📋 Tender Overview
Scope : Activated Sludge Process Improvements
PROJECT DESCRIPTION/JUSTIFICATION : This project provides for the design and construction of modifications to the high-purity oxygen-activated sludge basins for the implementation of the MLE nitrification/denitrification process. The MLE (Modified Ludzack Ettinger) process is used for total nitrogen removal and involves an anoxic zone and an aerobic zone. In this process, there is an internal recycle from the aerobic to anoxic zone, which provides nitrate as an oxygen source at the head of the tank. The bacteria remove the oxygen from the nitrate molecule, leaving a byproduct of inert nitrogen gas. The project was originally planned to begin in FY16 with completion in FY21. The WRRC's NPDES permit has since been amended to require an addendum to the Nutrient Reduction Study submitted in 2015. The permit amendment allows the City to research new or additional treatment technologies for the reduction of nitrogen, including the implementation of practices within the watershed for the most cost-effective nitrogen removal technology. The City is required to submit, by January 1, 2022, an addendum to the 2015 Nutrient Reduction Study. The addendum must include an updated schedule for making operational changes and/or installing new or additional treatment technologies to achieve the goal of 66% reduction in total nitrogen. This project is related to Water & Resource Recovery Center: Nutrient Trading.
