No More Waste, No More Pollution,
Plenty of Oil
[This article is reprinted from Discover Magazine,
Vol. 24, No. 5, 5 May 2003]
In an industrial park in Philadelphia sits a new machine that can
change almost anything into oil. Really. "This is a solution to
three of the biggest problems facing mankind," says Brian Appel,
chairman and CEO of Changing World Technologies, the company that
built this pilot plant and has just completed its first
industrial-size installation in Missouri. "This process can deal
with the world's waste. It can supplement our dwindling supplies of
oil. And it can slow down global warming." Pardon me, says a
reporter, shivering in the frigid dawn, but that sounds too good to be
"Everybody says that," says Appel. He is a tall, affable
entrepreneur who has assembled a team of scientists, former government
leaders, and deep-pocketed investors to develop and sell what he calls
the thermal depolymerization process, or TDP. The process is designed
to handle almost any waste product imaginable, including turkey offal,
tires, plastic bottles, harbor-dredged muck, old computers, municipal
garbage, cornstalks, paper-pulp effluent, infectious medical waste,
oil-refinery residues, even biological weapons such as anthrax spores.
According to Appel, waste goes in one end and comes out the other as
three products, all valuable and environmentally benign: high-quality
oil, clean-burning gas, and purified minerals that can be used as
fuels, fertilizers, or specialty chemicals for manufacturing.
Unlike other solid-to-liquid-fuel processes such as cornstarch into
ethanol, this one will accept almost any carbon-based feedstock. If a
175-pound man fell into one end, he would come out the other end as 38
pounds of oil, 7 pounds of gas, and 7 pounds of minerals, as well as
123 pounds of sterilized water. While no one plans to put people into
a thermal depolymerization machine, an intimate human creation could
become a prime feedstock. "There is no reason why we can't turn
sewage, including human excrement, into a glorious oil," says
engineer Terry Adams, a project consultant. So the city of
Philadelphia is in discussion with Changing World Technologies to
begin doing exactly that.
"The potential is unbelievable," says Michael Roberts, a
senior chemical engineer for the Gas Technology Institute, an energy
research group. "You're not only cleaning up waste; you're
talking about distributed generation of oil all over the world."
"This is not an incremental change. This is a big, new step,"
agrees Alf Andreassen, a venture capitalist with the Paladin Capital
Group and a former Bell Laboratories director.
Andreassen and others anticipate that a large chunk of the world's
agricultural, industrial, and municipal waste may someday go into
thermal depolymerization machines scattered all over the globe. If the
process works as well as its creators claim, not only would most toxic
waste problems become history, so would imported oil. Just converting
all the U.S. agricultural waste into oil and gas would yield the
energy equivalent of 4 billion barrels of oil annually. In 2001 the
United States imported 4.2 billion barrels of oil. Referring to U.S.
dependence on oil from the volatile Middle East, R. James Woolsey,
former CIA director and an adviser to Changing World Technologies,
says, "This technology offers a beginning of a way away from
But first things first. Today, here at the plant at Philadelphia's
Naval Business Center, the experimental feedstock is turkey
processing-plant waste: feathers, bones, skin, blood, fat, guts. A
forklift dumps 1,400 pounds of the nasty stuff into the machine's
first stage, a 350-horsepower grinder that masticates it into gray
brown slurry. From there it flows into a series of tanks and pipes,
which hum and hiss as they heat, digest, and break down the mixture.
Two hours later, a white-jacketed technician turns a spigot. Out pours
a honey-colored fluid, steaming a bit in the cold warehouse as it
fills a glass beaker.
It really is a lovely oil.
"The longest carbon chains are C-18 or so," says Appel,
admiring the liquid. "That's a very light oil. It is essentially
the same as a mix of half fuel oil, half gasoline."
Private investors, who have chipped in $40 million to develop the
process, aren't the only ones who are impressed. The federal
government has granted more than $12 million to push the work along. "We
will be able to make oil for $8 to $12 a barrel," says Paul
Baskis, the inventor of the process. "We are going to be able to
switch to a carbohydrate economy."
Making oil and gas from hydrocarbon-based waste is a trick that Earth
mastered long ago. Most crude oil comes from one-celled plants and
animals that die, settle to ocean floors, decompose, and are mashed by
sliding tectonic plates, a process geologists call subduction. Under
pressure and heat, the dead creatures' long chains of hydrogen,
oxygen, and carbon-bearing molecules, known as polymers, decompose
into short-chain petroleum hydrocarbons. However, Earth takes its own
sweet time doing this-generally thousands or millions of years-because
subterranean heat and pressure changes are chaotic. Thermal
depolymerization machines turbocharge the process by precisely raising
heat and pressure to levels that break the feedstock's long molecular
Many scientists have tried to convert organic solids to liquid fuel
using waste products before, but their efforts have been notoriously
inefficient. "The problem with most of these methods was that
they tried to do the transformation in one step-superheat the material
to drive off the water and simultaneously break down the molecules,"
says Appel. That leads to profligate energy use and makes it possible
for hazardous substances to pollute the finished product. Very wet
Waste -- and much of the world's waste is wet -- is particularly
difficult to process efficiently because driving off the water
requires so much energy. Usually, the Btu content in the resulting oil
or gas barely exceeds the amount needed to make the stuff.
