Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B9/00—General arrangement of separating plant, e.g. flow sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B9/00—General arrangement of separating plant, e.g. flow sheets
  • B03B9/06—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse
  • B03B9/061—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse the refuse being industrial
  • B03B9/063—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse the refuse being industrial the refuse being concrete slurry
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
  • B03B5/62—Washing granular, powdered or lumpy materials; Wet separating by hydraulic classifiers, e.g. of launder, tank, spiral or helical chute concentrator type
  • B03B5/64—Washing granular, powdered or lumpy materials; Wet separating by hydraulic classifiers, e.g. of launder, tank, spiral or helical chute concentrator type of the free settling type
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
  • B01D21/02—Settling tanks with single outlets for the separated liquid
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F2001/007—Processes including a sedimentation step
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/12—Nature of the water, waste water, sewage or sludge to be treated from the silicate or ceramic industries, e.g. waste waters from cement or glass factories
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/005—Processes using a programmable logic controller [PLC]
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/40—Liquid flow rate
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/16—Regeneration of sorbents, filters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/58—Construction or demolition [C&D] waste

Definitions

• the present invention relates to a plant for treating slurries deriving from washing of concrete mixers and to the relative method.
• each concrete mixer on its return presents a waste concrete concentration varying from 0.5 to 0.2 cubic metres per concrete mixer.
• a waste concrete concentration varying from 0.5 to 0.2 cubic metres per concrete mixer.
• about 4000 kg of waste is hence produced with a particle size up to a few millimetres, with the use of about 2000 litres of water to wash each concrete mixer.
• each truck-mounted concrete mixer discharges the wash liquid into a receiver tank associated with an inclined rotating conveying screw within the tank, which directly separates about 50% of the heavy materials contained in the liquid poured in. Hence only about 2000 kg of the 4000 kg of solid material discharged by the concrete mixers are recovered.
• the solids present in the water differ during the day.
• Document WO94/17917 describes an apparatus for treating effluent waters comprising a tank for the discharge water, and a first sedimentation tank into which this discharge water is fed. The cleaned water is transferred to a second tank while the solid part is transferred to a third tank.
• An object of the present invention is to provide a plant for treating slurries deriving from the washing of concrete mixers which represents a better-performing improvement on those of the known art.
• a particular object of the present invention is to provide a plant which is able to accumulate large percentages of treated water free of suspended particles, which can then be used and metered with precision.
• a further object of the present invention is to separate a greater quantity of solids than the known art, un such a manner as to be able to precisely control its metering and its return to the cycle.
• Figure 1 is a simplified schematic view of the plant according to the present invention, applied to already existing treatment areas;
• Figure 2 is a schematic view of the plant according to the present invention in an embodiment different from that of Figure 1 ; and Figure 3 is a variant of the plant of Figure 2.
• the separator 3 comprises a separator 3, suitably arranged on a masonry support structure 4.
• the separator 3 is provided with a first receiver tank 5 for the wash liquid discharged from the concrete mixer 2.
• the concrete mixer 2 arriving from the site is loaded with wash liquid (the method is described hereinafter) and, after the necessary wash time has elapsed, this liquid is slowly emptied into the receiver tank 5.
• the tank 5 is shaped as a hopper and presents at its base a mechanical separation means for the coarser (and hence heavier) slurry present in the wash liquid.
• the mechanical separation means in this case comprises a conveying screw 7 mounted within a casing 6 disposed with its axis diagonal.
• the conveying screw is rotated by a suitable motor 8.
• the coarse material (of diameter greater than 0.6 mm) which precipitates immediately onto the base of the tank 5 is raised by the conveying screw 7 and discharged into a zone 9 for accumulating recovered solid material.
