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WO2018222841A1 - Système de commande d'injection chimique et procédé de régulation de chloramines - Google Patents

Système de commande d'injection chimique et procédé de régulation de chloramines Download PDF

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Publication number
WO2018222841A1
WO2018222841A1 PCT/US2018/035349 US2018035349W WO2018222841A1 WO 2018222841 A1 WO2018222841 A1 WO 2018222841A1 US 2018035349 W US2018035349 W US 2018035349W WO 2018222841 A1 WO2018222841 A1 WO 2018222841A1
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WO
WIPO (PCT)
Prior art keywords
water
chloramine concentration
chlorine
ammonia
residual chloramine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2018/035349
Other languages
English (en)
Inventor
Billie FRITZ
Mark KUSHMAN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Process Solutions Inc
Original Assignee
Process Solutions Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Process Solutions Inc filed Critical Process Solutions Inc
Priority to NZ759634A priority Critical patent/NZ759634B2/en
Priority to EP18810726.2A priority patent/EP3634915A4/fr
Priority to AU2018275261A priority patent/AU2018275261B2/en
Priority to CA3065512A priority patent/CA3065512A1/fr
Publication of WO2018222841A1 publication Critical patent/WO2018222841A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
    • 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
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/001—Upstream control, i.e. monitoring for predictive control
    • 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
    • C02F2209/003—Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
    • 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]
    • C02F2209/006—Processes using a programmable logic controller [PLC] comprising a software program or a logic diagram
    • 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
    • C02F2209/29—Chlorine compounds
    • 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
    • C02F2303/04—Disinfection
    • 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
    • C02F2303/18—Removal of treatment agents after treatment
    • C02F2303/185—The treatment agent being halogen or a halogenated compound

Definitions

  • the present invention relates to chemical injection control systems for controlling chloramines and methods of operating such systems.
  • Water utilities typically add disinfectants to water systems to prevent contamination from germs and bacteria such as Salmonella. While chlorine is the most commonly used secondary disinfectant, many water utilities are turning to chloramines as an alternative. As compared to chlorine, chloramines have a longer residual life and are less prone to disinfection byproduct formation. Despite these advantages, chloramine usage can be problematic. For instance, a water system is typically dosed with hypochlorite and ammonia to produce monochlor amine; however, if the chlorine-to-ammonia ratio is not accurately controlled, undesirable side-effects occur such as nitrification, over-chlorination, and low oxidation levels. Thus, it is desirable to provide a chemical injection system that can be accurately controlled to continuously produce stable forms of monochloramine in a water system at a desired concentration.
  • a method of automatically controlling chloramine concentration in a body of water contained in a reservoir includes: (a) determining residual chloramine concentration in a water sample obtained from the body of water; (b) automatically engaging a supply of chlorine to add chlorine to the body of water when (i) the residual chloramine concentration in the water sample is determined to be below a predetermined residual chloramine concentration set-point or (ii) the residual chloramine concentration in the water sample is determined to be below a chloramine concentration percentage of a predetermined residual chloramine concentration set- point; (c) determining residual chloramine concentration in one or more additional water samples obtained from the body of water after step (b); (d) determining the rate of change in chloramine concentration based on the residual chloramine concentration obtained from at least two water samples of step (c) or based on the residual chloramine concentration obtained from a water sample in step (c) and the water sample in step (a) if the residual chloramine concentration in the additional water samples is below the predetermined residual
  • the supply of chlorine is added to the body of water in step (b) when (i) the residual chloramine concentration in the first water sample is determined to be below the predetermined residual chloramine concentration set-point.
  • the supply of chlorine is added to the body of water in step (b) when (ii) the residual chloramine concentration in the first water sample is determined to be below the first chloramine concentration percentage of the predetermined residual chloramine concentration set-point.
  • the rate of change in chloramine concentration is determined by comparing the chloramine concentration in at least one water sample of step a) or step c) with the chloramine concentration in a subsequent water sample of step c) obtained after a set period of time.
  • the ammonia and chlorine are both added to the body of water in step e) when two consecutive determinations in the rate of change in chloramine concentration are below the set rate of change in chloramine concentration.
  • the rate of change in chloramine concentration is determined to be at or above the set rate of change in chloramine concentration
  • the addition of chlorine only to the body of water is maintained.
  • the residual chloramine concentration in a water sample is determined to be at or above the predetermined residual chloramine concentration set-point in step c)
  • the supply of chlorine to the body of water is stopped.
  • the supply of chlorine and the supply of ammonia are added to the body of water during step e) until a subsequently obtained water sample is determined to be at or above the predetermined residual chloramine concentration set-point.
  • a supply of chlorine can be added to the body of water if the residual chloramine concentration is determined to be below the chloramine concentration percentage of the predetermined residual chloramine concentration set-point.
  • the chloramine concentration percentage is a percentage selected within a range of about 99% to about 80% of the predetermined residual chloramine concentration set-point.
  • the method can further include: (f) determining residual chloramine concentration in a subsequent water sample obtained from the body of water; and (g) automatically engaging the supply of ammonia and the supply of chlorine to add both ammonia and chlorine to the body of water if (i) the residual chloramine concentration in the subsequent water sample is determined to be below the predetermined residual chloramine concentration set-point or (ii) the residual chloramine concentration in the subsequent water sample is determined to be below the chloramine concentration percentage of the predetermined residual chloramine concentration set-point.
