IT201900013710A1 - PLANT AND METHOD OF TREATMENT OF WASTE WATER - Google Patents

Description

DESCRIPTION

Title: WASTEWATER TREATMENT PLANT AND METHOD

Technical field of the invention

The present invention relates to a wastewater treatment plant and method, in particular for the storage and recovery of water from the washing of means suitable for the production and / or transport and / or pumping and / or storage of material cementitious, e.g. vehicles such as concrete mixers and / or concrete pumps. State of the art

The expression "cementitious material" refers to materials including any type of cement. Among these materials, for example, we can mention: cement paste (in the jargon defined as grout and composed of cement and water), cement mortar (composed of cement paste and an inert granular element typically of fine grain size, e.g. sand), concrete (composed of cement paste and one or more inert granular elements having different granulometries according to requirements such as sand, gravel, gravel, etc.).

In cementitious material production plants, an area is typically provided for the washing of vehicles suitable for the production and / or transport and / or pumping and / or storage of this cementitious material. These means are usually washed by using mains water and / or recovery water (typically recovered from the washing itself). This washing area typically comprises a treatment plant, in particular for storage and recovery, of the washing water leaving the aforementioned means.

Such washing waters, after a washing cycle typically comprise different types of residues deriving from the aforementioned cementitious materials. These typically include undissolved and / or poorly suspended residues in water, such as sand, gravel, gravel, and residues dissolved and / or suspended in water, such as cementitious dust and / or silt.

Typically these waters undergo a first filtering phase in which they are conveyed to separator machinery, such as vibrating screens, augers, rotating drums, etc., used to separate the aforementioned undissolved residues and / or poorly suspended in water, obtaining water, defined waste water (or “gray water” cement water), containing the aforementioned residues dissolved and / or suspended in water.

The waste water is then conveyed and collected in storage tanks equipped with elements (called agitators, typically horizontally rotating blades immersed in the waste water) placed in continuous motion in order to keep the waste water agitated to avoid the deposit of the aforementioned dissolved residues and / or suspended.

From these tanks the waste water, by means of a special pumping system of the treatment plant, is typically pumped, according to pumping cycles with predetermined duration, to further filtering machinery (e.g. filter presses) and / or to the production areas of the plant. production of cementitious material and / or towards a washing station in order to be suitably reused in the washing cycles.

Typically, this pumping system comprises a duct having a suction section suitable for drawing the waste water itself. This suction section, typically made of a metal duct, crosses a wall of the tank itself to be able to connect, typically through one or more valves, to the rest of the duct, and has an outlet located inside the waste water collection tanks and, in use, immersed in waste water. Typically, this outlet is always open and in hydraulic communication (typically direct) with the tank.

The terms "upstream", "downstream" and the like are used with reference to the direction of the wastewater suction flow by means of the pumping system (i.e. from the storage tanks to the end user, through the duct).

The terms "horizontal", "vertical", etc., refer to an installation of the system according to the present invention.

By 'orthogonal' relative to geometric elements (such as straight lines, planes, surfaces, etc.) we mean that these elements (or elements parallel to and incident to each other) form an angle of 90 ° +/- 15 °, preferably of 90 ° +/- 10 °.

By 'parallel' in relation to the aforementioned geometric elements it is meant that these elements (or elements parallel to and incident to each other) form an angle of 0 ° +/- 15 °, preferably of 0 ° +/- 10 °.

Summary of the invention

The Applicant has found that, in waste water treatment plants, the deposit phenomenon of dissolved and / or suspended residues in waste water is of considerable importance.

In particular, the Applicant has observed that in known treatment plants, despite the presence of the agitators inside the tanks, between one suction cycle and the next, i.e. during the cycle of inactivity of the pumping system, it typically happens that the suction remains full of substantially still wastewater, ie substantially not subject to the action of the agitators. This is typically due to the geometry of the suction section which on the one hand allows the entry of waste water through the outlet mouth which is always open and in fluid communication with the tank, and on the other hand hinders the propagation of the wave generated by the agitators, which therefore cannot propagate sufficiently inside the suction tract.

Furthermore, even by washing the suction section by means of a flow of a washing liquid, given the outlet mouth open and in communication with the tank, this suction section would be immediately filled with waste water as soon as the washing is finished.

