Hi,

Landfilling is an important method in the disposal of wastes, as it collects the wastes in a site which then used for purpose of recycling as the waste are concentrated in various layers and is compacted to reduce the volume.

They are monitored for the control of liquid and gas emitted in order to make sure they don't destroy the environment.  Some wastes are burnt some are used to generate bioenergy. Hazardous wastes are segregated and treated.

A scientific landfill is termed so because of its scientific design during construction. One of the biggest problems of ordinary landfills is the seeping of solid waste into underlying soil and water, contaminating both. Scientific landfills eliminate the risk of waste seeping underground as the base layer is constructed of 90 metres of clay, thus arresting any seepage or leakage within the landfill. On top of the base layer, a drainage layer made of soil, measuring 15 metres in length and a vegetative layer of 45 centimetres to minimise soil erosion. The presence of these layers ensures that leachate is collected before it seeps underground.

Scientific landfills also act as degassing systems by reducing the production of methane. Since the layers soak most of the impurities in the waste disposed, methane generates slowly compared to the generation speed in ordinary landfills. Vertical wells installed in scientific landfills help extract methane regularly, and the gas can then be used for electricity and heat generation purposes.

Hope this helps.