MOUNTAINS OF TOXIC SLUDGE
China has been burying itself under heaps of toxic sludge, but one startup may have a technological solution. Innov8tia has developed a
microwave pyrolysis reactor that decontaminates industrial sludge, converting
it into valuable gases and chemicals.
China’s sewage and industrial
sludge has contaminated water and
soil with heavy metals, pesticides, and
pathogens. Some of the waste goes to
landfills that will accept it, but illegal
dumping has been easy and cheap.
“To dispose of 500 tons of toxic sludge
in the south China city of Guangzhou,
all you need is a hired boat and a little
money for petrol,” Yang Dazheng and
colleagues write in Chinadialogue.
There may be change on the horizon after a nationwide government
crackdown on polluters in late 2017
that swept up 12,000 officials and fined
The Dafeng Pesticide Factory in
Yancheng City, 250 km north of Shang-
hai, closed during a surprise inspection;
the company then turned to Innov8tia for
help processing its sludge.
Test runs of two scaled down versions of Innov8tia’s reactors found that
they could convert 30 to 35 percent of
a Dafeng sludge sample to char, and
65 to 70 percent into gas, most of which
was hydrogen and carbon monoxide.
Both gases are valuable. Hydrogen is
used in the petroleum and chemical
industries and as a coolant, and carbon
monoxide, also called syngas, is used in
chemical manufacturing, meat packing,
medicine, and even lasers.
The process also yields other use-
ful materials, including carbon nano-
tubes and more than 70 chemicals
(levoglucosenone, furfural, phenolic
compounds, 3-aminopiperidin-2-one, D-
allose, cresols, vanillin, and others) that
value at $1,200 to $250,000 per ton.
The process is more efficient than
traditional pyrolysis at harvesting materials from sludge, and it generates more
energy than it requires.
The three-person Innov8tia team
graduated from the Vatican’s Laudato
Si Accelerator in December 2017 and
returned home with a $100,000 grant.
Now the team has moved into a 530 m2
warehouse in the Ningbo National
Hi-Tech Zone, a government-operated
technology park. Their neighbors are 30
other startups, all better funded than
they are, says Seth Knutson, one of the
“Our current reactor system, capable of treating 20-40 kg of sludge per
hour, is up and running in this facility,
Jessica He, Seth Knutson, and Kaiqi
Shi (shown at left) created a microwave
pyrolysis system (above) for turning toxic
sludge into valuable chemical feedstock.