The Applicant has observed that, with the passage of time and despite the succession of pumping cycles, this presence of substantially still wastewater generates in a short time (typically in the order of months) a deposit, in the suction tract, of the aforementioned residues. dissolved and / or suspended in water. This typically involves an obstruction (more or less extensive) of the suction section and / or of one or more valves downstream of the suction section (e.g. one or more valves that connect the suction section to the rest of the duct), with consequent damage and / or problems in terms of operation of the entire pumping system and therefore of the plant, downtime and / or costs for washing and / or maintenance and / or replacement of components. The Applicant therefore posed the problem of developing a plant and a method for treating waste water that allow to reduce, even to eliminate, the risk of the aforementioned phenomenon of deposit of residues in one or more parts of the wastewater plant. treatment, in particular in the parts of the plant used for pumping waste water, in order to overcome related problems (such as those listed above) and increase the reliability of the plant.

According to one aspect, the invention relates to a waste water treatment plant. The plant includes:

- a storage tank for said waste water;

- a pumping system for pumping said waste water from said storage tank, said pumping system comprising a suction duct having an end section for drawing said waste water into said storage tank; And

- an adjustment device hydraulically connected to said suction duct upstream of said end section.

Preferably, said adjustment device comprises an elastically deformable locking element in order to alternatively assume a closure conformation in which it prevents hydraulic communication between said storage tank and said end section of said suction duct, and an opening conformation in which it allows said hydraulic communication between said storage tank and said end section of said suction duct.

According to one aspect, the invention relates to a wastewater treatment method. The method includes:

- preparing a waste water treatment plant according to the present invention;

- carry out an aspiration phase including:

- arranging said locking element in said opening conformation;

- by means of said pumping system, sucking said waste water from said storage tank;

- after said suction phase, carry out a washing phase comprising:

- by means of said pumping system, pumping along said end portion a flow of a washing liquid with said blocking element in the opening conformation;

- maintaining said flow of the washing liquid, arranging said blocking element in said closing conformation.

According to the Applicant, the adjustment device hydraulically connected to the suction duct upstream of the end section and having an elastically deformable locking element in order to alternatively assume a closure conformation in which it prevents hydraulic communication between the storage tank and the end, and an opening conformation, in which it allows the aforementioned hydraulic communication, allows to selectively isolate the suction duct from the storage tank, for example during the pauses between one suction cycle and the next, and to be able to put it in communication only when needed.

The elastically deformable block element allows the end section to be isolated from the storage tank while allowing the adjustment device to remain substantially free from the aforementioned residue deposit phenomena. Without wishing to limit ourselves to any theory, it is believed that any initial deposits of dissolved and / or suspended residues (e.g. cement dust and / or silt), in correspondence with the surfaces of the block element in contact with the waste water, are unable to adhere in a stable and lasting way, since for example, being typically rigid, they are unable to accommodate changes in shape between the opening and closing conformation (and / or vice versa). This entails their detachment from the aforesaid surfaces (returning dissolved and / or suspended in the waste water) typically before reaching dimensions such as to obstruct and / or damage the adjustment device. The Applicant has verified that comparative solutions, which use regulating devices of different types, such as ball valves and / or lens valves, placed upstream of the suction duct, are not suitable for the aforementioned type of system. In the case of ball valves, it has been observed that any deposits of the aforementioned residues and / or any inert granular elements not removed by the first filtering phase, can damage the valve (e.g. affect the surface of the mobile element of the valve) causing the loss of tightness of the latter. In the case of slow-action valves, it was instead observed that the presence of the rigid mobile element inside the suction duct, even when the valve is in the open position, is sufficient to obstruct the flow of waste water (e.g. slowing it down and / or disturbing it ). It is believed that this rigid obstacle facilitates the deposit of residues, acting as a privileged nucleation site for such deposits (it has also been observed that these deposit phenomena, once nucleated, in turn provide a privileged deposit site by increasing the accumulation rate as the size of the deposit increases).

The positioning of the adjustment device upstream of the end section allows the end section to be kept substantially clean and / or full of washing liquid, avoiding the stagnation and / or reflux of waste water inside it and the consequent formation of deposits. For example, it is possible to send a flow of a washing liquid (typically clean mains water) inside the end section to wash the end section and therefore, by closing the blocking element with this flow still active, it is possible leave the end section full of clean water. In the comparative case in which an adjustment device is positioned downstream of the end section, it may happen that the latter fills up again with waste water (with its residues), even after washing and closing the adjustment device. Therefore, the aforementioned characteristics make it possible to reduce, and possibly eliminate, the deposit of residues of cementitious material in correspondence with the end section of the suction duct, globally reducing the risk of obstruction and / or damage to the end section and thus improving the reliability of the treatment plant (and thus reducing machine downtime and costs associated with the latter and / or cleaning and / or maintenance operations).

