• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    determination of the turbidity of the liquid phase of multiphase wastewater. a turbidity sensor is provided inside multiphase wastewater, and generates a signal in response to a detected turbidity. the generated signal is sampled to produce a plurality of signal samples. samples are compared to a threshold, and wastewater turbidity is determined based on samples falling within the threshold. the threshold can be determined based on statistical analysis of the plurality of samples, or it can be adjusted to a predetermined value. the turbidity sensor can be provided inside a waste water flocculation chamber, and a control signal generated based on the determined waste water turbidity. this control signal can be used to adjust the amount of a chemical, such as a coagulant introduced into the wastewater.
    公开号:BR112015010552B1
    申请号:R112015010552-1
    申请日:2013-11-13
    公开日:2020-09-29
    发明作者:Mikel E. Goldblatt
    申请人:Solenis Technologies Cayman, L.P.；
    IPC主号:
    专利说明:

    CROSS REFERENCES FOR RELATED ORDERS
    [001] This application claims priority for United States Patent Application Series No. 61 / 726,637, filed on November 15, 2012, and entitled "SYSTEMS AND METHODS FOR DETERMINING THE MULTIPHASE WASTE LIQUID WATER PHASE", to disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD
    [002] The present invention in general concerns wastewater treatment and, more particularly, a system and methods for wastewater treatment that determines turbidity of the liquid phase of multiphase wastewater and adjusts the amount of chemicals added wastewater based thereon. FUNDAMENTALS
    [003] Chemical treatment of waste water to reduce contaminants is used in many industrial processes to allow the reuse of waste water, and to ensure that the discharge of waste water meets the required environmental quality standards. The type of treatment used depends on the source of waste water, the type of contaminants in the waste water, and the intended use for the treated water. Wastewater often contains suspended solids that comprise particles finer than approximately 0.1 pm, which are not only difficult to filter, but tend to remain in suspension indefinitely due to the repellent effects of electrostatic charges between the particles. To reduce the amount of fine particle contamination, or water turbidity, treatment systems typically introduce coagulation and / or flocculation agents into the wastewater. The coagulant agent neutralizes the electrostatic charges in the particles, which allows the particles to come into contact with each other and form larger particles. The flocculant can accelerate the agglomeration process giving rise to colloids and other particles suspended in the residual water to aggregate, thus forming large particles commonly referred to as flake or flake particles. The flake can then be removed from the treated water, for example, by sedimentation and / or flotation.
    [004] Coagulation and flocculation agents are usually added to the residual water in a mixing or reaction tank. Additional chemicals, such as acids or bases that are added to adjust the pH of the water to improve the effectiveness of the coagulant, or chemicals that react and neutralize other contaminants, can also be added at this stage. The amount of agents that must be added depends on the level of contamination and the volume of water to be treated. For example, if too little of the coagulant is added, the turbidity of the residual water may not be sufficiently reduced. On the other hand, the addition of excessive amounts of chemicals to the wastewater results in wasted chemicals, and can also result in making the chemicals / agents themselves into undesirable contaminants present in the treated effluent.
    [005] To determine if sufficient chemical treatment agents are being added to the waste water, samples of the treated waste water can be taken and analyzed by measuring turbidity, pH, and / or chemical content. Typically, residual water samples should be allowed to decant before measuring turbidity so that flake particles do not interfere with the measurement. For this reason, samples are taken normally after the sedimentation and / or flotation phases of the treatment. However, water samples obtained at this stage of treatment may reflect chemical levels from hours before. Thus, by the time an increase in turbidity or in the chemical content of the residual water is detected, the amount of treatment agents present in the reaction tank can be drifted significantly away from its best level. In addition, because the level of contamination of wastewater entering the system can change over time, measurements of samples that reflect wastewater introduced into the reaction tank hours earlier may not provide an accurate indication of the amount of agent treatment that needs to be added to the reaction tank at the present time. The measurement of the sample of sedimentation and flotation of the effluent can thus provide an inaccurate indication of the amount of a chemical for treatment that needs to be added to the waste water entering the system.
    [006] Consequently, there is a need for improved systems and methods to determine the turbidity of wastewater, as well as the optimum amount of chemicals to be added to the effluent in a wastewater treatment system. SUMMARY
    [007] In one embodiment, a method is provided to determine the turbidity of the wastewater. The method includes receiving a signal indicative of an amount of light dispersed by the waste water and sampling the signal to produce a plurality of sample values of the signal. These sample values are compared with a threshold, and the values of the samples falling within the identified threshold. The method also includes determining the turbidity of the waste water based on the values of the samples that fall within the threshold.
    [008] In another embodiment, an apparatus for treating waste water is produced. The device includes a processor and a memory that contains the program code. The program code is configured so that when the code is executed by the processor, the code causes the device to receive a signal indicating the amount of light dispersed by the waste water and sample the signal to produce a plurality of sample values from the signal. The code is further configured to make the device compare the values of the samples to a threshold, identify the values of the samples falling within the threshold, and determine the turbidity of the residual water based on the values of the samples falling within the threshold.
