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Remediation biotechnology |
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Canada-based Adventus Group’s patented bioremediation process
has found application in cleaning mineral oil (TPH) and
petroleum volatile organic compounds (PVOCs) in the
Netherlands. The proprietary EHC-OTM technology was selected
by a consortium of Dutch remediation engineering and
consulting companies for use at two industrial sites for
cleaning up PVOC and TPH contamination caused by underground
storage tanks leaking into soil and groundwater. The remedial
action at these sites involved in situ bioremediation
facilitated by the use of EHC-O, an oxygen-releasing compound
that accelerates the aerobic biodegradation of certain organic
constituents.
EHC-O is an integrated source of slow-release oxygen, major-,
minor- and micro-nutrients, and a pH buffering agent. This
unique combination of materials facilitates aerobic
bioremediation of groundwater, sediment or soil environments
impacted by various organic/inorganic compounds. For organic
constituents amenable to aerobic biodegradation processes (for
example, petroleum hydrocarbons, certain
pesticides/herbicides), EHC-O significantly stimulates the
catabolic activity of the indigenous microflora, thereby
accelerating the removal rate of con- taminant. It is supplied
in 77.175 kg pails as a powder that can be mixed with soil or
slurried in water.
Installation techniques vary widely, depending on the
application. For example, the powder can be mixed with soil
and placed at the bottom of an excavated pit. A slurry can be
made and the mixture injected into the subsurface using
techniques like direct injection through Geoprobe rods or
hydraulic fracturing. The powder is fine enough to allow
injection of the slurry through well screens.
Website:
www.solidwaste.com |
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Aerobic bioremediation for PAH-laden soil |
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Researchers at Gwangju Institute of Science and Technology in
the Republic of Korea have studied the applicability of a
combined process of solubilization and biodegradation using
soil-packed column. In the solubilization step, 50 pore
volumes of 150 mg/l biosurfactants solution was injected. The
removal of phenanthrene was 17.3 per cent and 9.5 per cent
from soil with pH 5 and 7, respectively. The highest
solubility was detected at pH 5 and this result confirmed that
adjusting the pH of the biosurfactants solution injected could
help enhance the solubility of phenanthrene.
Following this, soil samples were completely transferred to
batches and incubated for 10 weeks to monitor phenanthrene
degradation. It was found that the phenanthrene concentration
in all samples reduced significantly during the biodegradation
step, except for the one that was flushed with biosurfactants
solution at pH 4. This indicated that the degradation of
contaminants by specific species might not be affected by the
residual biosurfactants after application of the
solubilization process. These results also suggested the
possibility that the biosurfactant-enhanced flushing process
could be developed as a useful technology without any negative
effect on subsurface environments and could be combined with
the biodegradation process to increase removal efficiency.
Contact: Mr. Shin K.H, Department of Environmental Science and
Engineering, Gwangju Institute of Science & Technology 1,
Oryong-dong, Buk-gu, Gwangju 500 712, Republic of Korea.
Website:
www.ncbi.nlm.nih.gov |
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Harnessing bacteria to combat pollution |
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Researchers at the NRC Biotechnology Research Institute (NRC-BRI),
Canada, report to have found a solution for cleaning up the
millions of tonnes of cancer-causing chlorinated solvents that
have been dumped, poured, buried or leaked into soil and water
over the past few decades. NRC’s answer is simple: turn it
into harmless carbon dioxide and water. The NRC-BRI process
uses a proprietary two-in-one bioremediation technique that
almost completely removes chlorinated solvents from the
contaminated water. Presently, the bioremediation techniques
available on the market use either aerobic or anaerobic
bacteria, alone or consecutively. The NRC-BRI technology
capitalizes on the insight that these bacteria can work
together synergistically under just the right conditions.
Dr. Serge Guiot, Head of the NRC-BRI Environmental
Bioengineering Group, said that the new method is based on the
fact that aerobic and strict anaerobic micro-organisms can
grow together in a single natural habitat such as, for
instance, the biogranules. Biogranules are naturally occurring
microscopic aggregations of bacteria that provide a natural
tag-team environment for both aerobic and anaerobic bacteria.
Aerobic bacteria live on the oxygen-rich surface of the
granule, while anaerobic ones live in the oxygen-less core.
