Garbage has problems

It?s a robot designed to scale mountains of trash and traverse acres?sometimes hundreds of acres?of refuse commingled with putrefying garbage, all in search of one thing: methane gas.

Methane is a hydrocarbon greenhouse gas and is very explosive, but also valuable if you can find it and then extract it. The mobile robot?s prospecting laser is not on the hunt for just any kind of methane, but rather a particularly nasty and dangerous variant known as landfill methane.

Landfill methane

Although it contains forty to sixty percent methane, it also harbors carbon dioxide as well as nitrogen, sulfur, mercury and radioactive contaminants such as tritium (radioactive hydrogen).

According to the Environmental Protection Agency, the U.S. has 3,091 active landfills and over 10,000 old municipal landfills, which are responsible for about one-third of all methane emissions in the United States.

Methane is one of the most potent greenhouse gases: It’s 20 to 25 times more powerful in trapping heat in the atmosphere than carbon dioxide. Landfills are responsible for about one-third of all methane emissions in the United States.

Globally, methane emissions from landfills are estimated to be between 30M to 70M tons each year and account for two percent of the total greenhouse gas emissions released by human activity.

Although generated by decomposition not only in landfills but also in swamps, getting rid of as much methane as possible is a worthwhile effort that can also be quite profitable.

Nasty yet profitable

Rising up over these landfill wastelands, odorless methane gas mixes with hydrogen sulfide from decomposing organic matter, giving off a noxious odor of rotting eggs. The stronger the smell, the closer the robot is to hitting landfill pay dirt.

Extracting this landfill methane can realize significant profit by selling electricity from burning landfill gas?as much as $1 to $2 per ton of waste dumped; even more by selling the resulting energy as ?green energy? through energy marketers or using the power to meet a state?s Renewable Portfolio Standard, which can take in as much as $5 per ton or more.

Artificial olfaction

Global expertise in prospecting and finding gases such as landfill methane can be found at a small university in Sweden, orebro University, and its Center for Applied Autonomous Sensor Systems (AASS). The AASS specializes in the science of gas sensing with artificial sensor systems, called artificial olfaction.

?We study in particular open sampling systems,? they say, ?where the gas sensors are directly exposed to the environment.? Inother words, real-world sampling far away from any controlled laboratory, which is good because that?s where landfill methane lives.

?Combining artificial olfaction and mobile robotics, we are developing the foundations for Mobile Robot Olfaction where it is our goal to further develop systems known as “electronic nose” (e-nose) towards a “mobile nose” (m-nose). This is where their latest creation, Gasbot, enters the gas location and recovery process.

Recent PHYS.ORG report

PHYS.ORG recently filed this report on current activities going on with the AASS researchers.

?In a new effort, the team in Sweden affixed a Tunable Laser Absorption Spectrometer sensor to a Clearpath Robotics Husky A200?a mobile robot. They also added a GPS device.

?The idea is that the robot will roam around a landfill pointing its laser randomly around it as it goes. As it does so, it will be able to take measurements of methane levels around it and then use that information to build a map.

“Thus, to monitor methane levels at a landfill, all technicians would have to do is read the map sent wirelessly from the robot in the comfort of an indoor facility.

?The Husky A200 is essentially a programmable automated box on four wheels?its purpose is to carry equipment or supplies around in a ruggedized fashion. It was designed to be used by researchers working on various robotics projects and is thus highly amendable to multiple configurations via customization.

?The researchers report that while they were pleased with the initial successes of the robot prototype, they acknowledge that much more work will need to be done before such a robot will be ready for deployment in a real landfill.

?Specifically, it will need to be more ruggedized to deal with bigger and the more random nature of obstacles. Also it will need an upgrade to be able to scope out wide areas of terrain autonomously for long periods of time.

?The ultimate goal is to design a robot that can be produced in large numbers for use in a wide variety of environments as a for-profit venture.?