  • the feed rate of at least one of the chlorine and ammonia can be determined by reservoir water volume and dwell time. Further, when both chlorine and ammonia are added to the body of water, the chlorine and ammonia can be automatically added to provide a weight ratio of chlorine to ammonia of 5: 1.
  • determining the residual chloramine concentration in the water samples includes measuring a total chlorine concentration in the water samples.
  • the chlorine and, optionally, the ammonia are added to the body of water by a chemical dosing assembly that comprises chemical treatment flow tubes and a water motive tube.
  • the chlorine and, optionally, the ammonia are added to the body of water by the chemical treatment flow tubes in an area above the water motive tube to form a high energy mixing zone.
  • the method further comprises re-starting the method at step a) after a predetermined period of time when the supply of chlorine is stopped after step d).
  • a treatment delivery system for automatically controlling chloramine concentration in a body of water contained in a reservoir.
  • the system includes: a chemical dosing assembly at least partially submerged in the body of water; a water sampling assembly configured to extract water samples from the body of water at different points in time; an analyzer in fluid communication with the water sampling assembly and configured to determine residual chloramine concentration in the water samples; a controller in operable communication with the analyzer; and one or more computer-readable storage mediums in operable communication with the controller and containing programming instructions that, when executed, cause the controller to: (a) determine whether the residual chloramine concentration in the water sample obtained from the body of water is below a predetermined residual chloramine concentration set-point or below a chloramine concentration percentage of a predetermined residual chloramine concentration set-point; (b) engage the chemical dosing assembly to add chlorine to the body of water when (i) the residual chloramine concentration in the water sample is determined to be below a predetermined residual chloramine concentration set-point or (ii) the residual chloramine concentration in the water sample is determined to be below the chloramine concentration percentage of a predetermined residual chloramine concentration set-point; (c) determine residual
  • the water sampling assembly is a component of the chemical dosing assembly, and the analyzer is a total chlorine analyzer.
  • the chemical dosing assembly can also include a water motive tube positioned below a release point of at least one chemical treatment flow tube.
  • the chemical dosing assembly can further include a second chemical treatment flow tube with the water motive tube positioned below a release point of the second chemical treatment flow tube.
  • the first and second chemical treatment flow tubes are configured to deliver the chlorine and, optionally, the ammonia, to an area above a release point of the water motive tube to form a high energy mixing zone.
  • the system can include a hypochlorite storage tank, an ammonia storage tank, or both a hypochlorite storage tank and an ammonia storage tank.
  • the system includes a hypochlorite generation system.
  • the controller can also be programmed to provide a weight ratio of chlorine to ammonia of 5: 1.
  • a method of automatically controlling chloramine concentration in a body of water contained in a reservoir comprising: (a) determining residual chloramine concentration in a water sample obtained from the body of water; (b) automatically engaging a supply of chlorine to add chlorine to the body of water when: (i) the residual chloramine concentration in the water sample is determined to be below a predetermined residual chloramine concentration set-point; or (ii) the residual chloramine concentration in the water sample is determined to be below a chloramine concentration percentage of a predetermined residual chloramine concentration set-point; (c) determining residual chloramine concentration in one or more additional water samples obtained from the body of water after step (b); (d) determining the rate of change in chloramine concentration based on the residual chloramine concentration obtained from at least two water samples of step (c) or based on the residual chloramine concentration obtained from a water sample in step (c) and the water sample in step (a) if the residual chloramine concentration in the additional water samples is below the predetermined residual chloramine concentration set-point or the
  • Clause 4 The method of any of clauses 1-3, wherein the rate of change in chloramine concentration is determined by comparing the chloramine concentration in at least one water sample of step (a) or step (c) with the chloramine concentration in a subsequent water sample of step (c) obtained after a set period of time.
  • Clause 5 The method of any of clauses 1-4, wherein the ammonia and chlorine are both added to the body of water in step (e) when two consecutive determinations in the rate of change in chloramine concentration are below the set rate of change in chloramine concentration.
  • Clause 6 The method of any of clauses 1-5, wherein, if the rate of change in chloramine concentration is determined to be at or above the set rate of change in chloramine concentration, the addition of chlorine only to the body of water is maintained.
  • Clause 7 The method of any of clauses 1-6, wherein, if the residual chloramine concentration in a water sample is determined to be at or above the predetermined residual chloramine concentration set-point in step (c), the supply of chlorine to the body of water is stopped.
  • Clause 8 The method of any of clauses 1-7, wherein the supply of chlorine and the supply of ammonia are added to the body of water during step (e) until a subsequently obtained water sample is determined to be at or above the predetermined residual chloramine concentration set-point.
  • Clause 9 The method of any of clauses 1-8, wherein the chloramine concentration percentage is a percentage selected within a range of about 99% to about 80% of the predetermined residual chloramine concentration set-point.
  • Clause 10 The method of any of clauses 1-9, wherein a feed rate of at least one of the chlorine and ammonia are determined by reservoir water volume and dwell time.
  • Clause 11 The method of any of clauses 1-10, wherein, if it is determined that the body of water has a residual chloramine concentration at or above the predetermined residual chloramine concentration set-point after step (b) or step (e), the method further comprises: (f) determining residual chloramine concentration in a subsequent water sample obtained from the body of water; and (g) automatically engaging the supply of ammonia and the supply of chlorine to add both ammonia and chlorine to the body of water if: (i) the residual chloramine concentration in the subsequent water sample is determined to be below the predetermined residual chloramine concentration set -point; or (ii) the residual chloramine concentration in the subsequent water sample is determined to be below the chloramine concentration percentage of the predetermined residual chloramine concentration set-point.
