Solid Waste & Recycling


Gold in Them Thar Landfills!

At an environmental conference two years ago, I was awoken during a presentation about the value of material currently stored in municipal landfills across Canada. The value was estimated to be in the billions of dollars. At the time, I wasn't...

At an environmental conference two years ago, I was awoken during a presentation about the value of material currently stored in municipal landfills across Canada. The value was estimated to be in the billions of dollars. At the time, I wasn’t sure if I should rush for the door and get into the landfill mining business, start listening more intently, or go back to my nap.

Landfill mining is not new. It was first introduced in the 1950s as a means of remediation — fixing a leak or removing hazardous materials. What’s new is the idea that it can be profitable.

Value of material

The value in landfills can be found primarily in the metal content. Before recycling became fashionable (and mandatory), people threw out everything: single stream straight to the dump. This means that older landfills contain metals and (depending on the commodity price for ferrous or non-ferrous metal) the cost of excavating waste and processing it through a magnetic separator (removes ferrous metal) and eddy current separator (removes non-ferrous metal) may be worth it.

Another aspect long overlooked in North America is the high BTU value of some landfilled material. During the course of processing and separating landfilled material, high-BTU value material is concentrated. This material could then be utilized by a waste-to-energy facility (small incinerator or gasification unit) either constructed at the landfill or nearby.

Approximately forty percent of the material in a typical municipal landfill is organic. When processing for metal, the organic fraction could also be separated out and then anaerobically composted. The advantage of the anaerobic process is that it produces methane that could be used to generate heat, electricity, or both.

Hidden costs/hidden assets

One hurdle to landfill mining is the obtaining of regulatory approval. The history of landfill mining in Canada has been mixed. Excavating a landfill can produce two huge nuisances, mostly odour and dust. Furthermore, there may be health and safety as well as environmental issues. A well thought out plan is needed before digging into a landfill.

Another issue with landfill mining is that there’s always a question about what could be unearthed. Ask any longtime landfill operator and you’ll hear stories about asbestos, car batteries, liquid-containing drums, propane tanks, and lots of other nasty things being deposited over the years.

If you uncover leaking drums during your landfill mining project, your profit margin may drop to zero and it the project itself has just turned into a remediation job.

However, on the flip side, a major asset created through landfill mining is new air space. I’ve heard estimates for the cost of landfill mining ranging from $8 to $15 per tonne. If the material that’s not recycled is shredded and re-compacted, a great deal of air space could be created. Depending on the location of the landfill in Canada, the operator could refill the space at gate rates ranging from $20 to $40 per tonne, or higher.

Finding success

According to Environment Canada, there are over 800 municipal landfills in the country, yet fewer than 50 capture methane. With the rising cost of electricity combined with imminence of greenhouse gas emissions (GHG) trading, retrofitting a landfill with a landfill gas (LFG) collection system to generate electricity may soon become a very profitable venture.

With CO2e trading currently trading at $20 per tonne, capturing one tonne of methane from a landfill has the potential to generate $400 in emission credits (methane is 20 times more harmful a GHG than CO2).

Several companies in Canada specialize in installing LFG systems. In certain cases I’ve heard of companies talking about doing it for a deep discount in exchange for the right to utilize the methane to produce electricity and claim GHG credits.

A growing list of companies around the world view the material in landfills as cheap feedstock. One U.S.-based company has developed a patent technology to produce composite railroad ties from the plastics extracted from landfills. The process is such that it can use mixed plastics containing up to 20 per cent foreign material (dirt, wood, paper, etc.). Plastic recycled from a landfill fits the bill is an ideal feedstock for the manufacture of the railroad ties.

Several Canadian-based companies are developing systems to create biofuel from the organic matter found in landfills. The success of processing landfill waste to make biofuel is very much dependent on the worldwide price of oil. (See “Blog” article, page 46.)

For landfill mining to really work, a company will need to consider all of these factors, calculating all the costs associated with excavating and processing, weighed against the potential revenue from selling heat, electricity, metal, recyclable material, and additional landfill airspace and possible GHG credits.

John Nicholson, M.Sc., P.Eng., is a consultant based in Toronto, Ontario. Contact John at

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