With the expressions "hydraulically connected", "hydraulic continuity", etc., referring to elements of the pumping system and / or the treatment plant in general, it is meant that these elements are connected to each other continuously (e.g. directly and / or through the interposition of one or more additional elements) in such a way as to guarantee the passage of a liquid (e.g. waste water, washing liquids, etc.).

The present invention in one or more of the above aspects may exhibit one or more of the following preferred features.

Preferably, said closure conformation is an elastically deformed conformation of said locking element. Preferably, said opening conformation is a substantially undeformed conformation of said locking element. This facilitates the operation of the adjustment device, as it is sufficient to stop the stress that produces the closure conformation to return the locking element to its undeformed conformation and allow the passage of fluid (normally open device).

In an alternative embodiment, the closure conformation can be an undeformed conformation of the block element and the opening conformation can be an elastically deformed conformation of the block element. In this way, in the absence of forces acting on the blocking element, the latter tends to keep the end section isolated from the storage tank (normally closed device).

Preferably, said adjustment device comprises a base body, more preferably rigid, said base body comprising a through cavity having an inlet and an outlet. In this way, a path is identified within the adjustment device.

Preferably, said blocking element develops inside said through cavity.

Preferably, said blocking element in said opening conformation defines a channel joining said inlet and outlet mouth with hydraulic continuity. In this way, a passage of fluid is achieved in the regulating device.

Preferably, said blocking element is firmly fixed to said base body at end portions of said blocking element, more preferably distal from (at least) a (substantially) central portion of said channel along a joining said inlet and exit. In this way (at least) the (substantially) central portion of the channel is free to be elastically deformed. Preferably, said locking element in said closure conformation is elastically deformed (e.g. compressed) so as to occlude said channel, more preferably (at least) in correspondence with said (substantially) central portion. In this way the closure conformation is achieved in a simple way.

Preferably, a surface of said blocking element in direct contact with said waste water has a low degree of roughness. The low roughness favors the flow of waste water to further hinder the nucleation of deposit phenomena.

Preferably, said through cavity, with said blocking element in said opening conformation, comprises a residual volume interposed between said blocking element and said base body. Preferably, said residual volume (at least partially) surrounds said blocking element in correspondence with (at least) said (substantially) central portion of said channel. Preferably, said residual volume communicates directly with said block element (e.g. it includes at least one passage in communication with a surface of the block element opposite to that in direct contact with the waste water). In this way, a variation of a thermodynamic property of an operating fluid (e.g. air, water, oil, etc.) occupying the residual volume, such as pressure, can easily affect the blocking element, externally to the latter ( as will be better clarified by the following).

Preferably, said adjustment device comprises an actuation system structured and / or configured to elastically deform said blocking element. Preferably said actuation system comprises an operating fluid occupying said residual volume. In this way the operating fluid can appropriately act on the blocking element.

Preferably, said actuation system is structured and / or configured to elastically deform said blocking element by varying a pressure of said operating fluid. For example, an increase in the pressure of the operating fluid in the residual volume can compress the locking element obtaining the closure conformation. As the pressure decreases, the elastically deformed block element tends to return to its undeformed conformation allowing the passage of waste water. In this way, the blocking element can also assume a continuum of intermediate conformations between the aforementioned closing and opening conformations as the pressure of the operating medium varies, allowing to regulate the flow of waste water.

In an alternative embodiment, said drive system comprises a mechanical actuator acting directly on said blocking element to elastically deform the blocking element. For example, the mechanical actuator can be a vice operated manually or automatically to compress the locking element in order to occlude the channel.

Preferably said blocking element is made of elastomeric material.

Preferably, said blocking element has the shape of a sleeve.

For example, said regulating device is a sleeve valve. Preferably said actuation system is a hydraulic or pneumatic system. Preferably, said inlet mouth is arranged in direct communication with said waste water (e.g. there are no valves upstream of the regulating device). This facilitates the pumping of waste water.

Preferably, said outlet mouth of said adjustment device is hydraulically connected, more preferably directly, to said end portion. In this way a continuity with the suction duct is achieved in a structurally simple way.

Preferably said end section entirely crosses a wall of said storage tank, more preferably partially projecting inside said storage tank, even more preferably (substantially) parallel to a bottom of said storage tank. Preferably, said adjustment device is structured to be able to operate in immersion in said waste water. In this way the draft of the waste water is facilitated.

In one embodiment, said treatment plant comprises a suction element hydraulically connected, more preferably directly, to said adjustment device, upstream of said inlet.

Preferably, said suction element has a tubular shape, more preferably (substantially) rectilinear, with respective open longitudinal ends.

