Patent Publication Number: US-2021171381-A1

Title: Produced water treatment system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a divisional patent application of U.S. patent application Ser. No. 16/557,490, filed Aug. 30, 2020, now U.S. Pat. No. 10,927,025, which claims the benefit of U.S. provisional patent application 62/724,897, filed Aug. 30, 2018, the content of both of which are hereby incorporated herein by reference. 
    
    
     TECHNOLOGY 
     The present description describes methods and apparatuses for processing fluids such as brines and/or other water-based produced waters. 
     BACKGROUND 
     Significant produced water is generated at oil and gas wells. Produced water may include water found naturally in formations containing oil and gas or may be water that was injected into the formations during extraction operations such as water flooding or steam flooding. Oil and gas formations may also be stimulated using hydraulic fracturing in which water is injected under pressure to create pathways for recovery of the oil and gas. The water may return to the surface as flowback produced water. 
     The composition of produced water varies but typically includes high concentrations of suspended solids/particulates and dissolved organic and inorganic compounds. For example, produced water may include hydrocarbons, volatile organic compounds, high salt concentrations, organic acids, and metals such as iron, barium, strontium, magnesium, manganese, mercury, and calcium. Treatment of produced water is a major operating cost in oil and gas recovery operations. In addition to costs for treating produced water, which requires shipping the water to treatment facilities, replacement fresh water must also be shipped to well locations. 
     What are needed are cost effective produced water treatment systems and methods. It would be further beneficial if the water treatment systems and methods were suitable for on-site or nearby operation and are capable of separating a supply of clean water that does not need to be pulled from the local water supply or shipped long distances. Treatment of produced water to an extent suitable for agricultural or further industrial use would also be beneficial. 
     SUMMARY 
     According to various embodiments, produced water may be filtered for suspended solids. This may include passing the produced water through one or more filters and/or skim oil units. In some embodiments, filters may be located within a processing path after entering a skim oil unit, which may preferably include a dissolved air flotation (DAF) system. In one embodiment, the skim oil unit may be equipped for other or additional skim oil techniques, such as froth flotation or induced gas flotation. In some embodiments, a skim oil unit may be heated. Heating may increase VOC evaporation or sublimation. VOCs may be captured for combustion and/or incineration to one or more burners used for brine condensing and steam evolution. In some embodiments, chemical flocculation and/or pH adjustment may be used. Chemical flocculation may cause agglomeration of suspend oil droplets for removal in the skim oil unit, such as skimmed from a DAF system. 
     In some embodiments, solids removal may also include passing the produced water through a particulate/element filter to remove particulates. As described above, solids are preferably removed down to about 30 microns, or more preferably down to about 20 microns or less, such as about 10 microns or less. Suspended solids separated may be removed from the produced water by skimming the surface. Some large solids or sludge may also be present and drop out during skim oil treatment or within a pre-treatment holding tank or pre-filter and may be collected along lower ends of tanks or within filter cartridges, respectively. 
     Following initial removal of suspended solids, the process fluid may be further treated for liquid hydrocarbon removal. A portion of liquid hydrocarbons present in the produced water may be removed during suspended solid separation, e.g., in a skim oil unit as described above. Additional liquid hydrocarbons may be removed utilizing liquid/liquid coalescence processing. The processing fluid may then be flashed to concentrate the brine, preferably to approximate the saturation point of the brine solution. The flash evaporated water, or clean steam, may be released into the atmosphere or may be condensed in a condensing unit. In one example, the condensing unit comprises an ambient temperature passive condenser including a plurality of fins for dissipating heat. 
     In one aspect, a produced water treatment system includes a skim oil unit and a flash concentration unit. The skim oil unit may include a float tank for clarifying a volume of produced water within the float tank. The flash concentration unit may include a bath vessel to receive the clarified produced water and a burner configured to combust a fuel to generate hot flue gas that heats the clarified produced water within the bath vessel to generate steam and concentrate the clarified produced water. The hot flue gas may also indirectly heat the produced water within the float tank of the skim oil unit to flash volatile organic compounds (VOCs) and dissolved organics. 
     In one embodiment, the float tank comprises a dissolved air floatation tank wherein dissolved air is provided into a lower end of the float tank. 
     In one embodiment, a thermal transfer partition comprising a thermally conductive material separates the float tank and the bath vessel such that clarified produced water heated by hot flue gas within the bath vessel transfers heat energy to the thermal transfer partition, which further transfers the heat energy to the produced water within the float tank. In one example, the flash concentration unit comprises a direct fire bath system including one or more tubes defining a flow path through which the hot flue gas travels between the burner and a distribution end of the flow path where the hot flue gas is emitted into the bath vessel. In a further example, at least a portion of the flow path defined by the one or more tubes extends below a waterline of the bath vessel that corresponds to an operation level for process fluid within the bath vessel during flash concentration processing to indirectly heat the clarified produced water with the hot flue gas when flowed along the flow path. In still a further example, the one or more tubes include a distribution tube located at the distribution end. The distribution tube may include a plurality of ports through which hot flue gas exits into the bath vessel. One or more of the plurality of ports may be positioned below the waterline of the bath vessel. In still a further example, a first portion of the one or more tubes extends above the waterline such that a corresponding first portion of the flow path extends above the water line. The first portion of the one or more tubes and corresponding first portion of the flow path may be positioned between a second portion of the one or more tubes defining a corresponding second portion of the flow path and a third portion of the one or more tubes defining a corresponding third portion of the flow path. Both the second and third portions of the one or more tubes and the corresponding second and third portions of the flow path may be positioned below the waterline. 
     In one embodiment, a gas line is positioned to collect gas comprising the flashed VOCs and dissolved organics from the heated produced water in the float tank and supply the gas to the burner for combustion. In one example, the flash concentration unit further comprises a blower for providing a supply of oxidant to the burner. The gas line may comprise a VOC suction line coupled to a negative pressure side of the blower such that the collected gas is pulled into the blower and mixed with oxidant that is supplied to the burner. 
     In one embodiment, the system further includes a control unit, one or more pumps, and a salinity meter positioned to monitor salt concentration in the clarified produced water. The control unit is operable to control the one or more pumps to control supply of clarified produced water into the bath vessel and release of a concentrated clarified produced water generated by the release of the steam from the clarified produced water. The control unit may utilize salinity data collected by the salinity meter to control the supply of clarified produced water and release of concentrated clarified produced water to maintain a salinity within the clarified process fluid within the bath vessel of between 230,000 ppm and 250,000 ppm. 
     In one embodiment, the system includes a thermal transfer partition that separates the float tank and the bath vessel such that clarified produced water heated by hot flue gas within the bath vessel transfers heat energy to the thermal transfer partition, which further transfers the heat energy to the produced water within the float tank. The system may further include a gas line positioned to collect gas comprising the flashed VOCs and dissolved organics from the heated produced water in the float tank and supply the gas to the burner for combustion. The float tank may include a dissolved air floatation tank wherein dissolved air is provided into a lower end of the float tank. In one example, the flash concentration unit comprises a direct fire bath system including one or more tubes defining a flow path through which the hot flue gas travels between the burner and a distribution end of the flow path where the hot flue gas is emitted into the bath vessel. The one or more tubes may include a distribution tube comprising a plurality of ports positioned below a waterline of the bath vessel and through which hot flue gas exits into the bath vessel into the clarified produced water. A first portion of the flow path may extend above the waterline and is positioned between second and third portions of the flow path that extend below the waterline. 
