FEASIBILITY TESTING OF A COAL FIRED WASTEWATER SLUDGE ASH VITRIFICATION SYSTEM

THE INCINERATION OF SLUDGE FROM MUNICIPAL SEWAGE TREATMENT PLANT WASTEWATER STREAMS PRODUCES AN ASH THAT MUST BE DISPOSED OF SAFELY. ASH FROM THESE FACILITIES IS PRODUCED AT RATES RANGING FROM 10 TO 100 TONS PER DAY, WITH DISPOSAL COSTS AVERAGING $100 TO $150 PER TON. IN SOME LOCATIONS, THE CONCENTRATIONS OF METALS IN THE ASH IS SUFFICIENTLY HIGH TO CLASSIFY THE ASH AS A HAZARDOUS WASTE. ADDITIONALLY, THE VOLUME OF SLUDGE INCINERATOR ASH, FUGITIVE DUST EMISSIONS FROM ASH PILES, AND THE COST OF DISPOSAL ARE KEY ISSUES FACING THE MUNICIPALITIES THAT OPERATE THESE PLANTS. TO TREAT SLUDGE INCINERATOR ASH, THE DEVELOPMENT OF AN ADVANCED COAL-FIRED COMBUSTION/MELTING SYSTEM THAT WILL PRODUCE A NONHAZARDOUS VITRIFIED PRODUCT, REDUCE THE ASH VOLUME, ELIMINATE DUSTING, AND REDUCE DISPOSAL COSTS IS PLANNED. THIS TECHNOLOGY IS BASED ON AN ADVANCED COAL-FIRED GLASS MELTING PROCESS HEATER BEING DEVELOPED WITH SUPPORT FROM THE U.S. DEPARTMENT OF ENERGY. PHASE I OF THIS PROJECT INVOLVES THE FEASIBILITY TESTING OF THE VITRIFICATION PROCESS ON A SCALE OF 10 TO 15 TONS PER DAY. THE PROCESS PRODUCES A VITRIFIED (GLASSY) MATERIAL SUITABLE FOR USE AS AN AGGREGATE IN ROAD PAVING OR VARIOUS MUNICIPAL PROJECTS AND WITH POTENTIAL BROADER USE IN CONSTRUCTION MATERIALS. ALTERNATIVELY, IF PLACED IN A LANDFILL, THE RESULTING PRODUCT IS A NONHAZARDOUS MATERIAL AND HAS A REDUCED VOLUME COMPARED WITH THE ORIGINAL ASH. THIS RESULTS IN A NET SAVINGS IN DISPOSAL COSTS.