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Increased Water Quality Standards Require Innovative Solutions

As the waste stream generated by modern society grows larger and more complex, preserving¬†public health and the natural environment requires thoughtful improvements in wastewater engineering and treatment processes. Located in southeast Iowa, the City of West Burlington required just that remedy when their wastewater facility was notified their current treatment methods didn’t meet the state’s updated water quality standards.

Significant facility upgrades were necessary to meet National Pollution Discharge Elimination System (NPDES) compliance regulations about treating ammonia-nitrogen, E. coli, and dissolved oxygen limits. To spearhead this effort, the wastewater professionals with Snyder & Associates provided complete wastewater facility planning and design services and administered all aspects of construction management.

Extensive Facility Improvements Lead to NPDES Compliance

The original city-owned treatment facility included a gravity sewer main, lift stations, and a combination of an activated sludge wastewater treatment plant and a three-cell aerated lagoon. While this facility configuration effectively treated the community’s wastewater for many years, this process didn’t account for increased capacity and stringent regulation updates.

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One of several aeration chambers is included in an Aero-Mod system, where the air is cycling on and off before entering a clarifier.

The project included the construction of a new headworks building with grit removal and screening, a process the old facility didn’t previously contain. An ultraviolet (UV) disinfection system was included to treat E. coli concerns. Using the latest in Aero-Mod, Inc. technology and controls, the physical upgrades provided more efficient aeration equipment, blowers, and nutrient removal. The construction of a cast-in-place tank consisting of four aeration basins, four clarifiers, and two selector tanks significantly increased the plant’s total capacity.

Two of the existing aerated lagoon cells were converted to equalization basins to minimize the sizing of the mechanical treatment equipment, while the other became a stabilized sludge storage space. This transition made the plant 100 percent treated by activated sludge. The activated sludge process uses many organisms to aerobically treat wastewater and remove biodegradable organics from municipal and industrial wastewater. This process was determined to be the best fit for West Burlington as it resolved the ammonia-nitrogen and nutrient complications.

Improvements also included new controls and electrical upgrades, rerouting subsurface piping, and installing a standby generator. Our team created a design that kept all the upgrades confined to the existing wastewater treatment plant property.

Thoughtful Modifications & Efficient Planning Reduces Project Budget

With input from city staff and leaders, Snyder & Associates designed this treatment facility with an eye toward future growth in the city and the potential for increased nutrient reduction requirements. Our team’s foresight to plan for both eventualities saved the city countless hours of planning and construction.

Additionally, utilizing much of the existing wastewater system and simply modifying it to meet the new regulations minimized the required upgrades, creating lower overall project costs. Once crews completed construction, the project’s total cost was nearly $1 million under the proposed budget. The Snyder & Associates team is proud to provide efficient designs that keep communities compliant with ever-changing regulations and within the means of an ever-tighter city budget.