Why do so many landfill managers/owners list liner construction as one of their most significant costs… yet put so little effort into finding ways to make the existing airspace last as long as possible? Usually it’s because they don’t know how to do it.
It’s a simple fact: the more trash you can squeeze into your landfill, the longer it will last.
One of the best ways to do this is to make sure the trash is compacted to its optimum density.
Every compactor – even the one at your site – has an optimum production rate. If the compactor handles too much waste, compaction slips and airspace is wasted. But if the compactor spends too much, you’ll be over-compacting, wasting fuel…and gaining little additional airspace.
But at the optimum rate, compaction is good, machine expenses aren’t out of line…everything just seems to work. The optimum rate is usually selected to maximize net revenue or minimize overall operating costs.
For your information, the optimum rate for a 70,000-pound compactor is typically around 60 tons per hour. In other words, when the compactor is handling about 60 tons per hour (on average), it’s working at its optimum rate. The optimum rate varies based on machine weight, wheel configuration, technique, type of waste, etc.
With this in mind the spotter directs specific loads to specific places based on the type and quantity of waste in the load. If the compactor begins to fall behind, the spotter may ask the trucks to wait. Or, if there’s room on the tipping pad, he may allow them to dump their loads. A sharp dozer operator will also know if the compactor is falling behind. His response will be to hold back tonnage. Like the spotter, if there’s room he’ll let the loads stack up on the edge of the tipping deck. If the deck fills up, the dozer may push some loads toward the cell and leave them in a pile until the compactor is ready for more garbage. Also, the dozer can help increase the compactor’s optimum rate by spreading and trimming the cell. Obviously, if the compactor can spend a greater percentage of his time compacting, it can handle more tons per hour.
Can you control the ebb and flow if the incoming waste? No, probably not. But you can teach the spotter and dozer how to level out the tonnage going to the compactor so that it’s somewhere close to optimum.
A good indicator of whether or not the compactor is consistently working at a reasonable (optimum) rate is to talk with the compactor operator. Is he cool, calm and collected? Or is he somewhere between a nervous breakdown and a panic attack? If it’s the latter, there’s a good chance that the spotter and dozer aren’t doing a good job of smoothing the peaks and valleys of the incoming waste stream.
If you want to get good compaction and keep the waste stream moving, give the compactor operator a reasonable target (i.e., 60 tons/hour), and then step back and let him run the show.
Neal Bolton, P.E.
Optimum density is just one of the components we look at when we conduct a Comprehensive Operational Review (CORE). Contact us for more information on how we can help your facility streamline your operation and save money.
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