Once the environmental impact study is complete, the permits are granted and the funds have been raised, then construction begins. First, access roads to the landfill site must be built if they do not already exist. These roads will be used by construction equipment, sanitation (环卫) services and the general public. After roads have been built, digging can begin. In the North Wake County Landfill, the landfill began 10 feet below the road surface.

　　What Happens to Trash in a Landfill?

　　Trash put in a landfill will stay there for a very long time. Inside a landfill, there is little oxygen and little moisture. Under these conditions, trash does not break down very rapidly. In fact, when old landfills have been dug up or sampled, 40-year-old newspapers have been found with easily readable print. Landfills are not designed to break down trash, merely to bury it. When a landfill closes, the site, especially the groundwater, must be monitored and maintained for up to 30 years!

　　How Is a Landfill Operated?

　　A landfill, such as the North Wake County Landfill, must be open and available every day. Customers are typically municipalities and construction companies, although residents may also use the landfill.

　　Near the entrance of the landfill is a recycling center where residents can drop off recyclable materials (aluminum cans, glass bottles, newspapers and paper products). This helps to reduce the amount of material in the landfill. Some of these materials are banned from landfills by law because they can be recycled.

　　As customers enter the site, their trucks are weighed at the scale house. Customers are charged tipping fees for using the site. The tipping fees vary from $10 to $40 per ton. These fees are used to pay for operation costs. The North Wake County Landfill has an operating budget of approximately $4.5 million, and part of that comes from tipping fees.

　　Along the site, there are drop-off stations for materials that are not wanted or legally banned by the landfill. A multi-material drop-off station is used for tires, motor oil, lead-acid batteries. Some of these materials can be recycled.

　　In addition, there is a household hazardous waste drop-off station for chemicals (paints, pesticides, other chemicals) that are banned from the landfill. These chemicals are disposed of by private companies. Some paints can be recycled and some organic chemicals can be burned in furnaces or power plants.

　　Other structures alongside the landfill are the borrowed area that supplies the soil for the landfill, the runoff collection pond and methane (甲烷) station.

　　Landfills are complicated structures that, when properly designed and managed, serve an important purpose. In the future, new technologies called bioreactors will be used to speed the breakdown of trash in landfills and produce more methane.