FR2572067A1 - INSTALLATION FOR PURIFYING WASTEWATER THAT CAN BE MADE IN THE FORM OF SEVERAL CONSTRUCTION STAGES - Google Patents

Abstract

THE INVENTION CONCERNS A WASTEWATER TREATMENT PLANT THAT CAN BE BUILT IN THE FORM OF SEVERAL CONSTRUCTION STAGES. THIS INSTALLATION INCLUDES, IN ITS BASIC CONSTRUCTION STATE, A MECHANICAL DEPURATION STAGE INCLUDING A GRID 2, A VENTILATED BLASTING TANK 4, AN INTERMEDIATE CLARIFICATION DEVICE 15 AND A SLUDGE EVACUATION DEVICE 6, THIS SYSTEM CAN OPERATE AUTONOMOUSLY BEFORE THE ERECTION OF A BIOLOGICAL TREATMENT STAGE MOUNTED DOWNSTREAM AND INCLUDING AN ACTIVATION TANK 8 AND A POST-CLARIFICATION DEVICE 10. APPLICATION ESPECIALLY TO THE TREATMENT OF SEWAGE AND WASTEWATER OF HOUSING.

Description

The invention relates to a purification plant for

  wastewater that can be erected in the form of several

  building and having several functional floors

  and having a mechanical purification stage and, in the

  at least one biological purification stage mounted downstream and in which a wastewater collection device is mounted upstream of the mechanical purification stage, which comprises a preliminary purification device in the form of a grate or the like, a grit chamber provided with an aeration device and a clarification device

  intermediary mounted downstream and comprising an evaluation device

  sludge, and can be used independently, in the stand-alone mode of operation, as a basic building stage prior to the erection of the downstream biological purification stage, and can be used in The mode

  in combination with said solubilization stage

  biological diet downstream, after the erection of the latter.

  In the case of the installation of waste water of the type indicated and known (according to the practice), the tank of grit has a volume which corresponds to a required space equal to the maximum to 4 1 / inhabitant (the term of inhabitant is used here and also further to designate a unit equivalent to one inhabitant). The aeration device does not use, apart from

  of the grit removal device, no defined activation tank.

  No defined evacuation of activated sludge in order to achieve

  the setting of particular biological conditions of

  in the aerated grit removal device does not intervene.

  The basic floor is certainly the first floor of

  truction, but is merely an overall stage of

  mechanical ration. The purification power that can be obtained

  nir is insufficient and is well below 30%. The UTI

  The use of the mechanical scrubber stage as a basic building stage is rather a temporary solution than a recommendable disposal from the point of view of wastewater technology. If you connect a biological treatment stage

  or more stages of biological purification of this type in a

  stage of construction it is necessary, for the function-

  combined, to implement a construction expense

  tion, for example with a required space of approximately 179 1 / inhabitant for a purification power which is generally less than 93%. In the context of the known arrangements, the first biological purification stage, which is mounted downstream of the described mechanical purification stage, is a stage in which

ble charge.

  On the other hand purification plants are known

  multi-stage wastewater treatment (see

  German Patent Nos. 2,640,875 and 3,117,805), in which the first biological stage operates at a very high efficiency.

  with a sludge load of 2 to 12 as an adsorp-

  tion, and the second biological stage functions as a

  at low load (a sludge load implies that it is kg BSB5 per kg dry substance per day). In

  the adsorption stage, the sludge is maintained in the initial phase.

  tial. This initial phase is the phase presenting itself, so to speak, without the respiration of the substrate and during which the enzymes necessary for the disintegration of the substrate are formed. Therefore, the initial phase represents the zone

  limit in which substrate respiration begins

  but it is not yet fully active. In order to keep the mud of the first activation stage in this state, it is necessary to have a sludge obtained recently and to have made a correspondingly controlled withdrawal.

  excess sludge outside the international clarification system

  médiaire. In connection with the space charge indicated in the first stage of activation it results that in the latter, it occurs mainly an adsorption or a flocculation of compounds with high molecular weight and that these compounds are

  deposit without being degraded, in the clarifi-

  intermediate cation, at the same time as the excess sludge. We

  saves the important energy that otherwise is needed.

  for the degradation of these compounds. In the second

  activation, low molecular weight compounds and more

  easily degradable can then be

  particularly easy and rapid biological degradation

  that one works, in this stage, with a load of mud of approximately 0,15. In both stages of activation we put in

  consequently, mechanisms of action that are completely different

  ent. A mechanical purification stage remains downstream.

