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Industrial emission treatment (air pollution control) and odour control
- Industrial wastewater treatment - news
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Eurofinish 2011 - Flanders Expo Ghent -
September 27, 28 en 29, 2011
(September 2011) |
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Come and visit us on September 27, 28 and 29, 2011 at the
Eurofinish trade fair - Flanders Expo exhibition center in Ghent (stand 8133 - Suparator
oil separators). Eurofinish is one of the most important
biennal trade fairs in Europe for professionals in the field
of surface treatment technology.
Online preregistration on
www.eurofinish.be
- free access for professionals. Open every day from 10 a.m.
to 6 p.m., late night on wednesday untill 8 p.m.
Location ?
Flanders Expo, Hal 8
Maaltekouter 1, 9051 Ghent Phone +32 (0)9 241 92 11
Fax +32 (0)9 241 94 95
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Pilot
gas scrubber Task Environmental Engineering - air pollution and odour control test installation(February 2009) |
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 Last year Task Environmental Engineering has been investing in a
brandnew pilot gas scrubber for the treatment of industrial
emissions.
The
pilot gas scrubber consists of a twostage stacked column in
polypropylene, provided with the necessary dosing pumps, pH
and redox measurement and control circuits. The installation
can be operated as a one or two stage gas scrubbing unit, with several
possible combinations of acid, alkaline or oxidative stages.
The
gas scrubbing installation is also provided with an emission ventilator
placed downstream, after the column, allowing a simple and
easy evaluation of the treated gas emission. The most
important operating parameters, such as pH are constantly
registered, for wireless transfer by datalogger to be
consulted anywhere in the world.
As a general rule, the
pilot gas scrubbing installation is put at disposal of the customer on a rental
base for a period of 4 weeks.
During
this test period Task is of course following up the
installation, at site and at a distance through wireless
communication by datalogger. Task can also put basic
measurement equipment at disposal of the customer, for basic
gas emission sampling. For very specific sampling
and analysis Task is calling in the assistance of
specialized companies in this area.
After completion of the tests an
evaluation will follow ; the discussion of the results with
the customer will lead, if relevant, to a full scale project
proposal. The pilot testing stage has several important
advantages, for the customer as well as for ourselves, as
well as for a potential contractor. Many preliminary questions will be
answered, the tests are providing the customer and ourselves
a guarantee regarding the feasability of the desired
results. For more info call +32 (15) 24 21 15.
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Task is moving
(February 2009)
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 Task Environmental Engineering
moved to its new offices on February 10, 2009. New address :
Kerkhofstraat 33, 2220 Heist-op-den-Berg, Belgium. Phone,
fax and e-mail unchanged.
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The underestimated
biorotor
(Ecomagazine June 2008)
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THE UNDERESTIMATED BIOROTOR - A classic staple with a new twist
For more than 10 years now,
animal park Planckendael
has been proving that is was an ideal solution to opt for a
biorotor for the waste water treatment of its animal
hospital. Unfortunately, there are only few Belgian
companies to follow its example. And that's a pity, because
in the long run, the advantages cannot be neglected.
Planckendael is a young ,
spacious and open walking park with large animal
accomodations, well integrated in the landscape. Some parts
of the park remain untouched, allowing the visitor to find
wild plants and flowers throughout the year. Durable
management is an important issue for the domain's board
(rewarded in 2004 by the VBO - Association of Belgian
companies - with the Reward for best Environmental
Management).
And since more than 15 years Prof. Rik Van de
Werf, University Teacher Environmental Care at the Erasmus
College of Higher Education and University Teacher
Environmental Techniques at the VUB University of Brussels,
is playing an important role in this field. Because it was
he who conceived in 1994 an installation for the
purification of the waste water originating from an
important part of the animal accomodations, from the
sanitary facilities in the park, the animal kitchen and the
restaurant.