  • Clause 12 The method of any of clauses 1-11, wherein determining the residual chloramine concentration in the water samples comprises measuring a total chlorine concentration in the water samples.
  • Clause 13 The method of any of clauses 1-12, wherein the chlorine and ammonia are both automatically added to the body of water to provide a weight ratio of chlorine to ammonia of 5: 1.
  • Clause 14 The method of any of clauses 1-13, wherein the chlorine and, optionally, the ammonia, are added to the body of water by a chemical dosing assembly that comprises chemical treatment flow tubes and a water motive tube, and wherein the chlorine and, optionally, the ammonia, are added to the body of water by the chemical treatment flow tubes in an area above the water motive tube to form a high energy mixing zone.
  • Clause 15 The method of any of clauses 1-14, further comprising re-starting the method at step a) after a predetermined period of time when the supply of chlorine is stopped after step d).
  • a treatment delivery system for automatically controlling chloramine concentration in a body of water contained in a reservoir comprising: a chemical dosing assembly at least partially submerged in the body of water; a water sampling assembly configured to extract water samples from the body of water at different points in time; an analyzer in fluid communication with the water sampling assembly and configured to determine residual chloramine concentration in the water samples; a controller in operable communication with the analyzer; and one or more computer-readable storage mediums in operable communication with the controller and containing programming instructions that, when executed, cause the controller to: (a) determine residual chloramine concentration in a water sample obtained from the body of water; (b) automatically engage a supply of chlorine to add chlorine to the body of water when: (i) the residual chloramine concentration in the water sample is determined to be below a predetermined residual chloramine concentration set- point; or (ii) the residual chloramine concentration in the water sample is determined to be below a chloramine concentration percentage of a predetermined residual chloramine concentration set-point; (c) determine residual chloramine concentration in
  • Clause 18 The system of clauses 16 or 17, wherein the analyzer comprises a total chlorine analyzer.
  • Clause 19 The system of any of clauses 16-18, wherein the chemical dosing assembly further comprises a water motive tube positioned below a release point of at least one chemical treatment flow tube.
  • Clause 20 The system of any of clauses 16-19, wherein the chemical dosing assembly further comprises a second chemical treatment flow tube and, wherein the water motive tube is positioned below a release point of the second chemical treatment flow tube.
  • Clause 21 The system of any of clauses 16-20, wherein the first and second chemical treatment flow tubes are configured to deliver the chlorine and, optionally, the ammonia, to an area above a release point of the water motive tube to form a high energy mixing zone.
  • Clause 22 The system of any of clauses 16-21, further comprising a hypochlorite storage tank, an ammonia storage tank, or both a hypochlorite storage tank and an ammonia storage tank.
  • Clause 23 The system of any of clauses 16-22, further comprising a hypochlorite generation system.
  • Clause 24 The system of any of clauses 16-23, wherein the controller is programmed to provide chlorine and ammonia at a weight ratio of chlorine to ammonia of 5: 1.
  • FIG. 1 illustrates a treatment delivery system according to the principles of the present invention
  • FIG. 2 illustrates a chemical dosing assembly according to the principles of the present invention
  • FIG. 3 is a chloramine breakpoint curve
  • FIG. 4 are graphs illustrating the addition of chlorine in the presence of free ammonia to generate chloramine
  • FIG. 5 are graphs illustrating the addition of chlorine and ammonia in the absence of free ammonia to generate chloramine
  • FIG. 6 is a graph of the residual chloramine concentration and rate of change of chloramine concentration using a process according to the principles of the present invention.
  • FIG. 7 is a graph of the residual chloramine concentration and rate of change of chloramine concentration using a process according to the principles of the present invention.
  • any numerical range recited herein is intended to include all sub-ranges subsumed therein.
  • a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
  • the present invention is directed to a treatment delivery system 10 that can be used to automatically control chloramine concentration in a body of water 12 contained in a reservoir 14.
  • automated control refers to the absence of substantial participation of a human operator in normal operations manually controlling the controllable components.
  • the treatment delivery system 10 can be controlled without an operator monitoring or adjusting the various parameters of the treatment delivery system 10 during normal operations.
  • the treatment delivery system 10 can include a chemical dosing assembly 16 that can be at least partially submerged in the body of water 12.
  • the chemical dosing assembly 16 can include a water motive tube 20, a first chemical treatment flow tube 22, and, optionally, a second chemical treatment flow tube 24.
  • the water motive tube 20 and chemical treatment flow tubes 22, 24 of the chemical dosing assembly 16 can be oriented to expel water and chemicals, respectively, into the body of water 12 held in the reservoir 14.
  • the chemicals used with the chemical treatment tubes 22, 24 can be selected to form chloramine, such as monochloramine, when expelled into a jet of water expelled from the water motive tube 20.
  • the first chemical treatment flow tube 22 can be in fluid communication with a source of chlorine and can be configured to expel chlorine into the body of water 12 while the second chemical treatment flow tube 24 can be in fluid communication with a source of ammonia and can be configured to expel ammonia into the body of water 12. Because of the configuration of the nozzle ends of the first and second chemical treatment flow tubes 22, 24, the chemicals expelled through the ends thereof come into almost immediate contact with one another and can begin reacting soon after being expelled into the body of water 12.