  The invention is based on the fact that this technology of ad-

  sorption can make an essential contribution both from a construction and functional point of view for the development of sewage treatment plants of the type indicated above, which can be assembled and

  be put into service following several stages of construction

  tion. Until then the wastewater treatment plants of the type indicated above were not arranged in accordance with the indications of the adsorption technology and they were not

  did not operate according to these indications.

  The object of the invention is to develop an installation of the type indicated above so that already in the case of the autonomous operation of the basic building stage, it is possible to obtain a significant purification power of about

  % and much more, and that in the context of

  complete operation, during combined operation it is possible

  to hold, with a required space equal to the total simply to

  100 per capita or less, a purifying power at least equivalent or even significantly higher than

  known devices of the type indicated above.

  This problem is solved according to the invention thanks to

  this is because the volume of the grit floor

  corresponds to a space requirement of at least 6 1 /

  and preferably at about 8 1 / inhabitant and is arranged in the form of an adsorption vessel, that is, is arranged at

  the way of an activation stage that I can do

  in the aerobic field and / or optionally in the aerobic field.

  with a sludge load BTS equal to or greater than 2 (BTS =

  BR / TS, BR representing the space charge in kg of BSB5 by r.e.

  cube per day and TS representing the

  these dry matter in kg per cubic meter), and in which we can

  the sludge in the initial stage using the intermediate clarification device and the sludge disposal device out of the intermediate clarification device

  mud. The oxygen content must be maintained in the gamma

  from 0.5 to 1 mg / l in the adsorption stage. The invention takes advantage of the fact that the grit chamber of the installation

  known from the type indicated above can work as-

  adsorption stage, thanks to the provisions described. As a result, for an increase of only about 2% of the expenditure from the point of view of construction, reported to the entire sewage treatment plant, it already provides, in the autonomous operation, a power 30% and more. If the device is arranged to connect to the intermediate clarification device or the sludge removal device, a sludge recycling device is provided.

  used to introduce at least 20% of the sludge removed from the

  positive intermediate clarification and preferably

  40 to 60% of the sludge removed from this clarifying device

  cation, in the wastewater collection system, it is already possible, in the case of autonomous operation and with little additional expense, to

  approximately 60%. Correspondingly, this recycle

  It is also advantageous in the combined operation.

  Cerecyclagese produced at a sufficient distance from the floor of

  mechanical purge and in any case upstream of the tank of des-

  sandblasting. The excess sludge can be sent, as is usual, during the autonomous operation, to a digester. But

  it is also possible to introduce, during the operation

  the non-recycled sludge, with a view to further processing without any digester, to a device allowing the addition of Ca salts or Fe (or other

  packaging means), and then to a press filter with

  cakes. In addition, during autonomous operation, ef-

  flowing out of the intermediate clarification device

  may be sent to a device intended for watering and / or

  to use agricultural crops.

  If the basic building stage is

  According to the invention, the following construction can be arranged

  in different ways. One of these possibilities is

  the fact that, in the combined operation, the

  downstream biological purification unit is provided as a second stage of construction and activation vessel for a slurry load BTS in the range of 0.15 to 1, and is connected to the outlet of the clarification

  intermediate and is equipped with a post-clarifica-

  comprising a device for discharging the sludge. We can

  have a bacterial bed stage with a spatial charge

  between 0.2 and 2 or more, depending on the filling, in another stage of construction mounted between the intermediate clarification device and the activation tank. In the

  case of a filling formed of blocks, one does not exceed a

  space geometry equal to 2. In the case of a filling with

  the plastic material, we can go up to 6. Another pos-

  is characterized in that in the com-

  the downstream biological treatment stage is realized

  as a second stage of construction and a bacterial bed

  nothing downstream of which is mounted an activation tank arranged for a sludge charge of between 0.05 and 1, and the tank

  activation is connected to a post-clarification device.

  comprising a device for evacuating the sludge. It-

  to be in the context of the invention to connect the floor to bed

  bacterial directly to a post-clarification device.