    [009] In some embodiments of the invention, the signal indicating the amount of light dispersed by the waste water can be generated by detecting an amount of light scattered from a beam of light by the waste water, in which case the signal may have a higher value (that is, more light is detected) for cloudy water than for clean water. In other embodiments, this signal can be generated by detecting a quantity of light transmitted through the wastewater, in which case the signal may have a lower value (ie less light would be detected) for cloudy water than for clean water. .
    [010] In some embodiments of the invention, the threshold can be determined based on a probability density distribution of the plurality of sample values. The probability density distribution produced by the values of the multiphase residual water samples can have two pronounced peaks. One of these peaks can result from sample values produced from light scattered through the liquid phase or bulk water without further dispersion or flake reflections. That is, a peak can be produced from dispersion caused by residual water when the flake particles have not entered the path of the light beam. The other peak can be produced from the dispersion caused by the residual water when the flake particles are present in the path of the light beam, which can increase the amount of dispersion. The threshold can be adjusted to a value between these two peaks to classify the values of the samples as being indicative of the residual water turbidity or as being indicative of the flake dispersion. Because the thresholds determined in this way are based on sensor data, the threshold can be adjusted or moved in response to the wastewater condition so that the sample values are classified optimally.
    [011] In some embodiments of the invention, sample values that are classified as being produced by water in bulk in the absence of the flake can be used to produce a signal or value indicative of the turbidity of the waste water. This value can then be used to provide feedback information to a controller to control an operation associated with the treatment of waste water, such as a quantity of a treatment chemical dispensed into a reaction tank. BRIEF DESCRIPTION OF THE DRAWINGS
    [012] The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate various embodiments of the invention and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serves to explain the principles of the invention.
    [013] Figure 1 is a schematic view of a wastewater treatment system that includes a reaction tank and a controller.
    [014] Figure 2 is a schematic view of a part of the wastewater treatment system in Figure 1 showing additional details of the reaction tank and the controller.
    [015] Figure 3A is a schematic view of a multiphase wastewater sample having a first level of turbidity.
    [016] Figure 3B is a graph that illustrates the samples from a turbidity sensor output corresponding to the sample in Figure 3A.
    [017] Figure 4A is a schematic view of a multiphasic wastewater sample having a lower turbidity level than the first turbidity level.
    [018] Figure 4B is a graph that illustrates the samples from the output of a turbidity sensor corresponding to the sample in Figure 4A.
    [019] Figure 5 is a flow chart of a process for sampling the turbidity sensor output and which controls the delivery of coagulant within the reaction tank of Figure 2.
    [020] Figure 6 is a flow chart of a process for analyzing the samples obtained in Figure 5 to determine a signal threshold.
    [021] Figure 7 is a graph that illustrates a probability distribution for the samples illustrated in Figure 4. DETAILED DESCRIPTION
    [022] Embodiments of the invention address systems and methods for measuring the turbidity of wastewater in a treatment tank of a wastewater treatment system prior to flotation or sedimentation. This can be achieved by distinguishing light scattering caused by the liquid or "bulk water" phase from light scattering which includes scattering caused by particles from the solid or flake phase. These measurements, in turn, can be used to control the amount of chemicals dispensed to the waste water. Residual water in the treatment tank may contain particles of flakes that generate erroneous readings from the turbidity sensor. The system includes a controller configured to sample an output signal from a turbidity sensor, and to process the output signal samples for identity samples that are associated with dispersion by bulk water in the treatment tank. The controller can then determine the turbidity of the waste water based on the identified samples. The controller can also be configured to adjust the amount of one or more chemicals dispensed inside or upstream or downstream of the treatment tank based on the determined turbidity.
    [023] Referring now to Figure 1, a wastewater treatment system 10 is illustrated that includes a main reaction tank 12 that receives a wastewater inlet flow 14, a controller 16, and a Float unit by Dissolved Air (DAF) 18. The DAF unit 18 includes a floating material storage chamber 20, a skimmer 22, a sediment discharge chamber 24 that collects heavy sediment and removes the sediment with a screw 26, and a effluent chamber 28, containing effluent 30. A sludge pump 32 coupled to the floating material storage chamber 20 and sediment discharge chamber 24 transports solid waste that has either floated to the top or decanted at the bottom of the DAF unit 18 to a or more sludge treatment tanks 34. To add the dissolved air to the waste water, a part of the clarified effluent 30 can be removed from the effluent chamber 28 and transferred by a recycling pump 38 to a pressure tank 40 where the part of the clarified effluent 30 is mixed with the compressed air 42. For this purpose, the recycled effluent can be sprayed into the pressure tank 40 under various pressure atmospheres. The small drops of water formed from the spray can thus be saturated with pressurized air and accumulate at the bottom of the tank 40 to provide an aerated recycling stream 44.
