Settlement Characteristics of Mechanically Biologically Treated Wastes

The legal limitations on the amount of biodegradable municipal solid waste (MSW) disposed of to landfill have led to the development of a range of pretreatment processes known generically as mechanical biological treatment (MBT). This paper presents the results of a detailed study of the degradation and settlement characteristics of two such MBT waste residues. The effects of mechanical creep and biodegradation are quantified separately, and compared with each other and with those for raw (untreated) MSW. The effects of different degrees of treatment prior to landfilling are considered in the context of the relationship between biodegradation and settlement. The results are discussed with reference to uncoupled models for estimating consolidation, creep, and biodegradation-induced settlements in MBT wastes. The methods for determining appropriate parameter values and applying these models to practice are also suggested. (C) 2013 American Society of Civil Engineers.