  • the water motive tube 20 is positioned below the release point of the first and second chemical treatment flow tubes 22, 24 to circulate the chemicals into the body of water 12.
  • the flow of water out of the water motive tube 20 can also create a high energy, high velocity mixing zone directly above the water motive tube 20 where the chemicals can be released, which helps the chemicals interact and form a particular compound, such as monochloramine.
  • the treatment delivery system 10 can include multiple chemical dosing assemblies 16 strategically located throughout the reservoir 14.
  • the treatment delivery system 10 can further include a water sampling assembly 26 that is configured to obtain or extract water samples from the body of water 12 at different points in time, such as continuously, periodically, and/or according to a pre-programmed cycle.
  • the water sampling line 26 can be a component of the chemical dosing assembly 16.
  • the water motive tube 20, chemical treatment tubes 22, 24, and water sampling assembly 26 of the chemical dosing assembly 16 can be secured to a frame 27 that is adapted to rest at the bottom of the reservoir 14.
  • the water motive tube 20, the chemical treatment tubes 22, 24, and the water sampling assembly 26 can extend into the reservoir 14 to a desired depth.
  • the water sampling assembly 26 can be separate from the chemical dosing assembly 16 and may be located at any location within the reservoir 14.
  • Treatment delivery system 10 may also include multiple water sampling assemblies 26 positioned throughout the reservoir 14.
  • the treatment delivery system 10 can also include an analyzer 30 that is in fluid communication with the water sampling assembly 26.
  • the analyzer 30 is configured to receive the water samples and analyze the contents thereof.
  • the analyzer 30 is programmed or configured to determine the concentration of chloramine in the water sample.
  • a chloramine analyzer such as the APA 6000 Ammonia and Monochloramine Analyzer commercially available from Hach Company of Loveland, CO, which can directly measure the chloramine concentration in the water sample.
  • the analyzer 30 is, or includes, a total chlorine analyzer, such as the total chlorine analyzer commercially available from ProMinent Fluid Controls, Inc. of Pittsburgh, PA, which can be used to indirectly measure the chloramine concentration.
  • the analyzer 30 measures the total chlorine residual in a water sample and, from this measurement, the residual chloramine concentration is determined either by the analyzer 30 or by a controller 40 or other processor associated therewith. It will be appreciated that the analyzer 30 may be a standalone device or, in other embodiments, may be software and/or firmware executed by the controller 40 or other processor.
  • the treatment delivery system 10 can further include a controller 40 that is in operable communication with the analyzer 30 so that measurements and other data gathered, and/or determined by the analyzer 30, can be transferred or accessed by the controller 40.
  • One or more computer-readable storage mediums can be in operable communication with the controller 40.
  • the computer-readable storage mediums can contain programming instructions that, when executed, cause the controller 40 to perform multiple tasks. This includes programming algorithms such as those described herein that allow the controller 40 to control the administration of chlorine and/or ammonia into the body of water 12 for establishing, reestablishing, and maintaining target residual chloramine levels within the body of water 12.
  • the programming instructions can be updated and modified. For example, the target residual chloramine level can be changed as can the flow rates of the chlorine and/or ammonia and the water sampling frequency.
  • the programming instructions when executed, can cause the controller 40 to: measure and/or analyze a first water sample obtained from the body of water 12, and/or determine whether the residual chloramine concentration in the first water sample is below a pre-determined residual chloramine concentration set-point or below a first chloramine concentration percentage of a pre-determined residual chloramine concentration set-point; engage (or control) the chemical dosing assembly 16 to add chlorine to the body of water 12 if the residual chloramine concentration in the first water sample is determined to be below the residual chloramine concentration set-point or below the first chloramine concentration percentage of the residual chloramine concentration set-point; measure and/or analyze additional water samples obtained from the body of water 12 after chlorine is added, and/or determine the rate of change in chloramine concentration based on the residual chloramine concentration obtained from at least two water samples; and engage (or control) the chemical dosing assembly 16 to add ammonia and chlorine to the body of water 12 if the rate of change in chloramine concentration is below a
  • treatment delivery system 10 can include multiple chemical storage tanks, such as a first chemical storage tank 200 and a second chemical storage tank 300, which are configured to transport chemicals to the chemical dosing assembly 16 via one or more metering pumps.
  • the treatment delivery system 10 can deliver a source of chlorine and a source of ammonia into the body of water 12.
  • the chemical storage tanks 200, 300 can store a source of chlorine and a source of ammonia. Because the treatment delivery system 10 is capable of delivering any type of chlorine and ammonia source, the chemical storage tanks 200, 300 can be selected to store various sources of chlorine and ammonia.
  • Non-limiting examples of chlorine sources that can be used with the present invention include pressurized chlorine gas and hypochlorites such as sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite.
  • Non-limiting examples of ammonia sources that can be used with the present invention include pressurized anhydrous ammonia, aqueous ammonia, and liquid ammonium sulfate.
  • the chemical storage tanks 200, 300 can also be supplied by on-site chemical generation systems, such as an on-site hypochlorite generation system 400 as shown in FIG. 1 for example that can generate hypochlorite based chemicals (e.g., sodium hypochlorite or potassium hypochlorite) directly at the water treatment site.
  • Non-limiting examples of chemical dosing assemblies, chemical generation systems, and the like are disclosed in United States Patent No. 9,039,902, which is incorporated by reference herein in its entirety.
