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Central Valley, UT

Composting sewage residuals (989)

FROM BIOSOLIDS TO CLASS A COMPOST

The Central Valley Water Reclamation Facility (CVWRF) in Salt Lake City, UT, developed a state-of-the-art, 13-pile in-vessel covered aerated static pile composting facility. The facility is designed to process up to 150 tons per day of biosolids and sludge through contained composting. Approximately 30% of the dewatered biosolids produced at CVWRF are mixed with wood chips and composted into ‘Exceptional Quality’ Class A compost, which is sold to the public for landscaping and horticultural applications.

CVWRF uses MOR-Bioworks’ in-vessel aerated static pile composting method to ensure that its biosolids meet the U.S. EPA’s Class A – Exceptional Quality (EQ) standard, the highest rating for biosolids products. The Exceptional Quality rating signifies that the biosolids not only meet but exceed all regulatory Class A requirements.

The design-engineering-supply team provided an integrated solution, which included:

  • Specialized semi-pervious ePTFE bio covers supplied by Stedfast-MOR for enhanced environmental protection, trapping odors and moisture eliminating upwards of 90% of the VOC which are the source of undesired odors, and achieving the required pathogen reduction goals in minimal time.
  • The Airfloor® aeration and leachate collection system is engineered to optimize both airflow and moisture management, crucial for maintaining ideal composting conditions. Ensuring uniform aeration—especially in long static piles—is essential for controlling temperature and moisture throughout the composting process. The combination of variable speed blowers and the precise sizing of Airfloor plenums accommodates a wide range of airflow demands. During commissioning, the Airfloor system underwent smoke testing—a first for the composting industry—which demonstrated excellent air distribution across the full 165-foot length of the piles.
  • An integrated aeration management system with temperature feedback, ensuring precise control of composting conditions for maximum efficiency and quality output.

This comprehensive approach ensures CVWRF’s composting operations are both environmentally responsible and highly efficient.