Project Highlight: City of Northglenn - WWTP Headworks & Clarifier Project • Providence Infrastructure Consultants

ACEC Colorado 2019 Engineering Excellence Awards

Providence and the City of Northglenn are the proud recipients of an Excellence Award for the ACEC Colorado 2019 Engineering Excellence Awards. On this page you’ll find links to all related materials for this project and the award.

Executive Summary

The main purpose of the Northglenn Wastewater Headworks and Clarifier Project was to remove from service, and decommission, the primary lagoons. The lagoons, in some respects, had functioned as a debris trap. Because of this, removing them from service required construction of a headworks facility to prevent inorganic debris and trash from accumulating in the activated sludge biological nutrient removal (ASBNR) process basins, which were constructed and brought online in 2005. The City desired to decommission the lagoons for several reasons:

The City had experienced numerous complaints from nearby neighbors about the odors from the WWTP, and the situation became a local news story. The City was committed to reducing odors emanating from the WWTP, which meant targeting the odors emitted from the lagoons.
The lagoons were removing organic carbon that the ASBNR process needed for optimum performance.
Aerating the lagoons demanded a significant amount of energy. Discontinuing use of the lagoon blowers and aerators would result in impressive electricity cost savings for the City.
The lagoons were not effective as a “headworks facility” for removing inorganic trash and debris. As a result, an endless and immense amount of trash and debris accumulated in the ASBNR basins. This was costly and time consuming to remove. The new headworks facility would be much more effective at removing inorganic trash and debris, and the City would experience major operational and maintenance (O&M) benefits.
In addition to replacing the lagoons with a new headworks facility, a third secondary clarifier and back-up electric generator were installed to provide redundancy and operational flexibility. All of these improvements provided the City with a treatment facility that is far less odorous and much more flexible to operate.
The project used a Construction Manager-at-Risk (CMAR) and was completed about 3 months ahead of schedule. The project cost also finished $1.26 million below the project budget.