Preferably a longitudinal end face of said suction element distal from said adjustment device is inclined with respect to a direction (substantially) orthogonal to a suction direction that goes from one longitudinal end to the other of said suction element. Preferably, said inclined longitudinal end face faces in a direction concordant with a direction of rotation of an agitator of said plant. Preferably an angle formed by said longitudinal end face and said orthogonal direction is greater than or equal to 30 ° and / or less than or equal to 60 ° (for example 45 °).

The Applicant has verified that this arrangement and / or conformation of the suction element facilitates the pumping of waste water by limiting and / or preventing phenomena of instability and / or fluid dynamic disturbance (e.g. cavitation of one or more pumps connected to the suction duct) .

Preferably, an internal surface of said suction element in direct contact with said waste water has a low degree of roughness (in order to limit the nucleation of deposit phenomena).

Preferably the suction element is made of elastically deformable material (e.g. rubber). In this way the suction element, which can flexibly flexibly, for example as a result of the action of the agitators on the waste water, hinders the deposit of residues along itself.

Preferably, said pumping system is structured to pump a stream of a washing liquid along said end portion. In this way the end section is washed. Preferably, said washing phase is performed immediately after said suction phase (ie between the two phases, at most an interval of time not sufficient to allow the deposit of the aforementioned residues, typically of the order of a few minutes or a few tens of minutes, elapses).

Preferably, said pumping system is structured to pump said flow of the washing liquid along said regulating device, more preferably along said channel defined by said blocking element. Preferably, said washing step comprises, more preferably (substantially) simultaneously with said pumping along said end portion of said washing liquid flow, pumping said washing liquid flow along said regulating device, more preferably along said channel defined by said element block. In this way, the locking element is washed, further helping to prevent the formation of deposits.

Preferably, said pumping system is structured to pump said flow of the washing liquid in the opposite direction with respect to a direction of a suction flow of said waste water. Preferably, it is provided to pump said flow of the washing liquid in the opposite direction with respect to a direction of a suction flow of said waste water. In this way washing is facilitated and the washing liquid is easily discharged into the storage tank after washing is finished. Preferably, said pumping system comprises a further adjustment device (e.g. a hydraulic valve) hydraulically connected to said suction duct downstream of said end section. Preferably, said further adjustment device is structured to assume a closing configuration, in which it prevents hydraulic communication between said end section and a remaining part of said suction duct (excluding said end section), and an opening configuration, in which allows said hydraulic communication between said end portion and said remaining part of said intake duct. In this way it is possible to isolate the end section from the rest of the suction duct, typically for washing.

Preferably, said pumping system comprises at least one pumping device (e.g. a pump) hydraulically connected to said suction duct, more preferably downstream of said end section, even more preferably downstream of said further adjustment device.

Preferably, said pumping system comprises a first inlet channel for said flow of the washing liquid, said first inlet channel being (selectively) hydraulically connected to said suction duct at said end portion, more preferably to an outlet for said end portion is upstream of said further adjustment device. In this way the flow of the washing liquid can travel along the end portion.

Preferably, said pumping system is structured to pump a further flow of a washing liquid along said remaining part of said suction duct. In this way the rest of the duct is also washed.

Preferably, said further flow of the washing liquid has a direction concordant with a said direction of a suction flow of said waste water.

Preferably, said pumping system comprises a second inlet channel for said further flow of the washing liquid, said second inlet channel being (selectively) hydraulically connected to said suction duct downstream of said end section, more preferably downstream of said further adjustment device is upstream of said pumping device.

Typically, the pumping system comprises a first and a second valve interposed between the suction duct and the first and second inlet channels respectively. In this way, during the suction of waste water, the inlet channels can be isolated from the latter.

Preferably, said washing step comprises, more preferably (substantially) simultaneously with said pumping along said end portion said washing liquid flow, pumping, by means of said pumping system, said further washing liquid flow along said remaining part of said duct suction, and more preferably also along said pumping device.

Preferably said washing step comprises, more preferably prior to said pumping along said end portion of said washing liquid flow, arranging said further regulating device in said closing configuration. In this way the flow of the washing liquid goes through the end section, and possibly the adjustment device, flowing into the storage tank, while the further flow of the washing liquid can go through the rest of the suction duct and the pump.

Preferably, said method comprises, after said washing step, carrying out one or more further washing steps before a subsequent further aspiration step. In this way, during the pause between one pumping cycle and the next, the pumping system is kept clean (in order to actively counteract any residual deposits).

