Joint Centerfield – Gunnison sewer project still in first phase, as engineers try to measure expansion needs

By Robert Stevens and Gage Schluseer

Staff writers

9/4/2019

A plan to upgrade the sewer system shared by Centerfield and Gunnison City is moving forward, but with some changes from the original plan.

In an interview with the Messenger, Garrick Willden, an engineer with Jones and Demille, explained the scope of the improvements.

The current and first phase of the project is meant to address several problems.

The first issue is accurately metering the sewage going into the sewer lagoon shared by Gunnison City and Centerfield City.

Willden says the metering issue creates a problem because it makes it hard to tell how well the lagoon is functioning and at what rate the amount of sewage is increasing each year.

“It’s important to have those measurements as a city to know what your expansion needs are and if you are reaching capacity,” Willden says.

The inability to meter is caused by the conjoined sewer system and the effect Centerfield City’s sewer output has on the Gunnison City meter.

When Centerfield’s sewage gets pumped through to the pipe where Gunnison and Centerfield sewers meet, it causes a backflow up the Gunnison City sewer pipe. That influx of reversed sewage throws off the meter and produces inaccurate readings, Willden says.

Willden plans to install a meter that measures the sewage flow velocity and levels with the aid of a laser. By installing the laser meter upstream a ways from the current meter, it will prevent inaccuracy in readings.

Another problem plaguing the Gunnison City sewer system is trash getting into it. Willden says this is in part due to a large amount of trash that comes through the sewer pipes at the Central Utah Correctional Facility, but also from trash being flushed down the drains of homes and businesses in Gunnison.

Although the sewer project originally planned to install an automated screening system to reduce the trash problem, Willden is now suggesting a manual system, which will not only save money, but the manual cleaning will help them understand the amount and type of trash coming down the pipe. That information will help them decide on any further action.

The original plan for the automated screen was going to set Gunnison City back more than $100,000, but the manual screening system will only cost about $3600 says Willden.

The third issue Willden is trying to solve is the strong odor that has become prevalent along the main Gunnison City sewer line, which effectively begins at the prison and runs through town until it reaches the lagoon.

Willden says he needs to speak with Gunnison prison officials to better understand their sewer system. If the problem with the smell comes from the main sewer line, it will require a different approach to combat than if the problem stems from prison sewage being held too long in a holding tank, causing it to run out of oxygen and go septic.

Willden says after these three problems are addressed, they will begin work on a next phase of the project, which will split the sewer lagoons in compartments that can be individually isolated, allowing for easier cleaning and maintenance of the lagoon.

“Construction on phase one of the project is set to begin soon” , Willden says.