The ongoing debate over how and whether hydraulic fracturing poses a threat to the environment covers a whole host of issues – land use, earthquakes, drinking water contamination, methane emissions, and even the sustainability of fossil fuel use. While some issues remain mired in a lack of hard data or fundamental philosophical differences, companies all over the US are generating innovative solutions to those that can be addressed, such as methods to reduce water use and methane emissions during production.

Some of these technologies have already proven effective, while others are at the very early stages of commercial use. The following list provides a taste of some of the fracking clean-up technologies that companies have developed, or are in the process of developing, to address water use and methane emissions. We will be exploring them in more depth, looking at benefits as well as drawbacks, over the coming weeks.

Reducing water use:

Hydraulic fracturing usually requires large volumes of water – a single well can use millions of gallons, according to FracFocus, a voluntary disclosure registry where producers can provide information about the chemicals they use in the fracturing process. These water requirements can be costly – specifically when trucked to drilling sites – and have led to water-scarcity concerns in dry areas with considerable unconventional oil and gas reserves, such as Colorado.

Companies have developed, and are advertising, multiple ways to reduce water use, such as recycling well wastewater, and even cutting water out of the hydraulic fracturing process altogether.

Wastewater clean-up:

Technologies that remove organic materials and contaminants from water that has returned up the wellbore post-fracking – “flowback water” – can allow drillers to reuse at least a share of that water to drill new wells. Recycling can reduce water use dramatically, and if cost-effective, can also cut down on drilling expenses.

Florida-based EcoSphere provides oil and gas producers with mobile water-treatment plants that use oxidation to remove bacteria, petroleum products and other organic compounds from flowback water. Advanced biofuels firm OriginOil has developed a process that uses electromagnetic waves for the same purpose.

Waterless hydraulic fracturing:

Another method of reducing water use in the hydraulic fracturing process is to eliminate it altogether, and use liquefied petroleum gas (LPG), instead. The LPG category includes the propane you would use in a gas grill, or the butane you find in a cigarette lighter.

Calgary-based GasFrac uses LPGs, primarily propane, in gel form in lieu of more conventional hydraulic fracturing fluids. Texas-based eCORP, which is involved in various segments of the energy industry, announced plans to offer non-flammable liquid propane fracturing services in April.

Capturing fugitive methane emissions:

How much methane is released into the atmosphere during the hydraulic fracturing process is a matter of ongoing study and debate. The Environmental Protection Agency recently made a downward revision to estimates of methane released during the transmission and storage processes, citing voluntary reductions and a drop in the use of cast-iron and unprotected steel pipelines.

But reducing methane leakage from the drilling process remains a concern, and technologies already exist to help companies cut down on what are called “fugitive emissions”, which can occur at several points in the process of drilling, compression and processing. The EPA’s Natural Gas STAR program has been working to encourage producers worldwide – those that use hydraulic fracturing and those that do not – to adopt cost-effective mechanisms to reduce methane emissions for two decades.

The Natural Gas STAR program promotes the use of the following low-cost methane emissions-reduction technologies:

Plunger lift systems, which remove fluids that can accumulate in a well and disrupt gas production, can be used as a lower-emitting alternative to ‘blowdowns’, which involve venting the well. Providers of these systems include large oilfield services firm Weatherford.

Replacing “high-bleed” pneumatic devices – used to control liquid levels and vales, and to regulate pressure – with “low-bleed” alternatives – or retrofitting them can cut back on methane emissions.

There are several methane leak detection and measurement tools on the market, such as the acoustic leak detector and quantifier, which uses sound levels to gauge leaked volumes, according to EPA team leader for the Global Methane Initiative – Oil & Gas Roger Fernandez.

Green Completions:

As the use of hydraulic fracturing in US oil and gas production has become far more common, the EPA has established a rule requiring “green completions” – capturing volatile organic compounds (VOCs) and methane, and fracking fluid that return up the well bore  – from hydraulically fractured and refractured gas wells from January 1, 2015. Requirements include switching from high-bleed to low-bleed pneumatic devices and installing emissions control systems at drilling-site storage tanks.