RFB-27-2015 - 75th St Wastewater Treatment Facility Nitrogen Upgrades Project

Summary of Specifications:
The primary elements of the project, identified as base bid items, include aeration basin modifications (structural, mechanical, electrical, and controls upgrades to reconfigure three existing MLE process basins to a 4-stage Bardenpho process), and construction of a new external carbon storage and feed (ECSF) facility housing three 6,000 gallon holding tanks for acetic acid and brewery waste. The new ECSF Building is a one-story process building, internal dimensions of 30 feet by 50 feet (1,500 sf). A final base bid element is to replace the existing membrane tube diffusers in the existing solids contact tanks (SCT) with ceramic disc diffusers. In addition to the base bid elements, three bid alternates are included: 1. Conversion of an existing 70-foot diameter predewatering storage tank to a post aerobic digester (PAD) to decrease the ammonia concentration in centrate (mechanical, electrical, controls, and minor structural modifications), 2. Improvements to the existing centrate return control strategy, and 3. Addition of a bypass pipeline (18-inch diameter) around the primary sedimentation tanks.