    [024] The aerated recycling stream 44 can be introduced into the chemically treated wastewater 46 flowing out of the reaction tank 12 to provide dissolved air to the wastewater 46 before entering the DAF unit 18. As the recycling stream aerated 44 is introduced into the chemically treated wastewater 46, the air can leave the solution forming very small air bubbles that attach to the mass of particles floating in the chemically treated wastewater 46. Valve 48 can be used to control the amount of flow aerated recycling tank 44 introduced into the chemically treated wastewater 46, and to maintain pressure in the pressure tank 40, restricting the flow of the aerated recycling stream 44 outside the pressure tank 40. The effluent 30 which is to be discharged from the system 10 it can be removed from the effluent chamber 28 by a discharge pump 50.
    [025] Controller 16 can be coupled to one or more chemical dosers 52, 54, 56 that selectively deliver chemicals within reaction tank 12 in response to signals from controller 16. In one embodiment of the invention, a dosage of chemicals 52 can deliver a coagulant 60 within a coagulation chamber 62 of reaction tank 12. Suitable coagulants can include inorganic coagulants, such as iron or aluminum salts, including ferric sulfate or aluminum hydrochloride to name just a few. Suitable coagulants may also include a combination of organic / inorganic coagulants such as Ashland ChargePac ™ 55, ChargePac ™ 60, ChargePac ™ 7, ChargePac ™ 10, or ChargePac ™ 47, which are available from Ashland Inc. of Covington, Kentucky, USA. Likewise, another chemical doser 54 can deliver an acidic or caustic solution 64 to a pH adjustment chamber 66 of reaction tank 12 to adjust the pH of the waste water. The pH of the waste water can therefore be maintained at a level that optimizes the effectiveness of the coagulant. Finally, the additional chemical doser 56 can deliver a flocculant 68 to a flocculation chamber 70 in reaction tank 12. Suitable flocculants can include anionic flocculants, such as Ashland DF2205, DF2220, DF2270, and / or cationic flocculants, such as Ashland DF2405, DF2428, DF2445, which are also available from Ashland Inc.
    [026] Each chamber 62, 66, 70 of the reaction tank 12 can include an agitator 72, 74, 76 to ensure that the added chemicals are evenly distributed throughout the residual water. The operation of the stirrers can be adjusted to optimize the reactions in that part of the primary reaction tank. For example, the agitator 72 for the coagulation chamber 62 can operate at a higher speed than the agitator 76 for the flocculation chamber 70 to optimize flow formation.
    [027] Referring now to Figure 2, a schematic view is shown that illustrates additional details of controller 16, chemical feeders 52, 54, 56, and turbidity sensor 58. Each chemical feeder 52, 54 56 may include a chemical delivery pump 78, 80, 82 coupled to a respective chemical container 84, 86, 88. Each chemical delivery pump 78, 80, 82 is configured to provide a controlled amount of chemical from its respective chemical container 84, 86, 88 in the respective chamber 62, 66, 70 reaction tank 12 in response to signals from the controller 16. In an alternative embodiment of the invention, the respective chemicals can be gravity fed into reaction tank 12, in which case pumps 78, 80, 82 can be replaced by valves (not shown) that are actuated by signals from controller 16.
    [028] Controller 16 may be a commercially available controller, such as an OnGuardController ™, available from Ashland Inc., or any other suitable device for controlling chemical metering units 52, 54, 56 and monitoring the turbidity sensor 58 Controller 16 includes a processor 90, memory 92, an input / output (I / O) interface 94, and a user interface 96. Processor 90 may include one or more devices selected from microprocessors, micro- controllers, digital signal processors, microcomputers, central processing units, programmable field gate arrays, programmable logic devices, state machines, logic circuits, analog circuits, digital circuits, or any other devices that handle signals (analog or digital) based on operating instructions that are stored in memory 92. Memory 92 can be a single memory device or a plurality of d memory devices, including, but not limited to, read-only memory (ROM), random access memory (RAM), volatile memory, non-volatile memory, static random access memory (SRAM), dynamic random access memory ( DRAM), flash memory, cache memory, or any other device capable of storing digital information. Memory 92 may also include a mass storage device (not shown), such as a hard drive, optical drive, tape drive, non-volatile solid state device, or any other device capable of storing digital information.
    [029] Processor 90 can operate under the control of an operating system 98, which resides in memory 92. Operating system 98 can manage the resources of the controller so that the embedded computer program code as one or more software applications computer, such as a memory resident 92 controller application 100, may have instructions executed by processor 90. In an alternative embodiment, processor 90 may run applications 100 directly, in which case operating system 98 may be omitted. One or more data structures 102 may also reside in memory 92, and may be used by processor 90, operating system 98, and / or controller application 100 to store data.
