Advanced technologies //
Fortune favours the brave
By Jacqueline Ong
OR does it? By end of 2016, Hitachi
Zosen Inova (HZI) will deliver its
patented Kompogas technology to
Europe’s largest biogas plant for
dry anaerobic digestion in Bologna,
Italy but here in Australia, which the
company entered in February last year,
its pipeline remains empty.
Local HZI managing director Dr
Marc Stammbach is candid about the
challenges that stand in the company’s
way but is adamant that technologies
like Kompogas (see fact box for more
about the technology) should be a
fixture in Australia’s future if the
country is serious about improving its
environmental footprint and increasing
its landfill diversion rates for food and
organic waste. And he is confident
that despite a working dry anaerobic
digestion (AD) plant costing some $15
million and requiring at least 25,000
tonnes of organic waste a year, such a
facility can be sustainable.
Not an easy solution
Stammbach told Inside Waste failures
of the past have put a damper on the
progress of AD plants in Australia and
more education is needed to show that
these technologies can work. After all,
they are already proven elsewhere in
the world.
“We [as proponents] should explain
what these plants do more. There have
been several failures in Australia and
even today, we’ve got EarthPower
working but terribly written down and
Anaeco’s DiCOM is in dire straits...
we’ve not been very lucky with good
projects so far,” Stammbach said.
Then, for projects to work, large
volumes of organic feedstock are
required, which smaller regional
councils would not be able to provide.
Food waste, while interesting for a
high biogas yield, comes with higher
contamination than green waste on
its own. While not a problem during
the process itself, it affects the final
compost quality.
“We can work with a couple of
percent of contamination [before
having to do extra pre-treatment],”
Stammbach said.
“And I don’t know a project with
100,000 tonnes of food waste such
as in Bologna that has come on the
market in Australia so far. The best
you get is 50,000t of green waste and
maybe some food waste. But there are
not many tenders coming out where
you can offer that, which means you
have to build small and it’s expensive
and then you have to incrementally
increase capacity if you get more
volume to feed it.”
Throw in tyranny of distance, the
policy landscape - Stammbach believes
banning food and green waste from
landfill would help - and low energy
income and what you end up with is no
easy way to implement AD solutions.
Maximising the outputs
That’s not to say all hope is lost.
The outputs from the process, such
as electricity, can be used in-house
with the surplus fed to the grid,
both minimising processing costs and
offering an extra source of revenue on
top of the compost.
“At the moment, you need in-vessel
composting if you’re in an odour
sensitive site and that means you
need electricity coming from dirty
coal power generation. Instead, we
can produce our own clean electricity
What is Kompogas?
The Kompogas technology converts organic waste into carbon-neutral biogas
that is then transformed into green electricity and heat or upgraded biomethane
of equal quality to natural gas. The process is based on the continuous dry
anaerobic digestion of food and green waste in an anaerobic environment.
When organics are delivered to a site it is put through a coarse shredding
process where it goes over a screen that has a magnet and is sieved to a
maximum particle size of 60mm.
The prepared substrate is automatically conveyed to the digester feed-in point.
In the digester, thermophilic microorganisms decompose the organic matter
and produce carbon-neutral biogas. A temperature of 55 degrees Celsius and
an anaerobic digestion period of about 20 days destroy spores and bacteria.
The material that comes out of a reactor gets de-watered and mixed with the
oversized materials of the pre-treatment phase and that gives it some structure
so you can compost it typically by blowing air in a tunnel or a box, typically
enclosed. It needs around 10 days to make it into nice smelling compost.
The raw biogas from the digester is either upgraded and fed into the gas grid as
biomethane or compressed to CNG or used directly to generate electricity and
heat in a combined heat and power unit.
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INSIDEWASTE AUGUST 2016
More education is needed to show
AD technology can work in Australia:
Stammbach.
for the operation of the whole site,”
Stammbach explained.
“The surplus can be exported or
turned into clean biomethane, which
can then be injected into the natural
gas pipeline network. Further upgrading
turns it into compressed natural gas
(CNG), which is great because you can
replace diesel,” he added.
“We have a growing CNG market in
Australia, which is being fed from fossil
natural gas, but with the biomethane
derived CNG from an AD plant, we are
fully sustainable. Also, it burns cleaner
and it is more efficient that diesel.
“However, diesel in this country
is cheap compared to Europe and
in addition, there is no fuel excise
advantage unlike in Italy... it’s not a
game changer at the moment but it
would be if we actually start paying a
real price for fossil energy!”
Pricing and policies that
could do the trick
Ultimately, AD is a technology that
needs a gate fee because of the
various factors mentioned above and
Stammbach said the ideal gate fee
sits anywhere between $80 and $120
per tonne. This sounds somewhat
reasonable.
According to the Inside Waste
Industry Report 2014-15, the average
gate fee for alternative waste
treatment (AWT) in NSW was $165/t,
not including a component for disposal
of the residual waste from these
processes, while the processing cost
for organics was between $70 and
$140/t. Over in WA, the average gate
fee for AWT was $155/t.
With an appropr