From wastewater up to drinking
water
Three years later the domain's board came
knocking at the professor's door once more. Because
Planckendael was forced to find a solution for the waste
water coming from the breeding birdhouse. This was
discharged into a side channel of the Barebrook, but new
regulations now called for water treatment. After thorough
analysis of the situation Prof. Rik Van de Werf came to the
conclusion that the combination of a biorotor with a
constructed wetland was the best solution. He is explaining why
: “This system is offering a high resistance to fluctuations
in the degree of pollution : necessary for this kind of
application as in summer there are more jung birds in the
cage, and thus also more polluting manure than in winter.
Besides, this solution is taking hardly any space. And that
was a welcome bonus, as we only had 100 m2 at our
disposal.”
But what is it all about?
The
biorotor consists of a cylinder with a rotating spindle
holding circular discs. “65 in total”, Prof. Van de Werf
clarifies. “At one end, the wastewater flows in, at the
other end the purified water flows out. Between all those
circular discs, there is a porous, synthetic filling. Each
pore has a well-defined surface. Small of course, but when
you add the surface of all pores, you'll get a very large
total surface. About a third of each disc is hanging into
the polluted water. When the spindle is turning, the wet
part of the disc reaches a bit above the water surface. This
way, it reaches not only the wastewater, but gets also a
little bit of oxygen into the pores and to the
micro-organisms growing within. These microbes nourrish
themselves with the pollutants from the wastewater, thus
purifying it. After a while they will produces sludge plates
between the discs, who will eventually detach and fall into
the water in big lumps, catched by a downstream sandfilter
to separate them from the water.”
As the wastewater is not
sufficiently filtered after the biorotor treatment, the
water is then conducted through the sandfilter into a
helophyte field (only 1,5 meter away). Prof. Van de Werf
explains: “Helophytes are plants, growing partly under
water, just like reed. The water is slowly rippling through
the root area of the field. On the roots of the plants
micro-organisms are growing, feeding themselves with the
dirt in the water. Those who don't do this are disadvantaged
and will compete with those who do and thus absorb more
nutrients. The pollutants processed in their
metabolism will produce several substances serving at their
turn as food for the helophytes. The plants itself produce
oxygen, which will be led through the hollow stalks to the
bacteria, allowing them to breathe. This way, plants and
micro-organisms are helping each other and together they are
extracting the pollutants from the water.”
Ecologically sound and
economically operated system
This is an ecologically sound
and very economically operated system : the purification of
the water is obtained in a completely natural way, the
required energy (rotation of the spindle) is reduced to an
absolute minimum. The question is, of course, why this
system isn't adopted on a much larger scale. Because a
biorotor such as in Planckendael isn't used that much,
certainly not in an industrial environment.
Stefaan Kovacs,
Manager of Task Environmental Engineering, who installed the
wastewater treatment plant as conceived by Prof. Van de
Werf, is commenting. “In an industrial environment mainly
systems with activated sludge are used. Water is then mixed
with micro-organisms in large aeration tanks, resulting in
sludge flakes who will be separated from the water in
decantation tanks. A biorotor is also functioning according
to this principle of sludge on a support. Activated sludge
systems are generally cheaper in purchase (especially for
residential and small-scale applications) than a biorotor
and do not require a second, separate step to purify the
water entirely from all its nutrients. The activated sludge
system as well as the biorotor system in their base
configuration are often not sufficient to purify the water
entirely. On the other hand, the advantage of the activated
sludge concept is that the necessary extra purification can,
in most cases, be integrated in an existing installation,
what is cheaper than adding another module, which would be
the case with a biorotor. An example of extra purification,
easy to integrate in an activated sludge system is in case
of phosphor and nitrogen removal from industrial wastewater. The phosphor can for instance be removed by
adding certain chemicals such as iron or aluminium chloride
whilst nitrogen is removed in a microbiological way.
