Wastewater Treatment Plant 

 Clarifier Weir
Williams Monaco Wastewater Treatment Plant

The District’s Williams Monaco Wastewater Treatment Plant is located at 9702 Monaco Street in Henderson, Colorado. Over 300 miles of sewer lines collect wastewater generated in the District and deliver it to this location for treatment.

Construction and Upgrades

Originally constructed in the 1950s, the plant has undergone a series of expansions and upgrades over the years. These improvements were necessary not only due to growth in the District, but to meet increasingly strict state and federal regulations. 

A plant expansion project is currently underway. This project will convert the existing moving bed bio-reactor (MBBR) to an integrated fixed-film activated sludge process. This new process will allow the plant to meet State of Colorado discharge permit limits for ammonia and nitrogen. It will also be configured so that phosphorus can be removed from the wastewater using biological processes. 

Other components of the current plant upgrade project include installation of a state-of-the-art grit removal system. Removal of grit from the incoming wastewater protects pumps and maximizes efficiency throughout the treatment process. UV disinfection facilities will also be constructed. This change to UV disinfection is a safer alternative to chemical disinfection. 

Present and Future


This project is the latest step in the District’s continuing effort to keep pace with the needs of its customers. Planning is already underway to determine the District’s next step to meet future demands in the area of wastewater treatment. 

Aerated Basin