Let's be clear. No system exists that can properly treat fracking waste. As such, there are no safe ways to dispose of fracking waste. Municipal treatment plants are not designed or equipped to deal with chemical and radioactive contaminants. Waste treatment plants deal with biological contaminants, they cannot filter out chemicals and radioactive materials.
The options available to the industry today for the management of its wastewater can be categorised as either disposal or beneficial reuse. In other words, the large volumes of toxic waste water produced by shale and tight gas mining can either be dumped into deep disposal wells or reinjected into aquifer formations, trucked to holding ponds or storage tanks, or partially 'treated' and released into waterways or reused.
US studies have found high levels of radioactivity in waterways fracking companies use to dispose of their treated wastewater. Mainland Australia is still grappling with the challenges of disposing of gigalitres of toxic, and in some cases radioactive, flowback and produced water from fracking.
Reverse osmosis is prohibitively expensive and creates another waste disposal problem - tonnes of salt that needs its own waste disposal solution. Research is underway to develop forward-osmosis technology. If it can be made to work, and if it can be produced economically on a commercial scale, forward-osmosis claims to be able to return contaminated water to potable drinking water.
There are two types of wastewater from unconventional gas production: produced water and flowback. Produced water is the term the industry gives to the groundwater that comes to the surface over the life of a gas well once it’s in production. The amount of produced water varies from well to well, but typically ranges from 300 to 4,500 litres a day for shale gas wells.
Flowback is the wastewater recovered from wells shortly after fracking - within around 30 days. Flowback can contain strontium, radium, uranium, radon, and other radioactive substances, as well as heavy metals, such as lead, mercury, cadmium, chromium, barium, 4-nitroquinoline-1-oxide and arsenic. Volatile organic compounds (VOCs) have been shown to be present in fracking fluid flowback wastes at levels that far exceed drinking water standards. Testing of flowback samples from Texas revealed concentrations over 300 times above the US EPA's Maximum Contaminant Level for 1,2-Dichloroethane in drinking water.
The materials extracted from underground can be more toxic than the original fracking fluid. In addition to the chemicals used in drilling and fracking, flowback and produced water can contain a range of naturally occurring substances from the source rock, including heavy metals, naturally occurring radioactive materials (NORM - including radium, thorium and uranium), volatile and semi volatile organic compounds (VOCs) and high concentrations of salts.
No Solution for Flowback
One of the significant unsolved problems with shale gas drilling is how to safely dispose of the huge volume of wastewater fracking generates. While fracking practices can be improved to reduce the exposure of humans, livestock and wildlife to the toxicants associated with gas drilling, they can't eliminate it. The disposal of wastewater remains a significant environmental and public health risk.
The National Toxics Network says that after a decade in Australia, the unconventional gas industry still does not have an effective way to deal with its waste water, its solid wastes, such as drilling muds and salts, or its impact on groundwater aquifers.
The DPIPWE Review Team's final report on the government's review of fracking confirms that safely disposing of flowback is an ongoing problem:
In regard to water treatment, the Project Team is not aware of any onsite water treatment systems that can provide cost-effective treatment of contaminated flowback fluid to a standard suitable for safe disposal to local waterways or potable aquifers...
Dramatically understating the scope of the problem, the US Shale Gas Information Platform says that the treatment and disposal of the large volumes of flowback presents 'particular challenges'. Fracking as we know it today has been in operation since 1997 and the problem of safely disposing of flowback has still not been solved.
As things stand in 2015, the critical issue of a safe and effective means of disposing of flowback has no workable solution, for the simple reason that that the technology required to deal with fracking's toxic waste has not yet been developed. This technicality hasn't slowed the speed of the rush to extract unconventional gas, but it has encouraged the industry to test a variety of solutions on communities where fracking occurs.
The industry has explored 'beneficial reuse' as a means of disposing of its toxic wastewater. Undoubtedly, beneficial reuse is extremely beneficial to the unconventional oil and gas industry. Despite the serious risk the reuse of toxic, and in some cases radioactive, materials poses to contaminant-free food, soil, water and air, a report prepared for the NSW Chief Scientist and Engineer (CSE) states that beneficial reuse is now the industry's strongly preferred method of disposal. Beneficial reuse offers a wide variety of reuse applications, including:
- surface water discharge or in-stream flow augmentation
- agricultural use for crop irrigation and livestock watering
- on-site industrial use, such as drilling, lubrication, dust control and fracking
- off-site industrial use and potable use, eg augmentation of drinking water supplies
In mainland states beneficial reuse can also mean spraying toxic frackwater onto country roads for dust suppression, where it leaches into the surrounding soil, or gifting it to farmers for agricultural use. The Queensland Department of Environment and Heritage Protection says that:
Fracc flowback water may be reused in subsequent fraccing activities or treated to the appropriate environmental and human health standards for other uses.
This is in the flowback water now, which is all being carted away. But if these chemicals come up in the produced water, that produced water is...being sprayed out in the paddocks.
AGL also recently trialled beneficial reuse in NSW. The trial involved mixing the contaminated fracking wastewater with fresh water to irrigate crops such as lucerne, triticale and forage sorghum. It was discontinued after regulators found that even diluted fracking waste left behind unacceptably high levels of salt and heavy metals.