That's the challenge that Baskis, a microbiologist and inventor who
lives in Rantoul, Illinois, confronted in the late 1980s. He says he "had
a flash" of insight about how to improve the basic ideas behind
another inventor's waste-reforming process. "The prototype I saw
produced a heavy, burned oil," recalls Baskis. "I drew up an
improvement and filed the first patents." He spent the early
1990s wooing investors and, in 1996, met Appel, a former commodities
trader. "I saw what this could be and took over the patents,"
says Appel, who formed a partnership with the Gas Technology Institute
and had a demonstration plant up and running by 1999. Thermal
depolymerization, Appel says, has proved to be 85 percent energy
efficient for complex feedstocks, such as turkey offal: "That
means for every 100 Btus in the feedstock, we use only 15 Btus to run
the process." He contends the efficiency is even better for
relatively dry raw materials, such as plastics.
So how does it work? In the cold Philadelphia warehouse, Appel waves
a long arm at the apparatus, which looks surprisingly low tech: a
tangle of pressure vessels, pipes, valves, and heat exchangers
terminating in storage tanks. It resembles the oil refineries that
stretch to the horizon on either side of the New Jersey Turnpike, and
in part, that's exactly what it is.
Appel strides to a silver gray pressure tank that is 20 feet long,
three feet wide, heavily insulated, and wrapped with electric heating
coils. He raps on its side. "The chief difference in our process
is that we make water a friend rather than an enemy," he says. "The
other processes all tried to drive out water. We drive it in, inside
this tank, with heat and pressure. We super-hydrate the material."
Thus temperatures and pressures need only be modest, because water
helps to convey heat into the feedstock. "We're talking about
temperatures of 500 degrees Fahrenheit and pressures of about 600
pounds for most organic material-not at all extreme or energy
intensive. And the cooking times are pretty short, usually about 15
Once the organic soup is heated and partially depolymerized in the
reactor vessel, phase two begins. "We quickly drop the slurry to
a lower pressure," says Appel, pointing at a branching series of
pipes. The rapid depressurization releases about 90 percent of the
slurry's free water. Dehydration via depressurization is far cheaper
in terms of energy consumed than is heating and boiling off the water,
particularly because no heat is wasted. "We send the flashed-off
water back up there," Appel says, pointing to a pipe that leads
to the beginning of the process, "to heat the incoming stream."
At this stage, the minerals-in turkey waste, they come mostly from
bones-settle out and are shunted to storage tanks. Rich in calcium and
magnesium, the dried brown powder "is a perfect balanced
fertilizer," Appel says.
The remaining concentrated organic soup gushes into a second-stage
reactor similar to the coke ovens used to refine oil into gasoline. "This
technology is as old as the hills," says Appel, grinning broadly.
The reactor heats the soup to about 900 degrees Fahrenheit to further
break apart long molecular chains. Next, in vertical distillation
columns, hot vapor flows up, condenses, and flows out from different
levels: gases from the top of the column, light oils from the upper
middle, heavier oils from the middle, water from the lower middle, and
powdered carbon-used to manufacture tires, filters, and printer
toners-from the bottom. "Gas is expensive to transport, so we use
it on-site in the plant to heat the process," Appel says. The
oil, minerals, and carbon are sold to the highest bidders.
Depending on the feedstock and the cooking and coking times, the
process can be tweaked to make other specialty chemicals that may be
even more profitable than oil. Turkey offal, for example, can be used
to produce fatty acids for soap, tires, paints, and lubricants.
Polyvinyl chloride, or PVC-the stuff of house siding, wallpapers, and
plastic pipes-yields hydrochloric acid, a relatively benign and
industrially valuable chemical used to make cleaners and solvents. "That's
what's so great about making water a friend," says Appel. "The
hydrogen in water combines with the chlorine in PVC to make it safe.
