Note: Descriptions are shown in the official language in which they were submitted.
19~2-03-27-21:22 ID: +4g 511 49 25 62 F~F^CCIFAX^ P. 006
20~4~2
HP Biotechnologie
Braukstr. Sl
W-581 0 Witten
Germany
Flat bed reactor ror b~ologlcal clean~g o~ sol~ds con~ nated
wlth to~dc subst~noes.
The invcntion concerns a flat bed reactor for thc biological
cleaning of solids, e. g. with high clay and coarsc clay content,
contaminatcd with toxic substances, in particular hydrocarbons,
by bacteria cultures.
Thc problem of oleaning contaminatcd soils has resulted in the
erention of severnl diffcrent method~ and plant, c. g. dumping,
incincrRtion, in situ biological trcatment, biological trcatmcnt
in beds and chcmical cleaning and cxtraction processcs to mention
somc.
It i8 known that the decontflm;nntion of contamin~ted soils can bc
achieved through different variations of extraction processe~ and
corresponding plantl Most of these technical solutions are
" continuous processes" requiring considerablc technical equipment
and cxpensc and whioh in addition havc transport problems duc to
thcir size.
Other oxtraction processes use ~n extraction mixer, which works
on the principle of a concretc mixer, and whioh has several
downline wash drums depcnding upon the degrec of contflm;nntion of
the soil. Tho contaminated soil~ are mixed with an extract
ion solution or w~ter in severfll scquentifll stflges whereby flt
eflch st~ge thc solvent mix togethcr with thc contaminant
particles it contains is separated from the solid and drawn off,
Thc disadvantage of the~c variations is thcir high degree of
inflexibility.
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In ths case of some biological cleaning processes rotating drums
are used. Thus for example in DE-OS 38 24 009 contaminated soil
is placed into rotating drums together with an extraction fluid
additive and balls are formed which are then pressed to remove
the contaminant fluid in press rollers. The balls are then
reground. The powdered soil can then be dosed with micro-
organisms.
The counter current extraetion process has the disadvantage that
the mixing time of solvent and soils requiring decontamination
and tl-e dwell tiMe of these Materials in the counter current
extractor are very short. As a result the degree of cleaning of
these soils treated corresponds neither with expeetations nor
with official requirements of the degree of cle~ning.
A further method for deeontaminating soils is thermal treatment
in heat treatment plant, e. g. rot~ting pipe furnaces and
pyrolysis ohaMbers. These processes have, however, to be operated
with an extremely high energy reqUireMent and have high operating
costs.
All of these processes have certain specific disadvantages. They
require a considerable amount of equipment and are inflexible. In
addition they are in part environMentally polluting, produce
considerable amounb of critieal residue or have extremely high
operating costs, and in addition the decontaminated 80il is
output absent any organic constituents, ~nd is as such
biologically dead (rotating pipe furnace, pyrolysis chAMbers).
The invention is based on the task of dovoloping a flat bed
reactor for the biologicat cleaning of soil~, o. g. with high
elay/ eoarse clay and high liquid content, contaminated with
toxie substanees, in partieular hydroeArbons, by baeteria
oultures whieh is stackAble as well a8 of such diMensions that it
can be trAnsportod on road and rail without speeiAl perMission
and without reguiring additional loading eqUipMent as e. g. a fork
lift truck or a mobile crane.
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This task is solved in the invention in that material requiring
biological treatment in order to remove toxic substances, in
particular soils with high clay/coarse clay and liquid content
contaminated with hydrocarbons, are treated with bacteria
cultures in a flat bed reactor which consists of a rectangular
tub open at its upper side with a folding flap and a strainer-like
holed bottom as well as aeration and mixing equipment and a
sprinkler system.
One wall of the tub i8 designed as a sealed folding flap and the
bottom, which consists of strainer-like holed bottom, is covered
with a filter layer of compostable organic material to avoid the
1088 of any solids during transport.