Treat and Release
A favoured waste disposal method available to the industry is 'treat and release', otherwise known by the jingoistic phrase 'the solution to pollution is dilution'. Despite being another soft option for fracking companies, the National Water Commission report notes:
The production of large volumes of treated waste water, if released to surface water systems, could alter natural flow patterns and have significant impacts on water quality, and river and wetland health.
Fracking has a longer history in the US than in mainland Australia and there is a large body of research on its environmental and health effects. Volumes of research show that rivers and waterways where treated fracking waste is disposed of contain high levels of heavy metals, such as arsenic, barium and strontium, and higher levels of salinity. High levels of radioactivity in waterways where wastewater is disposed of are also common.
Treating contaminated waste to the highest possible standard must be expensive. There are known cases of companies deliberately dumping untreated waste directly into sewers and waterways in Australia.
Australia's first case of groundwater contamination as a direct result of CSG activity was confirmed in 2013. Drilling in the Pilliga State Forest by Santos contaminated an aquifer with a range of toxic elements, including uranium at levels 20 times higher than safe drinking water guidelines. For the record, although the NSW EPA had the scope to fine the company as much as $1 million, the company was fined a paltry $1,500.
Surface water has also been contaminated with toxic wastewater from fracking. Hunter Water warned AGL and Transpacific, the company AGL hired to dispose of its fracking waste fluids, that releasing flowback fluids into the region's sewer network was a breach of its wastewater criteria. Transpacific released it anyway and was fined $30,000 by Hunter Water. The EPA later found that neither AGL nor Transpacific had breached their environment protection licence conditions.
The EPA confirmed that Metgasco had illegally disposed of over 1 million litres of CSG wastewater at a Casino sewage plant, in breach of conditions for management of the plant. Metgasco's wastewater holding ponds were insufficient to hold the amount of waste produced, and the company was suspected of removing the wastewater from their ponds to stop them from overflowing.
In 2014, the US Environmental Protection Agency found that the fracking companies illegally injected about 3 billion gallons of fracking wastewater into central California drinking-water and farm-irrigation aquifers.
High levels of toxic chemicals, including arsenic, thallium and nitrates, were also found in water supply wells near the wastewater disposal sites. Arsenic is a carcinogen that weakens the immune system, and thallium is an ingredient of rat poison.
A subsidiary of Exxon Mobil faced criminal charges over a hazardous waste spill after it was alleged they deliberately removed a plug from a wastewater tank, releasing 57,000 gallons of contaminated water and allowing it to spill onto the soil. The company, XTO Energy, contested the charges and said their actions caused "no lasting environmental impact".
Deep Well Injection
Until recently, one of the industry's preferred solutions for disposing of its waste in the US was to inject it deep underground into purpose-drilled disposal wells. This practice, sometimes also called reinjection, is now strongly associated with increased seismic activity.
There is currently significant interest in deep-well injection as an alternative to evaporation ponds in Australia. Mineral Resources Tasmania has said reinjection will not be done in this state, but is silent on the issue of what will be done. The question of what measures will be adopted to treat and dispose of massive quantities of toxic and possibly radioactive waste remains a mystery.
Earthquakes are a significant issue now linked to fracking activities. In 2011 the British Geological Survey confirmed that the increase in seismic events (where) were a direct result of fracking by Cuadrilla Resources. Shortly thereafter the UK adopted a system of ceasing all fracking when there is a 0.5 increase in earth tremors. Other countries, including the US, British Columbia, Canada and Italy, where fracking and deep well reinjection haven't been banned, have also recorded an upsurge in seismic activity.
Geologists linked a series of tremors and earthquakes under Ohio's Appalachian Mountains to fracking. Fracking companies in Ohio are now required to install seismic monitoring equipment and to suspend fracking operations if tremors greater than 1.0 magnitude are recorded.
The US Geological Survey and Oklahoma Geological Survey established a strong link between the practice of disposing of waste water into wells and the sharp increase in the number and intensity of earthquakes in the state. Oklahoma historically experienced an average of two magnitude 3.0 or higher earthquakes per year. Since reinjection became relatively commonplace, the state has had a record number of earthquakes - 109 quakes in 2013 and 145 in 2014. Since 2009 twenty quakes have measured 4.0 to 4.8 on the Richter scale, and the largest quake in Oklahoma's history, a magnitude 5.6 earthquake, occurred in 2011.
The unconventional gas industry, which maintains that waste disposal, not fracking, is the probable cause of quakes, says the extent of fracturing can be monitored and controlled to prevent earthquakes. Chemical tracers and seismic data can be used to track the growth of fractures. The problem with chemical tracers is that they can take up to a week to be detected in flowback, so they don’t provide real-time tracking.
The tracers are naphthalene derivatives, which break down with heat and pressure to form benzene derivatives. The exact breakdown of the 16 tracers commonly used isn’t known because the breakdown is dependent on the presence of other chemicals. The use of tracers could be substantial in earthquake prone regions like the Midlands and northern parts of Tasmania.
Seismic data is real-time, but the cost of this equipment is a factor in determining its use during fracking. The immense pressures used in well operations can cause persistent tremors in the order of 2.0 to 3.0. Seismic activity is also regarded as a potential suspect in the number of well integrity failures.