  In all cases the wastewater is subjected in the basic building stage or adsorption stage, not only to the purification described, but, in relation to the effluent that is introduced in the downstream connected stages, also at

  a treatment or an active preparation for the ul-

  in a sense in the sense of cracking.

  The basic construction stage works in a way that

  re particularly effective for the high sludge load,

  when only bacteria occupy the space. This is guaranteed

  suitably (see German Patent No. 3,317,371) by operating the adsorption stage with prokaryotes as active biomass and prokaryotes, which occupy per cubic meter at least 1 % by weight of active biomass in a cubic meter of the adsorption stage,

  are permanently sent as additional biomass

  re, preferably in an amount of between 5 and 15% by weight per cubic meter, at the adsorption stage, together with the raw wastewater that arrives there. In this respect it is appropriate to achieve a strict separation of biocenoses between the basic building stage and the adsorption stage and downstream connected stages. However, good results can also be obtained when, in the combined operation, at least a portion of the excess sludge taken from the post-clarification device can be reintroduced into the reaction vessel.

  sandblasting working as an adsorption stage, through the

  intermediate of a corresponding recycling device. Indeed

  tests have shown that, in the case of high sludge loads,

  BTS, such as those indicated for the adsorp-

  Only bacteria occupy the space. The production of sludge in the adsorption stage is then 7 to 10 times more

  important than in weakly charged activation stages

  located and downstream. The percentage of eukaryotes,

  to say bacteria absorbers, in the adsorption stage

  and therefore in the basic building stage of the

  purification plant according to the invention, is relatively

  low. The bacteria population in the stages of activa-

  downstream equipment has approximately the same composition

  only in the adsorption stage, but in general the bacteria

  located in the downstream activation stages

  have a much lower activity. These characteristics

  such as the intense production of sludge containing bacteria with a 7 to 10-fold increase in sludge,

  lead in some way, despite the return of the mud in ex-

  from the post-clarification device, to a reduction

  concentration of eukaryotes and therefore a significant weakening or elimination of eukaryotes out of the biocenosis of the adsorption stage. The chances of survival in this biocenosis that is specifically oriented on the bacteria of the adsorption stage are very low

  for eukaryotes, so that in the context of

  paired with prokaryotes with raw sewage coming into this floor, the described recycling of mud can be put

implemented.

  In summary, we can consider that the advantages

  obtained is the fact that, in the case of an installation

  sewage treatment plant according to the invention, already during the autonomous operation of the construction stage of

  used as the first stage of construction, one can obtain

  a significant purification power of about 30% and more, with a minimal additional expenditure from the construction point of view. By simply recycling the sludge, the purification power can be increased to around 60%.

  According to the realization of the subsequent construction, we ob-

  in the combined operation, with a required space equal to only about 100 1 / inhabitant and less, a cleaning capacity at least equivalent to or even greater than that of known installations of the type indicated

  (in which the required space is approximately 179 1 / inhabitant).

  Other benefits can be summarized as follows:

  first of all we get practically a doubling of the

  purification plant in the first stage of construction,

  an expense necessary for the mechanical purification, compared to the known provisions. Another biological stage

  can be mounted without difficulty downstream so that the

  The final purification of this additional construction can be practically increased to any value in the context of the combined operation. If we only work with

  the first stage of construction, that is to say with the

  basic age achieved in accordance with the invention, this is achieved.

  during the addition of Ca or Fe salts or

  For other precipitation agents, sludge treatment can be continued in a plate filter press and fuel filter cakes can be obtained to extract twice as much energy from the mud. is possible to extract by means of the recovery of methane gas in

  digesters. Already the basic building stage allows us to use

  all the microbiological reaction mechanisms, which lead to permanent improvement thanks to mutated bacterial strains and therefore also guarantee

  a much higher stability of the treatment with respect to

  load shots. For countries oriented towards agriculture, especially in areas where there is a lack of wastewater, using only the basic building stage according to the invention, water can be obtained well.

  prepared and rich in nutrients that can be used

  as well for fertilization as for watering.

  In addition, methane gas is produced and in the case of

  of a digester, we obtain a mud rich in substances

nutritious for the crop.

