Neal Bolton

By Neal Bolton

For many people, especially those who work at urban landfills, liners and landfills go together like ham and eggs: You just can’t have one without the other. And certainly, as a standard, lined landfills provide a reliable, predictable means of containing waste and leachate.

But like many other things, if we get lost in the concept that the only good landfill is a lined landfill, we become blind to another way of doing things.

The fact is that there are many landfills in the US that are not lined–at least not in the traditional sense. These are not illegal dumps hidden back in the hills. Many are state-of-the-art facilities, well designed, properly licensed, and doing a good job of containing waste.

Why would anybody not want a lined landfill? One of the most common reasons boils down to the bottom line: money. Landfill liners are expensive.

Can’t Afford One

Is it legitimate for municipal owners of a small, rural landfill to say that they can’t afford to construct a liner? Well, yes and no. It’s "yes" in the sense that some municipalities truly can’t afford to build a lined landfill. But it’s "no" in the sense that avoiding expense alone is not a legitimate reason to avoid building a landfill liner.

Poverty is no justification to pollute. Economic challenges aside, many municipalities have found that they don’t necessarily need a lined landfill.

Don’t Need One

That’s right. There are many landfills that simply don’t need liners. What is the purpose of a liner? It keeps leachate from impacting groundwater. And in some cases, a liner makes sense.

Consider a scenario in which a landfill is located in porous soil, 25 ft. above an important aquifer. It’s a large landfill, receiving 500,000 tpy of waste. The only thing protecting that groundwater is a 2-ft. layer of clay and a 60-mil sheet of plastic. "No problem," you say. "That’s a Subtitle D standard liner." And even if the liner isn’t perfect (of course, nothing is), the amount of leachate getting to groundwater will not be significant.

Now picture a similar landfill. It has no liner, per se, but the site is underlain with a 200-ft.-thick layer of clay. For you technical folks, let’s say it’s bentonite with a permeability of 1 x 10^-9 cm/sec. In this case, it could take up to 200,000 years for leachate to reach the aquifer, depending on how much leachate (head pressure) there is.

Under these conditions, it’s hard (for me, at least) to see the sense in requiring a financially challenged municipality to spend money on a landfill liner so that in 200 millenniums it doesn’t pollute its groundwater … especially when right now, today, it needs a new school.

Keep in mind that rural states are not offering a free ride in terms of landfill liners. For an unlined landfill to be approved, the owner must demonstrate through a variety of testing and modeling that it will not damage groundwater.

If the alternative system will perform as well as the standard Subtitle D liner, then it’s acceptable. It is what’s known as a "performance standard" liner.

For many small municipalities, not only are lined landfills not needed, they might not be required either.

Not Required

That’s right–again. EPA does not require that all landfills be lined. Subtitle D allows an exemption for small, arid landfills. This applies to small landfills (20 tpd of waste) in arid locations (25 in./yr. of precipitation) with no reasonable disposal. According to EPA’s Subtitle D, these are the basic criteria. However, individual states have the authority to do some interpretation of their own (e.g., what does "no reasonable disposal alternative" mean?).

If you still aren’t convinced that small, unlined landfills have a place in our industry, perhaps you haven’t been looking in the right places. For example, in Kansas, unlined landfills outnumber lined landfills 33 to 21. In Nevada the score is unlined landfills 18, lined landfills 1.

Take a drive through rural America. While unlined landfills might not represent the overall industry majority, the fact is that, in many rural states, unlined landfills are the majority.

Neal Bolton is principal with Blue Ridge Services in Atascadero, CA.