     In one embodiment, the system includes a particulate removal unit comprising one or more element filters to receive the clarified produced water and remove particulates down to about 20 microns or less. The system may also include a liquid/liquid separation unit comprising a liquid/liquid coalescer to receive the clarified produced water after filtration in the particulate removal unit and separate remaining hydrocarbons from the clarified produced water. The system may also include a control unit, one or more pumps, and a salinity meter positioned to monitor salt concentration in the clarified produced water. The control unit may be operable to control the one or more pumps to control supply of clarified produced water into the bath vessel and release of a concentrated clarified produced water generated by the release of the steam from the clarified produced water. The control unit may utilize salinity data collected by the salinity meter to control the supply of clarified produced water and release of concentrated clarified produced water to maintain a salinity within the clarified process fluid within the bath vessel of between 230,000 ppm and 250,000 ppm. In one example, the system also includes a condenser unit. The condenser unit may comprise a condenser to receive the steam generated in the bath vessel and condense the same to produce a clean water stream. The condenser unit may comprise a passive ambient condenser. 
     In another aspect, a flash concentration unit for flashing and concentrating produced water includes a direct fire bath vessel to receive a supply of solute containing water to concentrate; a burner configured to combust a fuel to generate hot flue gas that heats the solute containing water within the bath vessel to generate steam and concentrate the solute containing water; and one or more tubes defining a flow path through which the hot flue gas travels between the burner and a distribution end of the flow path where the hot flue gas is emitted into the bath vessel. The one or more tubes may comprise a distribution tube positioned at the distribution end of the flow path. The distribution tube may include a plurality of ports positioned below a waterline of the direct fire bath vessel and through which hot flue gas exits into the direct fire bath vessel. At least a first portion of the one or more tubes and corresponding first portion of the flow path may extend above the waterline and be positioned between second and third portions of the one or more tubes and corresponding second and third portions of the flow path that extend below the waterline. In one example, the one or more tubes comprise a fire tube that defines an end of the flow path proximate to the burner. The fire tube may be positioned below the waterline to indirectly heat the solute containing water within the direct fire bath. In another example, the one or more tubes comprise a riser tube that couples to the fire tube and a return tube that couples to the distribution tube. The riser tube may extend vertically above the waterline and fluidically couples with the return tube above the waterline. The return tube may extend vertically from above the waterline to below the waterline to couple with the distribution tube. In a further example, the one or more tubes include a u-box return tube that couples between the riser tube and return tube above the waterline. 
     In still another aspect, a method of treating produced water includes clarifying the produced water in a dissolved air floatation tank into which dissolved gas is introduced into a lower end of the floatation tank; heating the produced water in the floatation tank during the clarifying with dissolved gas to flash VOCs and dissolved organics within the produced water; skimming the surface of the produced water in the floatation tank; flashing clarified produced water in a direct fire bath. The one or more tubes may extend through the direct fire bath and provide a flow path for hot combustion gas to flow between a burner and a distribution end of the flow path where the hot combustion gas directly heats and flashes a portion of the clarified produced water in the direct fire bath to generate steam and a concentrated brine solution. The direct fire bath may share a partition with the dissolved air floatation tank. The partition may include a thermally conductive material that transfers heat from the clarified produced water in the direct fire bath to the produced water in the dissolved air floatation tank. 
     In one embodiment, the method further comprises collecting the flashed VOCs and dissolved organic gas and supplying it to the burner for combustion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features of the described embodiments are set forth with particularity in the appended claims. The described embodiments, however, both as to organization and manner of operation, may be best understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic of a produced water treatment system according to various embodiments described herein; 
         FIG. 2  illustrates a produced water treatment method according to various embodiments described herein; 
         FIG. 3  schematically illustrates a produce water treatment system according to various embodiments described herein; 
         FIG. 4  illustrates an example of a produced water treatment method consistent with the method of  FIG. 2  according to various embodiments described herein; 
         FIG. 5  illustrates an embodiment of the produced water treatment system of  FIG. 3  according to various embodiments described herein; 
         FIGS. 6A &amp; 6B  are isolated views of the skim oil unit and flash concentration unit of the produced water treatment system of  FIG. 5 , wherein  FIG. 6A  is an elevated side view in perspective and  FIG. 6  is an elevated side view; 
         FIG. 7  is a plan view of the produced water treatment system of  FIG. 5  illustrating process flow through the system according to various embodiments described herein; 
         FIG. 8  is a schematic of a control unit control system of the produced water treatment system according to various embodiments described herein; 
         FIG. 9  is a further schematic of the control system including hardware units according to various embodiments described herein; and 
         FIG. 10  is an example of a distribution tube according to various embodiments described herein. 
     
    
    
     DESCRIPTION 
     The present description describes produced water treatment systems and methods. Produced water treatment may be performed by a fluid processing system to treat produced waters. The system may utilize various processing techniques such as hydrocarbon removal, volatile organic compound (VOC) removal, dissolved organics removal, rapid evaporation, brine concentration, clean steam condensation, chemical precipitation, and/or salt/solids removal. In some embodiments, an inlet stream is separated into a plurality of output streams comprising a clean output, recovered oil output, and a brine output. In a further embodiment, an inlet stream is separated into a plurality of output streams comprising a clean output, a recovered oil output, and at least one solid salt and sediment output. Clean output may comprise clean steam, which in some embodiments, may be condensed to a liquid state for further beneficial use in industry, agriculture, or other beneficial applications. 
       FIG. 1  illustrates an example produced water treatment system  1  for treating produced water according to various more treatment methodologies. The system  1  may include piping and pumping between units and apparatuses and devices thereof for transport of processing materials, agents, and products through the system  1 . In various embodiments, the system  1  includes inlet flow control piping and valve system for controlling flow. The inlet flow control piping and valve system may be manual or automated. A level control system may be operable with the flow control piping and valve system to control levels within the system  1 . The system  1  may also include a control unit (not shown), e.g., a programmable logic controller, operable to control operations of the system  1 . The control unit may be configured for manual operation, automated operation, or both. The control unit may include one or more sensors positioned to monitor flow rates, levels, fuel/air mixtures, pumps, actuators, and/or valves. The control unit may use collected data to modify flow rates, levels, fuel/air mixtures, pumps, actuators, and/or valves to obtain desired operations. Air may be used herein with reference to combustion together with fuel, it is to be appreciated that air is used generally to refer to oxidant in a combustion reaction and need not have the composition of standard air. The control unit may include a processor and a computer readable storage medium storing instructions that when executed by the processor control the operations of the system  1 . 