• the tank 5 comprises an aperture (weir) from which water, free of very heavy particles but in which a large quantity of particles of diameter less than 0.6 mm are suspended, is conveyed by falling, through a line 10, to a transition tank 11 coupled to a suitable loading pump 12.
• the transition tank is an intermediate passage, the only purpose of which is to not allow the pump 12 to intake directly from the tank 5.
• the vortices created by the pump suction would convey into the water flow on its delivery side a large quantity of suspended particles, including large-dimension, which could instead be separated by the separator.
• a tank for recovering effluent water from the yard could, if present, be used for the same purpose, such as that shown in the figure and indicated by the reference numeral 13.
• the intermediate tank in the configuration illustrated in Figure 1 , presents a sixth valve V6 which controls the overflow and discharges any excess liquid into the effluent water recovery tank 13.
• the loading pump 12 has its delivery connected to a feed line 15 of the decantation tank 14.
• the line 10 the feed line 15, the intermediate tank 11 and the loading pump 12 represent means adapted to place the first tank into fluid passage connection with the inlet of the decantation tank 14.
• the decantation tank 14 presents a first accumulation zone 14A for treated liquid substantially free of suspended particles. It is preferably of cylindrical shape of constant circular, square or rectangular cross-section.
• a second accumulation zone 14C for slurry formed from sedimented particles there is a second accumulation zone 14C for slurry formed from sedimented particles.
• This zone is constructed for example of stainless steel, and is suitably shaped (as shown in the figure) to enable the slurry accumulated by decantation to be conveyed towards a discharge 16.
• the adjustable tank seals are appropriately designed to maintain air- tightness, the supports for the external shafts not being in contact with the slurry.
• the first and second zone are interconnected by a hopper-shaped intermed iate zone 14B .
• First and second stirrer means are provided respectively in the intermediate zone and in the second zone.
• the first stirrer means 18 comprises substantially an impeller 18A mounted on a vertical shaft 18B and rotated by a suitable geared motor 18C.
• the first stirrer 18 is fixed to a walkway 19, to which access is gained by a marine ladder (not shown).
• the second stirrer 20, positioned in the second zone 14C, is formed from a pair of horizontal mixing shafts 21 to which suitably dimensioned blades 21 are applied, inclined in the opposite direction to the shaft drive motors 23.
• the shafts are easily accessible via access manholes for their extraction and via lateral inspection holes.
• the stirrer means prevent the particles/slurry present in the second zone and in the intermediate zone from undergoing sedimentation and mutual agglomeration.
• the vertical stirrer is obviously dimensioned to move water highly charged with particles, with the opposing propeller system of the horizontal mixer not allowing slurry agglomeration on the bottom.
• the first zone comprises an outlet 22 for treated liquid (i.e. substantially free of solid particles), suitably intercepted by first valve means V1.
• the outlet 22 is positioned at the interconnection between the first zone 14A and the intermediate zone 14B, in particular at the beginning of the intermediate zone 14B.
• the outlet 22 is connected to a purified liquid accumulation tank 23.
• this accumulation tank is installed underground, however it will be seen hereinafter that it can assume different configurations and positions and can for example be configured as a tanker.
• the second zone also comprises a slurry discharge 16, this discharge being intercepted by second valve means V2.
• the slurry discharge 16 is connected to the suction side of a first pump P1 , the delivery side of which is connected to a loading line 30.
• the loading line 30 presents a branch 32 intercepted by a suitable valve means V9, which diverts the fluid present therein to metering for a concrete production plant.
• the loading line 30 proceeds downstream of the branch 32 towards the concrete mixer via a valve V7.
• a second pump P2 is also present with its suction side drawing from the treated liquid accumulation tank 23 and its delivery side also connected to the loading line 30.
• a mass flowmeter M expressible in kg/h, for example of the Coriolis effect type, is provided on the loading line 30.
• the flow measurement based on the Coriolis effect generates a signal which is proportional to the mass flow rate, and is virtually independent of fluid properties, such as conductivity, pressure, viscosity or temperature.
