Hazardous Waste Disposal

<v ->So we’ve covered how most municipal,</v> industrial and wastewater is processed and disposed of. And now, what we want to talk about is how is hazardous waste dispose of. What are the sort of the safe options “for disposing of hazardous waste”. And it’s worth thinking about what are the goals of disposing of hazardous waste. And the first goal of disposing of hazardous waste is the prevention of the effects on human health and ecosystem degradation or contamination. And oftentimes, that desire to not contaminate the environment rolls back into because human health depends on environmental services, like clean water. We don’t want to contaminate that water. So storage of hazardous materials, the first thing is distance.

And I tell my students this all the time, the safest method for dealing with any problem really is distance. Distance solves almost any problem if it’s a safety-related problem. The farther you can get away from it, the less of a problem it’ll be. Inverse square law. So storage commonly occurs away from people. But as world population grows, it becomes more and more difficult to find sites that are isolated and away from people. And you also want to find sites that are away from wildlife, surface and groundwaters, and areas of unstable conditions, especially geologic conditions; earthquakes, landslides, the like.

Look, and so you can begin to think, “Okay, well, maybe Greenland and Antarctica; and maybe some places in the middle of Australia or Canada are the places to do this,” because you really do want to get away from all these things.

Typically, we’re not able to meet all those requirements. In fact, almost all the time. You’re always near some wildlife. You’re always near some surface or groundwater, or you’re near unstable conditions. And that’s because transporting hazardous waste comes with its own set of rules, regulations, and risks. So you also want to transport it as little as possible as well which conflicts with that idea of distance being safe. There’s three disposal methods typically; specific hazardous waste dumps and landfills, surface impoundments for liquid hazardous waste, and deep-well injection, again, for liquid hazardous waste. All the methods suffer from leaching, wind and water dispersal, and flood impacts. And so basically, man proposes God disposes.

We try to think of everything and plan for everything, but oftentimes, we’re unable to plan for everything. And so every waste disposal site will also have a mitigation plan and the spill mitigation plan in case something does go wrong. At least people thought about what’s the most likely thing to go wrong, and then how do we deal with that when something does go wrong.

So the first hazardous waste disposal method here is just specific dumps and landfills, and typically for a solid hazardous waste. They typically have a stricter design, construction and management conditions than your average municipal landfill. And the better because the consequences of a contamination event are more severe. But that said, the method is very similar. As you’ll notice here, it’s very similar to what you would find in a municipal landfill where you have a low permeability soil or clay that lines the bottom of the pit. The pit is above the water table or away from any surface, rivers, and the like. It has an impermeable lining.

It has a leachate collection and removal system, and attached to a treatment system somewhere or a monitoring system to look at contamination levels inside the pit. It has a drainage material to collect the leachate. And then you’ve got everything sort of stacked in there. Now here’s a picture from the Nevada test site. So this would probably be a high or low-level radioactive waste associated with nuclear testing in Nevada. You can see, it’s a very dry area, and they’ve basically loaded everything into label boxes. And once that pit is full, they’re going to cover it up. And they’ll cover it up with a low permeability surface layers of clay, and maybe even in permeable plastic.

The idea is you want to prevent water from getting into these sites. Water is the main problem because it will erode your other storage. It’ll erode those boxes of rock. The rock boxes that’ll rust to the containers. And once you get water into the site, you got problems then with the radioactive contamination or the hazardous waste spilling out, and then getting into the groundwater if your leachate system isn’t working. And remember, everything human made fails eventually. And because these are a high or low-level radioactive waste, that’s going to be around and hazardous for 10,000 years or more. These systems aren’t going to last for 10,000 years. And so it’s a real issue, continuing to monitor.

Maybe in a couple of 100 years, we might even have to dig these up again and restore them in another facility that’s similar or find a safer, more central storage solution for these.

Hazardous waste surface impoundments. You find these a lot around mines and mineral resource extraction sites where the mineral processing, the ore processing has led to a liquid hazardous waste. So like a cyanide leachate or some sort of water contamination. And the idea here is that you store the water in an open impoundment. Evaporation occurs, and you were left with your contaminant and a solid precipitate form on the bottom of the pond, or it’s stored temporarily in the impoundment until it can be processed and the water cleaned, or the liquid cleaned in a treatment facility, and then re-released in the environment, free of the hazardous waste.

They’re lined, they’re above ground. The real problem here, and especially in North Queensland where I live is we typically get cyclones. And because these are built above ground and often not in ground, there’s a real possibility that extreme weather events like a cyclone can actually overflow the impoundment and cause a breach in the berm, or the the dike or berm that holds the water in. And then those contaminated waters are allowed to flood freely through the environment and into the nearby river or coastal systems. So these are generally not ideal, but they are what they are.

Also, when they do dry up, there has to be action taken to prevent any dust or precipitate that has hazardous materials in it from leaving the site through wind. And so oftentimes, the impoundment will actually be kept full and prevented from drying out so that you don’t get a wind-driven transport of the hazardous material off site. And then finally, the last way is that hazardous waste deep-well injection where the liquid hazardous waste is actually pumped into porous rock that’s deep below any kind of aquifer. So aquifers, just a sort of a groundwater storage in porous rock. So think of it like a rock sponge, lots of little holes in it, and you can store water in there.