Preferably it is provided to carry out a temporal sequence of said further washing steps, more preferably temporally (substantially) equally distributed. Preferably a time interval between two further consecutive washing steps in said time sequence is greater than or equal to 0.5 h, and / or less than or equal to 3h. In this way they are performed in a rational way to cover the pause between pumping cycles in the best possible way, at intervals.

Preferably, each further washing step comprises, more preferably as a first step, arranging said locking element in said opening conformation.

Preferably, each further washing step comprises at least one of, more preferably all the characteristics of said washing step. In this way each further washing phase is efficient.

Brief description of the figures

The characteristics and advantages of the present invention will be further clarified by the following detailed description of some embodiments, presented by way of non-limiting example of the present invention, with reference to the attached figures, in which:

Figure 1 schematically shows, and with some parts removed, an overall view of a plant according to a first embodiment of the present invention; figure 2 shows a vertical section of a detail of the plant in figure 1;

figure 3 shows a vertical section of a detail of figure 2;

figure 4 shows a vertical section of a detail of a plant according to a second embodiment of the present invention;

figure 5 shows a horizontal section of a detail of a plant according to a third embodiment of the present invention.

Detailed description of some embodiments of the invention

In the figures, number 1 globally indicates a waste water treatment plant comprising, for example, a storage tank 2 for waste water, a washing station 3 for a vehicle 4 for the production and / or transport and / or storage of cementitious material (shown as an example of a concrete mixer), a hopper 5 suitable for collecting materials unloaded from the vehicle 4 (for example following washing) and a separator machine 6 (shown only schematically), for example a vibrating screen, arranged above the storage 2 and having a respective chute for discharging the screened materials, such as for example granular aggregates.

For example, the hopper 5 communicates directly with the separator machinery 6 to convey the materials unloaded from the vehicle 4 directly to the latter. For example, the plant 1 also includes a pair of agitators 7 arranged inside the storage tank 2 and not further described in as for example of a known type.

For example, plant 1 includes a pump room 99 located adjacent to the storage tank 2.

For example, the plant 1 includes a pumping system 8 to pump waste water from the storage tank 2.

For example, the pumping system 8 comprises a suction duct 9 having an end section 10 to draw the waste water into the storage tank 2. For example (fig. 1) the suction duct 9 also includes a delivery section 11 suitable for conveying towards the washing station 3 the sucked waste water to reuse the latter in washing the vehicle 4.

For example, the end section 10 entirely crosses both a wall of the storage tank 2 and a wall of the pump room 99, partially protruding inside the storage tank 2, parallel to a bottom of the storage tank 2.

For example, the system 1 comprises a regulation device 12 hydraulically connected to the suction duct 9 upstream of the end section 10. Given its positioning, the regulation device 12 is exemplarily structured to be able to operate in immersion in said waste water .

For example, the adjustment device 12 is a submersible sleeve valve.

For example, the adjustment device 12 comprises a rigid base body 13, the base body 13 comprising a through cavity 14 having an inlet 15 and an outlet 16 (shown in detail in Figure 3) arranged at the same height along a straight line.

For example, the inlet 15 is arranged in direct communication with the waste water (as there are, for example, no valves upstream of the adjustment device 12) and the outlet 16 is hydraulically connected directly to the end portion 10 (e.g. by means of a flange).

For example, the adjustment device 12 comprises a blocking element 17 made of elastomeric material that can be elastically deformed (shown in the sections of figures 3, 4 and 5) in order to alternatively assume a closure conformation (shown with a solid line in figures 3, 4 and 5) , in which it prevents hydraulic communication between the storage tank 2 and the end section 10. and an opening conformation (shown with dashed line in Figures 3, 4 and 5), in which it allows hydraulic communication between the storage tank 2 and the end section 10.

For example, the block element 17 develops internally to the through cavity 14 and in the opening conformation has a substantially tubular shape to define a channel 18 joining with hydraulic continuity the inlet 15 and the outlet 16.

For example, the block element 17 is firmly fixed to the base body 13 in correspondence with longitudinal end portions 19 of the block element 17 distal from a central portion 20 of the channel 18 along a joining the inlet 15 and outlet 16 .

For example (not shown) a surface of the block element 17 in direct contact with the waste water (i.e. an internal surface of the channel 18) has a low degree of roughness.

For example, as shown in detail in Figure 3, the through cavity 14, with the block element 17 in the opening conformation, includes a residual volume 22 interposed between the block element 17 and the base body 13.

For example, the residual volume 22 surrounds the blocking element at the central portion 20 of the channel 18 for an entire circumferential extension of the channel 18, and communicates directly with the blocking element 17 as it is exemplary open at the element of block 17 (e.g. there are no septa that divide the block element 17 from the residual volume 22).