  Other features and benefits of this

  invention will emerge from the description given below taken

  with reference to the accompanying drawings, in which: - Figure 1 shows a purification plant

  wastewater according to the invention, in its state of con-

complete truction;

  FIG. 2 represents the building stage of

  on a larger scale of the installation of Figure 1; - Figure 3 shows a basic construction stage of Figure 2, extended; FIG. 4 represents, in accordance with FIG.

  a known wastewater treatment plant of the type

  pointed out above; and FIG. 5 represents, according to FIG. 1, another embodiment of a purification plant

  wastewater according to the invention.

  The wastewater treatment plants represent

  Figures 1, 4 and 5 can be erected and put into operation in accordance with several building stages and operate on the basis of several functional stages. The basic construction includes a mechanical treatment stage and, in the fully constructed state, at least one downstream biological treatment stage. A wastewater collection device, which is indicated by the arrow 1, is mounted upstream of the mechanical purification stage. The mechanical purification stage comprises a preliminary purification device made in the form of a grid 2 or the like, of a grit chamber 3 comprising a ventilation device 4 and a device for cleaning.

  post-clarification 5 mounted downstream and comprising a device

  tif 6 sludge removal. The expression "available

  intermediate clarification system "since this

  positive clarification works as a device for

  intermediate clarification 5, when the installation is

  constructed. The mechanical purification stage can function

  independently as a stage of construction

  basic training, in the autonomous mode, that is to say before

  the biological treatment stage downstream. After the erection of this downstream biological purification stage, it can be operated in association with this stage,

according to the combined operation.

  Figures 1 and 5 show facilities that comply with

  to the invention, whose construction is complete. Figure 4 shows the contrary known embodiment. When

  the sanding tanks 3 are compared on the one hand with the installation

  lation according to the invention and secondly of the installation

  According to the state of the art, it can be seen that the grit chamber 3 of the installation according to the invention is of increased volume. This is visible when comparing Figures 1 and 5 on the one hand and when referring otherwise

  in Figure 4. The grit chamber 3 has, in the figures

  res i to 5, a volume that corresponds to a space required from

  less 6 1 / inhabitant and preferably about 8 1 / inhabitant.

  In Figure 4 this space required corresponds to 4 1 / inhabitant.

  The grit chamber 3 is made in the form of a floor

  adsorption. This means that this grit chamber 3

  as an activation stage in the aerobic domain and / or optionally in the anaerobic domain, and this with

  a sludge load BTS equal to or greater than 2, the sludge

  in the initial phase that can be retained in this

  blast tank 3, which works as an adsorp-

  tion, using the intermediate clarification device and the device 6 in which intervenes the evacuation of the sludge. We thus obtain a purification power of about

  33% when the basic stage operates in autonomous mode.

  This is practically a doubling compared to the

  purification power that can be obtained in the case of

  autonomous design of the basic building stage of a state-of-the-art installation (see

  Figure 4). Expenditure from the construction point of view is not

  but only 2% of the total expenditure. Figure 3 clearly shows that with a small additional expense, an increase in purification efficiency of up to about 60% can be achieved. We see here only in the mode

  autonomous operation, to the clarification device

  intermediate 5 or the device 6 for evacuation of the mud,

  connected to a device 7 for recycling sludge

  introducing at least 20% of the sludge withdrawn from the intermediate clarifying device 5, but preferably between about 40 and 65% of the sludge removed from the slurry device.

  intermediate clarification 5, in the collector device 1

  wastewater, which is installed upstream of the

  3. Recycling may be carried out at a distance of

  800 to 1000 m upstream of the grit chamber 3.

  Figure 1 indicates that in the functioning of the

  In combination, the downstream biological treatment stage is provided as a second stage of construction and as an activation tank 8 for a sludge charge in the range between 0.15 and 1, and is equipped with a device

  post-clarification device 10 comprising an evacuation device 11

  sludge. It has not been shown that in a

  another floor of construction located between the

  intermediate 5 and the activation vessel 8 of the second

  stage of construction one could have a bunk bed

  térien. Figure 5 shows that in the functioning of the

  In combination, the downstream biological treatment stage is constructed as a second stage of construction as a bacterial bed stage 12, downstream of which an activation tank 8 is arranged for charging. described above, in which case the activation tank 8 is connected to

  a post-clarification device 10 comprising a device

  11 sludge evacuation. In the embodiment of FIGS. 1 and 5, a strict separation of the biocenoses is carried out between the basic building stage operating