If you burn PVC [in a municipal-waste incinerator], you get
The technicians here have spent three years feeding different kinds
of waste into their machinery to formulate recipes. In a little
trailer next to the plant, Appel picks up a handful of one-gallon
plastic bags sent by a potential customer in Japan. The first is full
of ground-up appliances, each piece no larger than a pea. "Put a
computer and a refrigerator into a grinder, and that's what you get,"
he says, shaking the bag. "It's PVC, wood, fiberglass, metal,
just a mess of different things. This process handles mixed waste
beautifully." Next to the ground-up appliances is a plastic
bucket of municipal sewage. Appel pops the lid and instantly regrets
it. "Whew," he says. "That is nasty."
Experimentation revealed that different waste streams require
different cooking and coking times and yield different finished
products. "It's a two-step process, and you do more in step one
or step two depending on what you are processing," Terry Adams
says. "With the turkey guts, you do the lion's share in the first
stage. With mixed plastics, most of the breakdown happens in the
second stage." The oil-to-mineral ratios vary too. Plastic
bottles, for example, yield copious amounts of oil, while tires yield
more minerals and other solids. So far, says Adams, "nothing
hazardous comes out from any feedstock we try."
"The only thing this process can't handle is nuclear waste,"
Appel says. "If it contains carbon, we can do it."
This Philadelphia pilot plant can handle only seven tons of waste a
day, but 1,054 miles to the west, in Carthage, Missouri, about 100
yards from one of ConAgra Foods' massive Butterball Turkey plants,
sits the company's first commercial-scale thermal depolymerization
plant. The $20 million facility, scheduled to go online any day, is
expected to digest more than 200 tons of turkey-processing waste every
The north side of Carthage smells like Thanksgiving all the time. At
the Butterball plant, workers slaughter, pluck, parcook, and package
30,000 turkeys each workday, filling the air with the distinctive tang
of boiling bird. A factory tour reveals the grisly realities of
large-scale poultry processing. Inside, an endless chain of hanging
carcasses clanks past knife-wielding laborers who slash away. Outside,
a tanker truck idles, full to the top with fresh turkey blood. For
many years, ConAgra Foods has trucked the plant's Waste -- feathers,
organs, and other nonusable parts -- to a rendering facility where it
was ground and dried to make animal feed, fertilizer, and other
chemical products. But bovine spongiform encephalopathy, also known as
mad cow disease, can spread among cattle from recycled feed, and
although no similar disease has been found in poultry, regulators are
becoming skittish about feeding animals to animals. In Europe the
practice is illegal for all livestock. Since 1997, the United States
has prohibited the feeding of most recycled animal waste to cattle.
Ultimately, the specter of European-style mad-cow regulations may
kick-start the acceptance of thermal depolymerization. "In
Europe, there are mountains of bones piling up," says Alf
Andreassen. "When recycling waste into feed stops in this
country, it will change everything."
Because depolymerization takes apart materials at the molecular
level, Appel says, it is "the perfect process for destroying
pathogens." On a wet afternoon in Carthage, he smiles at the new
Plant -- an artless assemblage of gray and dun-colored buildings -- as
if it were his favorite child. "This plant will make 10 tons of
gas per day, which will go back into the system to make heat to power
the system," he says. "It will make 21,000 gallons of water,
which will be clean enough to discharge into a municipal sewage
system. Pathological vectors will be completely gone. It will make 11
tons of minerals and 600 barrels of oil, high-quality stuff, the same
specs as a number two heating oil." He shakes his head almost as
if he can't believe it. "It's amazing. The Environmental
Protection Agency doesn't even consider us waste handlers. We are
actually Manufacturers -- that's what our permit says. This process
changes the whole industrial equation. Waste goes from a cost to a
He watches as burly men in coveralls weld and grind the complex loops
of piping. A group of 15 investors and corporate advisers, including
Howard Buffett, son of billionaire investor Warren Buffett, stroll
among the sparks and hissing torches, listening to a tour led by plant
manager Don Sanders. A veteran of the refinery business, Sanders
emphasizes that once the pressurized water is flashed off, "the
process is similar to oil refining. The equipment, the procedures, the
safety factors, the maintenance -- it's all proven technology."
And it will be profitable, promises Appel. "We've done so much
testing in Philadelphia, we already know the costs," he says. "This
is our first-out plant, and we estimate we'll make oil at $15 a
barrel. In three to five years, we'll drop that to $10, the same as a
medium-size oil exploration and production company. And it will get
cheaper from there."
"We've got a lot of confidence in this," Buffett says. "I
represent ConAgra's investment. We wouldn't be doing this if we didn't
anticipate success." Buffett isn't alone. Appel has lined up
federal grant money to help build demonstration plants to process
chicken offal and manure in Alabama and crop residuals and grease in
Nevada. Also in the works are plants to process turkey waste and
manure in Colorado and pork and cheese waste in Italy. He says the
first generation of depolymerization centers will be up and running in
2005. By then it should be clear whether the technology is as
miraculous as its backers claim.