Glass Aggregate Technology

Minergy Corp. Develops Innovative Technology


Internal View of Cyclone Melter

Wastewater treatment systems, both industrial and municipal, produce large quantities of sludge that require disposal. Unfortunately, sludge disposal poses significant environmental liabilities, logistical problems and economic burdens.

Minergy Corp. has developed an innovative technology which recovers the mineral content of the sludge and transforms it into a useful glass aggregate product. This industrial material is used in sandblasting grit, abrasives, roofing shingle granules and cement additive.

The glass aggregate process meets all applicable government regulations for air quality and solid waste management. Organic compounds in the sludge are destroyed in a high-temperature, high-retention mixing environment. Trace metals present in the sludge are permanently stabilized in the product. And water leach tests of the final product meet primary and secondary drinking water standards.

Sludge plays two beneficial roles when it is processed in this way. First, its organic component provides a significant portion of the energy required for the process. These organics are considered a biomass fuel that is renewable through the cycle of water use and wastewater treatment. Second, the mineral content (ash, clay and mineral fillers) of the sludge is put to beneficial use.

At the heart of the technology are two (2) 7-foot-diameter cyclone furnaces in which sludge is co-fired with auxiliary fuel (coal or natural gas) and ambient air. The technology features two significant modifications to the standard cyclone furnace design:

  • Introduction of fuel into the cyclone using four (4) tangential secant ports on each cyclone.
  • The lower furnace of the steam generator is specially designed to maintain high temperatures to allow the molten slag to run down the lower furnace walls and through the discharge opening in the lower furnace floor.

The Glass Aggregate process offers many environmental and economic benefits to municipal wastewater treatment systems, paper mills and surrounding communities. These benefits include reducing long-term dependence on landfill disposal, providing residents and local industries with a cost-effective alternative for managing sludge, and providing public agencies with a more comprehensive and integrated approach to solid waste management.

In addition to manufacturing a marketable product, the Glass Aggregate Technology provides a complete solution to the disposal problem of sludge. Many other disposal technologies, including incineration, make significant quantities of ash or other waste that continue to pose disposal problems.

Fox Valley Glass Aggregate Plant

Minergy developeded the world’s first facility in Neenah, Wis., U.S.A., to recycle sludge into glass aggregate. Several paper mills in the area supplied the plant with paper sludge. The Fox Valley Glass Aggregate Plant is designed to receive and process up to 1,300 tons per day (450,000 tons per year on an as-received basis) of paper mill sludge with a moisture content of up to 60%.