     Produced water may be treated for removal of suspended solids in the suspended solids removal unit  2 . The suspended solids removal unit  2  may include one or more filters through which the produced water is filtered. Additionally or alternatively, suspended solids may be removed by gravity or gravity assisted techniques. For example, the suspended solids removal unit  2  may include a flotation tank. In some embodiments, the flotation tank includes dissolved an air flotation apparatus, froth flotation, or induced gas flotation unit. Solids rising to the surface may be skimmed with a skimmer. Additional solids and sludge may drop out and be collected along the lower end of the float tank. For example, one or more baffles may be used to collect drop out along the lower end of the tank. Additionally or alternatively, the suspended solids removal unit  2  may include a pre-filter that may be used to separate large solids and sludge. In an above or another embodiment, suspended solids removal unit  2  may include a particulate removal device. The particulate removal device may include a particulate/element filter to remove particulates down to a desired size. For example, the particulate removal device may filter particulates down to about 30 microns, or more preferably down to about 20 microns or less, such as about 10 microns or less. 
     The system  1  may also include liquid hydrocarbon removal unit  3  for removing liquid hydrocarbon. The liquid hydrocarbon removal unit  3  may include one or more oil separation apparatuses such as API separators, centrifugal apparatuses, chemical flocculation apparatuses, coalescing cartridges or plates separators, or skim oil separators, such as dissolved air flotation (DAF), induced air flotation, or froth flotation apparatuses. It will be appreciated that the system  1  may include one or more apparatuses that perform operations with respect to multiple units. For example, the system  1  may include one or more skim oil separators that are utilized by both the suspended solids removal unit  2  and the liquid hydrocarbon removal unit  3 . As described in more detail below, in a preferred embodiment, the liquid hydrocarbon removal unit  3  comprises a combination of DAF and liquid/liquid coalescing apparatuses. The liquid hydrocarbon separated from the produced water may be collected by the liquid hydrocarbon removal unit  3  for further treatment, use, recycle, or disposal. Liquid hydrocarbon removal  3  preferably removes about 98% to about 99%, e.g., about 98.8%, of hydrocarbon contaminates from the produced water. 
     In some embodiments, the suspended solids removal unit  2  and/or liquid hydrocarbon removal unit  3  may include a chemical addition device configured to add chemical to the produced water. The chemicals may include coagulants and/or flocculants, for example. The chemicals may be added in a separate chemical addition tank or may be added in-line with other processing apparatuses. 
     The system  1  may also include thermal concentration unit  4  configured to concentrate the process fluid following treatments by the suspended solid removal unit  2  and liquid hydrocarbon removal unit  3 . Thermal concentration unit  4  may include one or more burners for heating the process fluid to generate steam from a portion of its water component. The one or more burners may be used to apply direct or indirect heat to the process fluid. In one embodiment, the one or more burners include a natural gas forced draft burner. In this or another embodiment, the thermal concentration unit  4  includes tank positioned with respect to one or more burners to allow the burners to heat the process fluid by direct fire in a bath. The one or more burners may be fed a supply of fuel and combustible gas. As noted above, the fuel may include natural gas. 
     Separation of water, in the form of steam, from the process fluid reduces the volume of the process fluid through transition of a portion of the water to steam that drives concentration of the salt content in a remaining portion of the water. To maximize clean water separation, the volume of the process fluid may be concentrated to approximate saturation of salt in brine solution. For example, the process fluid may be preferably concentrated to a brine having about 230,000 ppm to about 250,000 ppm total dissolved solutes. Although higher and lower concentrations may be used, higher concentrations may be accompanied by salt drop out and lower concentrations may be less efficient for maximizing brine concentration and clean steam separation. The thermal concentration unit  4  may include salinity meters to measure salinity and initiate a pumping system that pumps brine out when the salt concentration is at a set level. The pumping system may also pump process fluid for thermal concentration  4  at a rate that maintains the set level concentration. The clean steam may be exhausted for release into the atmosphere or may be collected for further treatment or use, e.g., in agricultural or other beneficial use. As described in more detail below, the system may also include a condenser for condensing the clean steam. 
     In various embodiments, the system  1  may utilize excess heat generated by the thermal concentration unit  4  to perform preheating operations. For example, one or more burners may be used to directly or indirectly heat the produced water treated by the liquid hydrocarbon removal unit  3  and/or suspended solids removal unit  2 . In one embodiment, the one or more burners may heat a medium or structure positioned between burner flames and produced water in the liquid hydrocarbon removal unit  3  and/or suspended solids removal unit  2 . For example, burner flames may indirectly heat a thermal plate positioned between the condenser chamber and DAF system. The thermal plate may comprise, for example, a metal or other thermally conductive material. In some embodiments, burner flames may heat a liquid or gas that is flowed or positioned along a wall of a tank of the suspended solids removal unit  2  and/or liquid hydrocarbon removal unit  3  holding the produced water for treatment. In one embodiment, the liquid or gas comprises clean steam or process fluid being heated for thermal concentration by the thermal concentration unit  4 . 
     While not illustrated, the system  1  may also be configured for VOC and organic contaminant removal via an activated carbon bed, heating, or other suitable technique. In one example, as described above, heat from one or more burners used for thermal concentration may be used to heat the produced water contained in the skim oil unit, e.g., within a float tank, such as a float tank of a DAF system, to separate VOCs and organic contaminants. For example, the produced water may be heated to between about 130° F. and about 150° F. or greater, such as up to 175° F. In one example, the liquid hydrocarbon removal unit  4  includes a float tank for skim oil separation wherein a wall of the float tank is shared with a wall of the thermal concentration unit  4  such that the burner flames indirectly heat the wall via the process fluid being heated or the brine following concentration. In still a further embodiment, collected VOCs and organic contaminants may be supplied to the burner for combustion and/or incineration. In one example, a vent line may be used to pull the gas to the burner. In a further example, a blower, such as a forced draft blower, may couple to the vent line to provide a vacuum that pulls the gas into the blower where it is mixed with oxidant, e.g., air, and fed to the burner. 
     The remaining effluent or brine may be collected and reinjected, landfilled, or optionally treated further. The illustrated system  1  includes optional apparatuses for further optional treatment of the brine comprising a precipitation unit  5 , a drying unit  6 , and a gas/solid filtration unit  7 . 
     The precipitation unit  5  may be used to wash the brine clear of unwanted total dissolved solutes (TDS). For example, the precipitation unit  5  may be utilized to precipitate contaminants, such as undesirable minerals, from the brine. In the illustrated embodiment, the precipitation unit  5  is configured to handle forced precipitation of undesired materials contained within the composition such as, for example but not limited to, calcium, barium, strontium, magnesium, etc. The precipitation unit  5  may include a chemical treating system and settling system. The chemical treating system may include a pH precipitation module in which pH altering chemicals or materials are added to drive precipitation of unwanted TDS. The chemical treatment system may optionally also include an agitator to agitate the brine and combined pH altering chemicals or materials for consistent chemical reaction with the brine. The settling system may allow the precipitate to precipitate through the brine for collection. In some embodiments, the settling system includes a back washable ion resin bed filtration system that operates as a protection device to prevent unwanted upsets in the final salt product. At the pH precipitation phase, the salt may be washed of residual components. This waste stream may then be disposed of in a safe and environmentally sound manner. The pH precipitation phase removes contaminants such that the process fluid supplied to the drying unit  6  for processing is substantially comprised of water and dissolved salt. 
