Note: Descriptions are shown in the official language in which they were submitted.
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ADCIF H. BORST, SCHLOSS RA~ ERG~ DO~DORF
F~DERAL REPUBLIC 0~ GERMA~-
Proc~ss for combined was~ve utilization and the cl~ri~ica'vion
o~ waste water ar.d a multi-stage ~ilkration device for the
performance o~ fvhe process
The invention concerns a process ~or combined waste utiiization
/clarification of was4e ~ter, where~y the .laste water ~s
mixed wlth at least a part o~ the shredded wasteJ a se~aration
in'~o organic and inorganic components takes place, the ~2ste
water flow with the dissolved znd suspended componen~4s cf th~
waste in it is led through a two-stage filter of non-activated
and æctivated coal, in the first reactor of a multireactor
pile the ma~ority Or 'he fil'4er coal sa~u.a4ed with sludge
is thermally treated to .egenerzte the coal, whereby t~e sludge
which has been deposited on t~e filter coal is 'hermally
decomposedproducing coal and combustible gas3 ~n a~ least a
second reactor solid wasfe or a part of the filter coa~ Wh~ ch
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is saturated with sludge is incinera~ed or partl-y rcir.e~ated
producing heat and combustible ~as, and fhe regene~ted
er ccal of the ~ir~t reactor is ther. reintroduced in~o
the waste wa~er filter zone.
The inve~tion concerns additionally multi-stage filtrætion
devices ~or carryin~ ou~ the process.
From German Offenlegungschrift No. 25 58 703 of Adolf H. Borst
published July 7, 1977, a process of the first-named type is known.
In this process a simple and at the same time economic method
shows how:
1) the used wæter is employed as transport means for the
waste as well as to separate it in~o substantially inorganic
and organic components;
2) the contaminated waste-laden water is clarified by
filtration using normal and active coal;
~) a part o~ ~he waste or of the active coal carrying sludge
i5 incinerated gi~ing off a ~ombustible gas, which delivers
energy for thermolysis; and also
~) the majority o~ the ~ er coal laden wi~h sludge is
thermally decompo3æd in a thermolysis reactor, ~hereby the filter
c021 iS regenera~ed and a carbonlzation gas rich in hydrocarbons
is produced.
Even though by this process many advantages are obtair.ed, and
especiaily an optimal use of the energy content of the waste
as well as its utilization additionally for the treatment o~
waste water i~ made possibleJ in the practical implementation
of the proc~ss, some difficulties have appeared.
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These appear es~ecially if waste of a constantly chan~-n~
ini~ial composition is fed into the system, an.d there is
simultaneously a variation in the co~position of the -;;æste
water being supplied. Hereby, due to particularly obs~inate
and un~leasant pollu~ants there may be difficulvies ~arvicul-
arly for the vital separation and filtration processes. ~ne
continuous processing of waste and used water may ~e i~peded
by the clogging or stopping-up of the coal filter, by changes
o~ flow and by excessive abrasion o~ the filter coal. Thereby
there may also be some passage of impurities, espec1al1y of polar
substances, through the fine filter which is charged .ith active
coal.
The inv-ention therefore is based on the objective of -mproving
the filtration processes and separation methods in the process
mentioned initially in simple and continuously-operating ways.
Thus in particular, by varying the filter conditions cr by
establishing a new type of filtration device ænd oper~ti~g
them, an improvement Or the adhesion process OL the pcllu'ants
at the filter media is attaîned, without the passage OL the
used water which is to be clarified being impeded. B~J chosen
variations of the filter media and use of the waste assembling,
læstl~ a further improvement of the attainable filter effec~
with additional collection of the strongly polar substances
should be achieved.
This ob~ective is thereby attained in that the used water
carrying was~e is led throu~h a moving mu~ti-stage s-~ste~ o
fil~vers, in which the rou~hing filtration is a' leas'v ~artly
eLfected by loose fillinæs of coal, which are producec from
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the organic components of the waste and are optionally pretreated
to increase the adsorption and adhesion, and the filling laden
with organic contaminants is led back into the multireactor pile
for the carbonlzation of the sludge. The fillings of coal are
bulk matter which is (loosely) distributed over the filter or
poured into the containers respectively.
