american augers slurry handling

What’s the Fuss? Contractors Find New Solutions for Slurry Handling, Disposal

As Drilling Fluid and Slurry Handling Costs Increase Contractors Find New Solutions to Help the Bottom Line

Despite being thoroughly researched and presented as safe, contractors in the underground construction world still face hurdles and questions when it comes to disposing of their waste from underground boring projects.

This fact has prompted manufacturers and suppliers to design and develop new and improved options when it comes to slurry handling. It has also prompted some contractors – with the financial wherewithal – to find solutions of their own.

On the manufacturing side, the engineers and salespeople do the yeoman’s job teaching the benefits of mud recycling systems, shakers, centrifuges and the like. But these larger mobile facilities – while necessary on larger HDD projects and all microtunneling work – require almost a day for setup, and might not be suitable for smaller projects.

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Some companies, like Vermeer with its new Mud Hub slurry solidification system and MetaFlo Technologies with its liquid mixing systems and solidification reagents, have found ways to bring smaller systems to jobsites or at least a centralized solidification location. Other manufacturers have designed mud recycling systems to be trailer mounted, easily transported and able to fit in more constrained metropolitan rights of way. All of this is to make sure contractors have what they need to be successful on projects.

Vermeer mud hub

The Vermeer Mud Hub is a slurry solidification system and is a stationary plant where contractors can unload their wet slurry from vacuum excavation equipment. The unit then solidifies the slurry for easier disposal.

Adam Bates, product manager at Vermeer, notes that in the last decade more and more contractors have changed the way they work to include the use of bentonite, as well as mud recycling systems.

“It has been interesting, because 10 years ago contractors were still learning what the benefits of drilling with bentonite were. Not that bentonite was not out or utilized, but there were still people shying away from it,” he says. “The use of bentonite has gone mainstream. Contractors went from not using it at all to learning that there are challenges associated with disposing of drilling fluid mixed with bentonite.”

It is the cost of disposal that is one of the reasons many contractors have purchased mud recycling and fluid management systems. This is especially true on the larger projects using 100,000 lbs and up HDD rigs. Now that same mentality is shifting to contractors operating rigs in the smaller 50,000 lbs and below categories who are struggling with mud disposal. Contractors have watched disposal fees skyrocket and locations that will accept liquid waste are hard to find, especially in metropolitan areas where the smaller utility construction takes place.

disposal haul manifest

A sample disposal manifest for drilling fluid that a contractor would keep for its records.

Changing Times

“In the last three to five years there has been a greater focus by contractors looking to recycle or reclaim their drilling fluids onsite. From an American Augers standpoint that has been a fairly common practice because of the nature of the larger HDD systems and fluid capacities of our equipment,” says Richard Levings, American Augers’ director of product development. “That has now expanded down to the smaller 100,000 lb class on down even to the 40,000 and 50,000 lb class rigs. Many, many, more contractors are using reclaiming systems today.”

Levings, with decades in the industry, has watched as the issues associated with mud disposal went from the No. 1 issue on a contractor’s plate to No. 2 as workforce issues began to dominate the headlines. The problem is, he says, that the mud disposal issues never went away, rather contractors adapted to the environment. But those workforce issues are also tied to mud disposal issues because, as the fees for disposal have increased and locations for disposal have diminished, contractors have had to look for new employees or sub-contracted to handle disposal. In some instances, a trip to a liquid waste disposal facility with a loaded vacuum excavation unit can take one work shift.

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“From a contractor’s standpoint, the level of investment that they have had to make in the last 10 years in order to handle directional drilling fluid has been significant,” Levings says. “Everything has changed for them. It has certainly had an impact on their margins.”

According to Barry Sorteberg, vice president of Clean Slurry Technology, there was a time when the slurry could be spread onsite and in cases where it could not, the slurry could easily be sucked into a 5,000-gal truck and taken to a dump.

“Most contractors are running solids control equipment, and the disposal facilities don’t want to see anything with more than 15 to 20 percent liquids. If they don’t meet that criteria the disposal facility will not accept the waste coming in,” Sorteberg says. “Even when the contractor finds a facility to accept this waste, they charge by the pound. Water weighs 8.33 lbs.per gallon and contractors are paying a high disposal fee for the water left in the solids.”

Having a good separation plant with centrifuges and polymer (lime, fly ash, etc.) additive systems can dewater the slurry to remove anything that is 74 micron and larger. This gives them a dry solid out of the centrifuge that can be scooped up and disposed of or used onsite and the water can be run to the sewers.

As an example, Levings says that without a recycling system a contractor might use 150,000 gal of fluid, hauling off in 3,000 gal capacity vacuum trucks as needed either on their own or hiring a company to handle the removal. Using a recycling system, they can keep that to about 30,000 gal of fluid. That is 40 less trips to the dump and 120,000 gal of water the contractor did not have to buy. Disposal fees, by his estimate are in the $400 to $500 range.