     Following precipitation, the brine may be fed into the drying unit  7  for salts. In some embodiments, sediments may be present that may also be extracted in powder form. 
     The drying unit  6  may include a high-pressure pumping system and microatomization system. The high pressure pumping system may pump the brine to achieve the high pressure required for microatomization. 
     The atomization system may introduce the atomized brine into an insulated vessel in which a mass heat delivery system provides heat to the atomized brine to generate a water vapor and a solids process stream comprising dry salt, which may include sediments. The vessel may be sized and designed to sufficiently dry all of the soluble salts from the produced water via evaporation. In one embodiment, the drying unit  6  includes a vertical oriented thermo-insulated vessel housing the microatomization system and mass heat delivery system. 
     A forced draft heating/removal system may be used to remove dry salt from the drying unit  6  to the gas/solid filtration unit  7  for further separation of the solids from the process stream to be collected and used in industry, agriculture, or road deicing. 
     The gas/solid filtration unit  7  is configured to further separate and collect salts from the recovered solids process stream. For example, the gas/solid filtration unit  7  may include an extreme temperature filtering apparatus. In one operation, the solids process stream may be ducted to the extreme temperature filtering apparatus wherein captured salts are removed from the solids process stream. 
     The separated salts and/or solids process stream may be conveyed to a vessel  8  for storage, packaging, shipping, reuse, or disposal. 
       FIG. 2  schematically illustrates a produced water treatment method  10  according to various embodiments.  FIG. 3  schematically illustrates a produced water treatment system  100  operable to perform the produced water treatment method  10  according to various embodiments. While the produced water treatment method  10  and produced water treatment system  100  are described together, it is to be appreciated that different or modified water treatment systems may be used to perform method  10  and system  100  may be utilized to perform different or modified water treatment methods.  FIG. 4  schematically illustrates a produced water treatment method  10 ′ that is a further embodiment of the method  10  of  FIG. 2 , wherein like numbers identify like features. Thus, method  10  encompasses method  10 ′ and references to method  10  are to be considered equally applicable to method  10 ′. In various embodiments, the water treatment system  1  described with respect to  FIG. 1  may be used to treat produced water according to the methods  10 ,  10 ′. 
     The produced water treatment method  10  includes skim oil processing  20 , VOC removal  30 , particulate removal  40 , liquid/liquid coalescence  50 , thermal concentration  60 , and condensation  80 . In some embodiments, condensation  80  is optional. The method  10  includes a hydrocarbon removal process that includes skim oil processing  20  and liquid/liquid coalescence  50 . In other embodiments, other hydrocarbon separation processing may be used in addition to or instead of one or both of skim oil processing  20  or liquid/liquid coalescence  50 . 
     The produced water treatment system  100  includes an optional control unit  110 , a hydrocarbon separation unit comprising a skim oil unit  120  including a float tank  121  comprising one or more float tanks and a liquid/liquid separation unit  150  comprising a liquid/liquid coalescer  152  comprising one or more liquid/liquid coalescers or other liquid/liquid separation devices, a particulate removal unit  140  comprising a particulate/element filter  142  comprising one or more particulate/element filters, a flash concentration unit  160  including a burner  162  comprising one or more burners, and a condenser unit  180  including a condenser  182  comprising one or more condensers. 
     In the produced water treatment method  10  of  FIG. 2 , produced water may be processed via a skim oil processing process  20  to remove hydrocarbons and other contaminants, such as certain suspended solids. Skim oil processing  20  includes processing the produced water through a skim oil processing unit, such as skim oil unit  120 . The skim oil unit  120  includes a float tank  121  in which contaminates such as suspended solids and hydrocarbons are separated by flotation and then skimmed from the surface. The float tank  121  design may be rectangular, circular, or other shape. In one embodiment, the float tank  121  includes a series connected chambers or pathways providing flow paths that the process fluid snakes through. 
     The produced water treatment system  100  may include piping and devices for transport of processing materials, agents, and products through the system  100 . For example, the system  100  may include one or more pumps (not shown) for pumping materials and product through the system  100 . The produced water treatment system  100  may optionally include a control unit  110 . The control unit  110  may be configured for manual operation, automated operation, or both. The control unit may  110  include a pumping system comprising one or more pumps (not shown) operable to pump produced water, process fluid, agents, fuel, air, and/or other materials through the system  100 . In various embodiments, the control unit  110  includes a metering system including an inlet flow control piping and valve system for controlling flow. The inlet flow control piping and valve system may be manual or automated. Additionally or alternatively, the metering system may include a level control system operable with the flow control piping and valve system to control levels within the system  100 . In one example, the control unit  110  includes a controller, e.g., a programmable logic controller, operable to control operations of the system  100 . Operations of the controller may be automated. For example, the control unit  110  may include one or more sensors positioned to monitor flow rates, levels, fuel/air mixtures, pumps, actuators, and/or valves. The controller may use collected data to modify flow rates, levels, fuel/air mixtures, pumps, actuators, and/or valves to obtain desired operations. The controller may include a processor and a computer readable storage medium storing instructions that when executed by the processor control the operations of the system  100 . In one example, the control unit  110  may track flow rates to control inlet control valves to achieve and/or maintain maximum flow rates while not over running the system  100 . In a further embodiment, the control system may link to a remote user interface to provide remote monitoring and control of system  100  through the control unit  110  by suitable communication protocols, e.g., via cellular or satellite transmission as necessary. While the schematic of  FIG. 3  illustrates the control unit  110  as being associated with the supply of produced water entering the system  100 , it is to be appreciated that the control unit  110  may operatively couple to additional or other components and operations of the system  100 . 
     As noted above, skim oil processing  20  may include feeding produced water into the skim oil unit  120 , which may be mediated by the metering system of the control unit  110 . The skim oil unit  120  may include any suitable skim oil processing apparatus such as a froth flotation or induced gas flotation unit. In a preferred embodiment, the skim oil unit  120  comprises a DAF system. Gas may be introduced by feeding a gas saturated liquid into the float tank  121  of the DAF system. In some embodiments, the fluid may be a portion of the produced water fed into the float, typically a portion of the clarified process fluid that has already been flowed through the float tank  121 . For example, process fluid may be withdraw from the float tank  121  for saturation with gas. The DAF system may include a pressurization vessel, specialty pump, or air drum, into which the liquid is pressurized and compressed air is introduced to saturate the liquid with the gas. The saturated liquid may be introduced into the lower portion of the float tank  121  wherein the pressure reduction allows the gas to form bubbles within the liquid. In one example, the saturated liquid is passed into the float tank  121  through a pressure reduction valve. In some embodiments, the DAF system or another skim oil processing apparatus of the skim oil unit  120  may utilize gas bubbles other than air, such as an inert gas, e.g., nitrogen. 
     In some embodiments, skim oil processing  20  includes addition of chemicals such as coagulants and/or flocculants. In one example, chemical addition may be performed in separate chemical addition tank (not shown) of the skim oil unit  120 , which may include mixing structures (not shown), before introduction of the chemically treated produced water into one or more skim oil float tanks  121 . In other embodiments, chemical addition may be within a skim oil float tank  121 . 