Nevertheless, I think that these two disadvantages are
largely compensated by the advantages of the biorotor. The
aeration of the biorotor is obtained in a natural way,
without the use of a compressor for air injection, all that
is needed is one single motor to get the spindle with the
discs moving. An activated sludge system, on the contrary,
is requiring several electronically steered and fully
automatic air pumps for the aeration of the water,
which will result in a 10 times higher energy consumption.
The biorotor installation requires hardly any maintenance
and the installation's principle is quite simple, so that a
possible problem can be quickly solved. This lower operation
cost for the aeration of the biorotors can make it a more
economic system in the long run, compared to other
purification systems. And then I haven't even mentioned that
a biorotor hardly requires any space at all... I think
industry has a far too restricted view on the biorotors'
advantages, especially those in the long term. Industries with biodegradable wastewater
in particular, could better
seriously consider a biorotor solution. Think for instance
about agricultural companies and the food processing
industry, such as vegetable processing companies.”
Also for relatively small
municipal wastewater treatment plants, such as residential
areas out of reach, campings and so on, a biorotor can offer
an interesting alternative.
www.planckendael.be
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Task is helping Henrad
(Caradon Radiators) with an environmental friendly
installation - membrane technolology/membrane filtration
(Aquarama June
2008)
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 Radiator
manufacturer Henrad, part of the Caradon group, is attaching
great importance to environmental friendly production
methods. In its production plant in Herentals the company
aims to respect the environment in all possible areas and to
make the work floor as healthy and as pleasantly as possible
for its collaborators. In order to render the teststage of
the radiators as economical and as ecological as possible,
Henrad contacted Task three years ago. Task, specialized in
environmental engineering and directed by Stefaan Kovács,
has worked out a satisfying solution in close collaboration
with Henrad's project leader.
Henrad's
project leader is not only responsible for the company
buildings and the larger infrastructue, but is also
continuously engaged in all kinds of environment related
subjects. It's in this capacity that he could state that
waste water flows the company produced could be optimized.
“It was
especially during the testing of the radiators that the
situation was subject to improvement”, he is explaining.
“Our products are submerged in a testing tank, where they
are put under pressure with compressed air, to allow us to
detect possible leaks. However, we noticed that these
testing tanks got quickly polluted. This is quite logic,
because the radiators, made of large steel plates, continue
to carry traces of oil from the welding robots. These oil
traces were causing microbiological pollution of the testing
tanks. That way, the water got trouble. Which is a problem,
because we need clear water for optimal testing conditions,
where our people can visually detect the leaks. Clear water
is also necessary to prevent corrosion of the radiators and
is better for our collaborator's health.”
Thorough
audit
Henrad was
solving the problem by changing the water in the testing
tanks almost daily. Only, this procedure was consuming 40 to
50 m³ of water on a daily basis. Which led to an enormous
wastewater stream. “Ending all up in our traditional waste
water treatment installation, having to treat several other
waste water streams as well.”
In order to
continue to meet the severe environmental standards, Henrad
decided not to discharge the water any longer, but to
recycle it. After having consulted several partners, the
company found their way to Task. “We had been collaborating
with this company earlier”, continues the projectleader.
“Earlier they provided us with an installation for the
production of our process water. Being satisfied about their
intervention, we were confident to collaborate again.”
The first
contact with Task goes back to the beginning 2005.
After a thorough audit and extended lab tests, both parties
took their time for a thorough evaluation of the problem and
its possible solutions.“ After a thorough evaluation of all
the offers received, a decision was taken at the end of
2006. Henrad finally choose an installation based on
ultrafiltration technology", Stefaan Kovács ads. “The choice of the
membranes, but also preparation of the water was of crucial
importance to get a perfectly functioning water treatment
installation. Based on the test results Task proposed a
crossflow ultrafiltration installation, based on a batch
driven filtration process, allowing to further concentrate
the waste water a number of times."