    [030] The I / O interface 94 operationally couples the processor 90 to other components of the treatment system 10, such as the turbidity sensor 58, the coagulant delivery pump 78, the caustic delivery pump 80, and the flocculant delivery pump 82. The I / O interface 94 can include signal processing circuits that condition the input and output signals so that the signals are compatible with both processor 90 and the components to which processor 90 is coupled. For this purpose, the I / O (input / output) interface 94 may include analog-to-digital (A / D) and / or digital-to-analog (D / A) converters, voltage level and / or frequency change circuits , optical isolation circuits and / or actuators, and / or any other analog or digital circuit suitable for coupling to processor 90 for other components of the treatment system 10.
    [031] User interface 96 can be operably coupled to processor 90 of controller 16 in a known manner to allow a system operator to interact with controller 16. User interface 96 can include a monitor, such as a video monitor , alphanumeric displays, a touchscreen, a speaker, and any other audio and visual indicators capable of providing information to the system operator. User interface 96 may also include input devices and controls, such as an alphanumeric keyboard, a pointing device, keyboards, buttons, control buttons, microphones, etc., capable of accepting commands or operator input and transmitting the input entered for processor 90. In this way, user interface 96 can allow manual initiation or selection of system functions, for example, during system installation, calibration and chemical loading.
    [032] In the illustrated embodiment, the turbidity sensor 58 is a 90 degree scattered light sensor located in the flocculation chamber 70 of the reaction tank 12. An example of a suitable 90 degree scattered light sensor is the turbidity sensor Chemitec S461 / T from Liquid Analytical Resource, LLC of Shirley, MA, USA. The turbidity sensor 58 may be located in the flocculation chamber 70, and may include a housing 103 that contains a light source 104 and a light sensor 105. The light source 104 may include a laser diode, or other generating device. of adequate light that transmits a beam of light 106 in the residual water. Parts of the light beam 106 can be reflected and / or dispersed by large and small solids contained in the residual water of the flocculation chamber 70. Part of this scattered light 107 can be detected and measured by the light sensor 105, which can be configured to detect light scattered at an angle (for example, a 90 degree angle) from the light beam 106. Typically, the effluent will be multiphasic wastewater containing bulk water in the liquid phase and a flake of particles in the solid phase. Waste water can also contain gas-phase bubbles. As the light beam 106 passes through the waste water, light from the light beam 106 can be reflected off or scattered by the particles in the waste water, with a part of this scattered light 107 being received by the light sensor 105.
    [033] For this purpose, housing 103 may include one or more windows 108, 109 to prevent waste water from entering turbidity sensor 58. Windows 108, 109 may also allow beam of light 106 to exit housing 103 and that the scattered light 107 reaches the light sensor 105. In response to the reception of the scattered light 107, the light sensor 105 can generate an output signal 122 (Figure 3), which can be a voltage or current that is proportional to the amount of scattered light 107 incident on the light sensor 105. This output signal 122 can, in turn, be coupled to the processor 90 through the I / O interface 94 of the controller 16. Although shown as located in the flocculation chamber 70 , those of ordinary skill in the art will understand that the light sensor 105 can be located in other areas of the treatment system 10 to measure turbidity in the waste water containing flake particles. For example, the turbidity sensor 58 may be located in the pH adjustment or coagulation chambers 62, 66, or between the flocculation chamber 70 and the DAF unit 18. A person having normal skill in the art would also understand that a sensor transmitted light could be used in place of the described scattered light sensor. In embodiments using a transmitted light sensor, light sensor 105 can be placed in the path of light beam 106. The signal provided by light sensor 105 would thus be reduced due to the presence of flake and / or cloudy water , instead of increasing, due to the light being spread. Thus, the signal provided by a transmitted light sensor would have an inverse relationship with the amount of turbidity and / or flake compared to the signal provided by a scattered light sensor.
    [034] Referring now to Figures 3A-4B, Figures 3A and 4A are schematic views illustrating exemplary effluent samples 114, 128 from flocculation chamber 70 that include bulk water 116, 130 and flake particles 118, 132. Figures 3B and 4B provide graphs 120, 134 corresponding to the respective samples 114,128 which include traces of detected turbidity 122, 136 based on the output signal from the turbidity sensor 58 at a plurality of sampling points 124, 138. In the example graphs 120,134, turbidity is indicated in Nephelometric Turbidity Units (NTU), although any unit suitable for measuring turbidity, or even a voltage or current level could also be used.
    [035] As the waste water from the flocculation chamber 70 is mixed and circulated, the light beam 106 can sometimes find only bulk water 116, 130 as the light beam 106 passes through the measurement distance of the turbidity sensor 58. During these periods, samples 124, 138 of the turbidity detector output signal may cluster or aggregate within a range of values that reflects the turbidity of bulk water 116, 130. For example, in Figures 3A and 3B, bulk water contains a relatively high level of turbidity represented by a portion of samples 124 delimited by the dotted line, so that a subset 126 of samples 124 agglomerates within the range of 250 to 350 NTU. That is, subset 126 of samples 124 falls within 50 NTU from a central value of 300 NTU. In contrast, Figures 4a and 4B show a sample having bulk water 130 with a lower turbidity, so that a part, or a subset 140 of samples 138 falls within a range of 80 to 120 NTU, or within 20 NTU of a central value of 100 NTU. In each case, the subset of samples 126, 140 falls within a range that is correlated with the turbidity of the waste water.