Increased Costs

Gene Woodbridge, CEO of Ontario, Canada-based Earth Boring Co. Ltd., has witnessed the increased difficulties first-hand. Many consider Ontario, in particular the Greater Toronto Area (GTA), as one of the most stringent in North America when it comes to mud disposal particularly because of the classification of the waste and available facilities that accept it. And in early 2018, the province reclassified its regulations that pertain to vacuum excavators meaning that many of the trucks on the road can no longer haul the same amount of waste.

“There was a time, 10 years ago, where we could dump a truck for about $30 to $40 a load. Today that cost can be $120 to $300 a load,” Woodbridge says. “The more convenient the site, the higher the fee. Nothing is under that $120 mark now. This does not factor increased fuel and other fees.”

Earth Boring Co. has moved to not only using mud recycling systems on projects with its 45,000 lb and larger HDD rigs, but it has also started onsite solidification. Woodbridge says that with the addition of centrifuges, they can reuse the water or dump it straight to the sewer. All of the spoils, both from their HDD and microtunneling work, are dry enough to dispose of at a regular disposal facility.

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It is on the smaller side – under 45,000 lbs – that the company opts to vacuum the drilling fluid and has to cope with the disposal issues. On those projects, the company uses vacuum excavators to suck up the waste and any inadvertent returns.

But the company has an ace in the hole as it works through certification of a quarry it owns to be permitted to accept the liquid waste. “We had the quarry and it made sense to go through the permitting process,” Woodbridge says. “We’ll have the processing and drying equipment to process wet materials and we’ll be able to do it for our own waste, as well as our competitors. We are also in talks with some companies to set up mobile processing plants for working in the core of the GTA where we can setup at a centralized site to accept the slurry.”

The potential for its own quarry notwithstanding, in the last 10 years, Earth Boring has moved away from including a small lump sum for disposal in bid packages to making it an actual line item. To come up with that line item number they estimate disposal volumes, frequency, fees and other associated expenses.

Investing and Education

In the Northeast and Midwest of the United States Ellingson Trenchless faces many of these same problems on its projects. Much like Earth Boring Co., Ellingson has made a huge investment in mud recycling systems in the last decade. According to Rob Tumbleson, director of business development at Ellingson Trenchless, they also look at the specifications of the project before bidding to determine the best disposal solution.

“If we are working in the southern states or the Dakotas there are a lot of opportunities for spoils disposal,” Tumbleson says. “If we are working Pennsylvania, New Jersey or New York, transportation and disposal is more of a concern. In many cases, owners will generally find places for disposal and include in the specifications for us to choose from and then we include where we will dispose of it in our bids.”

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And though some may look at this issue as being one of regulators and legislators vs. the industry, these industry insiders say that is not often the case.

During a recent fly-in to Washington, D.C. with the Distribution Contractors Association Tumbelson discovered that most of the problems as it pertains to drilling fluid is at the state and local level. The federal EPA sets a minimum standard, he says, and many states then go above and beyond that.

“Most of the drama for mud disposal seems to be on the pipeline projects. Most of the big HDD work is for gas and oil pipelines and there seems to be more scrutiny on those projects,” he says. “The municipal projects we work on don’t seem to come under as much scrutiny as [like-sized] oil and gas pipelines projects.”

slurry system

The solids coming off a slurry system on a microtunneling project in Ontario.

Bates agrees, noting that much of the pressure is due to HDD’s link to the non-conventional oil and gas boom in North America and a lack of awareness on the part of many people as to the differences between the drilling fluid solutions used in downhole drilling and fracking vs. HDD and microtunneling.

Levings notes that the fluids are completely unrelated. The fluids developed to use with utility boring systems were developed to have a minimal impact. The industry has never needed the more complex oil and gas fluids that work in extreme depths and with extreme temperatures and lift loads.

The environmentalists are concerned about the heavy metals and hydrocarbons that are contained in solids or liquids and the negative impact those may have on plants and animals. Bates says that typically those are not existent when completing utility work. They are also concerned about liquids that can flow because it can enter natural bodies of water and it can impact the water environment.

“I think all of that attention has made utility owners aware that they are not just responsible for fluid management while the job is in process,” Bates say. “You will hear utility owners discuss now how they own those fluids from cradle to grave.”

It also requires a concerted effort on the part of all involved in the industry. For instance, Tumbelson says that after the meeting in Washington, D.C., the DCA is working to bring a similar presentation to the state and local level where many of the concerns appear to be. And Levings, a longtime advocate for educating the general public, sees a greater need for those efforts today.

“The fluid concerns will not go away. If contractors are not experiencing issues with fluid disposal today that is a good thing, but they need to be prepared because it is coming their way. We can’t sweep this under the rug, we can’t turn a blind eye to it, it is coming,” Levings says. “It might not be affecting everyone at this point in time, but it is headed towards everyone. As an industry we need to embrace it and work hard to educate the general public on the benefits if HDD, the benefits of the fluids that we use and the steps that we as an industry have taken to work in people’s neighborhoods to be environmentally responsible.”
Mike Kezdi is associate editor of Trenchless Technology.
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