The
installation has been designed for a capacity of 1000 li of
permeate per hour, but the actual performance score of the
installation reaches the double of these values.
Fluid integration
The polluted
water enters the working tank with a COD value of 500 ppm
and is then further concentrated with a factor 30 to 50. The
COD value of the permeate is below 50, the microbiological
desinfection of the water is completed at the same time as
well. The bright green colour of the permeate is due to the
corrosion inhibitor added, which is necessary to protect the
tested radiators.
“The concentrate is collected in a tank which is periodically
emptied and collected. Henrad isn't obliged any longer to
discharge it's wastewater stream. The permeate is collected
in the permeate tank, waiting for re-use in the
testing tanks. The energetic consumption of the entire
installation is approx. 7,5 kW. The installation works fully
automated, PLC-controlled according to Henrad's standards.
The system is entirely custom-made and perfectly
integrated in the production process. It has been installed
in the production hall.”
Experience
The
installation was started up at the beginning of 2007 and
thus has been functioning without interruption for more than
a year now. “The system is running fully automatically and
without any problem”, Henrad's project leader clarifies.
“Which is not that obvious, because it often are the small
details deciding on how succesfully an installation will
function. I'm following the machine on a daily basis. Thanks
to the very open communication with Task right from the
start, I already was familiar with the system even before it
was installed. We then started from zero and now can dispose
of an installation entirely adapted to our production
process. This environmental progress was crucial to us, but
on top of that, the system is saving us money in two other
areas. We don't have to pump up water any longer and we
don't have to discharge the water from the testing tanks.
This way, the discharge taxes the company has to pay are a
lot lower than before.”
“The smooth
functioning of this kind of installations depends for a
great deal on the internal follow-up by the customer”,
Stefaan Kovács says. “The responsible staff at Henrad's is
very professional and keeps the membranes in an optimal
condition, which is very important because those are the
heart of the entire installation.
Custom-made solutions
 Task Environmental Engineering, located in Heist-op-den-Berg, has
been managed since 11 years by Stefaan Kovács, who can show
22 years of experience in the environmental business. The
company is specialized in emission treatment, wastewater
treatment and odour control for small and mid-size
companies. “We take care of the entire problem : from design
up to realization, through a conceptual and precise
made-to-measure job. We can distinguish ourselves in the
realization of special environmental projects ; we attach a
lot of importance to the choice of the materials and to the
after sales services that this kind of "special"
installations are requiring."
Task has no
obligations to it's equipment suppliers nor is it part of a
bigger holding, which might impose certain purchase
obligations. “This independance is giving us the opportunity
to find the most suitable solutions for each customer and to
choose the best price worthy materials. We attach a lot of
importance to the training of the customer's operating
staff, to assure a good functioning installation in the long
run and in the best possible circumstances.”
Task also has
strong references in the area of complete renovation and/or
optimization of existing wastewater and emission treatment
plants. “More and more, we get customers who have realized
after a number of years that the installation chosen
previously does not meet the actual standards any longer. It
often happens that the old installation cannot cope with the
recent production increase. An optimization and/or
renovation becomes unavoidable. As far as possible we try to
keep a maximum of existing elements, in order to keep the
cost as low as possible aiming to obtain the proposed and
required result.”
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Jet aeration by Task Environmental
Engineering
(from
Milieugids (Belgium) ed. 2007)
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 Recently
Task Environmental Engineering, specialized in the
realization of industrial emission treatment and wastewater
treatment plants, has installed a number of jet aeration
installations at the plants of Vanheede Environment Group
(Sodecom Quévy), Recyc-Oil in Wielsbeke and Shanks Flanders
(Ghent site).
The most
specific feature of the jet aeration system is the unequaled
operational reliability and the very long life time cycle;
Task has been succesfully implementing this system for more
than 10 years.