    [036] In other periods, one or more flake particles 118, 132 and / or air bubbles can pass through the beam of light 106. On those occasions, the light reflected by the flake particles 118, 132 can make the amount of light incident on light sensor 105 increases, so that light sensor 105 generates a much higher output signal 122, 136. Therefore, samples 124, 138 of the turbidity detector output signal taken in these periods will normally fall well outside the range of values associated with subsets of bulk water 126, 140. In addition, these samples may fall within a range with a central value (for example, 1000 NTU) that is significantly greater than the central value associated with bulk water turbidity. The range of values for samples 124, 138 associated with flake can be relatively independent of the turbidity of bulk water, so there is little correlation between the values of samples 124, 138 taken while a flake particle 117, 132 is reflecting the beam of light 106, and the turbidity of the waste water. Therefore, these data can be identified and discarded so that only samples that have not been affected by the flake particles are used to indicate turbidity. The amount of light reflected by the flake particles 118, 132 can be sufficient to cause the light sensor 105 to indicate a signal level of maximum turbidity or saturated output, which in the exemplary embodiment, is shown as the reading of 1,000 NTU . However, people who have normal skill in the art will understand that this level may vary depending on the type of sensor used, as well as the characteristics of the flake. Embodiments of the invention are therefore not limited to any particular range of sample values being associated with detection of a flake particle.
    [037] It has been determined that by taking a plurality of samples and calculating a probability distribution of the indicated turbidity, accurate measurements of bulk water turbidity can be obtained from flake-containing water samples. Advantageously, this allows the determination of the turbidity of the residual water in the flocculation chamber 70 in real time or almost in real time. By allowing the turbidity sensor 58 to be placed in the flocculation chamber 70 instead of sometime after the DAF unit 18, or another suitable flake removal device, such as a sedimentation clarifier (i.e., after the flakes have been removed from wastewater), embodiments of the invention may allow controller 16 to react more rapidly to changes in wastewater turbidity than controllers in conventional systems. This faster response time can, in turn, improve the accuracy with which the coagulant levels are controlled, reducing the amount of chemicals wasted, as well as the contamination levels of the effluent 30.
    [038] Referring now to Figure 5, a flow chart 150 is presented according to an embodiment of the invention that illustrates a sequence of operations for the application of controller 100 that can be used to determine the turbidity of the residual water in the flocculation chamber 70. In block 152, controller application 100 samples the turbidity sensor 58 output signal. This sample can be assigned a value corresponding to the turbidity level indicated by the 58 turbidity sensor signal, and can be stored as a data structure 102 in memory 92.
    [039] In block 154, application 100 determines a threshold that can be used to classify the sample. The determination of the threshold may include the selection of a value from a lookup table based on values from one or more samples of the output signal stored in memory 92, or it may include a statistical analysis of a plurality of samples from a group of samples previously obtained. In an alternative embodiment of the invention, the threshold can be defined as a predetermined value based on empirical data or an expected turbidity level in the flocculation chamber 70, in which case block 154 can be omitted. In any case, the threshold can include one or more values that separate the samples within a plurality of sample sets or clusters. For example, the threshold may have a lower value and a higher value that defines a signal range indicative of a bulk water reading, or the threshold may be a single value that represents a signal value below which the reading it is considered to be a bulk water reading.
    [040] In block 156, application 100 compares the output signal sample obtained in block 152 with the threshold determined in block 154 before proceeding to decision block 158. If the output signal sample is outside the threshold ( for example, greater than the threshold) ("Yes" branch of decision block 158), the application marks the sample as outside the threshold in block 160 before returning to block 152 to take another sample. If the sample is within the threshold (for example, less than or equal to the threshold) (The "No" branch of decision block158), application 100 proceeds to block 162 and marks the sample as being within the threshold. Samples marked as outside the threshold can be discarded, or can be saved in memory 92 for use in determining future threshold levels. Samples marked as being within the threshold can be added to a set or subset of samples that are indicative of wastewater turbidity.
    [041] In block 164, application 100 determines the turbidity of the residual water based on the subset of samples that are marked as being within the threshold. The turbidity of the residual water can be determined based on a statistical value of the samples. This statistical value can be an average or average value of the samples within the threshold, a median value of the samples within the threshold, a filtered value of the samples within the threshold, for example, based on the output of a Finite Impulse Response (FIR ) or Infinite Impulse Response (IIR) filter, or simply based on the last sample obtained that was marked as being within the threshold. The subset of samples marked as within the limit can include a fixed number of samples selected based on a First In - First Out (FIFO) methodology, a series of samples obtained within a predetermined time window, or any other method definition of the subset.