The invention is substantially built upon the recognition that by using
a multi-stage filter system, in which the filtration processes take
at least partly through loose fillings which contain coal, the
avoidance of the formerly observed disadvantages is made possible.
By dividing the filtration processes into several stages, and
especially by the previous use of the roughing filters which
contain loose fillings of filtration materials, a mechanical
and partly also adsorptive separation of the sludge from the
used water is possible, without stoppages or the clogging OL
the perforated walls, screens and similar filtration devices.
~he blockage or clogging of the perforated walls and screening
units is avoided by the fact that the sludge adheres to Lhe
particles of the filtration fillings, and the removal by a simple
tipping or tilting process of the filtration material whl_h is
laden with sludge together with the freeing of the unclogged
perforated screen surfaces is possible. Thus the continuous
refilling of the emptied filter system with fxesh filtra.ion
material and thereby an undisturbed cycle of the filtration
process becomes possible. The fillings laden with sludge which
are extracted are then led back for the subsequent carbo?ization
of the contaminants into a reactor of the multi-stage reactor
pile~ producing new filtration coal.
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It is advisable to carry out the filt-ation by loose fillings
in suitable devices as roughing filtration, before later a
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further ~iltration and clarification of the used ~la'~r
which is passed through non-activated and 2ctivated ~
coal contained in further ~ilter units ta~cs place. Even
tnough it is possible to provide a ~echanical rakir.~ ~nit
be~ore the prelilter which has a loose ~illing of filtration
material containing coal, the unit can be completely r~placed
by the pre~ilter itsel~, since the blockage of the operational
parts of the ~iltration devices is largely excluded by the
filtratior. by means o~ the fillings.
The pre~ilters which serve as the ~irst rou&hing ~ilte. are
ln general operated in counter current to the p~ssing ~olluted
used water, whereby a filtration takes place on the basis of
the gravity effects. But the rou~hing filters can ælso be
rotated in standing water or can be moved by used water ~low-
ing away.
The fillings of filtnation material contain mainly coal.
In the roughing filters which are ~irst passed throu~h, thl~ coal
is in general in non-activated lumps and thus ser~es as 2
mechanical ~ilker. The coals are produced ~rom the organic com-
ponents of the waste without activation. Depending on the ~ype
of composition of the waste water to b~ treated or of its
contaminants, a certain proportion of activated ooal can be
added to the roughing filter, and this too is produced ~ro~.,
the organic components of the waste.
Acc~rding to a preferred embodiment of the invention, th~
fillings contain coal in a pelletized stateJ to ~.eep the
abrasion into coal dust as low as possible. This pelle'i7ation
of the coal fillings is pref~rably p~rLormed both or ~he
rou~hing ~iltration and ~or the fine filtration, in ~he case
of the latter with activated coal.
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Proceeding from the coal produced by carbonization in tre
reactor from waste, this is finely crushed after cooling, ~i~ed
with an organic binding means such zs tar, briquette pi~ch, 2~c
and then compacted at hi~h temperature and pressure, e.O. 80 C
with apressure of 1200 kp/cm .This compacted coal can then be
again reduced to the desired core size by crushing. It is
then non-activated filter coal which is suitable for roughing
filtration. Should the use of the coal for fine filters be
planned, the splint granu~te obtained is activated in the pe~ se
known manner, which for example can be achieved by heat treat~ent
for several hours in the gas-tight sealed reactor of the
multireactor pile, by introducing ste2m and/or zinc chloride.
The active coal which is pelletized and thus obtained from
the organic component~ of the waste has a good abrasive quality
with a simultaneously high surface development.
The quality of the pelletized coal can be additionally increased
by spraying the waste be~ore it is ~ed into the ~irst thermal
stage or in the first therm21 stage with liquid combustible
organic waste products, such as used oil, for example
By this kind of pelleti~ing, the abrasion ef~ects on the coal
and the stoppages caused by it can be largely avoided.
