In an interesting "band-aid" proposition, oil and gas exploration and production company Range Resources recently announced it would like to start using the waste rock material brought to the surface at fracking sites — known as gas well drilling “cuttings” — as a paving material.
Pennsylvania state Department of Environmental Protection spokesman John Poister says the Range application for a state general permit is the first by a Marcellus Shale gas drilling company under a state “beneficial use” general permit. The project would constitute the beneficial use of vertical drill cuttings from natural gas wells as an aggregate in a stabilized soil pavement for construction of Marcellus and Utica Shale well pads and access roads, according to a notice in Thursday’s Pennsylvania Bulletin, where state permitting actions are recorded.
The notice said DEP received the registration from Range Resources on January 10. A 60-day public comment period began February 1.
Range Resources says the company has long wanted to use drilling cuttings for road and pad construction, noting that it’s allowed in Texas. Granting the beneficial-use permit not only would save the company money by reducing its disposal and road and pad materials costs, it also would "benefit the environment" by reducing the amount of mined aggregate needed and the amount of waste material sent to landfills.
Currently, the drilling cuttings material is classified as “residual waste” and is either buried on site or mixed with wood chips and transported to a landfill for disposal. In 2012, shale gas drillers disposed of close to a million tons of waste in Pennsylvania landfills, most of it drill cuttings.
But these drill cuttings are not clean — some of those trucked to landfills set off radiation alarms, which compelled the DEP in January 2013 to start studying and testing for radioactivity in drill cuttings, wastewater and equipment at more than 100 sites across the Pennsylvania.
Range Resources insists there is no reason to believe there will be any adverse environmental impact, especially since the company would be using only vertical cuttings, not the horizontal shale cuttings, which can contain more radiation. Additionally, the material must pass state standards for road building materials before it can be used. The company suggests use of the cuttings could eventually be expanded to include local and state road paving.
There is a risk that drill cuttings can potentially contain radiation or other contaminants associated with drilling mud, according to Briana Mordick, a petroleum geologist and staff scientist with the Natural Resources Defense Council. If used as paving material, those contaminants can leach or wash out of the material and pollute soil and nearby waterways. To protect against this, drill cuttings would need to be properly tested and characterized prior to their use on roads and drill pads. To assess the risk to surface waters and the environment, scientists would need to know the contaminants in the cuttings.
On a more positive note, last year the Climate News Network reported that researchers from the University of Kansas are experimenting with ways to produce cement that will absorb CO2 emitted from factory flues, by adding waste residue from biofuel production to the cement mix. The by-product, lignin residue, is a woody substance produced from generating biofuel from cellulose waste such as wood chips and straw, which is usually burned or buried. When the Kansas team added 20 percent lignin waste to their cement, the subsequent chemical reaction delivered a concrete considered 30 percent stronger than traditional types. Civil engineer Feraidon Ataie, one of the lead researchers on the project, said the process not only delivers a stronger, more sustainable alternative to traditional cement; adding value to the by-product rather than just landfilling it can also help reduce the cost of bioethanol production.
In related news, the New York Times reported in December that Milwaukee is using cheese brine, usually a waste by-product of the cheese-making process, to de-ice the city’s icy roads this winter. The city says the brine is a cheaper and more environmentally friendly alternative to rock salt, which can end up polluting waterways.