new water plant is built in a year, they will have a brand new SCADA system, which should solve the current issues.
Other challenges the Department faced over a two week span
There were other challenges facing the Public Works department in the last couple of weeks. Over the course of 14 days, the department received 21 calls for service, primarily for winter road maintenance.
Another problem the Public Works Department faced last weekend was at Wrangell’s node five wastewater lift station. They began having issues with its electric panel last Saturday. Wetor said it was causing the pump to cycle 1000 times a day. He said cycling a few dozen times a day is a lot. After some guessing, they found that it was a bad copper coil and were able to fix the problem.
Additionally, Wetor said that they had a sewer main break on the force main from that same station on Monday morning. He said the station was constructed in 1976 with old vacuum-style pumps. Wetor said these pumps sit on top of the wet well, whereas other pumps they use are located inside the wet well.
To help with the lift station problem, R and M Engineers from Ketchikan will be in Wrangell next Tuesday to take a look at it. They will discuss sewer station analysis for five nodes and the force main from node 10. This will help the department prioritize how and what to fix.