    [042] In block 166, application 100 compares the determined turbidity with a reference level or value, which can represent a target level of turbidity for the residual water flowing out of the flocculation chamber 70. The difference between the level determined turbidity and the reference value can provide an error signal to a control algorithm in the application of controller 100. For example, the error signal can be processed using a Proportional-Integral-Derivative (PID) control algorithm that produces an output that indicates the amount of a chemical, such as the coagulant, to be added to reaction tank 12. In one embodiment of the invention, the reference value may comprise an acceptable turbidity range. The turbidity values that fall within this range would not produce an error signal, thus producing a dead band or neutral zone at the controller output.
    [043] For this purpose, in decision block 168, if the determined turbidity is greater than the desired range or reference value ("Yes" branch of decision block 168), the application of controller 100 can be moved to block 170. In block 170, the amount of coagulant added to reaction tank 12 is increased. This increase can, for example, be achieved by signaling the dispensing pump 78 to supply an increased amount of coagulant 60 to the coagulation chamber 62. If the determined turbidity is not above the desired range (The "No" branch of the decision block168 ), application 100 passes to decision block 172.
    [044] If the turbidity determined is less than the desired range or reference value ("Yes" branch of decision block 172), application 100 can be moved to block 174. In block 174, application 100 decreases the amount of coagulant added to reaction tank 12. For example, application 100 can signal delivery pump 78 coupled to coagulant container 84 to reduce the coagulant flow rate 60 provided to the coagulation chamber 62, or cut the flow of coagulant 60 by complete. If the determined turbidity is not below the desired range (The "No" branch of decision block 172), application 100 can return to block 152 and obtain another sample of the turbidity sensor output signal.
    [045] The application of controller 100 can thus be configured to determine the turbidity of bulk water 116, 130, and selectively activate one or more delivery pumps 78, 80, 82 in response to signals from the turbidity sensor 58 in order to that the quantities of chemicals added to the incoming wastewater are optimized. In one embodiment of the invention, determining turbidity may also include determining a sample probability density based on samples of the turbidity sensor output signal. This probability density function can be thought of as an expected distribution for a large population of samples, with a group of samples obtained by applying controller 100 serving as a random sample of that expected population.
    [046] Referring now to Figure 6, a flow chart 180 is presented according to an embodiment of the invention. Flowchart 180 illustrates a sequence of operations that can be used to determine a threshold used to classify or identify turbidity sensor output signal samples that are indicative of wastewater turbidity. In block 182, application 100 samples the sensor output 58. In block 184, this sample is added to a group of samples. The sample group can represent a set of samples with a fixed number of samples, a set of samples collected during a moving time window that ends with the last sample, or any other methodology suitable for the grouping of samples.
    [047] In block 186, application 100 determines a probability density based on the group of samples. To this end, the samples in the sample group can be seen as a random sample from a larger universe of samples representing an expected output from the turbidity sensor 58. To further illustrate this, Figure 7 presents an example graph 190 of a function of probability density represented by plotted line 192 for samples 138 shown in Figure 4B. In the illustrated embodiment, graph 190 has a horizontal axis 194 that provides the level of turbidity indicated in NTU, and a vertical axis 196, which indicates the probability that a sample having that turbidity value will be obtained. The application of controller 100 can use any suitable method for determining the probability density function 192, such as a Parzen window, a data grouping technique, such as vector quantization, or through the generation of a histogram scaled to from the samples in the sample group. Once the probability density function 192 has been determined for the samples in the sample group, the application of controller 100 can be moved to block 198.
    [048] In block 198, the controller application 100 can identify one or more peaks 200-204 of the probability density function 192. Although each one or more peaks 200 - 204 are shown as having a well-defined maximum value in the graph exemplificative 190, in embodiments of the invention, one or more of the peaks 200 - 204 may be flattened peaks, or may have a shape that does not have a well-defined maximum value. For example, if a large number of samples 124, 138 are clustered in the 300 NTU region, there may be samples 124, 138 that have other values (for example, 1000, 5000, or 10,000 NTU) that do not form a readily identifiable peak. In any case, peaks 200-204 can represent indicated turbidity values that are more likely to be indicated by the turbidity sensor 58 output. These expected turbidity sensor output levels can be concentrated into two peaks of 200, 204, with a peak 200 located at a lower horizontal axis value 205 associated with residual water turbidity readings (ie bulk water readings , in the absence of flakes dispersion) and the other peak 204 located at a higher horizontal axis value 206 associated with an erroneous reading resulting from the flakes in the residual water.
