Landfill gas and leachate

Landfill gas and leachate

Leachate and landfill gas comprise the major hazards associated with a landfill. While leachate may contaminate the surrounding land and water, landfill gas can be toxic and lead to global warming  and  explosion  leading  to  human catastrophe  (Phelps,  1995).  (Note  that global warming,   also  known  as  greenhouse effect,  refers  to  the  warming  of  the earth's atmosphere by the accumulation of gases (e.g., methane, carbon dioxide and chlorofluorocarbons) that absorbs reflected solar radiation.

Nature of waste: The deposition of waste containing biodegradable matter invariably leads to the production of gas and leachate, and the amount depends on the content of biodegradable material in the waste.

Moisture content: Most micro-organisms  require a minimum of approximately 12% (by  weight)  moisture  for  growth, and  thus the moisture content of landfill  waste is  an important  factor in determining  the amount  and extent of leachate and gas production.

pH: The methanogenic bacteria within a landfill produce methane gas, which will grow only at low pH range around neutrality.      

Particle  size and density: The size of waste particle affects  the density that can be achieved  upon compaction and  affects the  surface  area and  hence volume. Both affect moisture absorption and therefore are potential for biological degradation.

Temperature: An increase in temperature tends to increase gas production. The temperature affects the microbial activity to the extent that it is possible to segregate bacteria, according to their optimum temperature operating conditions.