  • United States Patent No. 9,039,902 describes chemical dosing assemblies, as well as a hypochlorite generation system, that can be used as the source of chlorine that is present in first chemical storage tank 200 and, ultimately, supplied to the body of water 12.
  • the treatment delivery system 10 can also utilize other mixing systems as well.
  • the treatment delivery system 10 can also utilize the mixing system disclosed in United States Patent No. 7,862,302, which is incorporated by reference herein in its entirety.
  • the treatment delivery system 10 can be used for automatically controlling chloramine concentration in a body of water 12 contained in a reservoir 14.
  • the present invention is also directed to a method of automatically controlling chloramine concentration in a body of water 12 contained in a reservoir 14.
  • the method can be implemented through one or more algorithms and controls contained in programming instructions that, when executed, cause the system 10 to take certain actions, as described below.
  • the method can first include measuring, analyzing, and/or determining the residual chloramine concentration in a water sample obtained from the body of water 12.
  • the water sample can be obtained with the water sampling assembly 26 and transported to the analyzer 30 that is in fluid communication with the water sampling assembly 26.
  • the analyzer 30 can then measure, analyze, and/or determine the residual chloramine concentration.
  • the determination of the residual chloramine concentration can include measuring the residual total chlorine concentration in the water sample.
  • the residual chloramine concentration determination can be reported to a controller 40 that is in operable communication with one or more computer-readable storage mediums.
  • the controller 40 also has knowledge of, or access to, information about the set-point (target) residual chloramine concentration. If the residual chloramine concentration in the water sample is determined to be below the residual chloramine concentration set-point (which can be based on a residual total chlorine concentration set-point, for example), then the programming instructions of the computer-readable storage mediums will cause the controller 40 to automatically engage (or control) a supply of chlorine to add chlorine to the body of water 12. The chlorine can be distributed into the body of water 12 through treatment tube 22 and/or 24 of the chemical dosing assembly 16.
  • the programming instructions can include algorithm I that, when satisfied, will cause the controller 40 to automatically engage (or control) a supply of chlorine to add chlorine to the body of water 12.
  • additional samples of water can be obtained from the body of water 12 with the water sampling assembly 26.
  • the analyzer 30 can again measure, analyze, and/or determine the residual chloramine concentration in one or more (but at least one) additional subsequent water samples.
  • the residual chloramine concentration determination in the subsequent sample(s) can be sent to the controller 40 in operable communication with the computer-readable storage mediums. If, after the passage of a length of time, the residual chloramine concentration in an additional water sample is determined to be below the residual chloramine concentration set-point, a rate of change in the chloramine concentration can be determined by the controller with the programming instructions.
  • the "rate of change in the chloramine concentration” refers to the change in the chloramine concentration value over time based on the chloramine concentration in two or more water samples.
  • rate of change [subsequently determined chloramine concentration value / a previously determined chloramine concentration value] - 1.
  • the programming instructions can include the rate of change formula to allow the controller 40 to determine the rate of change in chloramine concentration over time in the body of water 12.
  • the rate of change in chloramine concentration is determined with the chloramine concentration in the water sample used to determine if chlorine should be added to the body of water 12 and the chloramine concentration in a subsequently obtained water sample.
  • the rate of change in chloramine concentration is determined with the chloramine concentration in two subsequent additional water samples obtained after initiating the addition of chlorine to the body of water 12.
  • the rate of change in chloramine concentration is determined by comparing the chloramine concentration in two water samples obtained after a set period of time.
  • the rate of change in chloramine concentration can be based on the chloramine concentration in a first water sample and the chloramine concentration in a subsequent water sample obtained after a specified period of time, such as 10 minutes or 30 minutes or one hour for example, after determining the chloramine concentration in the first water sample.
  • a "set rate of change in chloramine concentration” refers to a predetermined (target) increase or decrease in the rate of change in chloramine concentration.
  • the set rate of change in chloramine concentration can be 0.02 mg/L/hour and if the rate of change in residual chloramine concentration is determined to be below 0.02 mg/L/hour, the programming instructions will cause the controller 40 to automatically engage (or control) a supply of chlorine and ammonia to add both ammonia and chlorine to the body of water 12.
  • the chlorine and ammonia can be added to the body of water 12 through treatment tubes 22 and 24 of the chemical dosing assembly 16.
  • the programming instructions can include algorithm II that, when satisfied, will cause the controller 40 to automatically engage (or control) a supply of chlorine and a supply of ammonia to add both chlorine and ammonia to the body of water 12.
  • ammonia and chlorine are both added to the body of water 12 when two consecutive determinations in the rate of change in chloramine concentration are below the set rate of change in chloramine concentration.
  • the set rate of change in chloramine concentration can be 0.02 mg/L/hour and if two consecutive determinations in the rate of change in residual chloramine concentration is determined to be below 0.02 mg/L/hour, the programming instructions will cause the controller 40 to automatically engage (or control) a supply of chlorine and ammonia to add both ammonia and chlorine to the body of water 12.
  • the two consecutive determinations in the rate of change in residual chloramine concentration can be obtained over a specified period of time. For instance, a first determination in the rate of change in residual chloramine concentration can be determined followed by a second determination in the rate of change in residual chloramine concentration after a specified period of time, such as 10 minutes or 30 minutes or one hour for example, after obtaining the first determination in the rate of change. If the first and second rate of change in chloramine concentration is below the set rate of change in chloramine concentration the programming instructions will cause the controller 40 to automatically engage (or control) a supply of chlorine and ammonia to add both ammonia and chlorine to the body of water 12.