• fluid properties such as conductivity, pressure, viscosity or temperature.
• by means of two signals it transfers the percentages relative to the passage of the liquid mass and of the slurry to a control centre which by means of a suitable software programme is able to effect by precise metering the correct ratio of water, inerts and slurry without altering the quantity of the new concrete.
• the loading line 30, downstream of the meter M indicated by the letter A, joins the loading line 30 at the point A which in the figure is in proximity to the motor 8.
• these flow regulator means comprise a mixing connection 25 provided with a first and second inlet which are coupled respectively to the second valve means V2 present in the slurry discharge 16 and to third valve means V3 present in a delivery line from the second pump P2 which draws from the accumulation tank 23.
• a first and a second outlet of said mixing means are coupled respectively:
• this provides the undoubted advantage of completely eliminating slurry residues, by reusing them in known percentages for new production cycles, and of having high percentages of clarified water for reuse, for example in the tanks of tank trucks/truck-loaded concrete mixers.
• the plant according to the present invention is advantageously provided with a recycling line 31 , intercepted by a suitable solenoid valve V8, arranged to deviate said loading line 30 into said receiver tank 5.
• a further solenoid valve V7 is also provided, required to operate the recycling line 31 , downstream (concrete mixer side) of the branch between the loading line 30 and the recycling line 31.
• the tank 13 for recovering the yard effluent water comprises a third pump P3 drawing therefrom, and having its delivery side connected to said concrete mixer loading line 30.
• the main purpose of the pump P3 is to recycle the liquid present in the tank 13 into the discharge tank 5 (valves V4, V5 and V7, V9 closed, valve V8 open), to enable the effluent and discharge water to be treated by the plant. Before being fed to the tank 5, this liquid can be conveyed through a deoiler.
• the plant operates in substantially the following manner.
• a concrete mixer discharges its wash liquid content into the tank 5 and the liquid is pretreated by the separator, which eliminates its coarsest and heaviest particles by accumulating them at the conveying screw exit.
• the first zone 14A of the decantation tank 14 is then automatically emptied by opening the valve V , to obtain clarified water equal to
• the tank 14 At the level at which the outlet 22 is located, the tank 14 is provided with a level sensor which automatically closes the valve V1 when the level falls too far.
• the described solenoid valve system controlled by the PLC and interfaced with a mass flowmeter M, enables the quantity of slurry fed to the loading line 30 to be controlled on the basis of the percentage to be obtained, acting on the valves V2 and V3 (V4 is closed and V5 opened).
• the mixed mixture is conveyed by the pump P1 , which is of vortex type.
• the pump P1 which is of vortex type.
• Pipe cleaning to prevent incrustation or residue deposition is controlled by the PLC, which automatically provides for washing by acting on the valves V2-V5 and the pumps P1 and P2. For example pipe and pump washing is achieved by reusing the liquid in the tank 23.
• the accumulation tanks had instead to be drained and the waste be disposed of.
• the concrete mixer loading procedure is started via the loading line 30.
• the described system enables the following regulations to be satisfied:
• the techniques of the invention enable the produced waste to be eliminated and totally reused.
• Sedimented aggregates can be reused by feeding them into the new concrete, with reduction of the fresh quantity required.
• the plants of Figures 2 and 3 can be provided in new installations, in which underground tanks are not already present.
• pumps can either be provided, or not provided, for transferring the liquids from one tank to the other, depending on the level at which these tanks are positioned.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Cleaning In General (AREA)
• Accessories For Mixers (AREA)
• Treatment Of Sludge (AREA)
• Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46466613

Family Applications (1)

Country Status (4)

Cited By (2)

Citations (4)

Family Cites Families (2)

• 2012
  • 2012-06-01 IT IT000024A patent/ITBG20120024A1/it unknown
• 2013
  • 2013-05-30 AT ATGM9007/2013U patent/AT14549U1/de not_active IP Right Cessation
  • 2013-05-30 WO PCT/IB2013/001092 patent/WO2013179122A1/fr not_active Ceased
  • 2013-05-30 DE DE201321000123 patent/DE212013000123U1/de not_active Expired - Lifetime

Patent Citations (4)

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