Specially favorable filtration ef~ects are achieved by loose
coal filtration material which contains a proportion of polar
substances. This share of polar substances can be achieved b-
~mixing with the waste and/or used water such waste products
as appear durinæ the heat treatment in ~iltration-produc~ive
ænd actively adsorptive form.
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This can be achieved for example by adding to the housekold
and industrial waste to be treated, which is conveyed or the
used water, usually communal effluent, a certain propo~4iGn
of used ~ater from paper manuf2cture or porcelain processing.
Waste or used water from industry usually contain pol~
substances, e.g. fillings such as alumina,cilicon oxide,
titanium oxide, etc which are o~tained during conversion of
the organlc components present in coal at coking te~peratures
of from ~00 to maximally 800 C. in activated form. O~rer polar
metal oxides ~Ihich come into question , which frequently have a
small positive charge, are e.g. iron oxide and mzgnesium
oxide, as they are found in the ceramic and aluminum ~roducing
industries as waste sludge. By the planned admixture cf waste
sludge which yield during the coking process activa~ed polar
oxides, it is possible to attain at the mechanical co~l filters
not only additional filtration effects due to pola~ electro- -
static effects, but there is also a favorable e~fect o~ the
clarification and sedimentation behavior Or the used ~ater.
Therefore this step of the composition of the loose fillings
from both ¢oal and also polar waste products, apart from the
pelletization of the fillingsJ is pre~erred in the ~xdi~nt of the
process according to the invention especially. This is particularly
true of the fine filtration.
According to a further embodiment of the process according to
the invention, at least the fine filters are backwashed with
usable water before the charged filling is emptied out~ and this
waker is preferably taken from already clarified used ~later
in a branch current,
The filtration processes using loose fillings, prefer2bly in
pelletized form~ can thereby be partly furkher improved by
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achieving the constant motion of the fillings. In ',he motiono~ the fillings, e,g. by the motion of the container holding the~,
care must be t~ken that tnis ~oes no~ attain a T71u~diz~d bed
state, since that reduces the mechanical filter e~ec~.
The process according to the invention is prel'rabl~ ^~rried
out so that the filtration system is constantl~ filled with
fillings, then traversed by the.used ~later lade~ wi~h waste,
optior~ally freed of polluted ~illings after previous bacl~ashing,
and after refilling with fillings is again used ~or fil~ration.
These various measures undertaken continuously can for example
be achieved at spatially s~parat~d s~ations of a single
filtrat~on davice. Such multi-st~ge ~iltration devices are
iater descriked ~or the performance of the invention's p-rocess
but it is to be understood that the invention is not limited
to these particular devices.
Fig. la, lb describe the principal stages of a multi-stage
filtratlon process according to the invention;
Fig. lc shows a circulating bucket filter, which can be used
both as roughing filter and as fine filter;
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Fig.2 shows a belt filter, and
Fig . 3a, ~b represent a continuously operating ~iltraticn belt.
Fig. la shows the ~ain filtration cycle of the pr~cess according
to the invention, whereby the necessary reactors required lor the
system to re~enerate and optionally to combust the ~iltration
coal which is polluted in the multireactor pile~ in which
the org~nic componentS of the waste ære converted in40 coal,
partly in activated and partly in non-activaked for~, as well
as the waste combustion can take place, 2re not shown. Re
these additional devices, the first-named DE.OS 25 58 7~
of the applicant, as well as the parallel patent application
to the present application which was simultaneousl~ filed
"Process for combined waste utilization and clarification of
waste water" File No ...~.., are expressly mentioned. As
multireactor pile~ the process according to the inven'~ion
uses an arrangement which consists of at least two, preferably
3 or more, essentially cylindrical, horizontally moun~ed ar.d
parallel drums which can each be rotat~d about their z~is. In
a preferred reactor arrangement, they are mount d in a trizngle
above one ano~her, so that one may speak of a pair of reactors
below and an upper reactor above them mounted between them.