     During skim oil processing  20 , produced water is fed into the float tank  121  and gas/air is bubbled from a lower end of the tank  121 . As the bubbles flow up through the produced water, the bubbles encounter suspended contaminants. In time, a plurality of bubbles may accumulate along surfaces of suspended contaminants to lift the contaminants to the surface of the produced water to thereby clarify the produced water wherein the contaminants may then be skimmed and removed by a skimmer (not shown). The contaminants may be suspended solids or liquids, such as dispersed hydrocarbons, hydrocarbon droplets, or hydrocarbons adhering to solids. Skimmed froth removed as an initial contaminate removal portion from the produced water may be caught or collected, e.g., in catch bin for further treatment, use, recycle, or disposal. Some solids and sludge may drop out and be collected along the lower end of a skim oil processing tank. For example, one or more baffles may be used to collect drop out along the lower end of the tank. In some embodiments, a pre-filter may be used to separate large solids and sludge. 
     The produced water or clarified process fluid may be processed for volatile organic compounds (VOC) removal  30 . Removal of VOCs during VOC removal  30  may also include removal of dissolved organics. In an embodiment, VOCs may be captured by adsorption. For example, the process fluid may subjected to activated carbon filtration treatment through one or more activated carbon filtration beds. In one such embodiment, VOC removal  30  may be combined with particulate removal  50  within the particulate removal unit  140 . 
     VOC removal  30  may additionally or alternatively include heating the produced water or process fluid to evaporate or sublimate VOC content, which may also be referred to as flashing herein. It is to be appreciated that some steps of method  10  may be combined or performed in different orders. For example, VOC removal may be performed at any time before flashing and concentration. In one example, VOC removal  30  may be performed before, during, or after skim oil processing  20  by heating the process fluid to between about 130° F. and about 150° F. or greater, such as up to 175° F., to ensure VOCs and dissolved organics are flashed. Performing VOC removal  30  during skim oil processing  20  may be used to beneficially reduce water treatment processing time. 
     The produced water treatment system  100  illustrated in  FIG. 3  includes a skim oil unit  120  that combines VOC removal  30  with skim oil processing  20 . That is, with reference to the produced water treatment method  10 ′ shown in  FIG. 4 , a skim oil process with heat  25  may be utilized to combine the skim oil processing  20  and VOC removal  30  steps according to method  10 . The skim oil unit  120  may be used to perform the skim oil processing with heat  25  of method  10 ′ by adding heat to the produced water during skim oil processing to heat the water to between about 130° F. and about 150° F. or greater, such as up to 175° F., to ensure VOCs and dissolved organics are flashed. The heat may be provided by jacketed float tank  121  through which heated fluid is flowed, a burner positioned with respect to the float tank  121  to directly or indirectly heat produced water, or other heating element arrangement. Skim oil processing with heat  25  of method  10 ′ may otherwise be executed in a similar manner as that described with respect to the skim oil processing  20  of method  10  of  FIG. 2 . As introduced above with respect to system  1  in  FIG. 1 , and as described in more detail below, heat used by the skim oil unit  120  in system  100  to heat the produced water may be provided in whole or in-part by burner  162  of flash concentration unit  160 . For example, produced water may enters the float tank  121  of the skim oil unit  120  comprising a DAF system that may be heated by a thermal transfer plate attached to the flashing and condensing unit  160 . Within this section the produced water enters the initial stages of skim oil processing  20  and VOC contaminate removal  30 . 
     Once separated, VOCs may be collected and treated and/or disposed of in an environmentally responsible manner, e.g., incineration, adsorption, absorption, or condensation. In one embodiment, VOC gas and/or vapors may be pulled from above the process fluid or from a heated adsorption medium onto which the VOCs have been adsorbed. In one example, the flashed VOC gas and vapors may be exhausted and/or pulled through an outlet or vent of the skim oil unit  120 , e.g., above the float tank  121 , or other apparatus in which the VOCs are removed and thereafter routed for further treatment and/or responsible disposal. In a further example, the captured VOC gas and/or vapors may be routed to a burner for combustion and/or incineration. In various embodiments, and as illustrated in the example embodiment in  FIG. 3 , the burner may be burner  162  of the flash concentration unit  160  used for thermal concentration  60  processing of the process fluid to generate a clean steam stream and a concentrated brine stream. In some embodiments, the captured VOC gas and/or vapors routed to the burner  162  may comprise a fuel component for the burner  162 . In one configuration, the burner  162  comprise a forced draft burner. 
     The produced water treatment method  10  may also include particulate removal  40 . Particulate removal  40  may include passing the process fluid through a particulate/element filter  142  of the particulate removal unit  140  to remove particulates. Particulates are preferably removed down to about 30 microns, or more preferably down to about 20 microns or less, such as about 10 microns or less. Particulate removal  40  will typically be performed after skim oil processing  20  and VOC removal  30 , e.g., following skim oil processing with heat  25 , but in some configurations particulate removal  40  may be at least partially performed prior to one or more of skim oil processing  20  or VOC removal  30 . Notably, some suspended solids may be removed during skim oil processing  20  in the skim or drop out. In some embodiments, a portion of the suspended solids may be removed within a pre-treatment holding tank or pre-filter and may be collected along a lower end of the holding tank or within filter cartridges, respectively. Particulate removal  40  reduces solid accumulation from building up during thermal concentration  60 . Thus, when the method  10  includes continuous and/or in-line apparatuses, particulate removal  40  is preferred. However, in some embodiments, a separate particulate removal  40  through a particulate/element filter down to 30 microns or less may be optional. In one example, the particulate removal unit  140  includes one or more particulate/element filters  142  of the kind known to those skilled in the art, such as those manufactured by Pentair, Minneapolis, Minn. 
     The hydrocarbon removal processing of method  10  may further include use of liquid/liquid coalescence  50  to remove remaining hydrocarbons. In some embodiments, other liquid/liquid separation techniques may be used in addition to or instead of liquid/liquid coalescence. The liquid/liquid separation unit  150  of system  100  may include one or more hydrocarbon removal elements. For example, the hydrocarbon removal elements may be of the kind known to those skilled in the art, such as those manufactured by Pentair, Minneapolis, Minn. In various embodiments, the hydrocarbons are separated using liquid/liquid coalescence  50 , may be collected and combined with or treated in a manner similar to the skim. According to various embodiments, following liquid/liquid coalescence  50  about 98% to about 99%, e.g., about 98.8%, of hydrocarbon contaminates have been removed from the process fluid. 