The
submerged jet aerators are mixing air with mixed liquor,
which is subsequently injected in the wastewater. The
actual jet aeration systems are usually mounted at a height
of 75 cm up to 120 cm above the tank bottom (against 30 cm
in the past) . This is resulting in considerable savings in
the field of investment and energy cost of the surpressors.
The jets
don't inject horizontally, the way the traditional systems
do, but at a downward angle of 15 tot 30 °, depending on the
tank configuration.
Remarkable for the jet aeration system is the absence of moving or
wearing parts in the aeration tank, as well as the absence
of mixers during the denitrification periods.
The jets
are typically realized in glass reinforced polyester, the
supports and other fasteners in stainless steel 316.
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Wet gas scrubbing in emission treatment compared
to other methods of emission treatment
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In the field of air pollution control
several techniques are at our disposal : gas scrubbing (physical,
chemical), biofiltration, bioscrubbing, biotricklingfiltration,
activated carbon filtration and post combustion (thermal – catalytic).
Obviously, every method has its own application area, advantages as
well as disadvantages, all at a different cost, depending on the
circumstances.
Gas
scrubbing
The base product for gas scrubbing
is usually water, with or without additional chemicals. It's a
relatively simple process, which, in contradiction to biological
processes, is well controllable. Gas scrubbing can be used for small
as well as for quite big air flows and when the pollutants are well
soluble in water, such as HCl, NH3, alcohols …. Oxidative
scrubbers, usually treating the pollutants (among others mercaptans)
by means of sodium hypochlorite or hydrogen peroxide are also
frequently used. A gas scrubber can take a relatively high charge of
scrubbing water and gas, still maintaining an acceptable energy
level. Furthermore, the cleaning process can be executed in a
relatively compact shape. Single waste gas treatment can be done in
a counterflow scrubber. For airflows exceeding 80.000 -100.000 m³/h a
crossflow scrubber will usually be more appropriate. Airflows requiring a multiple treatment will
preferrably be sent through a multistage cross and/or counterflow scrubber, which
- logically - will have a compact and cost advantageous
construction. Gas scrubbers are most often made of synthetic
material due to
the aggressivity of the pollutants and the chemicals used. Stainless
steel scrubbers will also be used, but less frequently.
Gas scrubbing
processes can perfectly be followed by monitoring parameters such
as
pH, rH, conductivity, gasdetection, flow,…. Gas scrubbing processes
can be exactly controlled. Performance is predictable and
guaranteed.
It is very
difficult to specify in which cases gas scrubbing can be used, but
it certainly isn't exagerated to put that in certainly 40-60 % of
the cases gas scrubbing will be the best solution. Gas scrubbers
will always be “custom made” and adapted to construction site situation and
circumstances. Furthermore in most of the cases the polluting
circumstances will not allow a commonplace and standardized
solution. Most often, specialised advice regarding measurements and
pilot plant testing is required. Pilot plant information is quite
simple to inter- or extrapolate in order to obtain a reliable
operational system. Disregarding such advice will certainly increase
the risk of a mis-investment. Dedicating 10 % of the forecasted
investment to preliminary investigations will always be a
responsible decision in order to optimize the performance of the
total investment. Advantages of wet gas scrubbing :
Activated carbon filtration
Activated carbon filtration is a
so-called adsorption technique, allowing the activated carbon
to adsorb the pollutants present in the emission flow. This emission
treatment method will be frequently used to eliminate solvents from
waste gas.
The necessary installations vary from quite simple to more complex,
according to the present explosion or fire risks. Usually the
activated carbon saturated with pollutants will be collected by an
authorized waste collector and recycled or incinerated. In some cases the activated carbon will be recycled at site, frequently
with steam. About 10-20 % of the waste gas can be treated with
activated carbon filtration.
Post combustion
Post combustion is a very effective
method, leaving in most cases only a remainder of carbon dioxide and
water, but it is unsuitable for most anorganic pollutants. In all
cases where hydrochloric acid and/or sulphur dioxide are part of the
combustion products, an ulterior wet scrubbing will be necessary.