The walls of the tub are dcsigned as a support frame with fixing
devices in order to allow several flat bed reactors to be stapled
over a base tub and tipped to empty.
The corners of tub are fitted with crane-transport corner eyes to
allow loading the flat bed reactor with lifting cables.
The aeration system consisb of perforated aeration tubes
permanently fixed to the inner walls and along the bottom of the
tub in a longitudinal direotion whereby the ends of the aeration
tubes opposites the front end are sealed with removable caps and
can be removed for cleaning purposes. The microorganbms nre
6upplied with oxygen by passing air through the perforated
aeration tubes via the front end of the flat bed reactor.
The mixing units for mixing the oontaminated soil of high olay
and coarse clay oontent with the microorganism~ Imd the water-
based nutrient solution oonsists of several, proferontially three
to four mixing shafts arranged with parallel axes and fit ted
with agitator paddles and equippod with a hydraulio, electric or
external drivo.
Tho flat bed reactor is fitted with a sprinkler system for
watering and add;ng nutrient solutions.
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The flat bed reactor as per the invention has a gross volume of
mflx. 16 m3 and hence has an overall weight of approx. 30 Mg. The
design of the flat bed reactor is therefore such that its outer
dimensions allow transport by road and rail without special
permit. For road transport the equipment fitted on self loading
vehicles is sufficient to allow transport without the need for
additional loading system, e. g. fork lift trucks or mobile
cranes.
The flat bed reactor as per the ;nvention for the biological
cleaning of soils contaminated with toxic substances, in
particular hydrocarbons, is described in detail below in a
diagram.
In which:
Fig. 1 shows the flat bed reactor.
The soil, which oan have a fluid oontent of up to 40 ~0,
oontaminated with hydrooarbons, is filled into the flat bed
reaotor at site via a meohanioal digger or tipper truok, whereby
the flat bed reaotor oonsists of a reotangular tub (1), open at
its upper side and fitted with a folding flap (2) and strainer-
like holed bottom (3), also has aeration equipment (4) and mixing
units (S) and a sprinkler system (6). The bottom (3) of the tub
(1 ) is fitted with a strainer-like holed bottom (3) such that in
order to avoid loss of solids during transport it is covered with
a filter layer of compostable organic material, e. g. filter
paper.
To supply the microorganisms with oxygen the front side of the
flat bed reactor is provided with air from the aeration system
(4) via the perforated aeration tubes (12) fitted permanently on
the inner walls (11 ) of the tub (1~ with a variable amount of
air. The caps (13) fitted to the opposite ends of the aeration
tubes (12) can be removed for cleaning purposes.
The watering and provision of nutrient solutions to the
contaminated soil is provided by a external sprinkler system (6).
, ~ , . .
19~2-03-27-21:26 ID: +49 511 49 25 62 f~ FAx~ P. 010
n ~
The mixing units (S) which preferentially consists of three to
four mixer shafts (14) arranged with parsllel axes and fitted
with agitator paddles (l S) allows the contaminated 90il, in
particular that with high clay and coarse clay content, to be
intensively mixed with rnicroorganisms, a variable amount of
nutrient solution and water. The drive of the slowly turning
mixer shafts (14) is e. g. electric.
To allow more efficient, multiple stacking of the flat bed
reactors the walls of the tub (S) are designed as a support frame
(7) with fixing points (8).
The flat bed reactors are operated at temperatures of
approximately 25 C. The drainage i9 achieved by the water and
the nutrient solution trickling through the strainer-like holed
bottom (3) via a filter layer of the stapled flat bed
reactors to the base tub (16).
The dwell time in the flat bed reactors can be up to several
months.
The unloading of the flat bed reaetor is achieved by tipping and
opening the folding flap (2) which is equipped with a seal (I O)
to avoid escape of liquid as could oeeur due to ex-mixing
processes arising due to vibration during transport.
10
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