ABSTRACT
Moisture content, pH, temperature, availability of macro- and micro-nutrients and the presence of suitable microorganisms are the main parameters controlling the process of landfill stabilization and, therefore, are the parameters typically manipulated in the laboratory studies. A number of pilot-scale studies were conducted in the US and other European countries to investigate the effects of leachate recirculation on landfill stabilization, leachate quality, landfill gas production and other parameters. A pilot-scale landfill project was started in 1972 at Sonoma County, California, to study the effect of moisture on the rate of refuse stabilization, and on leachate quantity and quality. The objective of the pilot scale demonstration project conducted at Mountain View Landfill, California, was to study the effectiveness of the methods used to enhance methane gas generation. Some of the shortcomings of bioreactor operation observed were: production and escape of gas before completion of landfill, leachate ponding, and leachate toxicity due to high ammonium content.
