||Engineering and Economic Assessment of Autoheated Thermophilic Aerobic Digestion with Air Aeration.
||Camp, Dresser and McKee, Inc., Boston, MA.;Municipal Environmental Research Lab., Cincinnati, OH.
Aerobic processes ;
Sludge digestion ;
Active sludge process ;
Sewage sludge ;
Economic analysis ;
Autoheated thermophilic aerobic digestion process ;
Organic material ;
Sludge treatment ;
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A major disadvantage of aerobic digestion is that it requires long detention times, particularly in colder climates, to insure adequate stabilization. Autoheated thermophilic aerobic digestion (ATAD) offers the potential to decrease the required detention time. ATAD takes advantage of the heat generated by microorganisms as they degrade organic material. Heat losses are controlled so that the system will be self heating (authothermal) and reach thermophilic range (at least 45C). This study performs engineering and economic analyses of earlier work done on ATAD. ATAD has been shown to be feasible with a mixture of thickened waste activated and primary municipal sludge. ATAD systems appear economical compared with ambient aerobic digestion and anaerobic digestion. The system is also more effective in decreasing the pathogen content of sludge. However, further testing is needed to investigate the proper selection of an aerator. These studies should provide designers with adequate design tools so that the system capabilities could be maximized.