The effect of landfill design and operation practices on waste degradation behavior: a review

Abstract

Landfill design and operational practices can be used, sometimes in combination with municipal solid waste (MSW) pretreatment techniques, to control effectively landfill behavior. The effect of specific practices during landfill design and operation on landfill decomposition is an area that has attracted investigation since the 1970s. Work has taken place on practices such as leachate recirculation; layer (or lift) development; and buffer, nutrient, sludge, partially degraded refuse and moisture addition. Much of this work was directed at the use of methane as an energy source. These and other techniques have led to the concept of the bioreactor landfill, in which the goal is to control or enhance decomposition within the landfill, which usually includes enhancement of methane production. This paper discusses techniques that can be implemented either during design or operation of a landfill under the bioreactor landfill concept. Several experiments have shown that a necessary condition for methane enhancement is to overcome or minimize the acid generation phase. Moisture content and flow are known to be important factors affecting degradation but should be considered along with buffer addition if methane enhancement is an objective. In general, the effect of several design or operational techniques on landfill decomposition seems to be a result of interactions between them, rather than individual effects and is often based on the principle of balancing the acid and methane generation stages of decomposition.