  • Chlorine and ammonia are added to the body of water 12 until a subsequently obtained water sample is determined to be at or above the residual chloramine concentration set-point, at which point the programming instructions will cause the controller 40 to stop the supply of chlorine and the supply of ammonia into the body of water 12.
  • the programming instructions can include algorithm III that, when satisfied, will cause the controller 40 to stop automatically engaging (or controlling) a supply of chlorine and a supply of ammonia, and therefore, stop adding chlorine and ammonia to the body of water 12.
  • the programming instructions will cause the controller 40 to continue to automatically engage (or control) a supply of chlorine to add chlorine only to the body of water 12.
  • the programming instructions can include algorithm IV that, when satisfied, will cause the controller 40 to continue to automatically engage (or control) a supply of chlorine to add chlorine to the body of water 12.
  • the programming instructions will cause the controller 40 to stop the supply of chlorine into the body of water 12.
  • the programming instructions can include algorithm V that, when satisfied, will cause the controller 40 to stop automatically engaging (or controlling) a supply of chlorine, and therefore, stop adding chlorine to the body of water 12.
  • the controller 40 is programed to stop the supply of chlorine or the supply of chlorine and ammonia into the body of water 12 when the residual chloramine concentration is above a particular percentage of the residual chloramine concentration set-point.
  • the controller 40 can be programmed to stop the supply of chlorine or the supply of chlorine and ammonia into the body of water 12 when the residual chloramine concentration in a water sample is a percentage selected within a range of 101% to 110% of the residual chloramine concentration set-point, or a percentage selected within a range of 101% to 105% of the residual chloramine concentration set-point.
  • different programming algorithms are used to control when the supply of chlorine and/or the supply of chlorine and ammonia into the body of water 12 is stopped.
  • the programming instructions can include, or can be modified to include, algorithms VI and/or VII that, when satisfied, will cause the controller 40 to stop automatically engaging (or controlling) a supply of chlorine and/or a supply of chlorine and a supply of ammonia.
  • the supply of chlorine is stopped after determining the rate of change in chloramine concentration.
  • the supply of chlorine can be stopped in such embodiments because ammonia is not available or the system is only being used to tie-up free ammonia.
  • the process described herein will re-start after a predetermined period of time.
  • the previously described method works in accordance with the chloramine breakpoint curve, shown in FIG. 3.
  • the previously described steps are used to achieve and maintain an ideal state of monochloramine disinfectant by predicting where the chloramine concentration in the body of water 12 resides along the breakpoint curve, the rate at which chloramine concentration is increasing and decreasing in the body of water 12 over time, and adjusting the input of chlorine or chlorine and ammonia into the body of water 12 to achieve and maintain a position at or near the ideal state.
  • the ideal state i.e., the maximum monochloramine concentration obtainable in a body of water 12
  • the method includes at least two modes, or stages, in view of the chloramine breakpoint curve.
  • the first mode shown in FIG. 4 it is assumed that free ammonia is present in the body of water 12.
  • water samples are periodically drawn from the body of water 12 and analyzed to determine the chloramine concentration.
  • this determination is accomplished by measuring the total chlorine present in the sample using a total chlorine analyzer, such as the total chlorine analyzer commercially available from ProMinent Fluid Controls, Inc. of Pittsburgh, PA.
  • the controller 40 is configured to engage (or control) the treatment tubes 22 or 24 to add chlorine to the body of water 12. Because free ammonia is assumed to be present, newly added chlorine will react with the free ammonia to generate chloramine, thus increasing the concentration of chloramine in the body of water 12 and reducing the concentration of free ammonia, as reflected in FIG. 4. Once the residual chloramine concentration set-point is reestablished, or established in the first instance, the addition of chlorine can cease.
  • the system 10 can conclude that free ammonia is absent from the body of water 12.
  • the controller 40 is configured to engage (or control) a source of chlorine and a source of ammonia to inject into the body of water 12, as reflected in FIG. 5.
  • the ammonia and chlorine can continue being added until analysis of water samples extracted from the body of water 12 determines that the residual chloramine concentration set-point has been reestablished (or established).
  • the second mode is initiated by the ability of the system 10 to predict the location of the chloramine reaction on the break point curve and the rate at which the chloramine concentration is increasing or decreasing. For instance, if the measured total chlorine residual concentration continues to decrease as chlorine is added, which in turn results in a negative rate of change in chloramine concentration, the system 10 can conclude that no free ammonia is present and that the residual chloramine concentration is decreasing past the ideal state shown in FIG. 5. As a result, the second mode is initiated and the controller 40 will add chlorine and ammonia into the body of water 12.
  • the method uses a chloramine concentration percentage to determine when to engage (or control) and add a supply of chlorine to the body of water 12.
  • the programming instructions can cause the controller 40 to engage (or control) a supply of chlorine and add the chlorine to the body of water 12 when it is determined that the residual chloramine concentration in a water sample is below a percentage selected within a range of 99% to 80% of the residual chloramine concentration set-point, or below a percentage selected within a range of 99% to 85% of the residual chloramine concentration set-point, or below a percentage selected within a range of 99% to 90% of the residual chloramine concentration set-point, or below a percentage selected within a range of 99% to 95% of the residual chloramine concentration set-point.