In the following the filtration process according to the irlvent-
ion is ex~lained separately on the basis of follow~n~ the
path of the used water and the solid waste:
The usad water, ~ooth urban used water and industrial e~luent~
is led ~hrou~h aneffluent intake channel 108 via a nozzle
system 170, in which by gas in~ection, e.gl airJ æ mixirO
and ~ine distribut~on of the incoming pollutants takes place,
to a set41ing basin 110, a scree~ 112 and then to a m-lti-st20e
filter device 106.In front of ths multi-stage coal filte- 106,
a prefilter 142 ls provided: which can be inserted in the used
water as a roughing filter. This pre~ilter serves acco-^ding to
the invention to catch very heavy or stubborn impu~ities~
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and can if desired fully replace the mechanical rake or t~e
screen li2 This pre~ilter 142 rotates in counter cu~rer,~
to the arri~ring lls~d .JatQr. Tn a pre~er~Qd ~or~ of the i"-Jer.ticr.,
as sho~m in Fig. lb, the pre~ilter consists of individua
filter elements 144, which contain a coal filling, whereby the
filter elements are mounted on a slowly or intermitterltly
moving chain belt 146 or the like, which transports the
filter element in the direction of the arrow in Fig.2 into
the used water condu~ in the outflow end 148 of the prefilter
and then in the counter ~low direction upstream to the up-
stream point 150, at which the now polluted single filter
elements are withdrawn from the ~low in the upstream direction.
An advantage of this design of the rotating prefilter ~s that
the duration of the insertion o~ the filter elements in ~he
used water can easily be made dependent on the observed
degree of i~purities by increasing or reducing the speed of
the conveyor chain 146. Naturally this type or a similar
desi~n can also be used ~or tha subsequent roughing filter
and fine ~ilter 116.
The ~ilter elements 144 of the prefilter comprise in general
a suitable frame, wh~ch contzins a loose filling at least
of a proportion of coal particles, preferably in pelletized for~..
This frame is perforated in the area laden with fillings,
to allow the passage of liquids.
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After removal of the filter elements from the used T,rater f' o7~r,
the polluted c021 fillings are led by ch~in conve~or 1~6 to a
reactor of the multireactor pile(not sho~m 'n the Li~ure~,
in which the regeneration of the coal and the simult~neous
pyrolysis of the collected organic impurities takes ~l~ce.
Thus the impur~ties are transformed directly into usæb~e
~ilter coal. Here it is advantageous to provide a dr~ppi~
mechanism for the filter elements, through which the liquid
assembled on the polluted filter coal can be best removed before
the coal is regenerated or incinera~ed. This drip device
can contain e.~. a shaker mechanism(not shown) to improve
the remo~al of the water.
The now empty filter elements, whose per~orated screen s~lr-iaces
are maintained in a non-blocked and non-clogged form bg the
filling can now be charged with ~resh, regener~ted coal from
a reacto~ ol the mul'ireactor pile(not shown in the ~iOure.
Here it may be advisable to provide interim washing processes
in the event of stoppages, but this is not shown in the figure.
The empty filter elements a~e then led back with fresh coal
fillings to the prefilter 142. Between the coal outlet of the
(not shown) reactor and the prefilter, a heat collector device
156 for cooling the hot regenerated coal via suitable heat
exchangers (not separately shown) by heat transporting media,
e.g. water can be provided.
By the rotating prefilter 142, to which optionally a mechanical
rake can be connected before or after it, a large part of the
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suspended or floating organic components in the water, which
have been brought into the used -~ater by the waste, can be
relatively simply removed.Further it can be seen from the
figure that the floating or suspended, primaril~J organic
impurities, which are caught by the screen or rake 112,
can be led through b~J means o~ 2 upwards moving conveyor bel~
132 from the used water and fed into the combustion or coking
process.Here the conveyor 132 is so designed or arranged ~hat
relatively unimpeded passage of water is possible during tne
c~le~ion: and removal of the floating and suspended p2rticles.
The prepurified used water cleaned by the prefilter 142 and option-
ally b~ screen 112 now enters a system of roughing filter 114 and
fine filters 116, before it leaves as usab'e water via outlet
conduit 118.
