Seeking Recycled Materials From a Mixed Wastestream

In Part 1 of this series, author Daniel P. Duffy explained the characteristics of municipal solid waste and the potential of extracting recycled materials from a mixed wastestream. As Duffy wrote in the previous segment:

Recent advances in recycling technology over time will pay far greater dividends for our environment and our economy. From integrated systems to individual pieces of equipment, recycling has increased in quantity of output, efficiency of production, and quality of final product. While market demand greatly influences which materials get recycled, it is the technology of material separation and sorting that determines how costly and profitable these materials are.

The questions, then, are these: Can these increases in productivity and efficiency be maintained? Or will they flatten out in the future or even hit a wall where additional improvement are either not possible or cost effective? Will improvements in recycling technology meet a point of diminishing returns, or will they continue in an ever-upward spiral? Will changes in waste extraction methods alter the cost equation, making certain materials more profitable to recycle than others? What does the future hold?

Below in Part 2, Duffy explores the most common recycled materials withheld from entering the wastestream and those extracted through present-day landfill operations.

The Promise of MRF Technology (Part 2)
By Daniel P. Duffy

One of the less noticed areas of advancement has been in the fields of environmental protection in general, and waste recycling in particular.

Useful Products From Recycling, Today and Tomorrow

What materials get recycled the most today, and what can we expect in the future? Oddly enough, the most recycled product is not normally part of a typical wastestream. It is the lead acid battery, the kind used in most cars and trucks. These items are recycled at an exceptional 99% rate. This is the result of legal and regulatory mandates intended to keep toxic lead out of landfills where it could possibly impact ground water through leaks and surface water by runoff.

The most recycled material, asphalt pavement, is also not part of municipal solid waste. Again, 99% of asphalt is ground up and reused to fix and build pavement. This material has the unique property of being recyclable over and over again without loss of quality or strength characteristics. Furthermore, asphalt can include a wide variety of recycled materials (ground-up roof shingles, shredded tires, crushed glass, foundry sand, and chunks of slag).

Of the main wastestream, America generated 251 million tons of MSW and recycled almost 35%, or about 87 million tons (USEPA 2012 data). But after a sharp increase in recycling rates in the decade from 1985 to 1995, increases in recycling percentages have since flattened out somewhat, with little change since 2008. The total amount of MSW recycled in tons has followed this same trajectory.

The constituents of the recycled stream vary according to the state of various extraction technologies as well as by market demand. Of the amount recycled, organic waste makes up 27% (versus 34% of waste generated), paper and cardboard are 51% (compared to 27% of generated), plastics at 3% (compared to 13%), metals at 9% (with 9% of the amount generated as well), glass at 4% (5% of generated). Other items make up almost 6% of the amount of recycled materials (12% of generated) and are mostly bulk items like salvaged furniture or clothing.

These differences between percentage of waste generated and percentage of materials recycled provide a strong indication of which materials have the strongest market demand and the technology advanced enough to allow easier recycling. By the numbers, we can see that paper and cardboard lead all other recyclables, with a recycling percentage greater than its generation parentage. Metals come in second with matching recycling and generation percentages. Every other category shows lower percentages of recyclables compared to percentage of waste generated. Plastics come in last with only 3% of the amount recycled, compared with 13% of the waste generated.

So what can we infer from this data? Obviously, market demand and technology play major roles. Population density also has an impact. This is shown by the lower recycling rates achieve by sparsely populated states like Montana compared to those of densely populated states like Connecticut. In low population areas, the costs of transporting relatively small amounts of low-density, recycled materials over long distances to MRFs, and from MRFs to markets, negatively impacts the overall cost and marketability of recyclables. As such, while major cities may achieve recycling rates of 50% or more, rural areas have little economic incentive to recycle at all except for activities like composting of organic waste, which can be done completely at the local level. For this reason alone, which is outside the control of the recycling industry, it is doubtful that America as a whole will soon achieve recycling rates greater than 50%, let alone the often-stated goal of 100%.

Of all recycled materials, metals represent the easiest materials to extract from a wastestream and provide the highest prices per ton on the scrap market. Paper and cardboard are the next most popular recycled materials. Plastics come in last due to the difficulty of extracting and sorting out the myriad types of commercially used plastics.

But recycling is now an integral part of our manufacturing base. Over three-fourths of steel produced in the US is made from scrap iron instead of iron ore (Earth Policy Institute 2006). Over 90 million tons of scrap metal (worth more than $60 billion) is recycled in the US each year. Why? Because it is very cheap and profitable to do so. The electric arc furnace allows the production of steel from scrap with only one-third of the energy used to make steel from iron ore. Aluminum recycling is nearly as high with 51 billion tons recycled annually. The American scrap-metal recycling industry by itself is now a $65 billion nationwide industry employing 50,000 people and recycling 150 million tons of scrap materials annually (Institute of Scrap Recycling Industries 2008).

Paper recycling has had a proportional equal impact on the pulp and paper industry. In the past decade, American manufacturers have built 45 pulp and paper mills that utilize recycled paper as feedstock and only a few that use virgin wood exclusively. Again, it is because using recycled paper is a cheaper and more profitable way to increase the production of pulp. In neither case does the goal of environmental protection directly affect these business decisions. But the bottom line is positively impacted by environmental protection.