Next generation dredging

The 30-ft.-long “speed bump” sits alongside the river, serving as a tangible example for curious passersby of the hardware that’s submerged in the waters below.

That visible speed bump, which sits behind a Kurtz Bros. Inc. facility in Independence, Ohio, is actually a collector that’s capable of capturing sediment on the riverbed as it moves upstream. Sediment can be processed into salable sand, and as Jason Ziss, manager of business development at Kurtz Bros. points out, the technology can be effective in a number of applications.

“I see this equipment as a really good fit for people who are running sand-and-gravel operations, especially people who are using river dredging as their source of raw material,” says Ziss, whose Cleveland-area company supplies bulk landscape material and offers services related to recycling, construction waste disposal and the environment.

Kurtz Bros. was introduced to the sediment collection system through a multi-party initiative to prevent sediment dredged in the Cuyahoga River from being dumped into connecting Lake Erie. According to The (Cleveland) Plain Dealer, the U.S. Army Corps of Engineers dredges more than 200,000 cu. yd. of sediment each year from the riverbed to ensure the Cuyahoga River remains navigable.

Sediment from the river used to be dumped into the lake, but the Ohio Environmental Protection Agency (EPA) no longer allows such dumping because of concerns the lake is being polluted. To that end, the Port of Cleveland sought an alternative destination for the river sediment.

One solution was found through a partnership with Kurtz Bros., which ultimately processes excavated Cuyahoga River sediment into salable sand. A second solution is the sediment collection system, a fully automated setup that also delivers salable sand.

The Port of Cleveland, which collects a royalty on harvested material, received a grant from the Ohio EPA and the Ohio Department of Natural Resources that essentially paid for its own sediment collection system. The system has met the port’s expectations.

“It definitely works,” says Jim White, the director of sustainable infrastructure programs at the Port of Cleveland. “We produce really high-quality material. It’s cheaper to operate than we thought it would be, and it doesn’t take nearly the footprint we expected it would.”
Perhaps of most interest to sand-and-gravel operations, however, is this new method of “dredging” material along riverbeds.

“This is the next generation for those people,” says Randy Tucker, president and CEO at Streamside Technology, who developed his company’s sediment-collecting technologies.

How it works

Jason Ziss, manager of business development at Kurtz Bros., stands next to the company’s screw dewatering plant that receives Cuyahoga River-harvested sediment. Photos by Kevin Yanik

According to Tucker, a Streamside sediment collection system is capable of processing 800,000 cu. yd. of sand each year if a river continuously brings sand to a collector. Kurtz Bros. hasn’t approached that maximum production figure at its location on the Cuyahoga River, but the river flows behind the company’s Cleveland-area facility haven’t dictated as such.

“This summer has been incredibly dry,” Ziss says. “Our river has been significantly slow, and you’re not going to build up much sediment with a slow river flow rate.”

Steadier rains will increase Kurtz Bros.’ opportunity.

“When it’s rainy and that [river] speed increases, that material has more capacity to get caught in the trap than with a really slow trickle,” Ziss says. “The flow rates of the river really predicate the effectiveness of the unit.”

So how exactly is material collected? Ziss describes the process by which Kurtz Bros. harvests material behind its facility.

“It’s a speed bump with a grate system on top, and this is really buried into the bed of the river,” Ziss says. “Really, all that’s exposed from the bottom of the bed is about 18 inches.”

According to Ziss, heavier sediment tumbles while lighter sediment remains in suspension. As heavier sediment approaches a collector on the riverbed, it moves up the “speed bump,” slows down and enters a grate. As that grate fills, material is pumped ashore and partially dewatered in a screw plant.

“People ask, ‘How am I going to manage water?’” he says. “Well, the water stays in a tank and then gets discharged back into the river.”

The material that emerges from the plant is of low moisture content – somewhere around 14 percent, Ziss adds. And the system remains on as long as sediment is available to process. The system is capable of processing 100 cu. yd. per hour.

“The [processed] material is very close to a concrete sand the way it is,” says Ziss, adding that the system is especially effective at capturing coarser grain material. “We looked at using this material as a spec’d product for DOT (Department of Transportation) projects.”
The opportunity Ziss describes is one on which others could easily capitalize, he says.

“Other companies could have a system that is being fed automatically from a river into a partially dewatered unit and then into another screen plant that’s going to cut it into different sizes,” Ziss says.

Sound alternative

Jason Ziss shows the processed sand that emerges from the plant.

For an outfit like the Port of Cleveland, which commits a tremendous number of dollars each year to dredge sediment from the Cuyahoga River, the collection system helps to mitigate costs – particularly those tied to dredging.

“The thing we like is it has the potential to be self-funding once you get past the capital costs,” White says. “I think it’s about $1 per [cu.] yd. for production as opposed to $17 [per cu. yd.] with dredging.

“We dredge about 250,000 [cu.] yd. per year,” he adds. “If we could intercept 20,000 [cu.] yd. in bed load it’s got great market value.”

Adds Ziss: “Imagine eliminating an excavator and a person from excavating, scooping and then having to sort. You’d have a pre-sorted, pre-dried material with less of the silts and fines that you wouldn’t want anyway – all generated by the natural flow of the river.”

According to White, the Port of Cleveland is even exploring the possibility of adding cross-veined infrastructure along the riverbed that could direct more sediment to collectors.

“We want these things to work, and work effectively,” White says.

Other ports along Lake Erie may have an interest in the systems, as well. Several Lake Erie ports east of the Port of Cleveland have expressed an interest because the state plans to ban the placement of sediment in the lake by 2020, White says.

“Other ports that have been using the lake are going to have to stop,” he says. “The question then is how do you minimize? There may be cost-effective ways. [Ports] have been over to look at [our system], and they’re starting to understand this is a more cost-effective way to minimize.”

Beyond ports, White sees a number of opportunities for the sediment collection system. In fact, White sees opportunities for sand-and-gravel operations to generate additional salable materials if the right partnerships are established.

“If we treat [our] confined disposal facility more like a sand operation, could we be putting [material] more through a shaker system to yield more high-quality material and graded material for different market uses?” he says. “We can, in fact, segregate this material, but if we can run it through one more process as we harvest it, we could have higher merchant value.”

Tucker agrees the opportunities for the system are vast. He even established his own mining company, Streamside Materials, to put the technology to use.

“Streamside Materials is looking at frac sand at the moment,” Tucker says. “We’re just getting ready to set up the plants. We’re going after frac sand in Minnesota.”

Tucker actually began to develop his sediment-collecting technologies more than 20 years ago after sediment filled a favorite fishing hole of his in Michigan. With a research-and-development background, he devised a series of technologies to provide solutions to river and stream sedimentation issues.

Now, Tucker has a number of sediment-collecting projects in the works across the United States and Canada. And he and others are excited about the possibilities.

“People who should be interested are those dredging rivers for raw materials to be sold that are in faster-flowing rivers with heavier, coarser material,” Ziss says.