If you have ever watched someone load a moving van, you've noticed that they pack as much material as possible into a limited space. Every nook and cranny is full by the time the vehicle is ready to go because a partially full van costs the moving company money. This “airspace” philosophy also holds true for landfill operations.

From the moment a company decides to build a landfill, it incurs high capital costs for acquisition, permitting, development, closure, capping and monitoring. A site owner can recover some of those costs by filling the landfill's airspace with waste. Profitability depends on how much tonnage can be disposed of in the airspace.

How do you successfully pack a variety of garbage into a finite area using people, heavy equipment and technology to get a return on your investment? The answer: effective compaction.

It can be said that the landfill mantra is “push, spread, compact and cover.” How much waste you push, what kind of waste you push, what you push it with and what you cover it with affects compaction.

Inadequate compaction shortens the life of a landfill and increases operation costs. Reduced site life means the waste must be taken elsewhere or perhaps that a new facility must be built.

Here are some key issues to examine when addressing landfill density. Each landfill is different, so how you apply these tips may vary slightly.

Waste Mix

You've probably heard the expression, “What weighs more: a pound of feathers or a pound of lead?” They both weigh the same but consume different volumes (airspace). You can't compact lead, but you can compact feathers. Such is the strategic thinking process of the landfill operator.

Waste mix is one of the bigger factors affecting density. Knowing that each load of waste is different from the previous one, operators must learn methods to handle the different types of waste to get the best compaction. Republic Services generally mixes the waste together as it comes into the facility but some pre-processing aids compaction.

For instance, bulky items can present a challenge. Pre-crushing them in the turn-around area can make them easier to compact. Municipal solid waste (MSW) tends to compact tighter and rebound less due to its moisture content. Some landfill operators don't mix bulky items with MSW and instead place the bulky items in a different area. In the end, though, all types of waste consume airspace and compacting them requires careful attention. Material like concrete and large pieces of furniture can get caught up on the bottom of the compactor, hanging it up. Pre-crushing the bulky items and placing them in with the MSW can lessen the likelihood of hang-ups.