by Michael Smith
Try to imagine an air-tight dome with teams of robots working alongside people in space suits as they sift through the corrosive waste of past generations, looking for scraps of plastic and nuggets of precious metals.
This isn't the opening scene of the latest Sci-Fi movie about to hit the screens of our movie theatres, but the vision of one of the leading thinkers of the British waste industry, describing how landfill mining might look a few decades down the line.
Freelance waste consultant Peter Jones, until recently a director at waste giant Biffa, was among the speakers at a London conference looking at likelihood of our old rubbish dumps becoming the mines of the future.
With raw materials becoming increasingly scarce and the price of oil rising it isn't stretching credibility too far to assume that what we threw away in times of plenty might be seen as a valuable resource in the not-too-distant future.
But is digging up this booty technically and economically feasible, and what will be left after years of decomposition in a hole in the ground?
Mr Jones warned that it might be a while before its safe to unearth these tarnished treasures, describing the grim reality of the rotting mess that remains underground for years after a landfill is capped and the fields above landscaped.
"This is not a friendly or benign environment - it's an extremely corrosive atmosphere," he said.
"When you open these things up,”, he said, “you will certainly discover that it's pretty awful in terms of decomposition.”
"We won't be able to go into any landfill that's closing today for about 30 years."
He said the waste would need to be sorted in air-tight domes and those inside would need to wear hazmat suits, or leave the work to machines.
And when it comes to recovering materials, there will be a fairly short list of useful resources left, according to Peter Jones.
Organics will have decomposed - and hopefully the subsequent methane burnt off as fuel - and all but the most inert of metals will be eaten away in the corrosive soup.
But one waste stream of today could still be a major resource tomorrow.
"When you dig up landfills the only recoverable tonnage material is going to be plastics," said Mr Jones.
And these, he added, would not be found in large sheets but rather shreds of different polymers here and there, making sorting for recycling an almost impossible task.
This still leaves the option of using the oil-based plastics as fuel however, most likely using relatively clean technologies such as gasification rather than simple energy-from-waste incinerators.
While I am trying to imagine the air-tight dome and all that I wonder why we should even have to do such mining in landfills. Why do we not prevent the metals, including precious metals, get into landfill in the first place?
As far as I am concerned my view is that we best leave the old landfills, once we have extracted the methane gas as fuel, alone as opening them could open a real can of worms, and I am not talking of the real worms that will be found there in abandon too.
Opening such a landfill could, despite supposedly air-tight domes, cause problems and we do not even know whether any disturbance might not cause leakage of one way or the other.
I also do not think that this plastic would be a financial viable concept for use as fuel and why should one even consider that as, theoretically, if we would do it right, there could be methane in abundance all over the place. All we would need to do it tap the sewerage works and use up all the slurry and human waste too for the production of methane.
We must not forget that the first every electricity power station was designed to run of effluent and also the original Ford motorcar designed by good ol' Henry was meat to run on methane.
What we should concentrate on is to keep as much as possible out of future landfills and deal with everything before it even reached the landfill.
Every bit of metal, plastic, etc. should be salvaged well before it reaches the landfill stage and the only thing that should go into landfill is that what really cannot be reused, recycled, composted or burned in furnaces to the generating of combined heat and power. And that would be such a small amount that any attempt to digging it up in the future for any salvage would not be worth the effort, especially not if we make sure that, as I said, everything that can be dealt with in one way or the other does not make it into landfill.
After reducing, reusing, recycling, composting waste and incineration and gasification of what is left for combined heat and power generating there will be precious little left to go into any holes in the ground, and a good thing that is going to be too.
So, let's get going in doing it all and get our waste mountain to a nigh on zero.
© M Smith (Veshengro), October 2008
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Could landfills resurrect Britain's mining industry?