     The process fluid may be thermal concentrated  60  to generate a clean steam stream and a concentrated brine stream. For example, the flash concentration unit  160  may include a bath vessel  161  and burner  162  comprising a direct fired-bath configured to perform flash evaporation and volume condensing. Burner  162 , which may include multiple burners, may be directed at process fluid contained in the bath vessel  161  to drive flash evaporation to achieve thermal concentration  60 . The burner  162  may include a burner known to those skilled in the art, such as one or more Eclipse ThermJets manufactured by Eclipse, a Honeywell company. A forced draft fan may also be used to provide excess oxidant, e.g., air, to the burner  162 . The forced draft fan may include a blower known to those skilled in the art, such as one or more blowers manufactured by Hauk, a Honeywell company. In a preferred embodiment, the one or more burners comprise a forced draft natural gas burner. In one embodiment, the flash concentration unit  160  comprises a direct fire bath wherein one or more tubes provide a flow path for hot flue gas to travel between the burner  160  and a distribution end where the hot flue gas is emitted into the bath vessel  161  to heat the process fluid. The distribution end may comprise a distribution tube portion comprising a plurality of ports from which hot flue gas may exit the flow path. A portion of the path defined by the tubes may be positioned below an operable waterline or fluid level as to be submerged during operation to indirectly heat the process fluid as well as directly heat the process fluid. For example, the distribution tube or ports thereof may be positioned below the waterline. In one embodiment, a portion of the path extends above the waterline. In a further embodiment, the portion of the path extending above the waterline may be positioned between portions of the path extending below the waterline. In one embodiment, an end of the one or more tubes proximate to the burner  162  is positioned below the waterline. In some embodiments, the waterline corresponds to a maximum liquid level in which the bath vessel  161  is designed to operate. However, as bath vessels  161  may be suitable for operation at multiple levels, the waterline may correspond to a designed liquid level suitable for operation. Those skilled in the art are aware of operable designed operation levels. 
     Flashing may comprise subjecting the process fluid to a directed fired water bath treatment wherein the process fluid acquires heat required to separate the water from the remaining composition. The separation of water reduces the volume of the process fluid through transition of a portion of the water to steam and concentrates the salt content in a remaining portion of the water. To maximize clean water separation, the volume of the process fluid may be concentrated to approximate saturation of salt in water solution. For example, the process fluid may be preferably concentrated to a brine having about 230,000 ppm to about 250,000 ppm total dissolved solutes. Higher concentrations may result in the solution breaking out and turning to solid. Lower concentrations may also be used but may be less efficient. Thus, the method  10  may include maximizing water separation and volume reduction while maintaining a brine solution product by concentrate the brine solution product to approximate its saturation point. 
     In some embodiments, the flash concentration unit  160  or control unit  110  includes one or more salinity meters for measuring salinity of the process fluid in the bath vessel  161 . For example, in one embodiment the method  10  may include utilizing salinity meters that measure brine concentration during heating. When a target concentration point below or approximating saturation is hit, a pumping system of the concentration unit  160  or control unit  110  may initiate to pump brine from the bath vessel  161 . The pumping system may also pump additional process fluid into the bath vessel  161 . The pumping of brine from the bath vessel  161  and process fluid into the bath vessel  161  may be performed at a rate that maintains a set point below or approximately at the saturation point of the brine at the bath temperature. For example, pumping volumes that are too low may drive the concentration up and allow solids to build while pumping volumes that are too high may allow brine concentration to drop. Again, as noted above, pumping is preferably set to maintain maximum concentration for maximum efficiency. Notably, as the temperature of the bath is high, in some embodiments, the set point may correspond to a supersaturated brine solution. In one example, the control unit  110  includes or is in data communication with salinity meter data and may be operable to initiate pumping and or modification of fuel/air to burner  162 . In another example, responding to salinity meter data may be manual. 
     As introduced above, the method  10  may include utilizing excess heat generated from the flash concentration unit  160  to perform preheating operations. For example, the flash concentration unit  160  may be used to directly or indirectly heat the produced water supplied to the skim oil unit  120 . The burner  162  may heat a medium or structure positioned between burner flames and produced water in the skim oil unit  120 . For example, burner flames may be directed to a thermal plate that positioned between the burner flames and produced water in the skim oil unit  120 . The thermal plate may comprise, for example, a metal or other thermally conductive material. In some embodiments, burner flames may heat a liquid or gas that is flowed or positioned along a wall of the float tank  121  or a pre-float tank holding tank. 
     The remaining effluent or brine may be collected and reinjected, landfilled, or treated further. In further embodiments, the brine may be optionally treated as described above with respect to  FIG. 1  to separate salt and sediments from the brine. 
     The flash concentration unit  160  may include a steam outlet for a clean steam stream to exit the unit. The clean steam stream may also include portion of the flue gas resulting from combustion at the burner  162 . The clean steam may exit to the atmosphere or may be collected for further treatment or use. 
     In one embodiment, the method  10  may optionally include condensing  80  the steam. For example, the steam may be supplied to condenser unit  180  including a condenser  182  comprising one or more condensers for conversion of the clean steam back to liquid state for industry, agricultural, or other use. Any suitable condenser  182  may be used. In some embodiments, the condenser  182  comprises an ambient passive condenser. The ambient passive condenser may include piping for transport of the steam and condensed water. The ambient passive condenser may include thermally conductive structures having high surface area for heat dissipation along the piping. For example, the piping may be coupled to fins. In one embodiment, the ambient passive condenser includes about 1 inch to about 10 inch, about 1 inch to about 5 inch, or about 3 inch piping coupled to heat dissipating fins. The condenser  182  may operate at any suitable pressure. In one embodiment, the condenser  182  operates at a vacuum pressure. For example, the condenser  182  may operate at about 6 psi, about 3 psi, about 1 psi or less. In other embodiments, the condenser  182  may operate at ambient pressure or an above ambient pressure. 
     In some embodiments, the condenser  182  of the condenser unit  180  may include one or more condensers that may be actively cooled with refrigerant or cooled fluid. In one example, the condenser  182  includes an ambient passively cooled condenser and an actively cooled condenser. In some embodiments, ambient cooled condensers may be selectively operable to cool actively. In one example, fans may be used to direct air along piping and/or fins. 
     The various units may be provided in modular configurations. For example, one or more units may be provided on one or more skids for convenient onsite setup. In various embodiments, the skim oil unit  120  or float tank  121  thereof may be provide on the same skid as the flash concentration unit  160  or bath vessel  161  thereof. In a preferred embodiment, the bath vessel  161  and the float tank  121  share a partition or wall comprising a thermal transfer plate. 
       FIGS. 5-7 &amp; 10  illustrate various views of an embodiment of the produced water treatment system  100  described above with respect to  FIG. 3 , wherein like features are identified by like numbers.  FIG. 10  illustrates an example distribution tube  178 . The produced water treatment system  100 ′ illustrated in  FIG. 5  includes a hydrocarbon separation unit comprising a skim oil unit  120  including a float tank  121  comprising one or more float tanks and a liquid/liquid separation unit  150 , a particulate removal unit  140 , and a flash concentration unit  160 . The produced water treatment system  100 ′ also includes an optional control unit  110  and condenser unit  180 . In various embodiments, the produced water treatment system  100 ′ may also include a precipitation unit, drying unit, and/or gas/solid filtration unit as described above with respect to  FIG. 1 . 
