Expanding the Capacity of a Controlled Discharge Lagoon System
The Iowa Woodward Resource Center’s wastewater treatment facility was experiencing incoming hydraulic loads that exceeded the capacity of its controlled discharge lagoon system. As a result, the treatment system was struggling to achieve wastewater storage requirements of 180 days.
The project began with a review of existing and future treatment requirements, analysis of existing facilities, and an evaluation of lagoon alternatives. During the investigation, it was determined that efforts to reduce inflow and infiltration along with a significant expansion of the three-cell controlled discharge lagoon would be necessary to meet treatment requirements long-term.
The removal of roof drains and downspouts on buildings in the area was key to addressing inflow and infiltration. Manholes were also repaired or replaced depending on condition. Targeted sections of the collection system were lined to improve performance.
The existing influent lift station was upgraded. This included replacing two 400 gallon-per-minute (gpm) influent pumps with 800 gpm pumps controlled by Variable Frequency Drives (VFD). The pump station was also equipped with larger force main piping to achieve capacity needs.
Significant earthwork was necessary to increase hydraulic capacity with a new primary lagoon cell. New control structures were also included with the project to help manage water flows.
Key project accomplishments include:
- Reduced inflow and infiltration
- Increased pump station capacity
- Improved structures
- Increased hydraulic capacity