In March 2018, the 50-foot digester, the tank that breaks down sludge at the Wastewater Treatment Plant in Delta Township, became plugged. Plant workers could no longer pump into or out of the digester.
The township recommended Merrell Brothers clean out the digester for $168,700.
“We clean them at a routine regular basis,” said Richard Kane, the director of the utility department at the Wastewater Treatment Plant in Delta Township. “This is our fourth or fifth time and this is pretty unprecedented that our crews could not finish this project.”
Since 1984, township staff has cleaned the digesters every five to seven years, according to digester maintenance records. In the late 1990s, plant employees started to notice more disposable cleaning wipes and debris in the digester.
“We’ve seen a lot more of these rags,” said Kane. “They’re great for cleaning, great for projects, I mean, they’ve built these papers to sustain the function and they work wonderful for cleaning and whatnot. Because of their chemical bonding, they do not shred apart and that is part of the problem.”
Normally, the treatment plant has a 50-foot and a 35-foot digester working together to break down the sludge. While the larger digester has been out-of-service since March 2018, the township’s 35-foot digester has been taking on the whole load and is now showing signs of problems, officials say.
“We have dealt with sand in the past, but this is a lot more and it is to the point where it is not only plugging some of the piping, but when we do pump it, it starts to destroy our current plate press,” said Kane.
Sand in sewage comes from several sources including normal domestic sewage, construction sites or wherever water infiltrates into the underground sewage pipes, Kane said. When sand builds up in the digester, it is taken out of service for cleaning. If the 35-foot digester plugs, the plant has limited options of what workers can do with the 25,000 gallons of sludge it produces per day.
“This is a predicament that nearly every community is facing. The use of these rags and wipes that are labeled as ‘flushable’ has increased dramatically,” said Brian Reed, the manager of Delta Township. “The public needs to know these rags and ‘flushable’ wipes such as baby wipes should be discarded in the trash and not flushed.
“The properties in these products do not break down and cause problems and damage at all waste water treatment plants,” Reed said. “Delta is not alone in this and it is going to continue to be a big problem in the future if these products keep ending up in the wastewater route versus the trash.”
Once the plugged material is removed, some of the sludge from the from the digester can be used as fertilizer in agriculture or sent to a landfill for disposal. But the wipes and rag material must be landfilled since it should not be put on the fields, Kane said.
“It just seems kind of shameful that we’re spending that kind of money for something that’s avoidable, and I don’t mean avoidable because the township isn’t doing its job,” said Delta Township Trustee Andrea Cascarilla. “It seems like it’s something that we, maybe, need to do a better job of making residents and property owners aware of.”