Case Study of Controlled Air Addition into Landfilled Municipal Solid Waste: Design, Operation, and Control

The addition of air to landfilled municipal solid waste (MSW) was examined at an operating bioreactor landfill in Florida. An air-addition system was designed to provide sufficient capacity to aerobically degrade a targeted mass of waste in a 3-year period. Approximately 1.385 million standard m(3) [at 15.5 degrees C and 101.3 kPa (1 atm)] of air in total was added to 78 small-diameter vertical wells located in clusters of three different depths (6, 12, and 18 m deep in the landfill). The cumulative volume of air added was much less than design capacity, a result of difficulties in adding air to deeper and wetter landfill areas and rapid temperature increases in waste near some of the wells. Consistent long-term aerobic conditions could never be established. Gas concentration measurements throughout the experiments were not in the explosive range, but temperature measurements corresponding to continuous air addition did require frequent adjustment and cessation of air addition to wells to avoid fire formation. Although air addition could play some role in bioreactor landfill operation, results from this study suggest that maintaining aerobic conditions as the dominant waste decomposing environment within typical large bioreactor landfills operated with liquids addition is very difficult to achieve. (C) 2013 American Society of Civil Engineers.