For example, the adjustment device 12 comprises an actuation system 24 of the pneumatic type comprising by way of example an operating fluid (not shown, e.g. compressed air) occupying the residual volume 22. For example, shown only schematically in figures 2 and 5, the actuation system 24 comprises a transport duct 97 for the operating fluid.

For example (Figures 1 and 2) the pumping system 8 comprises a further regulating device 25 (e.g. a hydraulic valve) hydraulically connected to the suction duct 9 downstream of the end section 10, and a pumping device 26 (e.g. a pump , shown only schematically) hydraulically connected to the suction duct 9 downstream of the further adjustment device 25. For example, the further adjustment device 25 is structured to assume a closed configuration, in which it prevents hydraulic communication between the end section 10 is a remaining part of the suction duct 9 excluding the end section 10, and an opening configuration, in which it allows hydraulic communication between the end section 10 and the remaining part of the suction duct 9.

For example (Figure 2), the pumping system 8 comprises a first inlet channel 27 selectively hydraulically connected to the suction duct 9 at an outlet of the end section 10 and upstream of the further adjustment device 25, and a second inlet channel 28 selectively hydraulically connected to the suction duct 9 downstream of the further adjustment device 25 and upstream of the pumping device 26.

For example, the pumping system 8 comprises a first 29 and a second valve 30 (shown only schematically) interposed between the suction duct 9 and respectively the first 27 and the second inlet duct 28.

With reference to Figure 3, in a first embodiment of the plant 1, the end section 10 comprises a first portion 95 passing through the wall of the storage tank 2. For example, the first portion 95 is made of cast iron or other rigid metal material. For example, the end portion 10 comprises a second portion 96 hydraulically connected directly to the first portion 95 and to which the adjustment device 12 is directly hydraulically connected. The second portion 96 is exemplarily made of elastically deformable material (e.g. a rubber tube) and is aimed at bringing the adjustment device 12 close to an agitator 7, at the same time being able to take advantage of the advantages of the elastically deformable section (e.g. bending as a result of the wave motion generated by the agitators to hinder the formation of deposits inside). For example, the plant 1 also comprises in the first embodiment a support plate 94 of the adjustment device 12, having a portion protecting the inlet 5.

With reference to Figure 4, in a second embodiment of the system 1 having greater constructive simplicity than the first embodiment, the end portion 10 comprises only the first portion 95, similar to that of the first embodiment, to which it is directly hydraulically connected the adjustment device 12. With reference to Figure 5, in a third embodiment of the plant 1, the end portion 10 is similar to that of the second embodiment and the adjustment device 12 is directly hydraulically connected to the first portion 95. For example, the system 1 comprises a suction element 31, made of elastically deformable material (e.g. rubber) having a rectilinear tubular shape, with respective open longitudinal ends, and hydraulically connected directly to the adjustment device 12, upstream of the inlet 5.

For example, a longitudinal end face 93 of the suction element 31 distal from the adjustment device 12 is inclined with respect to a direction orthogonal to a suction direction 100 which goes from one longitudinal end to the other of the suction element 31. For example the inclined longitudinal end face 93 faces in a direction concordant with a direction of rotation of an agitator 7 (for example clockwise, as shown by the arrow 200 in Figure 5) of the plant so that the waves of waste water pushed by the agitator do not directly hit the longitudinal end face 93 (e.g. in order to reduce fluid dynamic instability phenomena). For example, an angle formed by the longitudinal end face 93 and the orthogonal direction is approximately 30 °. For example (not shown) an internal surface of the suction element 31 in direct contact with the waste water has a low degree of roughness.

In use, plant 1 allows you to perform a wastewater treatment method. After having suitably positioned the vehicle 4, the vehicle 4 is washed using clean mains water, or by means of the waste water stored in the tank 2 and coming from previous washes. In this last case, the method initially comprises carrying out a phase of aspirating the waste water from the tank.

By way of example, it is provided to arrange the block element 17 in the opening conformation, which by way of example corresponds to an undeformed conformation of the block element 17.

For example, it is provided to arrange the additional adjustment device 25 in the opening configuration and close the valves 29, 30 of the first 27 and of the second inlet channel 28.

For example, by means of the pumping device 26, it is therefore provided to suck the waste water from the storage tank 2 and convey it to the delivery section 11 to use it in the washing of the vehicle 4. In other embodiments (not shown) the sucked waste water can be sent (in addition or as an alternative to what is exemplary shown) to different areas of a cementitious material production plant including the treatment plant 1.