This means that for bioremediation, the biogranules deliver a
one-two punch and is the basis of this technology, notes Dr.
Guiot.
Anaerobic bacteria begin the breakdown of chlorinated solvents
while aerobic bacteria conclude the job, digesting the
by-products of their cousins’ work. Carbon dioxide, water and
harmless chloride salts are the only by-products of this
tag-team digestion. The patented NRC tech-nology stimulates
and accelerates this natural biodegradation by using
electrolysis of water into oxygen and hydrogen to fuel the
various bacteria. Anaerobic methanogenic bacteria use hydrogen
to dechlorinate the solvents and produce methane. In turn,
methane and oxygen energize the aerobic digestion of the end-
products of anaerobic breakdown.
Website:
www.nrc-cnrc.gc.ca |
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Treatment of sewage discharges |
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At the Australian Nuclear Science and Technology Organization,
Dr. Tony Taylor has developed a technology for the
purification of sewage and wastewater. The revolutionary
membrane bioreactor cleanses the effluent streams to such an
extent that the end product can be used for potable purposes.
Dr. Taylor describes his invention as a simple arrangement of
gills that uses bacteria to operate as a lung and a stomach.
The system literally “eats” waste matter and “breathes” air,
and so is self-perpetuating. The inexpensive nano-particulate
membrane bioreactor (NMB) can be made in different sizes for
houses, complexes or municipal treatment plants.
The secret of this technology is in the bioreactor’s unique
membrane. “On one side of the membrane, cells are grown in
direct contact with air and on the other side, the sewage and
wastewater flows, but at the same time feeds the cells through
the extremely porous material,” says Dr. Taylor. Compared with
other membrane surface culture technologies, this process
enables 50 times more biomass growth. “At about US$1/m2, this
technology is cheaper than current membranes which can cost up
to US$500/m2,” he said. There are many other uses to this
invention, including antibiotic production, mining,
bioremediation and aquaculture.
Contact: Australian Nuclear Science and Technology
Organization (ANSTO), PMB 1, Menai, NSW 2234, Australia. Tel:
+61 (2) 9717 3111; Fax: +61 (2) 95 43 5097
E-mail:
enquiries@ansto.gov.au
Website:
www.azonano.com
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Cleaning up soil pollutants |
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Biosaint Co. Ltd., the Republic of Korea, is offering a
process for the rapid and highly efficient degradation of
various soil pollutants. This process combines two
technologies – washing to dissolve pollutants and
bioremediation, in which selected micro-organisms are applied
to the soil media. Important features of the process include:
- Remediation to depths of 3-6 m possible;
- Saturated soil or pollution under groundwater table can
also be effectively treated; and
- Land heavily polluted with hard-to-biodegrade pollutants
can be ef-efectively cleaned through the use of Biosaint’s
agent.
Contact: Biosaint Co. Ltd., 104-1, Sangdo-5 dong,
Dongjak-gu, Seoul 156-746, Republic of Korea. Tel: +82 (31)
4785 271; Fax: +82 (31) 47 85 270
E-mail:
info@biosaint.com
Website:
www.apec-vc.or.kr
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Removal of PAHs |
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Researchers at the National University of Singapore have
developed a technology for the rapid clean-up of Polycyclic
aromatic hydrocarbons (PAHs) from contaminated soil. The new
method is based on a combination of non-ionic surfactant soil
washing, followed by PAH removal from the wash water in a
rotating biological contactor (RBC) reactor using immobilized
Phanerochaete chrysosporium, the white rot fungus.
Experiments have shown that soil washing is able to remove
over 90 per cent of PAH from the soil to the aqueous phase
using only a low concentration of 0.5 per cent (w/v) Tween 80
surfactant with a soil/water ratio of 1:10 (w/v). Subsequent
treatment of the PAH-contaminated wash water in the RBC
reactor resulted in more than 90 per cent removal for any of
nine PAHs.
The treatment has particular applications for: the rapid
abiological remediation of soil for compliance with
international environmental soil quality standards; and using
white rot fungi to oxidize PAH in soil wash water for
compliance with aqueous discharge guidelines.
Contact: Department of Chemical and Environmental Engineering,
The National University of Singapore, #4 Engineering Drive,
Singapore 117576. Tel: +65 6874 2186; Fax: +65 6779 1936.
Website:
www.chbe.nus.edu.sg
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