Construction, Infrastructure Improvements

A Growing City Means Growing Treatment Plants

When you reflect on jobs that people are passionate about, wastewater treatment plant operators aren’t usually at the top of that list. However, the passion was palpable as I spoke with three employees at the Mallard Creek Wastewater Treatment Plant, which is currently undergoing updates and expansion due to our growing community. They have a deep understanding of the importance of the work they are doing in the community and how it contributes to the growth of the area and our current quality of life.

An architect’s rendering of the new influent pump station and equalization tank.

If growth in the area was allowed to outpace the development of the sewer infrastructure, it would cause a very messy problem for the city. Development can only occur where there is the infrastructure to support it. As the University area continues to grow quickly, the infrastructure must be built and updated to meet the increase in demand. Recent studies have shown that for every one million dollars Charlotte Water invests into its utilities and infrastructure, it leads to 17.7 million dollars in economic output. Investment in our infrastructure allows the kind of growth that protects our quality of life.

As such, the Mallard Creek Wastewater Treatment Plant has several updates and additions planned over the next eight years. The original facility was built in 1979 and has been expanded over time. The original buildings are still in operation, but some of the equipment and buildings need to be replaced. By updating the facility, the plant will grow and have increased capacity and efficiency. The current facility handles 12 million gallons per day, however, when all the updates are completed, the plant will be able to handle 16 million gallons per day!

One concern of an expanding wastewater treatment plant for many is the odor. One goal for the updates is to increase odor control so that the plant isn’t a nuisance. As many would imagine, before touring this wastewater treatment plant, I had mentally prepared for a strong odor throughout the facility. However, I was pleasantly surprised that the odor was mostly contained to the part of the facility where the wastewater entered untreated. Throughout the rest of the facility, I wouldn’t have known that I was standing so close to millions of gallons of wastewater.

This is where sewage is strained of larger pieces of garbage before entering the rest of the plant. This equipment is being replaced. It will be covered to help with odor control.
This is the pump house, built in 1979 with various changes made over the years. This building will also be replaced with new pumps and a new building to accommodate the new pumps.

These ad hoc additions over the years left the facility with a mismatch of equipment of assorted sizes and capacities. For example, right now there is an assortment of pumps that have been added over the years of all different sizes. This makes redundancy difficult. Redundancy is the ability of the other pumps to handle the extra flow when one pump is down for maintenance. By replacing the pumps with six new pumps that are all equal in size and capacity, the strain on individual pumps is lessened, and their capacity to handle maintenance issues is increased.

This is the day tank that assists the plant in managing capacity during times of fluctuating flows.

Another portion of this project is the equalization tanks that are being added. One that handles five million gallons and another that can hold 15 million gallons. Throughout the day and night, the flow of sewage coming into the plant varies; the equalization tanks hold flow during the higher flow times to even the flow into the plant. This reduces the strain on the equipment and makes testing more accurate. The smaller tank handles day-to-day variations while the larger tank handles large storms and flooding. These tanks also allow the plant to temporarily shut down sections of the plant for updates and maintenance.

The location of the new equalization tank. Charlotte Water and its contractors will be digging 65 feet under the ground to place the influent pump station which will be adjacent to the equalization tank.

Many systems and buildings within the plant will be touched by at least one phase of the project. There are four phases, with phase one being launched by the end of 2022. Most of the work of phase one will begin in 2023 with plans to be completed by the end of 2026. 

It is easy to ignore or not even consider how much work goes into keeping our city clean and sanitary for the more than one million people (and counting!) who live here. As we continue to grow, we are grateful for the City employees who plan for and accommodate the continued growth of our city. There is a lot of work that goes into planning and sustaining the foundation that keeps Charlotte running.