    [049] In block 207, application 100 can identify peak 200 occurring at the lowest value 205 of the horizontal axis (for example, the lowest level indicated in NTU) having a peak location 208. Application 100 can then , go to block 210 and define a limit 212 based on the location 208 of the identified peak 200. This threshold 212 can, for example, be adjusted to a value that provides a desired distance 214 from the location of peak 208. This distance 214 can , for example, be at a predetermined distance (for example, 100 NTU) or adjusted to a predetermined number of standard deviations (for example, 2x o) calculated for the group of samples. Application 100 can also set a lower threshold 216 which defines a lower limit for the samples to be included in the sample group. That is, the application can define a range with thresholds 212, 216 that identifies samples to be included in the sample group.
    [050] The terminology used here is for the purpose of describing only particular embodiments and is not intended to limit the invention. As used here, the singular forms "a" "one", and "the" are intended to include plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise" and / or "comprising," when used in the present description, specify the presence of established aspects, integers, steps, operations, elements and / or components, but do not prevent the presence or addition of one or more of other characteristics, whole numbers stages, operations, component elements and / or groups thereof. In addition, references in this document to terms, such as "vertical", "horizontal", etc., are made by way of example, and not by way of limitation, to establish an absolute frame of reference.
    [051] It should be understood that when an element is described as being "attached" or "coupled" to / or with another element, it can be directly attached or coupled to the other element or, instead, one or more elements stakeholders may be present. In contrast, when an element is described as being "directly linked" or "directly coupled" to another element, there are no intervening elements present. When an element is described as being "indirectly linked" or "indirectly coupled" to another element, there is at least one stakeholder element present.
    [052] As used herein, the term "in response to" means "in response to" and / or "after" a first event. Thus, a second event that occurs "in response to" a first event may occur immediately after the first event, or it may include a time interval that occurs between the first event and the second event. In addition, the second event can be caused by the first event, or it can simply occur after the first event, without any causal relationship.
    [053] Although the invention has been illustrated by describing one or more embodiments thereof, and, while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the claims attached to such details . Additional advantages and modifications will appear easily to those skilled in the art. For example, although the invention has been described with respect to a turbidity sensor 58 that has a 90 degree configuration between light source 104 and light sensor 105, people who have normal skill in the art will understand that other types of sensors could be used. For example, a sensor that detects the attenuation of a light source, or that is located at an angle other than 90 degrees to the light source. In these alternative embodiments, the output signal from the turbidity sensor can be inverted relative to the 90 degree sensor described herein. That is, a higher level signal may be indicative of a lower level of turbidity. The invention in its broadest aspects, therefore, is not limited to specific details, representative apparatus and methods and illustrative examples shown and described. Therefore, divergences can be made from such details without departing from the scope or spirit of the Applicant's general inventive concept.
    权利要求:
    Claims (15)
    [0001]
    1. Method for determining the turbidity of the liquid phase of a multiphase wastewater in a wastewater treatment system (10) comprising a flocculation chamber (70) and a flake removal device (18), the method comprising the steps placing a turbidity sensor (58) including a housing unit (103) containing a light emitter (104) and a light sensor (105) in multiphase wastewater before the flake removal device (18); emit a light signal and receive a signal on the light sensor (105) indicative of an amount of light scattered or transmitted by the wastewater, characterized by further comprising the steps of: sampling the signal to produce a plurality of signal sample values where the sample values produced by the liquid phase of the wastewater in the absence of flake particles (118) produce a first set of sample values and where the sample values produced when the flake particles (118) are in the path of the signal produce a second set of sample values; identify the first set of sample values based on a threshold, comparing the sample values with the threshold to identify and discard the second set of sample values, based on which the flakes particles (118) reflect light, so that a central value of the first set of values in the sample is significantly greater than the central value of the second set of values in the sample; and determining the turbidity of the wastewater liquid phase based on the first identified set of sample values.
    [0002]
    2. Method according to claim 1, characterized by the fact that it additionally comprises: determining the threshold based at least in part on the values of the samples.
    [0003]
    3. Method according to claim 1, characterized by the fact that the determination of the threshold includes: identifying the first group of samples that have values grouped around a first signal value; identify the second group of samples that have values grouped around a second signal value; set the threshold to a value between the first signal value and the second signal value.
    [0004]
    Method according to claim 3, characterized in that the second signal value is a value that indicates a higher level of turbidity than the first signal value.
    [0005]
    5. Method according to claim 1, characterized by the fact that it additionally comprises: generating a control signal based on the determined turbidity of the residual water.
    [0006]
    6. Method according to claim 5, characterized by the fact that: determining the turbidity of wastewater includes determining a statistical value from the first set of sample values; and generating the control signal includes comparing the statistical value with a reference value and defining a control signal value based on the difference between the statistical value and the reference value; where the statistical value can be an average or average value, a median value or a filtered value from the first set of sample values, or it can be based on the last sample obtained in the first set of sample values.
    [0007]
    7. Method according to claim 5, characterized by the fact that it additionally comprises: the adjustment of a quantity of a chemical product added to the residual water based on the control signal.
