Initial Research on Landfills (Space)

Landfills are basically places where trash or other forms of disposable waste are gathered and buried as a means of storing garbage. It involves a process of digging a hole (really of any size but generally quite large) and once the hole is full of trash it is then covered with soil or other materials such as wood chips or sand. They can also be used for other purposed such as a pile to sort trash into different categories (example trash vs recycling) or for temporary storage before the contents are moved to a more permanent location. 

The type of landfill is usually determined by its contents. Some landfills might be designated for chemical or industrial waste while other might be for nuclear, household, or toxic waste. The waste is typically compacted prior to dumping in the landfill as a means of adding both stability and increasing the amount of waste that can be put into a given landfill hole. 

Landfills tend to be the most common form of large-scale waste disposal since they are efficient (in that you can store a lot of material in a relatively small area through compaction) and allow for a degradation cycle of the garbage contained in the landfill. Certain material may be grouped together to allow bacteria, fungi, and other microbes to process and dissolve the waste contained within the landfill.

Some common issues associated with landfills are: groundwater contamination (particularly with landfills in areas with high rainfall), landfill gases (several types of gas form within landfills and they can be toxic to the surrounding land and air), carbon/methane emissions, spread of diseases (through rats, mice, and other wildlife that may travel to the landfill in search of food), loss of habitat (landfills require a lot of space), odor, noise, destabilization/soil liquefaction (since landfills are compacted trash, they can degrade and destabilize during earthquakes causing the soil to collapse, potentially creating sinkholes and contaminating groundwater).

Landfill regulation changes based on country/region/state. They are rich in materials and energy and are often harvested for those purposes. There are usually taxes and other municipal regulations that determine how much a landfill will cost to build and maintain as well as how they must be managed, contracted, operated, expanded, etc.