  • the programming instructions can include, or can be modified to include, algorithm VIII that, when satisfied, will cause the controller 40 to automatically engage (or control) a supply of chlorine to add chlorine to the body of water 12.
  • the residual chloramine concentration set-point is 2.5 mg/L and the controller 40 is programmed to engage (or control) a supply of chlorine and add the chlorine to the body of water 12 when it is determined that the residual chloramine concentration in a water sample is below 95% of the residual chloramine concentration set-point.
  • the controller 40 will engage (or control) a supply of chlorine and add the chlorine to the body of water 12 only when the residual chloramine concentration in a water sample is below a residual chloramine concentration of 2.375 mg/L.
  • the method can be programmed to add chlorine to the body of water 12 when it is determined that the residual chloramine concentration is below a selected percentage of the residual chloramine concentration set-point.
  • the programming instructions also utilize algorithm II that, when satisfied, causes the controller 40 to automatically engage (or control) a supply of chlorine and a supply of ammonia to add both chlorine and ammonia to the body of water 12.
  • chlorine and ammonia are added to the body of water 12 until a subsequently obtained water sample is determined to be at or above the residual chloramine concentration set-point or above a particular percentage of the residual chloramine concentration set-point, at which point the programming instructions will cause the controller 40 to stop the supply of chlorine and ammonia into the body of water 12.
  • the method step of stopping the addition of chlorine and ammonia into the body of water 12 can be controlled, for example, with programming algorithm III or with programming algorithm VII.
  • the programming instructions will cause the controller 40 to continue to automatically engage (or control) a supply of chlorine to add chlorine only to the body of water 12.
  • the method step of continually adding chlorine after further analysis can be controlled, for example, with programming algorithm IV.
  • the programming instructions will cause the controller 40 to stop the supply of chlorine into the body of water 12.
  • the method step of stopping the addition of chlorine into the body of water 12 can be controlled, for example, with programming algorithm V or with programming algorithm VI.
  • any of the previously described method steps, or combination of steps can be used to establish, reestablish, and maintain a desired residual chloramine level within the body of water 12.
  • at least one of the previously described method steps, or combination of steps are used to establish or reestablish a desired residual chloramine concentration set-point.
  • a different algorithm can be used to reestablish the desired residual chloramine concentration in subsequent treatment cycles.
  • the controller 40 is programmed to only engage (or control) a supply of chlorine and a supply of ammonia to add both chlorine and ammonia to the body of water 12 in order to reestablish the desired residual chloramine concentration set-point.
  • chlorine alone is not added to the body of water 12 in a second treatment cycle.
  • the programming instructions of the computer-readable storage mediums can be configured to cause the controller 40 to automatically add both chlorine and ammonia to the body of water 12 when the residual chloramine concentration in a water sample is determined to be below the residual chloramine concentration set-point.
  • the programming instructions can include algorithm IX for use in a second treatment cycle that, when satisfied, will cause the controller 40 to automatically engage (or control) a supply of chlorine and a supply of ammonia to add both chlorine and ammonia to the body of water 12.
  • the method can also use a chloramine concentration percentage of the residual chloramine concentration set-point to determine when to add both chlorine and ammonia to the body of water 12 in a second treatment cycle.
  • the chloramine concentration percentage can include, for example, a percentage selected within a range of 99% to 80% of the residual chloramine concentration set-point.
  • the programming instructions can include algorithm X for use in a second treatment cycle that, when satisfied, will cause the controller 40 to automatically engage (or control) a supply of chlorine and a supply of ammonia to add both chlorine and ammonia to the body of water 12.
  • Chlorine and ammonia are added to the body of water 12 until a subsequently obtained water sample is determined to be at or above the residual chloramine concentration set-point or above a particular percentage of the residual chloramine concentration set-point, at which point the programming instructions will cause the controller 40 to stop the supply of chlorine and ammonia into the body of water 12.
  • the method step of stopping the addition of chlorine and ammonia into the body of water 12 can be controlled, for example, with programming algorithm III or with programming algorithm VII.
  • the programming instructions will cause the controller 40 to revert back to the original algorithm or cause the controller 40 to continue to use the modified algorithm.
  • the controller 40 can be programmed to alternate between different algorithms for any desired number of treatment cycles. For example, in a first treatment cycle, the controller 40 can be programmed to supply chlorine alone in a first step and, optionally, both chlorine and ammonia in a second step in order to establish the residual chloramine concentration set-point. Then, after a first treatment cycle is completed, the controller 40 can be programmed to supply both chlorine and ammonia only in order to reestablish the residual chloramine concentration set-point in the next three treatment cycles. Finally, to reestablish the residual chloramine concentration set-point in a fifth treatment cycle, the controller 40 can be programmed to use the original algorithm and supply chlorine alone in a first step and, optionally, both chlorine and ammonia in a second step.
  • the feed rate of chlorine and/or ammonia in any of the previously described steps can be determined from the reservoir 14 water volume and dwell time.
  • dwell time refers to the rate at which water volume changes in the reservoir 14.
  • the feed rate of the chlorine and ammonia can also be controlled by the speed at which the metering pumps distribute the chlorine and ammonia into the body of water 12.
  • the metering pumps can distribute chlorine and ammonia at a maximum speed rate.
  • the metering pumps can also be reduced to half (i.e., 50%) of the maximum speed rate to adjust the feed rate of chlorine and ammonia.
  • the controller 40 when adding both chlorine and ammonia into the body of water 12, the controller 40 typically adds each chemical at an amount that provides a particular weight ratio of chlorine to ammonia.
