Settlement in seawater-saturated waste fills

Landfills remain, in the vast majority of cases, the most economic form of municipal solid waste disposal. Historically, landfill sites have been cons tructed on large areas of land adjacent to urban communities. The continuou s growth of these communities pushes urban boundaries towards landfilled ar eas. Although the development of such areas becomes a necessity, particular ly near land-limited locations, it is invariably hindered by settlements du e primarily to biodegradation of organic materials within the landfill. The rate and magnitude of landfill deformations are often nonuniform, resultin g in differential settlements that can have devastating effects on the inte grity of any structure erected on the landfill. The biodegradation-settleme nt process is relatively slow, and can continue in excess of several decade s after landfill closure unless appropriate management practices are implem ented to enhance biodegradation processes and achieve rapid waste stabiliza tion, This paper presents results from laboratory and mathematical modeling studies that have been conducted to correlate settlement rates with stabil ization processes at a closed coastal landfill, Test cells were designed an d constructed to evaluate the effect of salt-water intrusion on the biodegr adation and settlement of municipal solid waste. The laboratory results are used to provide the basis for the calibration of empirical models that can be used to estimate the rate and magnitude of landfill settlements after s ite closure.