    [0008]
    8. Method according to claim 7, characterized in that the chemical includes a coagulant.
    [0009]
    9. Method according to claim 1, characterized by the fact that it additionally comprises: determining a probability distribution of the samples; identify a first probability peak that occurs in a first location associated with the liquid phase of the wastewater in the absence of flakes particles (118); identify a second probability peak that occurs at a second location associated with the values produced when the flakes particles (118) are in the signal path; and determining wastewater turbidity based on a value from the first location, where the value from the first location is indicative of a different level of turbidity from a value from the second location.
    [0010]
    10. Apparatus (16) for determining the turbidity of the liquid phase of a multiphase wastewater in a wastewater treatment system (10) comprising a flocculation chamber (70) and a flake removal device (18), in which a turbidity sensor (58) includes a housing unit (103) containing a light emitter (104) and a light sensor (105) is placed in multiphase wastewater before the flake removal device (18), the apparatus comprising: a processor (90); and a memory (92) containing program code which, when executed by the processor, causes the device to: control the turbidity sensor (58) to emit a light signal and receive a signal on the light sensor (105) indicative of an amount of light scattered by or transmitted by the wastewater, characterized in that the apparatus still samples the signal to produce a plurality of signal sample values in which the sample values produced by the liquid phase of the wastewater in the absence of flakes particles ( 118) produce a first set of sample values and wherein the sample values produced when the flakes particles (118) are in the signal path produce a second set of values; identify the first set of sample values based on a threshold, comparing the sample values with the threshold to separate the first and second sets of sample values, in which the flakes particles (118) reflect light so that a central value of the first set of sample values is significantly greater than a central value of the second set of sample values; and determining wastewater turbidity based on the first set of sample values identified.
    [0011]
    11. Apparatus according to claim 10, characterized by the fact that the program code is further configured to make the apparatus (16) determine the threshold based on the sample values by: identifying a first group of samples with values grouped around a first signal value; set the threshold so that at least part of the first group of samples is below the threshold.
    [0012]
    12. Apparatus according to claim 11, characterized by the fact that the program code is still configured to make the apparatus (16) further determine the threshold by: identifying a second group of samples with values grouped around a second signal value; and setting the limit to a value between the first signal value and the second signal value, wherein the second signal value is a value that indicates a higher level of turbidity than the first signal value.
    [0013]
    13. Apparatus (16), according to claim 10, characterized by the fact that the program code is further configured to generate a control signal based on the determined turbidity of the liquid phase of a multiphase wastewater.
    [0014]
    Apparatus (16) according to claim 13, characterized by the fact that: determining the turbidity of the wastewater includes determining a statistical value from the first set of sample values; and generating the control signal includes comparing the statistical value with a reference value and defining a control signal value based on the difference between the statistical value and the reference value; where the statistical value can be an average or average value, a median value or a filtered value from the first set of sample values, or it can be based on the last sample obtained in the first set of sample values.
    [0015]
    15. Apparatus (16) according to claim 13, characterized by the fact that the control signal is used to adjust a quantity of a chemical added to the wastewater.
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    同族专利:
    公开号 | 公开日
    CN104823037B|2018-10-26|
    US10281383B2|2019-05-07|
    WO2014078382A1|2014-05-22|
    EP2920572A1|2015-09-23|
    PT2920572T|2019-04-26|
    NZ707814A|2018-06-29|
    ES2718207T3|2019-06-28|
    AU2013344908B2|2017-03-09|
    RU2015122396A|2017-01-10|
    KR102179804B1|2020-11-18|
    DK2920572T3|2019-04-15|
    AU2013344908A1|2015-05-07|
    US20140131259A1|2014-05-15|
    EP2920572A4|2016-06-22|
    TW201428263A|2014-07-16|
    EP2920572B1|2019-01-09|
    ZA201504281B|2017-11-29|
    TWI585389B|2017-06-01|
    CL2015001270A1|2015-10-02|
    BR112015010552A2|2017-07-11|
    KR20150084008A|2015-07-21|
    CA2888724C|2019-09-17|
    MX2015005446A|2015-07-17|
    MX344181B|2016-12-08|
    CN104823037A|2015-08-05|
    CA2888724A1|2014-05-22|
    RU2660367C2|2018-07-05|
    PL2920572T3|2019-06-28|
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    法律状态:
    2018-11-21| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2019-10-29| B06U| Preliminary requirement: requests with searches performed by other patent offices: suspension of the patent application procedure|
    2020-04-22| B09A| Decision: intention to grant|
    2020-09-29| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 13/11/2013, OBSERVADAS AS CONDICOES LEGAIS. |
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    US61/726,637|2012-11-15|
    US14/075,613|2013-11-08|
    US14/075,613|US10281383B2|2012-11-15|2013-11-08|System and methods of determining liquid phase turbidity of multiphase wastewater|
    PCT/US2013/069844|WO2014078382A1|2012-11-15|2013-11-13|Determining liquid phase turbidity of multiphase wastewater|
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