An externally-fired rotary kiln furnace system has been evaluated for cost-effectiveness in carbon reactivation at the Pomona Advanced Wastewater Treatment Research Facility. The pilot scale rotary kiln furnace was operated within the range of 682 kg/day (1,500 lb/day) to 909 kg/day (2,000 lb/day). The rotary kiln furnace was found to be as effective as the multiple hearth furnace in reactivating the exhausted granular activated carbon. The operating and maintenance of the rotary kiln system required less operator skill than the multiple hearth furnace system. However, the corrosion rate was higher in the rotary tube than in the multiple hearth furnace. Cost estimates based on a typical regeneration capacity of 182 kg/hr (400 lb/hr) have been made for both rotary kiln and multiple hearth furnace systems. These indicate that the capital cost for the multiple hearth furnace is about two times that of the rotary kiln furnace. The operation and maintenance costs for both furnace systems are similar. The overall process costs for the multiple hearth and rotary kiln furnace systems are estimated to be 33.2 cents/kg (15.1 cents/lb) of carbon regenerated and 29.2 cents/kg (13.3 cents/lb) of carbon regenerated, respectively.

Prepared for U.S. Environmental Protection Agency, Office of Research and Development, Municipal Environmental Research Laboratory, Cincinnati, Ohio, submitted by the County Sanitation Districts of Los Angeles County, under contract no. 14-12-150. Includes bibliographical references (page 35).