City working on wastewater upgrade; public hearing Oct. 8
Monticello residents can learn more about the city’s plans for wastewater treatment plant improvements by attending a 7 p.m. public hearing Monday.
The estimated costs for the facility improvements range from $15,000 to $6.2 million, depending on which options are approved by the city council.
City Engineer Bruce Westby said a project feasibility report will be presented to the public and reviewed by the city council as part of the Oct. 8 public hearing.
If completed, the proposed facility improvements will address pending biosolids management issues and help the city reduce its wastewater treatment costs.
Biosolids are nutrient-rich by-products of wastewater treatment that can be used as a fertilizer and soil conditioner or removed to a landfill or incinerated.
“We’re primarily looking at dewatering improvements and energy efficiency,” Westby said.
“If approved, those improvements will save us money over time.” Westby said if pumps fail at the front of the plant, the city only has about 9 minutes of reaction time until potential sewage backups occur on Mississippi Drive.
“It’s an issue we have to address,” he said. “We’re also looking at our headworks. Right now, we’re not screening things out of the wastewater until after it’s gone through some of our pumps.” Material should be screened before the pumps are used so the pumps don’t get clogged up and wear out, he said.
The low-range cost for the improvements ($15,000) would only address old heat pasteurization equipment removal and open up storage, Westby said.
“If you did everything, it would cost $6.2 million,” he said. “Staff is recommending dewatering and energy efficiency improvements as part of a Phase I project.”
According to Westby, the city wants to reduce its biosolids down to about 16 percent solids, removing enough water to get the sludge to a consistency so it can be moved to a landfill or hauled to a regional drying facility. “If we don’t do the dewatering, the city will have to start buying more land for application,” Westby said.
According to Westby, the headworks and miscellaneous site improvements would also provide immediate and long term benefits to the city.
However, those two improvements could be deferred until a later date if Monticello council members decide to minimize the cost of the wastewater treatment plant improvements.
Financing sources for the wastewater treatment facility will be determined after the city council actually orders the project, Westby said.
Estimated costs for the proposed facility improvements are as follows: Biosolids dewatering; $1.8 million; energy efficiency, $700,000; headworks, $3.6 million and miscellaneous site work, $85,000.
“What we’ll do Monday night is ask the council to accept the feasibility report,” he said. “Once that’s done, staff can order plans and specifications.”
Westby said the energy efficiency improvements are currently eligible for rebates and would result in reduced energy costs.
City staff has met three times to discuss the wastewater improvements with Cargill Kitchen Solutions, since portions of the wastewater improvement project will be assessed to significant industrial users.
“We’re still talking to Cargill,” Westby said. “We’re locked into an existing agreement where they pay for some cost improvements, but those were based on our current treatment process. “If we switch to a new process, the city will be looking at something different, and negotiating with them on how we roll those costs into the new process.”
The city’s existing agreement with Cargill calls for the company to pay $464,000 for new storage tank construction.
That figure is based upon a 2001 construction estimate. Cargill currently produces about 26 percent of the plant’s biosolids.