DUKE ENERGY COAL ASH LANDFILL

Unlike most of our projects where we are creating something for this project we are working with a pre-existing coal ash landfill. The purpose of this project is to excavate a already filled coal ash landfill in order to add a geotextile covering to the top of the coal ash in order to prevent any unintended seepage of coal ash into the surrounding wetlands. This landfill is adjacent to the Asheville Regional Airport and is a 30 acre landfill. Once we have covered the coal ash with the geotextile covering we will be adding drainage pipes to properly drain the runoff as well as monitoring wells to constantly measure the groundwater to ensure it stays nice and clean. 

Project State Date: July 2022
Project End Date: December 2022

Project Location: Asheville, NC
Project Acreage: 30

Project Intention: Coal Ash Landfill
Project Customer: Duke Energy

UPDATE 1

WHAT IS COAL ASH?

Coal ash, also referred to as coal combustion residuals or CCRs, is produced primarily from the burning of coal in coal-fired power plants.  Coal ash includes a number of by-products produced from burning coal, including:

  • Fly Ash, a very fine, powdery material composed mostly of silica made from the burning of finely ground coal in a boiler.
  • Bottom Ash, a coarse, angular ash particle that is too large to be carried up into the smoke stacks so it forms in the bottom of the coal furnace.
  • Boiler Slag, molten bottom ash from slag tap and cyclone type furnaces that turns into pellets that have a smooth glassy appearance after it is cooled with water.
  • Flue Gas Desulfurization Material, a material leftover from the process of reducing sulfur dioxide emissions from a coal-fired boiler that can be a wet sludge consisting of calcium sulfite or calcium sulfate or a dry powered material that is a mixture of sulfites and sulfates.

THE GEOTEXTILE LINER

Currently the coal ash has a geotextile liner underneath. The geotextile liner was installed with the landfill was developed and placed under the coal ash in order to keep it from seeping down into the groundwater and polluting the local water table. 

Over time, and with changing environmental standards, just having a geotextile liner underneath the coal ash has become an inadequate solution to the storage of this material. This is why JL Raper was contracted to come up with a solution and fix the problem.

The problem is the possibility of seepage into the surrounding wetlands and the solution is to add a second geotextile liner on top of the coal ash and basically create an impenetrable barrier around the coal ash to keep it contained. 

We then will add in more effective drainage solutions while we are grading the land as well as monitoring wells in order to constantly measure groundwater. 

UPDATE 2

PROTECTING THE WETLANDS

The coal ash landfill is adjacent to very sensitive wetlands that are heavily protected by environmental regulations. When working on such a sensitive project like this is it is paramount to use a grading and land development company that has a history with erosional control and environmental protection.

JL Raper has been one of the top corporations in erosion and groundwater runoff control for the entirety of its life. We offer the greatest expertise when it comes to ensuring a project doesn’t negatively affect the environment during the grading process or in the years after the project is complete. 

SIFTING THE SOIL

One of the unforseen problems with placing down the geotextile liner on the landfill during the site development is that there is a chance of the liner being punctured by large rocks. JL Raper has experience working with projects like this and foresaw this problem. For this reason we have brought in screeners and have been using them to screen the soil of the site to separate anything rock larger than a half inch. At the time of this update over 180,000 yards have been screened. 

CARRYING THE LOAD

A lot of grading and land development companies rely on the customer to forsee any problems and to bring in any needed equipment. JL Raper is a full site contractor on this project, This means that we know exactly what it takes to get the site developed and we take all the necessary actions that are required to complete the grading, drainage, sifting, and whatever else is needed with as little effort required by the customer as possible. 

UPDATE 3

MANAGING THE ASH

The largest liability with this type of grading project is managing the coal ash once we have reached the depth at which it is at. Working with this type of waste, adjacent to a windy airport can be challenging. To overcome these challenges we take extreme care when we reach the waste. We have developed a process to contain and then cover the coal ash as soon as it is exposed to the elements of the landfill that we are redeveloping. Keeping the surrounding environment pristine is our number one goal in this project. 

THE SCREENED SOIL

One question that sometimes comes up is what is done with the topsoil that is removed and what happens to the screened soil that is too big to be used on this site? 

The topsoil for this particular project will be reused on this site in order to minimize costs and project time. Its also best for the environment to use the natural topsoil to the site.

The screened soil that was too large for this site, because of the liner being used, will be recycled for other projects that don’t require any soil specifications. This is good for saving money for multiple clients. The current project client won’t need to pay for disposal of soil and future clients won’t be required to pay for filler soil. 

When doing grading and land development we always strive to institute cost saving measures for our project clients. 

UPDATE 4

LAYING THE COVER

Installation of the geotextile cover has begun on the site. This unique covering will form a protextive barrier between the coal ash below and the soil above to guarantee that no cross contamination occurs. Laying this covering is a very delicate procedure. It requires complete control to be sure to install it correctly and to not damage it in the process. A job this sensitive requires a seasoned company like us here at JL Raper to ensure that it is done to standards and done in an time-effective manner.

HANDLE WITH CARE

It should be no surprise that this job is a highly sensitive job. It doesn’t get much more sensitive than working with coal ash, next to protected wetlands, adjacent to a windy airport with planes taking off and landing constantly. There are a lot of factors at play that are all working to try to spell disaser for this project. But we here at JL Raper are not rookies when it comes to land development. We have seen all the problems before and know how to plan ahead for them. We also know that there are always problems you don’t forsee so we put in place redundant safety measures to ensure we are covered for those as well. Developing and grading a site like this is very sensitive, and we are the type of grading company that can handle it.

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