City of Westminster Big Dry Creek WWTF | HDR Dewatering Project Earns Envision Bronze Verification

HDR Dewatering Project Earns Envision Bronze Verification

A dewatering project near Denver has achieved a special distinction for its beneficial contributions to sustainable infrastructure.

The City of Westminster's Big Dry Creek Wastewater Treatment Facility Dewatering project earned an Envision® Bronze verification. The facility is designed for biochemical oxygen demand removal, nitrification and denitrification, and limited phosphorous removal. The project provides the city with new solids dewatering equipment and facilities, an improved central handling system, enhanced nutrient removal, biosolid beneficial use optimization at the city’s farm, operational optimization and campus-wide improvements throughout and around the facility.

This project is the first Envision achievement for Westminster. By using Envision on this project, the city is affirming its commitment to sustainability and the use of Envision as an important tool to improve the sustainable performance of its infrastructure assets.

The city worked closely with HDR on the project. “Sustainability and safe, reliable service are top priorities for our residents and will be a continued focus of our strategic infrastructure investments,” said Max Kirschbaum, City of Westminster’s public works and utilities director.

The Envision framework assesses project sustainability across five categories: Quality of Life, Leadership, Resource Allocation, Natural World, and Climate and Resilience. These areas contribute to positive social, economic and environmental impacts on a community during the planning, design and construction of infrastructure projects.

Key factors contributing to the treatment facility's bronze verification:

Pursuing byproduct synergy opportunities Biosolids are a byproduct of the wastewater treatment process. Because they are nutrient rich, they can be used as fertilizer to increase crop yields. However, the Environmental Protection Agency reports that only 50% of all biosolids in the U.S. are captured and put to beneficial use, with the remaining 50% sent to landfills or incinerated. One of the main purposes of the BDCWWTF Solids Dewatering Project is to reduce the water content and nitrogen load of the city’s biosolids. As a result, more biosolids from the city’s wastewater treatment processes can be used as fertilizer by the city’s Strasburg Natural Resource Farm and other contracted farms nearby. 

Improving efficiencies and saving costsBy reducing the water content of biosolids and allowing more material to be applied to the same acreage, the city is able to reduce the number of truck trips to the SNRF and other contracted farms by 75%. The effect is a more efficient use of employee time and reduced storage requirements at the site when farmland is unavailable for biosolids application.

If not for this project, it's anticipated that by 2035 an increase of biosolids produced at the facility would lead to significant composting expenditures, further burdening utility ratepayers. Instead, this project will lead to savings of $100,000 per year, ensuring ratepayers are not unduly burdened in the future.

Extending the life of the projectThe Solids Dewatering Building — a key component of this project  was designed with future loading in mind, reducing the need for a redesign in the near term, and leading to reduced maintenance spending. In addition to the design and construction of the building, other campus-wide improvements and updates provide flexibility, durability and resiliency for the facility.



Institute for Sustainable Infrastructure

Dyan Lee, Director of Marketing and Communications


Jennifer Ninete, Senior Sustainability Consultant


About the City of Westminster: Westminster, Colorado, is a thriving community of safe neighborhoods and beautiful open space located in the heart of the U.S. 36 Tech Corridor connecting Denver to Boulder. The city maintains a $4 billion utility system including over 900 miles pipe and four treatment facilities serving over 27,000 utility accounts. For more information, visit

About HDR: For over a century, HDR has partnered with clients to shape communities and push the boundaries of what’s possible. Our expertise spans more than 10,000 employees in more than 200 locations around the world — and counting. Our engineering, architecture, environmental and construction services bring an impressive breadth of knowledge to every project. Our optimistic approach to finding innovative solutions defined our past and drives our future. For more information, please visit

About ISI and Envision:  Envision is the product of a joint collaboration between ISI, which was founded by three national engineering associations: American Society of Civil Engineers, American Council of Engineering Companies and American Public Works Association; and the Zofnass Program for Sustainable Infrastructure at Harvard University Graduate School of Design. For more information, please visit