Energy and Civilization Series: Porcupines and Environmental Stewardship

It feels like the last few articles have been kinda curmudgeonly so it’s time to shift the outlook and focus on aspirational things today. Namely that everyone’s favourite oil and gas whipping boy, Tailings ponds, can be cleaned up much faster than current estimates by application of nuclear power and the helping hand of a bunch of these guys.

I mean, not really… But look how adorable she is!

A quick recap on what tailings ponds actually are. Contrary to popular belief they are not unmonitored dumping grounds for toxic materials and waste products. There is actually a huge amount of design and consideration that goes into the operation and upkeep of tailings ponds. Hell, at my university there was almost an entire engineering department devoted to studying how to optimize the operation and efficiency of tailings separation and remediation in tailings ponds.

First and foremost, tailings ponds are meant to reclaim and purify water. They do it in the simplest and easiest way possible, by letting it sit still for a long time so all the gunk in it can sink to the bottom. Then when they are acceptably separated, the water is drained and chemically purified so that it can either be returned to the environment or used again. The solids that are left are then used as a base layer, tested for any kind of contamination from process materials and if found acceptably clean, covered with topsoil and planted with local flora. Now depending on the size of the pond and the kinds of solids in it, this can take a while

Estimates for how much water is currently tied up in the various tailings ponds in the Alberta Oil Sands can reach as much as 1.2 trillion liters ( a cube of water 1.25 Burj Khalifas on a side) of contaminated water spread out over 220 square kilometers (85 square miles). To boil that water off from 0 Celsius (cause Fort Mac is wicked cold) would take 101.7 GWYears of energy. So a 1 GW powerplant would take 101.7 years to boil away all the water and completely dry out the pond.

But! Thanks to the black magic of heat transfer and the fact that we want to capture this water and not simply blow a bunch of steam into the atmosphere, we can capture a large portion of the heat in that steam to pump more heat into the tailings that need to be dried which will help us condense that steam back into distilled water that is pure enough to drink, that can be returned to the environment. Depending on how efficient we are at retaining the heat and using it effectively we could reduce the total time to dry out the tailings ponds from 102 years to potentially as little as 20 years.

I don’t know about you but the faster we can get all the tailings ponds from looking like the left to looking like the right can only be a good thing right. (Also yes I know the left side is actually an open pit bitumen mine, so sue me)

But all this would have to take some seriously intensive processing right? Some technology we don’t have or is only on the cusp of commercialization to be able to handle the amount of material at the temperatures we are talking about. Also what the hell was I talking about at the beginning that porcupines can help us with this? Well, wonder no more!

Not nearly as cute, but arguably more useful.

This is called a porcupine dryer. It’s basically if a car radiator had a one night stand with a food processor. Blades heated by internally circulating hot oil or steam rotating against scraper bars to prevent clumps from sticking make this a little heard of but, immensely useful piece of equipment for forcing liquid out of slurries. Some of the bigger standard models can handle 40 tonnes per hour and reduce them from 30% water to 1%.

The inevitable question is, “well if this is so simple why aren’t the oil companies doing it?” The answer to that is that no one has made them do it. Tailings ponds are cheap, simple, and long term enough that they can basically forget about them for a few decades (financially speaking, they have to keep a pretty close watch on them to prevent birds landing on them or dam breaks).

But here’s the thing. I think it’s time that people start saying “No, we aren’t going to allow a society where passing the buck down the road is appropriate anymore.” If you want to make a business in this world you should be responsible for cleaning up your own mess while you are still around. Passing our problems down the road is what has gotten us into most of our current messes as a civilization so maybe it’s time we force ourselves to be better.

All the components for the answers are in front of us. So let’s start putting them together so that we don’t merely leave a better world for our children, but for us as well.

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