The roughing filter 114 consists of a multitude of roughing
~ilter elements 120, which leave the roughing filter b~J raising
and lowering it for regeneration or can be led bac~ into it.
The filter elements 120 are usually filled with normal filter
coal o~ suitable particle sizeJ preferably in pelletized ~orm.
The fil~er elements are moved during operations in counter -
current from the ~nd of filter 122 to the start of filter 124.
The fine filter 116 consists also of a number of fil~er elements
126, which are also moved in counter current to tha used water
from the lower end 128 to the upper end 1~0 by st2ges. The
fine fi1ter can be cleaned by bac~^lashing, optionally in a
bac~washing unit 134 which is provided for the purpose.
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Pre~erably the bac~ash water is taken direct ~rom the
usable water conduit 118 and can if desired be stored .~ the
reSerVO~r 136J which has a heat~r coil 1~8.The water cortamin-
~ed by the backwashing ~lows through a return condui~ 3~ck to
the used water inlet 108,
After the end of the back~iashing, the ~ilter element 1~6
can again be led back into the ~ine ~ilter 116 to be ~sed again.
The back~ash is however only an optional measure, since the
usual regeneration o~ the individual filter elements ~ich are
polluted and used up is carried out in a reactor of ~ke not
shown multireactor pile, where also optionally a co~le~e .
ashing and removal of the ash can take place from the ~eactor.
In the latter case the bins o~ the fine filter elements 126
aPe filled with fresh active coal ~rom a irst re~ctor-of.
the multireactor pile, whose heat content is still usable
within the heat collector 156 before inserting it in the used
water.
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If we now ~ollow the path o~ the mainly solid waste to be proce-
ssed, ~-hich inter .alia may comprise ~oodstuffs wastes, p2per,
synthetic materials, oil and tar residues, old tyres, -,Jocd~
glass~ ashes, etc~ th-s is sub~ected to a first trea~e~ or
separation ~rom a bin 160 via a magnetic belt 162, a coveyor
belt 166, and the shr~dd~ rollers 16~. In the set~lir~ b2sin llo
the substances of a density of ~1 are left, and re~oved 3y means
o~ a conveyor, e.g. the bucket conveyor 168. Via a se~ies
of Jet nozzles 170 a basic mixing o~ used water and waste
takes place to improve the desired separation in~o or~aric and
inor~anic compnn~nts . Via a conveyor
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1~2 ~he swimming organic co~ponents o~ the waste are remoYed
from the screen 112 and are transferred to a reactor for co~ins.
In the multireactor pile tal~es pl2ce in the indi-~7-dual reactors
which are directly adjacent to each other(not sho~n in the
figure) a thermolysis and p~rolysis both of the mechanically
removed impurities and o~ the polluted filling coal ar.d other
caol filters, whereby to the desi~ed degree a partly direct
introduction of waste into the reactors can bs provided.
In Fis. lc another preferred embodiment of a prefilter 188,
which also can be used as a fine filter, is shown. This consists
of mainly a track 1~o mounte~ sytem of tipping, upwards opened
single buckets 182, whose floors 184 are perforated and contai~
loose filter material 186, whereby the track 180 makes possible
the unloading of the polluted filter material and t~.e reloading
with f~esh filter material by e.g. a tipping, tilting or
-~eight-induced guide motion sro. As can be seen from Fig. lc,
the single containers 182~ here shown as buckets, move to
meet the used water, which unloads its sludge on40 the ~illings
and then penetrates the perforated floors. Here the fili~a~ion
can easily be ad~usted to the requirements deper~ding on speed,
charge of used water with contamlnants etc, so that a selected
number of containers 182 are led toward the used wa~er.Thus a
used water flow t:~ough one or more containers ca~ be achieved
as desired, as the single bins can be taken sideways out of
the used -.~ater stream 194 round the track 180 ænd can be
inserted in it. The empvying provoked e.g. by the tirp-n~
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of the polluted filtration material leads the poll~tec
filtration material to a belt which leads to the f~lrnzce 190.
The re-.illing of the container 182 with filtration ~a'er~al
then takes place ~ith a conveyor device, e.g. 192. co~-rg
from the furnace.
