Lean, Green Transfer Machine

TRANSFER STATIONS PLAY A LARGE role in managing municipal solid waste (MSW), especially in an area as large as the Dallas-Ft. Worth Metroplex, population 5.5 million, where there are sizeable tonnages to process and dispose of. The city of Dallas' three transfer stations alone handle roughly 1,800 tons of waste each day. In 2002, the Dallas Department of Sanitation Services began a process to upgrade the existing material handling system at its Bachman Transfer Station. Equipment at the site was reaching the end of its normal life cycle and, based on the continued expected wear, needed to be replaced. Additionally, Frank Sturgeon, the facility's manager (who recently retired), saw this as an opportunity to, perhaps, streamline onsite operations.

Easier Said than Done

Three transfer stations — Fair Oaks for northeast Dallas, Oak Cliff for the southwest, and Bachman for the northeast part of the city — feed material to the McCommas Bluff Landfill, which serves approximately 250,000 of the north Dallas region's 3 million residents. Situated on nearly seven acres, the Bachman facility's value lies in its ability to efficiently accept material, load it into trailers and send it off to McCommas for disposal.

Similar to the layout at other transfer sites, trucks approaching Bachman enter an area below the tipping floor and are staged for loading, according to Sturgeon. Front-end loaders then push material that has been dumped onto the tipping floor into a pit and the trailer below. Once loaded, a boom-type material handler redistributes the material, removes any oversized waste or material that could cause a vehicle to be overweight, then tamps material down in the trailer.

In the past, material handlers handled this operation, Sturgeon says. However, the continued wear on the existing handlers prompted a move to re-evaluate the equipment in use and look at alternative loading methods.

Comparing Apples and Oranges

In researching the available options, Sturgeon says he spoke to industry colleagues who offered a range of opinions on how to improve operations. Some of the suggestions were worth considering, while others were out of the question, Sturgeon says.

“I talked with a friend who operates a transfer site similar to ours and was initially impressed with the fact that, using a track hoe, he was loading trailers at his site in only 10 minutes,” he says. “However, because they were not redistributing the material in the trailer, nor were they tamping it down afterwards, they were not getting the maximum tonnages possible with each truckload leaving the site. That, we felt, would not work for us.”

Shared Knowledge

Another one of Sturgeon's colleagues in the Dallas-Ft. Worth area was looking for a new transfer station material handler, too. So the pair began to examine some equipment features that would be beneficial at their facilities.

In particular, they were interested in a unit that operated using electric hydraulics as opposed to diesel power that usually comes standard with an excavator-type machine.

“There are certainly benefits which a track hoe can offer such as mobility, versatility, parts replacement, and so on,” Sturgeon says, “but you have to think about the workers and the conditions in which they have to work on a daily basis.”

Sturgeon says because both sites were indoor operations, they believed electric would be cleaner and quieter than a diesel-powered unit.

The colleague's material handlers were delivered prior to Bachman's order, so Sturgeon saw first-hand how the machine fit into a transfer setting. “Seeing them in action, I knew immediately that we had made a good decision,” he says. “The unit's ability to level loads within the trailer, remove oversized material that might be causing voids and, of course, tamp down material for a denser load, was everything we hoped it would be and more.”

A Perfect Fit

Bids for replacement equipment came in throughout 2003 and, based on specifications and costs, the city of Dallas committed to a Builtrite Model 1300 material handler built by Northshore Manufacturing, Two Harbors, Minn. The material loading package also included a Builtrite tamping grapple, which, according to Sturgeon, has played a big role in improving the Bachman site's efficiency.

“Our old grapple had a rounder design and, as a result, had a tendency to slip and damage the trailer,” he explains. “Every time the trailer was damaged, we were looking at a likely increase in our insurance rates.” On the other hand, the new grapple has a flatter front-end design, which Sturgeon says has “dramatically reduced trailer damage incidents since making the switch.”

Looking to the Future

Upgrading the loading and transfer operation at the Bachman site has improved load times. According to Sturgeon, production has measurably increased: The site is now averaging about 13 minutes per load, compared with 25 minutes per load with the former units.

“There's no doubt we are now able to keep things moving though here much more smoothly than ever before,” Sturgeon says. “And because it is a cleaner, quieter operation, our workers have benefited from the change as well.”

Larry Trojak is a marketing communications specialist based in Ham Lake, Minn.