Effluent Force Main Evaluation/Study for WWTP No. 3

Trigon was selected by the City of Kenner (COK) to perform engineering services to identify and evaluate alternatives to enhance the reliability of the existing effluent force main through which treated wastewater is discharged from the Kenner Wastewater Treatment Plant No. 3 (WWTP) to the Mississippi River (River). The existing effluent force main is 48-inches in diameter and is approximately 30 years old.

The Effluent Pump Station within the WWTP was being upgraded around the time of this project and would modify the pumping strategy to the effluent force main, so that was considered as part of the evaluation. The area of greatest concern along the force main route was where it travels under the Louis Armstrong New Orleans International Airport property, particularly an active runway.

Trigon was contracted to evaluate options for redundancy of the force main so that an unforeseen breakage would not leave the COK unable to discharge to the Mississippi River nor cause an unplanned disruption of airport operation that would be very costly and possibly shut down the critical east-west runway.

The initial phase of this project resulted in Trigon submitting a Summary Report that included five (5) possible alternatives for adding reliability to the force main, and three (3) of these options were recommended for further investigation. The second phase of the project included further evaluation and presentation of the results to the COK for the following options, including opinions of probable construction cost (OPCC):

• Replace existing force main along entire route
• Replace existing force main from WWTP to past airport
• New force main section around airport