Landfills have many layers and are built from the bottom up. First, there is the groundwater drainage layer, usually made up of gravel. Following this is a compacted clay layer and a rubber liner. On top of that is the leachate (garbage juice) collection layer.

When it is time to put the garbage in, it goes in cells. The garbage has to be covered every night with a daily cover. In most places, this daily cover is still dirt, but some places use foam or tarps.

“That is to keep the birds and rats from coming in, but also keeps the garbage from blowing all over,” said Lorrie Hanson, principal clerk at the Ames Resource Recovery Plant, 110 Center Ave.

The leachate has to be collected and stored.

“[The leachate] immediately goes to a leachate storage area, which is like a pond that sometimes has a building next to it which treats the leachate,” Hanson said. “What we do with the leachate from our closed landfill is collect it out of the pond into a truck and take it to a water pollution control facility where they treat it.”

The immediate hazards associated with landfills are fire, explosion, litter and odor.

“We worry most about the long-term hazards,” Hanson said.

These hazards include groundwater contamination, explosion from methane buildup and settling of the ground.

Landfills must be taken care of for 30 years after they close.

“We go to the landfill on a regular basis to make sure there is no erosion occurring that might get down in the layers,” Hanson said. “If it is, we get right on it and cover it back up properly.”

To take care of the landfill, trees are cut down, because the roots will grow and penetrate the membrane.

“It is a very unusual fact, but tires float in a landfill,” Hanson said. “That is why nobody landfills them anymore, because sooner or later they pop out of the ground.”

Hanson is not sure why exactly this happens.

“They just float, it’s bizarre,” she said.

Care for the landfill also includes mowing the grass and making sure everything stays the way it is supposed to stay.

Many times playgrounds and recreational areas are built on landfills. A storage facility was built on Ames’ old landfill.

“Settling is a definite problem with the storage facility,” Hanson said. “The concrete foundation is broken in some places and some of the storage units are taller than the other units.”