Drying for the Future: Selecting the Right Technology for Rogers Water Utilities

Introduction and Objectives Rogers Water Utilities (RWU) initiated Phase II of its Solids Handling Facility Improvements to replace an aging biosolids dryer that had become unreliable, difficult to maintain, and unable to meet future solids production needs. The Rogers Pollution Control Facility (RPCF) operates a three train oxidation ditch activated sludge process, producing waste activated sludge (WAS) that is dewatered to roughly 20% solids and heat dried to over 90% solids for beneficial use as a Class A, Exceptional Quality (EQ) biosolids product. While the existing process consistently meets regulatory standards, persistent equipment failures, obsolete components, and significant downtime created operational risk and limited the facility's ability to manage increasing loadings. Solids production is projected to grow from approximately 5.1 dry tons per day (2020 annual average) to 12.5 dry tons per day by 2045 maximum month conditions, requiring a new system capable of handling higher evaporation rates while maintaining a safe and stable Class A/EQ product. Additional constraints-including the need to interface with recently upgraded conveyance and dewatering systems, accommodate the existing dried product storage silo, and preserve continuity of operations during construction-added complexity to the challenge. At the same time, RWU sought to address workforce efficiency, reduce maintenance burden, and ensure resilience in the face of regulatory trends such as nutrient management requirements and emerging PFAS considerations. Selecting reliable, maintainable, and scalable drying technology became essential for supporting long term biosolids management for the growing Rogers community. Approach to Solution RWU and the project team conducted a structured evaluation of drying technologies to determine the most suitable solution for long term solids management. The team developed solids projections, established dryer sizing criteria based on anticipated 2045 maximum month loadings, and evaluated multiple drying options-including belt, paddle, rotary drum, fluidized bed, and tray dryers-using technical workshops, reference facility interviews, and site assessments as shown in Figure 1. A detailed technology screening narrowed the field to three manufacturers for deeper evaluation: HUBER (belt), Gryphon (belt), and Wyse (tray). Each vendor received a Request for Information (RFI) outlining required throughput, Class A performance, redundancy, and integration with existing processes. Vendor responses were analyzed for drying performance, energy consumption, operating temperature, air handling requirements, capital cost, O&M demands, installation footprint, and compatibility with RWU's two shift operating model. All three options were considered for piloting and testing, however, one of the three backed out of the process. With only two potential technologies and based on this assessment, HUBER and Wyse advanced to 15% design to support CMAR cost estimating and constructability review. Field visits to operating facilities provided further insight into real world maintenance needs, product quality, safety systems, operational complexity, and manufacturer responsiveness. These observations, combined with paired matrix scoring across RWU's prioritized criteria-system flexibility, product quality, intermittent operation capability, maintenance history, experience, and manufacturer support-enabled a clear and objective comparison of the candidate systems. A present worth analysis evaluated 20 year life cycle costs to further support decision making. Conclusion and Recommendation The paired matrix evaluation identified HUBER and Wyse as the highest scoring technologies, each demonstrating strengths aligned with RWU's goals. To differentiate between these options, RWU applied a 20 year present worth analysis covering capital cost (provided through the CMAR process), installation needs, and operating expenses. The HUBER belt dryer system demonstrated a lower life cycle cost, driven by reduced capital requirements, lower operating temperature, and more efficient energy use. Technical evaluation further supported HUBER's selection. The system offers greater automation, enhanced control capabilities, stainless steel construction as standard, and broader operational experience, with multiple U.S. municipal installations. Site visits confirmed reliable performance, strong manufacturer support, and favorable operator feedback. The low temperature drying process (205°F) also aligns with RWU's goals for safety, maintainability, and compatibility with odor control strategies. While both HUBER and Wyse could produce a Class A/EQ product meeting regulatory requirement, HUBER's advantages in experience, support infrastructure, product consistency, and long term cost made it the preferred solution. RWU selected the HUBER belt dryer system for Phase II implementation. The project has advanced into CMAR led construction and is expected to provide improved reliability, reduced maintenance burden, and sustained biosolids quality to support long term operational resilience. The components of the Huber Dryer are shown in Figure 2. The Dryer will be operating in the late Summer of 2026.