To enhance influent treatment and improve regulatory compliance related to discharge, the City of Torrington required design modifications to its wastewater treatment plant. Trihydro designed a wastewater pre-treatment system to improve operations and allow for future system expandability. 

The City of Torrington’s wastewater treatment system is an aerated lagoon treatment system consisting of a lift station with grinder pumps that convey sewage to three aerated lagoons. Treated wastewater flows from the third lagoon cell to a 14-acre finishing pond, which then discharges to the North Platte River.

Without a pre-treatment system, solids collect in the aeration ponds and the City of Torrington faces continual maintenance costs and operational challenges in removing solids from the lagoons. The City of Torrington identified the need for wastewater pre-treatment processes prior to the lift station and selected Trihydro to design the pre-treatment system. 

Trihydro evaluated pre-treatment options such as grit collection, course screening, and fine screening to capture solids before they enter the treatment system. The final headworks structure was designed to remove large solids, rags, grit, and other sewage debris from entering the treatment process. By reducing the quantity of lagoon organics, the City of Torrington can reduce the frequency of time-intensive and costly sludge removal from the aerated lagoons. Additionally, removing organic solids at the headworks reduces the biological loading on the lagoon system, thereby reducing biochemical oxygen demand (BOD) and total suspended solids (TSS) in the discharged effluent. 

During pre-treatment system design, Trihydro also considered the following elements: 

  • Evaluating ammonia levels in the summer and winter to assess potential system modifications
  • Duplex versus triplex pumping system for the proposed bypass lift station
  • Analyzing components (generator, automatic transfer switch, existing pumps, existing motor control center, and existing control system) to determine if the system could be changed to 3-phase power to increase system efficiency

Trihydro supported the City of Torrington with project funding applications, a field survey, Wyoming Department of Environmental Quality - Water Quality Division and Fire Marshal permitting, and bidding assistance.

In addition to the wastewater pre-treatment system, The City of Torrington plans to install a new pre-engineered building to house their Vactor truck and camera truck. Trihydro designed a water line to provide potable water to the building and completed overall site grading. Trihydro also designed modifications to an existing restroom to comply with American with Disabilities Act (ADA) requirements.  

The project also involved coordinating with several funding mechanisms, including the Clean Water State Revolving Fund, Mineral Royalty Grant, and Water and Sewer ARPA Grants.

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