Council has decided to proceed with the tender process for a new aeration system at the wastewater treatment plant, which is expected to cost at least $346,000.
At the same time, council has also decided to forego the removal of sludge in the main cell (number two) – at least until the spring.
At a special meeting of council on July 10, Bob Mayberry and Steven Nutt, from R.J. Burnside and Associates, provided an update on the aeration system.
“The question has come up as to whether or not this would be an appropriate time to remove the accumulated biosolids [from cell number two],” Mayberry told council.
He explained the removal would likely have to take place within five years anyhow.
Nutt said the sludge at the bottom of the main cell ranges in depth from about 15 centimetres in the middle to 35cm in the corners. He does not consider that a huge amount because the lagoon has been in operation for about 25 years, but he told council there is some risk with delaying the sludge removal.
“The question is if you’re willing to take that risk,” he said. “Sooner or later, it’s going to have to be done.”
There is a possibility that after the installation of the aeration system, the sludge could be agitated and transferred to cell number one.
But considering sludge in that cell ranges from just 6cm to 15cm, Nutt and Mayberry don’t see that as a big problem, because both cells could be cleaned out once the new cell (number four) comes online.
“The new cell will definitely provide more operational flexibility, there’s no doubt about it,” Mayberry said.
The problem is, in order to remove the sludge from a cell it must be isolated, with no new effluent coming into it. R.J. Burnside does not have an estimate on the cost of removing the sludge, but Minto paid nearly $400,000 for a similar job.
One thing seemed to be certain: the sludge removal will be more complicated – and thus, likely more expensive – if the new aeration system is already installed.
“It’s a little more labour intensive than the other options,” Mayberry said.
He also noted doing the sludge removal prior to the aeration system would mean about 20 years of uninterrupted operation, with electricity costs about half of what they would be if the sledge removal was not completed.
“It sounds like a spring project to me,” Mayor John Green said of the sludge work.
Councillor Jim Curry said he would like to see the issue resolved before spring, when the township annually applies for a discharge into the Conestogo River.
Nutt said assuming the township will be spreading the biosolids on local fields, the sludge removal would likely have to wait until at least fall because most farms are currently full of crops.
Mayberry said council could delay both the aeration system and sludge removal until the spring.
Yet clerk Patty Sinnamon wondered if delaying the aeration installation until next year would have an effect on spring discharge. She also asked how the delay would look to the Ministry of the Environment.
About a year ago the MOE ordered the township to submit a “wastewater management contingency plan” because the ministry “did not concur” with the township’s emergency discharge in May 2008.
The new aeration system in cell number two – as well as the construction of a brand new lagoon cell with a capacity of about 115,000 cubic metres – formed part of that plan, which was submitted by R.J. Burnside last July.
Nutt said the new aeration system may not improve the quality of effluent enough to secure spring discharge approval anyhow, but the biggest issue is quelling MOE concerns.
Council voted unanimously in favour of a resolution directing R.J. Burnside to prepare a tender package for the installation of a “FlexAir” aeration system, which was previously valued at a minimum of $346,000.
Mayberry said the project could go to tender by the end of July, for a “later summer or early fall” installation.
