How Landfill Works: There's Way More Going on Here than You Think (REUPLOAD)

Unless you’re a naturally curious or environmentally conscious person, chances are you don’t think too much about your garbage once you put it out on the curb. Why would you? The science of garbage dumps, or landfills if you prefer, has pretty much been perfected, and if you’re not thinking about it, it’s a good sign that things are working exactly the way they’re supposed to. You’d probably think about it a lot more after a bit of dysentery or bubonic plague, of course, but that these problems aren’t occupying your mind on a daily basis, as they once would have, is testimony to just how effective modern sanitation is.

Virtually all countries have adopted sanitation regulations, and to varying degrees, depending on where we’re talking about, refuse disposal services operate according to these rules. Guidelines specify how refuse is to be collected, how environmentally friendly refuse disposal should occur, the acceptable conditions at landfills, as well as plans for landfills well into the future. The fact is that modern refuse collection standards and environmentally friendly disposal practices are some of the most underappreciated services today, ticking along in the background and in most cases remaining more or less invisible. Compare this to as recently as the mid-1800s when dumping garbage in the gutter was the accepted norm, including everything from dead animals to human faeces, and thank whichever deity you prefer that we live after the “Age of Sanitation.”

So before we get to the details of how modern refuse is handled, let’s first get a better idea of how the Age of Sanitation transformed sanitation standards into what they are today.

The Age of Sanitation

First and foremost; public sanitation standards are a shockingly new addition to society. Now yes, there is a reference to the banning of throwing garbage in the street dating back to 3,000 BCE in Crete, and in Athens, 500 BCE, a regulation was passed decreeing that garbage had to be transported outside city limits. But these rare early mentions don’t represent a global standard by any means, and the rather disturbing truth is that waste disposal didn’t start to become a widespread focus until around the 15th century. Or at least, it was around the 15th century that the population density of major metros began to spike dramatically, and sanitation got so bad as to demand some sort of solution.

Even then, the problem wasn’t so much solved as it was moved around, as was the case with Paris. Paris during the 15th century had a reputation for being filthy even by the standards of the time, and when the levels of squalor got so bad as to start causing a public outcry the city eventually had to take action. Thousands of waste collectors were hired and refuse was transported outside the city walls for disposal, but since there were no clearly thought out regulations the hoped for solution devolved into a secondary disaster. The garbage was simply dumped outside the walls, and before long the piles grew so high as to provide easy access into the city to any would be attackers.

We’re not singling out Paris, of course, similar problems existed in virtually every major metropolis at that time, and, not surprisingly, this era also happened to coincided with rampant disease including the infamous Black Plague.

The Age of Sanitation officially kicked off in 1842, prompted by a report in the United Kingdom that directly linked unsanitary conditions to widespread disease. The report was a breakthrough, and although really just confirming what had long been suspected, that the report came from official sources was enough to jumpstart governments into taking sanitation seriously. However, it certainly wasn’t a case of the problem being solved overnight. On the contrary, over a very long and complicated timeline sanitation standards were generally first introduced starting with upper-class neighbourhoods until gradually spreading out across whole metros.

Sewers and water treatment facilities were the primary focus, while refuse disposal remained a secondary priority for decades. Lacking any concrete regulations, the general approach to refuse disposal was an “out of sight, out of mind” mentality, meaning that refuse was simply piled where it wouldn’t be seen without too much thought given to environmental impact. The position of landfills was also completely uncontrolled, and it wasn’t uncommon for a dump to be located just a mile outside city limits.

Refuse was simply piled as high as possible before moving on to a new location, and in some cases it was burned immediately upon arrival. Thankfully it didn’t take too long before a connection was made between the toxic fumes wafting into cities and a new wave of serious respiratory ailments.

Meanwhile, in places like New York City refuse was often dumped into waterways or even directly into the ocean, a norm that lasted until it was fully outlawed in the mid-1900s.

Sanitation regulations were, of course, eventually introduced in every city in the world, though this occurred across different timelines and in general, although progress was made and sanitation did increase substantially, it wasn’t until around the 1960s and 70s that the regulations we live under today were firmly in place.

As far as landfills are concerned, the modern layout we use today was actually researched and sometimes put into practice since at least the early 1900s. But, due to the costs and efforts involved modern landfill compositions didn’t become standard until laws forced garbage disposal companies to get on board.

Speaking of modern landfill standards, let’s get into the globally accepted standard by which a landfill must operate.

Modern Landfill Science

So what happens at landfills, can this sort of solution be environmentally friendly, and can it possibly be sustainable? Well, keeping in mind the situation of just a few decades ago, modern landfills really are incredibly well controlled and regulated, and although having garbage in the ground is always going to have environmental impact to some extent, the effects have been dramatically minimised.