  • the chlorine and ammonia are added to the body of water 12 to provide a weight ratio of chlorine to ammonia of 5: 1.
  • the method of automatically controlling chloramine concentration described herein allows for a desired amount of chloramine in a body of water 12 to be effectively maintained without directly measuring or initially adding free ammonia.
  • the system and method can also be used to respond to an adjustment, such as an increase, in the target chloramine concentration.
  • FIGS. 6 and 7 show the residual chloramine concentration and rate of change in chloramine concentration in a water storage reservoir that utilized the treatment delivery system 10 and the method of automatically controlling chloramine concentration by adding a source of chlorine only.
  • the treatment delivery system 10 was programed to add chlorine when the residual chloramine concentration was below the residual chloramine set-point. Further, while adding chlorine, the treatment delivery system 10 was also programmed to add chlorine and ammonia when two consecutive determinations in the rate of change in residual chloramine concentration obtained over a specified period of time were below the set rate of change in chloramine concentration of 0.02 mg/L/hour.
  • the system was turned on around 8: 15 AM and hypochlorite was added to the body of water 12 after determining that a water sample had a residual chloramine concentration below the residual chloramine set-point. After adding the chlorine, the residual chloramine concentration in additional water samples were determined and the rate of change in chloramine concentration was calculated throughout the process. Because two consecutive determinations in the rate of change in residual chloramine concentration obtained over a specified period of time were not below the set rate of change in chloramine concentration, the supply of ammonia was never engaged. Moreover, the chloramine set-point was reached around 10:00 AM and the supply of chlorine into the body of water 12 was stopped.
  • the system was turned on around after 9:00 AM and hypochlorite was added to the body of water 12 after determining that a water sample had a residual chloramine concentration below the residual chloramine set-point. After adding the chlorine, the residual chloramine concentration in additional water samples were determined and the rate of change in chloramine concentration was calculated throughout the process. Because two consecutive determinations in the rate of change in residual chloramine concentration obtained over a specified period of time were below the set rate of change in chloramine concentration, the supply of ammonia was engaged such that both chlorine and ammonia were added to the body of water 12. Moreover, the chloramine set-point was reached around 11 :30 AM and the supply of chlorine and ammonia into the body of water 12 were stopped.

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  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Abstract

La présente invention concerne un procédé de régulation automatique de la concentration de chloramine dans une masse d'eau contenue dans un réservoir qui comprend : (a) la détermination de la concentration de chloramine résiduelle dans un échantillon d'eau ; (b) l'actionnement automatique d'une alimentation en chlore pour ajouter du chlore lorsque (i) la concentration de chloramine résiduelle dans l'échantillon d'eau est déterminée comme étant inférieure à un point de consigne de concentration de chloramine résiduelle prédéterminé ou (ii) inférieure à un pourcentage de concentration de chloramine d'un point de consigne de concentration de chloramine résiduelle prédéterminé ; (c) la détermination de la concentration de chloramine résiduelle dans un ou plusieurs échantillons d'eau supplémentaires après l'étape (b) ; (d) la détermination du taux de changement de la concentration de chloramine ; et (e) si le taux de changement de la concentration de chloramine est inférieur à un taux de changement de concentration de chloramine défini, (i) l'actionnement automatique d'une alimentation en ammoniac et de l'alimentation en chlore pour ajouter à la fois de l'ammoniac et du chlore à la masse d'eau, ou (ii) l'arrêt de l'alimentation en chlore après l'étape (d).
PCT/US2018/035349 2017-05-31 2018-05-31 Système de commande d'injection chimique et procédé de régulation de chloramines Ceased WO2018222841A1 (fr)

Priority Applications (4)

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NZ759634A NZ759634B2 (en) 2018-05-31 Chemical injection control system and method for controlling chloramines
EP18810726.2A EP3634915A4 (fr) 2017-05-31 2018-05-31 Système de commande d'injection chimique et procédé de régulation de chloramines
AU2018275261A AU2018275261B2 (en) 2017-05-31 2018-05-31 Chemical injection control system and method for controlling chloramines
CA3065512A CA3065512A1 (fr) 2017-05-31 2018-05-31 Systeme de commande d'injection chimique et procede de regulation de chloramines

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050137118A1 (en) * 2003-11-26 2005-06-23 Silveri Michael A. System for maintaining pH and sanitizing agent levels of water in a water feature
US20060096930A1 (en) * 2004-11-08 2006-05-11 Beardwood Edward S Process for treating an aqueous system with chlorine dioxide
US20120021062A1 (en) * 2006-12-29 2012-01-26 Amit Gupta Methods for the on-site production of chloramine and uses thereof
US20160362318A1 (en) * 2015-06-12 2016-12-15 Process Solutions, Inc. Chemical Injection and Control System and Method for Controlling Chloramines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050137118A1 (en) * 2003-11-26 2005-06-23 Silveri Michael A. System for maintaining pH and sanitizing agent levels of water in a water feature
US20060096930A1 (en) * 2004-11-08 2006-05-11 Beardwood Edward S Process for treating an aqueous system with chlorine dioxide
US20120021062A1 (en) * 2006-12-29 2012-01-26 Amit Gupta Methods for the on-site production of chloramine and uses thereof
US20160362318A1 (en) * 2015-06-12 2016-12-15 Process Solutions, Inc. Chemical Injection and Control System and Method for Controlling Chloramines

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