Immediately after the suction phase, a washing phase is scheduled. For this purpose, it is provided by way of example to arrange the additional adjustment device 25 in the closing configuration and thus isolate the end section 10 from the rest of the suction duct 9. For example, it is provided to open the valves 29 and 30.

By way of example, it is therefore provided, by means of the pumping system 8 (e.g. by means of a further pump not shown), through the first inlet channel 27 and with the block element 17 in the opening configuration, to pump along the end section 10 and along the adjustment device 12, precisely along the channel 18 (and possibly in the second portion 96 and / or in the suction element 31) a flow of a washing liquid in the opposite direction with respect to a direction of a water suction flow wastewater.

During the washing phase, by means of the pumping system 8, through the second inlet channel 28 and substantially at the same time as pumping the flow of the washing liquid, a further flow of a washing liquid is pumped along the remaining part 93 of the suction duct 9, and along the pumping device 26. For example, the further flow of the washing liquid has a direction which is concordant with the direction of the suction flow of the waste water.

By way of example, it is therefore envisaged, while maintaining the flow of the washing liquid, to arrange the block element 17 in the closure conformation, corresponding by example to an elastically deformed conformation. To this end, the actuation system 24 is exemplarily structured and / or configured to elastically deform the blocking element 17 by increasing the pressure of the operating fluid in order to elastically compress the blocking element 17 in correspondence with the central portion 20 in a manner to occlude the channel 18 (figures 3, 4 and 5 solid line). In this way the end section 10 and the adjustment device 12 (and possibly the second portion 96) can remain full of clean washing liquid and isolated from the waste water contained in the storage tank 2.

For example, the method comprises, after the washing step, carrying out one or more further washing steps before a subsequent further aspiration step. By way of example, a temporal sequence of the further washing phases is provided, which are temporally equidistributed. For example, a time interval between two further consecutive washing phases in the temporal sequence can be equal to about 90 minutes for a pause, between the suction phase and the subsequent further suction phase, corresponding to the night hours of system inactivity. For example, the washing phase and each further washing phase each use about 10 L of washing liquid, thus keeping the consumption of clean mains water low.

For example, each further washing step comprises, as a first step, arranging the locking element 17 in the opening configuration and includes all the characteristics of the washing step (possibly with the exception of the closing step of the further adjustment device 25 which can be already in the closing configuration following the washing phase).

Claims (10)