The core idea of modern landfills is to keep refuse separate from water and air, therefore allowing it to decompose without spreading harmful chemicals to the surrounding environment. As refuse begins to decompose the primary concerns are “leachate,” contaminated liquid that may seep into the ground, and methane which naturally vents into the atmosphere. As far as methane is concerned, it has been linked to global warming which we won’t be getting into in this video.

For now, we’re only going to acknowledge that the methane created in landfills is monitored to ensure that the venting process occurs normally and that there’s no dangerous build-up. Methane can also be harvested and may even be fairly lucrative, which we’ll get to later.

Let’s focus on the biggest immediate environmental threat; leachate. To prevent leachate contaminating the surrounding soil, and by extension leaking into ground water, each landfill is contained with a layer of plastic lining and an additional layer of compressed clay. Plastic liners are generally 30 to 100 millimetres thick and are carefully installed to ensure that no leaks occur. Compacted clay layers, meanwhile, although not always used are exactly what you think they are and act as a secondary safety layer.

The problem with water-tight containing layers, however, is that they create a secondary problem, namely that the landfill will gradually begin to fill with natural rain water. Hence, each landfill also comes with a built-in drainage system. Drainage systems pipe rainwater out as it gathers, first to concrete or gravel lined ditches which provide filtering, then to collection ponds.

Collection ponds, referred to as “sed ponds,” are where the liquid is allowed to settle, and if no leachate contaminants are detected the water is allowed to return to the environment. If leachate is detected, it’s a sign that the leachate filtering system isn’t working correctly and action will be required to get the system back in order.

The leachate drainage system is similar to the rainwater drainage system but concentrates exclusively on draining out harmful chemicals. Gravel layers between landfill cells collect leachate, and a network of pipes drain the liquid out into separate collection ponds, referred to as sumps. Liquid in sumps is drained into a treatment facility before also being allowed to return to the environment.

Now, ensuring that harmful chemicals are contained is obviously a primary concern, hence why each landfill is required to have a set of mandatory monitoring wells. Wells are sunk on either side of a landfill, uphill and downhill, providing a means for testing ground-water prior to it moving beneath the landfill, and once it’s passed beneath the landfill. The quality of water from each well is compared, thus giving a good indication of whether any contaminants are seeping through the containment layers.

But what about the refuse itself? Solid waste delivered to landfills is first compacted by specialised machinery, after which it’s arranged in the landfill in so called cells. Cells themselves may be arranged according to the type of refuse, but generally speaking are arranged in a layered grid, with each layer separated by the various drainage and filtration systems already mentioned.

Once a layer is completed, it will again be heavily compacted before being covered with a final layer of soil. This pattern is repeated until the landfill reaches capacity, with enormous effort going into making the most of available space.

Lastly, once a landfill reaches capacity it is capped and prepared for repurposing. Capping refers to putting an additional layer of containment plastic and clay over the top, an additional 2 feet of soil, as well as erosion mats and finally a layer of vegetation. Carefully selected low root penetration vegetation, along with the specialised mats, helps to prevent erosion.

Once capping is complete, the landfill is monitored for an additional 30 years, though work generally starts on converting the space immediately. In most cases landfills are converted into parks or sometimes golf courses, with a perfect example being the now picturesque, ineloquently named Mount Trashmore in Virginia Beach.

In the case of Mount Trashmore the developers clearly leaned into the area’s reputation as a previous landfill, essentially inviting visitors to see for themselves how serene and beautiful the location is today. The primary draw of Mount Trashmore is an 18 meter (60 foot) tall by, 243 meter (800 foot) long manmade mountain created using compacted refuse. The entire area is 165 acres including two lakes, vast playgrounds, skate parks and multiple hiking trails.

So, I guess this means that landfills really are a sustainable solution, and we have nothing to worry about. Of course, it’s not that simple.

Are Landfills Sustainable?

In 1987 a fairly well-known story unfolded, now often referred to as the Long Island Garbage Barge incident. Residents of Islip Town and New York City witnessed a barge carrying 3,100 tons of solid refuse stuck out at sea for months, forced to sail back and forth as the delivery was denied again and again. It seems that landfill space on Long Island was rapidly dwindling, and so a deal had been struck for the garbage to instead be transported to North Carolina.

However, once North Carolina residents got wind of the plan they weren’t particularly pleased, and so the barge was turned away at the last minute. In desperation the trash shipment was rerouted to Louisiana, Texas, Florida, Mexico and Cuba, each of which also refused to let the barge dock. Mexico and Cuba allegedly even threatened to sink the barge with artillery should it approach, so anxious were they to not have the garbage anywhere near their shore.

