Teschler on Topic

When all materials are sustainable

More and more manufacturers are making an effort to use sustainable materials. With that trend in mind, consider what happened about five years ago when China, which once imported a lot of U.S. refuse for recycling, stopped accepting 24 different recyclables.

Paper and plastics were on the list. The price of recycled paper collapsed, and prices for discarded cardboard boxes dropped precipitously. Bales of mixed plastic lost 75% of their value. Consequently, a few municipalities canceled their recycling programs.

Since then, the market for recycled material has recovered somewhat. North America has begun using more recycled paper, ditto for recycled plastic. Much of this is “mechanical” recycling where sorted plastic is milled and washed, passes a flotation separation, and is dried. The resulting plastic flakes are then either used in new plastic materials or processed into granulates.

These developments might lead you to wonder what the stuff in your recyclables container is actually worth these days. You can figure out the value of individual plastic containers using data from RecyclingMarkets. net, a site that lists prices for postconsumer recovered materials. As an example, consider the one-gallon plastic milk jug. Most plastic milk containers are made from highdensity polyethylene, also known as HDPE or No. 2 plastic. Traditional one-gallon HDPE dairy jugs weigh about 60 gm, though special versions can get that down to 52 gm. Prices for post-consumer HDPE fluctuate, but a recent price for natural HDPE is 48 cents/lb in bales. Colored HDPE goes for much less, about 15 cents/lb, and rigid HDPE as used in butter tubs is only 10 cents/lb. Milk jugs are made from the natural stuff.

A 60-gm milk jug is a little over a tenth of a pound, so the going rate for a recycled one-gallon milk jug works out to a little over six cents. But not so fast. One development arising from the Chinese recycling ban is that that now most recycling programs require “clean” plastic containing no food residue. So if you simply chuck your milk jug into the recycling bin without rinsing it, chances are it will be culled out at the processing center and sent to a land fill.

To actually get your milk jug into the recycling stream, you are obliged to spend some amount of energy cleaning it. And that cleaning cost must be subtracted from its recycled value to yield the overall advantage gained from recycling.

Suppose you use eight ounces of water to do the rinsing. There may be some soap and water heating involved, but we’ll ignore those to make things manageable. In my municipality, the water and sewer charge for eight ounces of water is a little less than two cents (mainly because sewer charges here are expensive). Thus for me, there might be a net gain of about four centsworth of resources every time a clean milk jug hits my recycle bin. And of course, the economics are worse for smaller or less valuable plastic containers.

The economic realities illustrate why some households see no point in recycling. But note: There are now about seven facilities that use heat and chemical reactions, rather than mechanical means, to break down plastics into raw materials. Indications are more such facilities are on the drawing board. Chemical recycling could drastically simplify the process of reusing materials— when only heat and chemicals are involved in breaking down plastics, there’s less need to worry about contaminants.

Thus if chemical reprocessing lives up to its promise, we may see the day when nearly everything in the trash gets reused with no extra hassle on the part of consumers. DW

Leland Teschler • Executive Editor lteschler@wtwhmedia.com