     The control unit  110  includes a pumping system including one or more pumps  112  operable to pump produced water and process fluid through the system  100 ′. The control unit  110  also includes a metering system having a level control system that together with a flow control piping and valve system controls flow and process levels within the system  100 ′. For example, the flow control piping and valve system may include one or more valves  114  that may be opened and closed by the metering system to control system levels. In various embodiments, the inlet flow control piping and valve system may be manual or automated. The control unit  110  may include one or more sensors to monitor flow rates, salinity, pressure, temperature, fluid levels, or other operation parameters. In one example, the control unit  110  may track flow rates to control inlet control valves to achieve and/or maintain maximum flow rates while not over running the system  100 ′. The piping and valve system may also include piping and valves for providing fuel/air to burner  162 , VOC vapor to burner  162 , and/or supply and withdraw process fluids and materials to the various units of the system  100 ′. In a further embodiment, the control unit  110  may provide a remote user interface allowing remote monitoring and/or control of operation of the system  100 ′. 
     In one example, the control unit  110  includes a controller, e.g., a programmable logic controller, operable to control operations of the system  100 ′. The controller may be configured for manual operation, automated operation, or both. The controller may include or communication with one or more sensors positioned to monitor flow rates, fluid levels, temperature, pressure, fuel/air mixtures, salinity, pumps, actuators, and/or valves. The controller may integrate with the metering system and pumping system to collect and analyze operation data to modify flow rates, levels, fuel/air mixtures, pumps, actuators, and/or valves to obtain desired operations. The controller may include a processor in data communication with a computer readable storage medium storing instructions that when executed by the processor control the operations of the system  100 ′. The controller may receive process data from a salinity sensor and, based on analysis of the data, initiate, terminate, or modify one or more supply and/or withdrawal pumps (not shown) of the pumping system that deliver process fluid and withdraw concentrated brine from a bath vessel  161  of the flashing and condenser unit  160 . 
     The skim oil unit  120  includes a float tanks  121  in which contaminates such as suspended solids and hydrocarbons are separated by flotation and then skimmed from the surface. As noted above, the skim oil unit  120  may include any suitable skim oil process; however, as illustrated, the skim oil unit  120  comprises a DAF system in which dissolved air is introduced into the float tank  121 . The float tank  121  includes a pathway through which the produced fluid travels, as indicated by the broken lines in  FIG. 7 . A plurality flow panels  122  are positioned in the float tank and include arches and u-bends to assist in driving flow up to the surface of the produced water within the float tank  121 . As most clearly shown in the view of  FIG. 6B , a skimmer  124  is positioned in the float tank  121  and includes an inlet along the waterline therein to skim the surface of the produced water. The skim may continuously or periodically be withdrawn from the skimmer  124  by a skim oil blowcase  126  for collection. 
     The produced water treatment system  100 ′ includes a combination skim oil unit  120  and VOC removal unit. For example, as described above and elsewhere herein, heat is provided to the float tank  121  to heat the produced water to between about 130° F. and about 150° F. or greater, such as up to 175° F., to flash VOCs and dissolved organics are flashed. While separate heating may be used, in the illustrated embodiment, heat is provided by the flash concentration unit  160 . As shown, the bath vessel  161  and the float tank  121  share a partition or wall comprising a thermal transfer plate. The shared wall or thermal transfer partition  128  between the float tank  121  and the flash concentration unit  160  transfers heat to the produced fluid in the float tank  121  to indirectly heat the same. The thermal transfer partition  128  preferably comprises a thermally conductive material such as a metal or allow, e.g., steel. The thermal transfer partition  128  runs the length of the float tank  121  and the corresponding length of the bath vessel  161 . In other embodiments, the thermal transfer partition  128  spans additional or less area. In one embodiment, the thermal transfer partition  128  includes a portion of a fire tube  170 , riser tube  172 , and/or return tube  174  that forms a partition with or extends within the float tank  121 . For example, a fire tube  170  may abut or extend through a portion of the float tank  121  to indirectly heat the produced water to flash VOCs and dissolved organics. The thermal transfer partition  128  is generally planar, but in other embodiments the thermal transfer partition may be curved or otherwise include surface area increasing formations. 
     The particulate removal unit  140  includes two particulate/element filters  140  to remove particulates down to a desired size. For example, the particulate/element filters  140  may filter particulates down to about 30 microns, or more preferably down to about 20 microns or less, such as about 10 microns or less. In some embodiments, fewer or additional particulate/element filters  142  may be used. 
     The liquid/liquid separation unit  150  includes ae liquid/liquid coalescer  152  configured to separate remaining hydrocarbons from the process fluid. It will be appreciated that in some embodiments, additional or other liquid/liquid separation apparatuses may be used. Following liquid/liquid coalescence about 98% to about 99%, e.g., about 98.8%, of hydrocarbon contaminates have preferably been removed from the process fluid. 
     The flash concentration unit  160  includes a bath vessel  161  for containing process fluid during the flashing and concentration process. A blower  134  comprising a forced draft blower is positioned to deliver oxidant, e.g., air to two burners  160 . A fuel line  165  is positioned to deliver a fuel supply for combustion at the burners  160 . In the illustrated embodiment, the fuel comprises natural gas. Some embodiments may use other fuels. As noted above, the VOCs and dissolved organics flashed in the skim oil unit  120  may be supplied to the burner  162  for combustion and/or incineration. In the illustrated embodiment, a VOC gas suction line extends between the float tank  121  and the blower  163 . The operation of the blower  163  creates a vacuum that pulls the dissolved organics and VOC gases into the blower  163  where the gas mixes with the air supply that is further supplied to the burners  162  along with the fuel for combustion. It will be appreciated that in some embodiments, VOCs and/or dissolved organics are supplied to the burner passively or actively in another manner than pulling with a blower  163 . 
     In one embodiment, the flash concentration unit  160  comprises a direct fire bath wherein one or more tubes provide a flow path for hot flue gas to travel between the burner  160  and a distribution end where the hot flue gas is emitted into the bath vessel  161  to heat the process fluid. The distribution end may comprise a distribution tube  178  comprising a plurality of ports  179  (see, e.g.,  FIG. 10 ) from which hot flue gas may exit the flow path. A portion of the path defined by the tubes may be positioned below an operable waterline or fluid level as to be submerged during operation to indirectly heat the process fluid as well as directly heat the process fluid. For example, the distribution tube  178  or ports  179  thereof may be positioned below the waterline. In one embodiment, a portion of the path extends above the waterline. In a further embodiment, the portion of the path extending above the waterline may be positioned between portions of the path extending below the waterline. In one embodiment, an end of the one or more tubes proximate to the burner  162  is positioned below the waterline. Further to the above, one or more tubes extending into the bath vessel  161  may be fed hot flue gas by the burner  162  and provide a flow path for the hot flue gas to flow into the bath vessel  161 . The one or more tubes may include a fire tube  170  for coupling the tubes to the hot flue gas and a distribution tube  178  comprising a plurality of ports  179  for hot flue gas to exit the flow path into the bath vessel. In the illustrated embodiment, the fire tube  170  extends through the bath vessel  161 . The fire tube  170  includes two ends  170   a ,  170   b , each associated with a burner positioned to direct flames into the fire tube  170 . Thus, a fire tube  170  may be fed by multiple burners  162  at two or more openings or ends. The fire tube  170  fluidically couples to the distribution tube  178  having a plurality of ports  179  providing passages for hot flue gas to exit the interior path of the distribution tube  178 . A plurality of hot flue gas jets may extend into the surrounding process fluid contained within the bath vessel  161  to flash the process fluid for steam generation and concentration of the process fluid. The ports  179  are sized and numbered to handle the burners  162  plus all the excess oxidant volume, e.g., air, generated by the forced draft blower  163 . For example, in one embodiment, ports  179  may be between about 0.01 inches and about 5 inches in diameter. The ports  179  may be around all or a portion of the circumference of the distribution tube  178 . In some embodiments, all or a majority of ports  179  may be positioned along a bottom half of the distribution tube  178  to maximized residence in the process fluid. In one embodiment, the distribution tube includes a plurality of about 2 inch diameter ports  179  along the bottom half of the distribution tube  178 . In an above or another embodiment, a cross sectional area of the ports  179  is about equal to the cross section of the distribution tube. It will be appreciated that different size tubes, bath volumes, burner outputs, and other parameters may result in altering size, location, and/or number of ports  179 . The ports  179  may be distributed along the length and/or perimeter of the distribution tube  178  in any suitable manner. For example, ports  179  may be distributed along a full or partial length of the distribution tube  178  and around all or a portion of the circumference of the distribution tube  178 . The illustrated distribution tube  178  extends about 60% of the length of the bath vessel  161 . In other embodiments, the distribution tube  178  extends less than 60% or greater than 60% of the length of the bath vessel  161 . In the above or illustrated embodiment, ports  179  may be distributed along about 20%, about 40%, about 60%, about 80%, or about 100% of the length of the distribution tube  178 . 