This device has proved itsel~ for the constantly cha~ing
conditions of the waste water/waste utilization operation to
be excellent, since both a stoppage of the filter media is
avoided by a simple feeding and removal of filtration material,
and also by the easy switching in of containers 182, ~;hcse speed
can be regulated against that of the used water,a ver~ flexible
system is attained
In Fi~. 2 an equall~ suitable filtration system is sho~n,
which has an endless bucket filter ~0 on a belt, which can be
placed in the used water flow at a suitable point. ~ne bucket
filter comprises in general a pair of laterally moun~ed
conveyor belts ~32 which are driven by rollers ~34, ~ha~ 2n
upper part of the belt 336 is moved upwa~ds to the left, as
sho~n in Fig.2,on the belt a number of buckets are mo~nted,
of which the solid floor surfaces 340 may be square, rectangular
or the like, and are closed off by a pair of e.g. triæ~ular
side walls. The single buckets are connected with e~c:~ other
by per~orated walls 34~ hich allow the flow of the -~sed
water to be clarified and the deposi~ of the suspendec conta~-
inants from the filtratior, ma~erials.Via correspondin~
topped up fillings~ the protection of the screen ~lalls is
attained and thereby a continuous operation of the pr~cess is
possible~As car, well be seen from Fig 2s a 102din~ of fresh
filtration materials or the empt~Jing of polluted filt-a'ion
matPrials can easily be carried out at the ends o~ ~h~
arrangement.
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It is preferable that the floor surface of the bucket-- ,38 is
struct~red, i.e. knubbed~ to prevent as far as possible s~rong
movements of the filter materials. For this, option211y further
subdivisions of the surface of the containers c2n be ~rovided,
which is preferably done in the longitudinal direction.
Tn Fig 3a and ~b there is finally a device 400 usable as
prefilter and/or as fine filter shown in cross-section znd
in longitudinal section, which essentially consists of
a circulating endless bel~ 402 which is perforated and is loa~ed
with filtration materials at spatially separated stations
420, 4~0 440, passed through by polluted used water ar.d freed
of contaminated fillings. As shown in Fig 3b, in the 102ding
area 440 via a conveyor coming from the furnace 4289 ~resh
filtration materials are c~rried, while the fillings which are
polluted in the ~hroughput area 420 are then tipped in a suitable
manner in the unlQading area 430 onto a belt 426 leading to
~he furnace. Here the belt can be driven by suitable
drive elememnts 422, which preferably are located outside
the throughput ar~a.
According to a preferred embodiment of the process accord~ng
to the invention, the circulating belt is V-shaped in the
throughput area ~20, in the loading area 440 it is V-shaped or
flat and in the unloading area 430 it is led flat on the drive
element~ 422 in the tipping or tilted posikion. In ~ic. ~a,
~here is a V-shaped guide track of the belt 402 visible in the
throughput area.Here the belt 402 is led on the drive rollers
404 whereb~J the filtration mater~als 406 are loc~ted on the
surface structure of the belt 412. By these or s~milzr me2nsJ
the s~rong displacement o~ the filtration materials ccn be
prevented~ In
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Fig ~a the unloading of sludge particles is sho~m as 410,
while the water 408 exits via the porous belt downwards at
424.
It should be noted that the belt can be continuously
driven a~ varying speeds or intermittently.Here too the cor-
tinuous supply and removal of the ~iltration fillings permits
a surface pro~ection of the otherwise easily blocked
perforated filter elements.
It is ezsily recognised that by the use of filter elements
~hich provide:a continuous protection ~or the perforated
screen surfaces of the system by means of filtration materials
and which can conveniently be continuously supplied or removed,
a ~lexible and trouble-free operation of the whole system is
achieved. This is especially favored by the pelleti~a~ion of
coal materials, which are used in the prefilters, rough~ng
filters and fine filters~ as well as by the planr.ed prasence o~
proportions of polar materials, which are also producible from
waste and/or used water, particularly calcinated metal oxides,
such as ferrous oxide, alumi~a, silica etc, as they e...erge
from the multireactor pile.
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