Eye in the Sky Could Track Methane Emissions : IN DEPTH: Game of Drones - Landfill Gas Monitoring Development

A landfill site in the UK is using a drone to help monitor gas emissions and get a better picture of landfill behaviour throughout different seasons. With the potential to lower monitoring costs and provide increase frequency of monitoring, what does it mean for site operators? Matt Clay investigates.

Is it a bird? Is it a plane? No it’s an Unmanned Aerial Vehicle (UAV), or drone, for short. While this expression might not prove as snappy or heroic as the original version in the Superman films, it’s one you could soon start hearing more. Not to be confused with military, unmanned drones, the commercial remote controlled alternative is now proving extremely popular with both amateur photographers and professional organisations.

A report from Juniper Research predicts that annual revenues from commercial drone sales are expected to reach $481 million this year. That’s an impressive 84% increase from $261 million in 2015.

A low price point has significantly reduced the barrier to entry for most people and even online retailers are jumping on the drone bandwagon. Amazon launched an impressive yet controversial PR campaign suggesting that in the future its Prime Air service would deliver packages to customers using drones.

Such success and the increased buzzing of drones in our skies has inevitably lead to questions over safety and privacy: many drones can be fitted with cameras to capture aerial footage.

This month headlines emerged that an Air France plane came within 16 feet of colliding with a drone as it was preparing to land at Paris’s Charles de Gaulle airport. Birds of prey are even being trained in Holland to view a drone as a potential meal and take them down. London’s Metropolitan Police has reportedly shown interest.

Despite the controversies, as expected with many new technologies, UAVs, or UASs (unmanned aerial systems) are increasingly being applied to commercial applications in new fields such as mapping, inspection and monitoring. And it’s the latter where the technology is being integrated with the waste management industry: UK landfill gas monitoring.

A project is being run by the University of Manchester and regulator, the Environment Agency (EA). The trial covers both an active and a closed landfill near Bury, a town in Greater Manchester with the aim to identify methane emissions during seasonal fluctuations. After all – landfill gas emissions will vary drastically from winter to summer.

Speaking to WMW magazine, Professor Peter Hollingsworth, a lecturer in aerospace engineering at the university says one of the main objectives is to develop a cheaper way to monitor methane more regularly.

“The estimation for the inventory for these sites is done using a dial instrument, which is a lorry mounted instrument and is quite large,” he says. “It has its limitations. The EA is hoping to improve this process and make it substantially less expensive to implement.”

To comply with the Landfill Directive, currently operators of closed sites need to monitor methane emissions through the cap, measured at a number of points using flux boxes.

Mark Bourn is a principal scientist on climate change in the EA’s resource efficiency team, as well as the project manager for the Manchester trials.

He tells WMW: “We don’t really currently have a particular effective or cost effective means of actually quantifying whole site emission for methane. What the current environmental permitting regulations cover in England are for an annual flux box, sometimes called flux chambers, so these are boxes that you place on the capped areas and the change in concentration and time gives you an estimate of flux. They’re not particular good at giving a picture of what’s coming off the site whole site. They tend to under estimate the methane emissions and you can capture all the different types of emissions.”

The aim of the project is to attach gas monitoring systems to drones, fly above the landfill sites and provide data on how the landfills behave and fluctuate during different seasons.

Currently, the type and scale of methane sensors needed for the project are not available on the market but are verge of coming to the market. To date, the trial in Manchester has been developed using a CO2 monitor. Hollingsworth says by measuring the downstream and upstream CO2 coming off the landfill, methane can be estimated.

The professor is also quick to distinguish the landfill UAV trials from the “rogue” drones making the mainstream media headlines.

Commenting on the stories of the near collision with the French airplane, he says: “I hate to call them rogue but they are rogue drone operations that are in airspace and being operated outside of the law in airports and potentially endangering aircraft, which is forbidden. All of our operations are done following the Civil Aviation Authority (CAA) rules and anybody that would offer this as a service would have to have permission for aerial work from the CAA, so at least they would be tracked and monitored.”

With the adoption of the drone technology, it raises the question of how bad are the UK’s greenhouse gas emissions (GHG)? In total, when broken down by gas, carbon dioxide is the big hitter, accounting for around 80%. Methane comes up second, with 10% and the remainder is a mix of nitrous oxide and other fluorinated gases.

However, with methane estimated to be 25 times more potent than its bigger CO2 brother, this is the reason why efforts are being increased to get a clearer picture on what’s being emitted.

In terms of the country’s waste industry, between 1990 and 2013 GHG emissions decreased by 67%. This has been attributed to a variety of factors, including less organic waste being landfilled and more landfill gas being used for energy. During this same period methane emissions were also reduced by 69%.

Yet it’s not just environmental reasons why the UK wants more data on its landfill sites; it also makes business sense for landfill operators.

“One landfill operator is interested there because any methane emissions are captured for energy generation at the onsite power plant,” says the University of Manchester’s Hollingsworth. “Any fugitive emissions from the closed cap site are a potential loss of revenue.”

So if a landfill operator is running a landfill gas to energy business, it’s within his/her interest to make sure as much gas as possible is being captured and not escaping. The latter only leads to a “reduction in overall costs or improvement in their profit line” says Hollingsworth.

Efforts from the government’s Waste & Resources Action Programme (WRAP), coupled with an increased environmental awareness with the general public means that we are throwing away less, specifically less food. For example, between 2007 and 2012 there was a reduction of 1.3 million tonnes of household food and drink waste.

Hollingsworth believes the monitoring project will help us understand the knock-on effect such disposal habits are having on landfill sites.

“What we’re seeing is a change in the characteristics of the food being dumped in landfill,” he says. “There’s the reduction in food waste. We’re also seeing a lot of other non-food waste, carbon based waste going to waste to energy and so that does not end up in landfill. Going forward one of the things that will be interesting, especially if we can measure methane directly, is to be able to categorise how that’s evolving. We have ideas and have estimates but we don’t really know what’s happening yet until we can measure.”

Hollingsworth concludes by saying that as well as data on emissions, the aim of the project is to get landfill operators comfortable with the UAVs flying around their sites.

“One of the things we’re doing in our test sites is proving to the landfill operator that the UAVs can be operated safely over an active site and around a closed site,” he says. “Every time we fly up there we get a little leeway. They were very conservative on where we can operate when we started operating. As much as we’re proving the technology and realising yes we can do this with a CO2 sensor but the methane sensors is where we want the final product to be, we’re also providing the operational concept. I think that’s actually the bigger outcome as the landfill operators and the community become more accustomed to the operations it makes the overall process much more feasible.”

Although initial reports suggest UAVs could soon start monitoring methane across 200 landfill sites in the UK, this is a long way off, according to the EA’s Bourn.

“Understanding how much methane is coming from landfill sites would be helpful as we will be able to quantify when you put waste into a landfill how much is capture and how much methane is emitted to the atmosphere,” he adds.

The project manager says that further discussions will be required with Defra and the industry following final results from the Manchester trials.

“I think there is a big step to be taken from this technology. I think it needs a bit more work to make sure we can validate it and make sure it’s an effective method to quantify emissions…I can’t say this stage if it will be applied to the modern permitted landfill sites – that is a possible outcome and it’s possible that we could look to replace the current requirement to do an annual flux box survey to an annual survey using this method.”

Still at a relatively early stage, the Manchester trial is proving that drones can be applied to modern waste management practises. Had mobile methane technology already been on the market, the project would no doubt have been closer to a full role out across other sites. So a few years from now, drones could soon be making an appearance at a landfill site near you.