Wastewater Pre-Treatment System Design
The City of Torrington partnered with Trihydro to improve its wastewater treatment operations by addressing solids accumulation in its aerated lagoon system. Trihydro designed a new headworks pre-treatment structure to remove grit, rags, and debris before wastewater enters the lagoons, reducing maintenance costs and enhancing treatment efficiency.
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 before solids reach the lift station and selected Trihydro to design the system.
Evaluating Solutions to Improve Operations
Trihydro evaluated pre-treatment options such as grit collection, coarse 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
- Comparing duplex versus triplex pumping systems 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
Supporting Project Delivery and Enhancing Infrastructure
Trihydro supported the City of Torrington with project funding applications, a field survey, permitting, bidding assistance, and construction administration and observation services.
In addition to the wastewater pre-treatment system, the City of Torrington plans to install a new pre-engineered building to house its Vactor truck and camera truck. Trihydro designed a water line to supply potable water to the building and completed overall site grading. Our team also designed modifications to an existing restroom to meet Americans with Disabilities Act (ADA) requirements.