  in the manner of an adsorption stage and the stages of activation

  downstream. This separation is not absolutely

  necessary. On the contrary, in the combined operation, some of the sludge removed from the post-clarification device

  could be introduced again into the desiccation tank

  3 functioning as an adsorption stage, by means of

  intermediate of a corresponding recycling device 13, which has been indicated in Figure 5 by means of a dashed line. In the embodiment of FIG. 5, the effluent

  could be sent downstream of the post-clarifica-

  10, through a separate return line

  particular, in an amount which may be equal to

  of the intake quantity, in the device 1 of col-

  wastewater, in order to achieve denitrification

tion and / or dilution.

Claims (10)

  1. Sewage treatment plant capable of being erected in the form of several stages of construction and having several functional stages and comprising a mechanical purification stage and, in the fully assembled state, at least one biological treatment stage mounted downstream, and in which a wastewater collection device is mounted upstream of the mechanical purification stage, which comprises a preliminary purification device in the form of a grid (2) (3)   or the like, a grit chamber / provided with a device for   (4) and a downstream intermediate clarification device (5) having a sludge removal device (6) and can be used independently in the stand-alone mode of operation as a building stage.   before the erection of the biological treatment stage   downstream, and can be used in a modunction   compound in association with said biological purification stage mounted downstream after the erection of the latter, characterized   in that the grit chamber (3) has a volume which cor-   corresponds to a required volume of at least 6 1 / inhabitant and   at least 8 1 / inhabitant, and is carried out in the form an adsorption stage. -   2. Sewage treatment plant according to the   1, characterized in that, in the autonomous operation and in the combined operation, a device (7) for recycling the sludge, which serves to supply at least 20% of the sludge removed from the postclarification device (5) and from preferably about 40 to 65% of this sludge, is connected in the device (1) for collecting wastewater, the post-clarification device (5) or the device (6) for evacuation mud.   3. Sewage treatment plant according to one of   claims 1 or 2, characterized in that in the function   stand alone sludge can be transferred   for further processing without digester, has a   tif used to add Ca salts or Fe salts and to a filter press with trays.   4. Sewage treatment plant according to one of   any of claims i to 3, characterized in that,   in the autonomous operation, the effluent coming out of the   intermediate post-clarification system (5) can be sent   to a device used to irrigate and / or fertilize crops   agricultural resources. 5. Sewage treatment plant according to one of   claims 1 or 2, characterized in that in the   combined operation, the downstream biological treatment stage is used as a second stage of construction and as an activation tank (8) for a sludge charge   (BTS) in the range of 0.15 to 1, and is   strung at the output (9) of the post-clarification device   intermediate (5) and is equipped with a post-closure device   complementary rification (10). comprising a device (11) evacuation of the mud.   6. Sewage treatment plant according to Regulation   5, characterized in that in a second stage of   construction, a bacterial bed stage (12) comprising a   spatial geometry between 0.2 and 2 and more, depending on the   is disposed wise, / between the post-clarification device (5) and the tank   activation (8) of the second building stage.   7. Sewage treatment plant according to one of   claims 1 or 2, characterized in that in the   combined operation, the downstream biological purification stage is provided as a second stage of construction and a bacterial bed stage (12) having a downstream activation vessel (8) and provided for an equal spatial charge   or greater than 0.15, and that the activation vessel (8) is   corded to a post-clarification device (10) comprising   a device (11) for evacuating the sludge.   8. Sewage treatment plant next   one of claims 1 to 7, characterized in that   in the combined operation, at least a portion of the sludge taken from the post-clarification device (10) can be   again introduced into the grit chamber (3), which   in the manner of an adsorption stage, via   of a corresponding recycling device (13).   9. Sewage treatment plant according to one   any of claims 1 to 8, characterized in that   the adsorption stage works with prokaryotes used   as active biomass and that prokaryotes, which   of at least 1% by weight of the active biomass per cubic meter of the adsorption stage, are continuously fed as a complementary biomass, preferably in an amount of between 5 and 15% by weight. weight per cubic meter, adsorption stage, in addition to raw waste, which is coming.   10. Sewage treatment plant according to   any of claims 1 to 7 and 9, characterized   in that a strict separation of the biocenoses is carried out   between the adsorption stage and the stages mounted downstream.