And oftentimes, a great deal of our water supply comes from aquifers, either unconfined aquifers or confined aquifers. So hazardous waste deep-well injection has a risk that if there’s a hole or a leak in that pipe somewhere as it passes through the aquifers, you’ll actually be injecting hazardous waste into your aquifer if you’re not super careful about the lining of the well itself. There’s also the possibility that unseen or undetected faults or geological features will allow that injected hazardous waste to move back into the aquifer, either along the fault plane or joints in the rock.

It takes a lot of careful work to make hazardous deep-well injection work. And if the hazardous waste is a long-lasting waste as well, you’ve got to think about geologic time and how it might move not only in 100 years, but in 1,000 years as well. So all of these are methods for storing hazardous waste. Look, these are the ways that waste your store today. In the past, people just sort of dumped the stuff in the middle of nowhere, and they assumed it would just disappear or be diluted. And it turned out that dilution was not the solution to pollution. And I think I’ve said this before.

People used to just drive barges out into the middle of the ocean and dump their nuclear waste. And there are still parts of the ocean floor today where you can find hazardous nuclear waste. And it’s not a good idea. But since the 1980s, and since the sort of after Rachel Carson’s “Silent Spring”, we see that cities, especially cities and regions have begun to designate hazardous waste sites. And to complement that, they’ve begun to gather household hazardous waste. And there’s this recognition that hazardous waste isn’t just generated by industry, it’s generated by households as well. And so oftentimes, there’ll be a hazardous waste collection day.

Or in Australia here, we can take our hazardous waste any time to the pit generally and dispose of it properly there.

This idea that you could just sort of dump stuff anywhere in the past has led to a number of contamination sites. And it’s not just the United States. I’m using this because it’s a publicly available image of what we call Superfund sites in the United States. And these are hazardous waste sites, either regulated or unregulated. And they are extremely expensive to clean up. Especially if it’s a contaminated soil, you’ve got to essentially scrape the contaminated soil off the surface. And then you’ve got to take that soil, and you’ve got to bury that soil in a pit somewhere that’s lined and all that stuff. You’ve got to bury your soil in your soil in its very inception.

But all the red sites are current national priorities list sites. So these are hazardous waste sites that haven’t yet been dealt with. Yellow or proposed sites that have contamination, but haven’t been fully identified,

having been fully identified or accepted yet as a national priority. And then the green sites are few and far between, but they’re sites that have been dealt with. And so they were a hazardous waste site, and they’ve been cleaned to a level that’s deemed relatively safe. Because of these kinds of waste sites and the expense of these waste sites, in most developed nations, we’ve developed a polluter pays principle. And this kind of stuff still goes on today. We still generate hazardous waste on industrial sites. But now, what we do is we ask that polluters pay to clean up or we actually ask for a deposit in advance.

That is equivalent to what it would cost to clean up the site if that company abandons the site. And this is what typically happens, not typically, but what often happens is a company will come in. They’ll mine, or extract a resource, or they’ll produce a product on a site. And then when they are done producing, or when they go out of business, they say, “Op, sorry, we’re out of money. We don’t have enough to clean up.” And they leave it to the taxpayer or the government to clean up the site. And when this happens, everybody pays to clean up that site. And essentially, the business or enterprise gets away scot-free

without applying the environmental cost to the cost of their product. So we moved towards a polluter pays principle when we can. And now, we’re actually beginning to collect in advance the cost of clean-up. So in case a company does go bankrupt, it’s environmental responsibilities can be met. Illegal dumping is also being reduced. It still occurs, but it is being reduced. Illegal dumping creates health risks along with the financial headaches for dealing with it. And now, industrial nations used to illegally dump in developing nations to avoid the costs in developed nations. ‘Cause heavy environmental regulation, you say, “Oh well, it’s cheaper if we take our hazardous waste to Indonesia.

We’ll just dump it there because it doesn’t cost us anything to dump it there.” And essentially, what you’re doing is you’re offshoring the environmental cost; again, that footprint onto another nation

and another nation’s people. So there is an international treaty called the Basel Convention, which seeks to reduce illegal dumping of hazardous waste. And it also seeks to reduce the illegal dumping of hazardous waste in other countries, which I think is a really interesting part of this is that it essentially says, “Look, you need to be responsible for your own waste. And you can’t just offshore your environmental responsibilities. And so you need to take on the cost of correctly and appropriately disposing of your hazardous waste.” And that’s also led to this mandated cradle to grave tracking of hazardous waste.

So if I order a liter of toluene for my environmental research or my geochemistry, then I need to keep track of that one kilogram of toluene, not only when I receive it, but when I use it. And then when I dispose of it, I need to keep track of where did I dispose of it. I can’t just pour it down the drain. I have to put it in the appropriate containers. And then I have to take those containers to the appropriate disposal facility and get a receipt for that, so that I can prove that I have not only purchase that hazardous waste or hazardous material, but I’ve disposed of it in the correct manner.

And this is a big deal, and it’s costly, and it’s expensive. But I tell you what, it’s a hell of a lot cheaper than trying to clean up an illegal waste dump. So by doing this, we reduce the cost of hazardous waste disposal. And it does. These kinds of legal mandates actually do encourage responsible and accountable behavior. And along with things like the Basel Convention, it really forces people to think about the cost of what they’re doing and what they’re using, and how to appropriately dispose of it.