Problem: The Madison (Wisconsin) Metropolitan Sewerage District in Wisconsin faced disruptions and high maintenance for direct steam injectors in its acid-phase digester system. The 12-year-old injectors could no longer handle the increasing volume and variability of foreign material in the process stream. Frequent plugging and fouling caused by solids larger than two inches meant two three emergency work orders per week.
Solution: The district chose the Hydro-Thermal NOH system (Energenecs), designed to allow particles up to four inches to pass through. The straight flow-through design minimizes clogging, and its compact footprint allows it to be installed in the existing skids with minimal modification. The heaters use direct steam injection to heat the solids at nearly 100% thermal efficiency.
Result: The district experienced immediate improvement. Maintenance related to plugging was eliminated. “The unit has run reliably with no failures,” says Erik Rehr, maintenance and reliability manager. Smooth operation meant lower operating cost, fewer interruptions and more time for preventive maintenance. 800-952-0121; www.hydro-thermal.com