CLAIMS 1. Waste water treatment plant (1) comprising: - a storage tank (2) for said waste water; - a pumping system (8) for pumping said waste water from said storage tank (2), said pumping system (8) comprising a suction duct (9) having an end section (10) for drawing said waste water in said storage tank (2); And - an adjustment device (12) hydraulically connected to said suction duct (9) upstream of said end section (10), wherein said adjustment device (12) comprises an elastically deformable locking element (17) in order to alternatively assume a closure conformation, in which it prevents hydraulic communication between said storage tank (2) and said end section (10) of said suction duct (9), and an opening conformation, in which it allows said hydraulic communication between said storage tank (2) and said end section (10) of said suction duct (9). 2. Plant (1) according to claim 1, where said closing conformation is an elastically deformed conformation of said locking element (17), where said opening conformation is a substantially undeformed conformation of said locking element (17), where said end portion (10) entirely crosses a wall of said storage tank (2), preferably partially projecting inside said storage tank (2), and where said adjustment device (12) is structured to be able to operate in immersion in said waste water. System (1) according to any one of the preceding claims, wherein said adjustment device (12) comprises a base body (13) comprising a through cavity (14) having an inlet (15) and an outlet ( 16), where said inlet (15) is arranged in direct communication with said waste water, where said outlet (16) is hydraulically connected to said end section (10), where said block element (17) in said opening conformation defines a channel (18) joining with hydraulic continuity said inlet (15) and outlet (16), where said blocking element (17) is firmly fixed to said base body (13) in correspondence with end portions (19) of said blocking element (17), preferably distal from at least a substantially central portion (20) of said channel (18) along a joining said inlet (15) and outlet (16), where said block element (17) in said conformati closure element is elastically deformed so as to occlude said channel (18), preferably at least in correspondence with said substantially central portion (20), and where a surface of said block element (17) in direct contact with said waste water has a low degree of roughness. 4. Plant (1) according to the preceding claim, where said through cavity (14), with said blocking element (17) in said opening conformation, comprises a residual volume (22) interposed between said blocking element (17) and said base body (13), where said residual volume (22) at least partially surrounds said block element (17) in correspondence with at least said substantially central portion (20) of said channel (18), where said residual volume (22) communicates directly with said blocking element (17), where said adjustment device (12) comprises an actuation system (24) comprising an operating fluid occupying said residual volume (22), and where said actuation system (24) is structured and / or configured to elastically deform said blocking element (17) by varying a pressure of said operating fluid. 5. Plant (1) according to any one of the preceding claims, comprising a suction element (31) hydraulically connected to said regulating device (12) upstream of an inlet (15) of said regulating device (12), where said suction element (31) has a tubular shape with respective open longitudinal ends, where a longitudinal end face (93) of said suction element (31) distal from said adjustment device (12) is inclined with respect to a substantially direction orthogonal to a suction direction (100) which goes from one longitudinal end to the other of said suction element (31), where said inclined longitudinal end face (93) faces in a direction concordant with a direction of rotation of a agitator (7) of said plant (1), where an angle formed by said longitudinal end face (93) and said orthogonal direction is greater than or equal to 30 ° and / or less than or equal to 60 °, where an internal surface of said suction element (31) in direct contact with said waste water has a low degree of roughness, and where said suction element (31) is made of elastically deformable material. Plant (1) according to any one of the preceding claims, where said pumping system (8) is structured to pump a flow of a washing liquid along said end portion (10) and along said regulating device (12), preferably along a channel (18) defined by said blocking element (17) in said opening conformation, where said pumping system (8) is structured to pump said flow of the washing liquid in the opposite direction with respect to a direction of a flow for the suction of said waste water, where said pumping system (8) comprises a further regulating device (25) hydraulically connected to said suction duct (9) downstream of said end section (10), where said further regulation (25) is structured to assume a closing configuration, in which it prevents hydraulic communication between said end section (10) and a remaining part of said suction duct (9) excluding said end portion (10), and an opening configuration, in which said hydraulic communication between said end portion (10) and said remaining part of said suction duct (9), where said pumping (8) comprises a first inlet channel (27) for said flow of the washing liquid, said first inlet channel (27) being selectively hydraulically connected to said suction duct (9) at said end portion (10 ), preferably at an outlet of said end portion (10) and upstream of said further adjustment device (25). 7. Plant (1) according to the preceding claim, where said pumping system (8) is structured to pump a further flow of a washing liquid along said remaining part of said suction duct (9), where said further liquid flow direction of washing has the same direction as said direction of a suction flow of said waste water, where said pumping system (8) comprises a second inlet channel (28) for said further flow of the washing liquid, said second inlet channel (28) being selectively hydraulically connected to said suction duct (9) downstream of said end section (10), preferably downstream of said further adjustment device (25) and upstream of a pumping device (26) of said pumping system (8), and where said pumping system (8) comprises a first (29) and a second valve (30) interposed between the suction duct (9) and respectively the first (27) and the second input channel (28). 8. Waste water treatment method comprising: - providing a waste water treatment plant (1) according to any one of the preceding claims; - carry out an aspiration phase including: - arranging said locking element (17) in said opening conformation; - by means of said pumping system (8), sucking said waste water from said storage tank (2); - after said suction phase, carry out a washing phase comprising: - by means of said pumping system (8), pumping along said end portion (10) a flow of a washing liquid with said blocking element (17) in the opening conformation; - maintaining said flow of the washing liquid, arranging said blocking element (17) in said closing conformation. Method according to claim 8, wherein said washing step is performed immediately after said suction step, where said washing step comprises pumping said flow of the washing liquid along said regulating device (12), where it is provided to pump said flow of the washing liquid in the opposite direction with respect to a direction of a suction flow of said waste water, where said washing step comprises, preferably substantially simultaneously with said pumping along said end portion (10) said washing liquid flow, pumping , by means of said pumping system (8), a further flow of a washing liquid along a remaining part of said suction duct (9) excluding said end portion (10), and where said washing step comprises, preferably previously a said pumping along said end portion (10) said washing liquid flow, arrange a further regulating device action (25) in a closing configuration in which it prevents hydraulic communication between said end section (10) and said remaining part of said suction duct (9). Method according to claim 8 or 9, comprising, after said washing step, carrying out one or more further washing steps before a subsequent further aspiration step, where a temporal sequence of said further washing steps is provided, preferably temporally substantially equidistributed, where a time interval between two further consecutive washing phases in said temporal sequence is greater than or equal to 0.5 h, and / or less than or equal to 3h, where each further washing step comprises, preferably as a first step, arranging said locking element (17) in said opening conformation, and where each further washing step comprises at least one of, preferably all the claimed characteristics of said washing step.