The barge was eventually accepted in Brooklyn where the refuse was incinerated, and the ashes buried.

Now, that story is remembered as somewhat of a whimsical joke today, but it certainly does also raise more than a few questions. If landfill space was already so scarce in 1987, isn’t it a sign that a serious problem was already brewing even back then? In fact, where does the refuse in that region go today, if there was such a drastic lack of space more than two decades ago? You’ve perhaps even heard that the world is projected to run out of landfill space in the next 10 years, or something along those lines, which must mean that humanity is already on the edge of catastrophe.

We are, of course, not making light of environmental concerns, but if you stop and think about it for even a moment you’ll quickly realise that clickbait claiming landfill space will run out any time soon is purposefully taking information completely out of context. There isn’t, speaking in strictly practical terms, a shortage of space for landfills. There is, however, an escalating cost associated with creating new landfills, expanding existing landfills, transporting refuse to wherever available landfills happen to be, monitoring old landfills and transforming capped landfills into usable space. For a quick bit of perspective, it can cost 10s of millions, or even 100s of millions to convert a capped landfill into a park, and the return on that investment isn’t exactly scintillating.

As far as running out of space goes, the truth is that cities generally operate on a 15 to 20 year buffer, meaning that the space currently available will last for roughly that period before the situation starts to get critical. What this means in turn is that there is always around a 10 to 15 years period to organise new landfills and prepare them for future use.

Now, let’s go back to the Long Island trash-barge story for a moment. At the time the Long Island Barge was stuck out at sea, roughly 80 percent of all refuse in the area landed up in landfills, 13 percent was dumped in alternative locations, 6 percent was incinerated, and just 1 percent was recycled. Today in that same region 50 percent is incinerated, 35 percent recycled, and just 15 to 20 percent is put into landfills. So, does this mean that progress is being made and the situation has been brought under control?

Again; it isn’t really that simple.

Relatively new initiatives have been adopted in various regions, and with a surface glance it does seem that rapid strides are being made in sustainability. However, these sustainability efforts themselves have been the source of much debate, recycling in particular. Critics refer to recycling as a “zero sum game,” meaning that the amount of energy, effort and cost required to recycle more or less equals the environmental harm of the recyclable item itself. We won’t be going into that controversy in this particular video, but let’s just say that, as with most globe spanning issues of this nature, it’s all much more complicated than it first seems.

As for other sustainability initiatives, there is “gas to energy” and “waste to energy.” Gas to energy refers to collecting naturally occurring methane from landfills, treating it and converting into energy. The practice can be rather profitable, with it being estimated that “gas harvesters” can potentially make around $12 million annually for 3 straight decades.

“Waste to energy,” meanwhile, refers to a process whereby refuse is incinerated, the heat generated used to create steam, and the steam used to generate electricity. There are, however, once again criticisms with these initiatives. “Gas to energy” is non-renewable and requires expensive infrastructure, while “waste to energy” allegedly creates air pollutants that outweigh any positive energy gains.

To be clear; we aren’t arguing in favour or against either; the point we’re trying to make is that true sustainability isn’t simple, and that existing solutions perhaps need more refinement before being widely accepted.

So back to the original question; are landfills sustainable? There is no doubt that the world generates over 2 billion tons of refuse annually and that the overall number is expected to increase 70% by 2050. Taking that into account, as well as the exponential increase in costs, and that capped landfills aren’t intended to be reused, it logically seems like certain, more densely populated regions are going to be running into problems at some point in the future, be those problems related to cost, logistics or both. But in reality, those impacted regions will likely be handling the problem on a local scale rather than a global scale, so it also seems likely we won’t be seeing any sweeping, transformative changes that suddenly eliminate the challenges of refuse any time soon.

With that being said, if you step out your front door and don’t find yourself ankle deep in dead horses and human waste, you’ll probably agree that humanity has made enormous strides as far as sanitation standards are concerned; and, in a remarkably short period of time. To put it another way; as much as we still have room to improve, it helps to remember that we live in the best possible time to be alive as far as sanitation is concerned.

Key Takeaways

• Modern sanitation standards have significantly improved public health since the mid-1800s.
• Landfills are designed to minimize environmental impact by controlling leachate and methane.
• The Long Island Garbage Barge incident highlighted early landfill space issues, but space isn’t the primary concern today.
• Sustainability initiatives like recycling, gas-to-energy, and waste-to-energy face debates and criticisms.
• While landfills are well-regulated, future challenges include increasing costs and local waste management issues.

Sources

• Original MegaProjects video: How Landfill Works: There’s Way More Going on Here than You Think (REUPLOAD)
• Hero image source by Mustang Joe / openverse, cc0.

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