The risk of explosion is basically always present at any
combustion process. Post combustion can be very expensive when there
is no possibility of heat reclycing and/or use of a catalyst. At an
autotherm process the energy consumption will be low to very low.
Post combustion will also be rather expensive at air flows larger
than 5.000 m³/hour. For an estimate of 5% of the cases post
combustion will be appropriate.
Biological emission treatment
Very well known are biofilters used
for odour control. These biofilters are to be run and maintained
very carefully. Recent development in connection to biofilters are
among others the universal use of synthetic material, a special inoculated
biomass, the addition of moderators and a good preliminary treatment
and humidification. Bioscrubbers are often used in combination with
an activated sludge basin in waste water treatment. The biotricklingfilter is
another version of the biofilter, allowing a better control of the
process by adding nutrients and by a pH correction of the circulating
humidification water. The pollutants to remove with this equipment
have to be well soluble in water and biologically decomposable in a
reasonably short period. The eliminative performance of biological
systems is an elastic notion and strongly depends upon circumstances
such as : charges, temperature, humidity, biological
decomposition... These so-called microbiological treatment
techniques remain rather sensitive and in many cases difficult to
control. At the start up and after a calamity a considerable
readaptation period of the microbiology has to be taken into
account. For certain agricultural applications (such as composting)
biofilters are a very succesful solution. In approximately 15 % of
the cases biological systems will be used.
Multidisciplinar approach
A pollution problem caused by industrial emissions
cannot be solved with a technical proposal only. Investments in this
area don't save anything or don't lead to any extra revenue. Part
from a plan following points have to be seriously taken into
consideration :
As in many cases the adage "best is
not cheapest" will go. The higher the quality and the reliability level of the
installation the lower the exploitation cost will be. At the
purchase of a gas treatment installation future developments at site
have to be anticipated, in the area of gouvernmental regulations and
in the area of production capacity, which will require the
installation to take a higher charge.
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Press
release : Shanks Roeselare - odour control and emission treatment
(published in several
technical/professional journals and -websites - November 2002)
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 Task
Environmental Engineering in Heist-op-den-Berg recently
realised a complete multistage industrial emission treatment
plant for one of the most known and most experienced waste
collectors and - processors, Shanks-Sobry
in Roeselare.
Shanks placed the
order with Task Environmental Engineering further to a very thorough
evaluation of several Belgian and foreign suppliers.
This emission treatment
unit , a multistage gas scrubbing installation has a capacity of
approx. 35.000 m³/h, treating industrial emission effluents coming from
several sources within the company.
The complete odour
control unit has been operational since november 2002 .
Task Environmental
Engineering has achieved with this realization a very important
reference in the field of industrial emission treatment.
For more
information concerning industrial emission treatment and odour
control techniques, please consult our website www.task.be or call +32/(15)
24 21 15.
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Indaver-Vlar Grimbergen - odour control
(published in several
professional/technical journals and -websites - August 2002)
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 Task
Environmental Engineering in Heist-op-den-Berg (Belgium) realised an
odour control unit to treat the emissions produced by the composting
plant of Indaver – Vlar Compost in Grimbergen Belgium. The
installation combines a scrubber unit, heat exchanger and cooling tower for
the treatment of emissions at a flow rate of 120.000 m³/h.
The installation was taken into service on May 28, allowing
for a thorough testing and evaluation during the first months. The initial
evaluation is showing that the physical and chemical design criteria are met
without any problem. The installation will be further evaluated during the
months to come with regard to its odour elimination capacities. It is
Indaver-Vlar Compost’s goal to
reduce the olfactif impact of its composting activities to an acceptable level
for the industry and inhabitants of the surrounding area.
For more information with regard to odour control and
emission treatment, please consult the Task Environmental Engineering website www.task.be or contact us at phone number +32/(15) 24 21 15.
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