     In various embodiments, at least a portion of the path through which the hot flue gas flows between the burner  162  and the distribution ports  179  extends above an operative waterline within the bath vessel  161 . This configuration prevents process fluid from entering the flow path of the hot flue gas to foul the burner. In one embodiment, a portions flanking both sides of the portion of the path extending above the waterline are positioned below the waterline to thereby be submerged during operation of the flash concentration unit  160 . In some embodiments, a burner end  170   a ,  170   b  is positioned above the waterline. In the illustrated embodiment, the burner ends  170   a ,  170   b  are positioned below the waterline and at least a portion of the flow path of the hot flue gas between the burner  162  and distribution tube  178  extends above the waterline. 
     The flash concentration unit  160  includes both a submerged fire tube  170  and a submerged distribution tube  178 . The fire tube  170  has a u-shape and extends through the bath vessel  161  along a u-shaped path. Extending a portion of the hot flue gas flow path through the bath vessel  161  provides indirect heating of the surrounding process fluid. The u-shaped path increases tube surfaces exposed to processing fluid to increase heat transfer to the process fluid, which also operates as a coolant to reduce heat stress to the fire tube  170  as well as to the other submerged tubes. Combining indirect and direct heating of the process fluid within the bath vessel significantly increases heating efficiency, lowering operating costs and increasing production output. A riser tube  172  is fluidically coupled to the fire tube  170  and extends vertically to a position above a waterline of the bath vessel  161 . The waterline corresponds to the operative level of process fluid within the bath vessel  161  during flashing and concentration and may be the top of the bath vessel  161  or a level below the top. The riser tube  172  fluidically couples with a return tube  174  that extends to a flue gas mass distribution tube  178 . As shown, the return tube  174  extends to below the waterline along with the distribution tube  178 ; however, in some embodiments, only the distribution tube  178  extends below the waterline. A u-box return tube  176  is also coupled between the riser tube  172  and the return tube  174  to provide a path for hot flue gas to flow between the interior paths of the riser tube  172  and return tube  174 . 
     The present disclosure contemplates other variations to the illustrated embodiment. For example, in some embodiments, the fire tube  170  extends partially or entirely outside of the bath vessel  161 . The fire tube  170  may extend along paths of various shapes, e.g., linear, arcuate, or u-shaped (as shown), for example. Similarly, the distribution tube  178  may extend along various shaped paths, e.g., linear (as shown), arcuate, or u-shaped. In one embodiment, the flash concentration unit  160  includes multiple distribution tubes. Each distribution tube  178  may be fluidically coupled to one or more fire tubes  170 . In some embodiments, fire tube  170  is fed by one or more burners only at a single end. In some embodiments, the flash concentration unit  160  includes multiple fire tubes  170  each fed with one or more burners  162 . In one embodiment, multiple fire tubes  170  and/or distribution tubes  178  extend through or partly through the bath vessel  161 . The orientation and relative positions of the fire tube  170  and the distribution tube may vary. For example, in one embodiment, all or a portion of a distribution tube  178  may position vertically below all or a portion of a fire tube  170 . While the fire tube  170  and distribution tube are shown as extending along horizontal planes, in some embodiments, one or more of the fire tube  170  or distribution tube may extend at an upward or downward directed angle with respect to the horizontal. In various embodiments, the distribution tube  178  may have ports  179  or sections including ports  179  that may be selectively opened or closed to modify flue gas output to handle different mass flows of flue gas. For example, a partition within or over the distribution tube  178  may be selectively operated to increase or decrease available ports  179  for release of hot flue gas. Separation of water from the process fluid reduces the volume of the fluid and concentrates the salt content in a remaining portion of the water. To maximize clean water separation, the volume of the process fluid may be concentrated to approximate saturation of salt in water solution. For example, the process fluid may be preferably concentrated to a brine having about 230,000 ppm to about 250,000 ppm total dissolved solutes. Higher concentrations may result in the solution breaking out and turning to solid. Lower concentrations may also be used but may be less efficient. Thus, the method  10  may include maximizing water separation and volume reduction while maintaining a brine solution product by concentrate the brine solution product to approximate its saturation point. As introduced above with respect to  FIGS. 1-4 , the system  100 ′ may include one or more salinity meters for measuring salinity of the process fluid in the bath vessel  161  during heating. When a target concentration point below or approximating saturation is hit, the pumping system initiates to pump brine from the bath vessel  161 . The pumping system may also pump additional process fluid into the bath vessel  161 . The pumping of brine from the bath vessel  161  and process fluid into the bath vessel  161  may be performed at a rate that maintains a set point below or approximately at the saturation point of the brine at the bath temperature. Pumping is preferably set to maintain maximum concentration for maximum efficiency. In one example, the control unit  110  includes or is in data communication with salinity meter data and may be operable to initiate pumping and or modification of fuel/air to burner  162 . In another example, responding to salinity meter data may be manual. 
     A steam stack  166  extends from the direct fire bath vessel  167  for release of steam generated within the bath vessel. As noted above with respect to  FIGS. 1-4 , the steam may exhaust into the atmosphere or optionally be condensed.  FIG. 6A  illustrates the steam stack  166  attached to the steam stack flange and  FIG. 6B  illustrates the steam stack  166  substantially removed wherein a coupling pipe may attach at the steam stack flange to fluidically couple the steam stack  166  to an inlet  181  of the condenser unit  180  for condensing in a condenser  182 .  FIG. 5  illustrates the steam stack  166  attached prior to its removal from the flange (see  FIG. 6B ) and replacement with a coupling pipe to supply steam to the condenser unit  180  in the manner indicated in the flow depiction in  FIG. 7 . 
     The condenser  180  is configured to convert the clean steam to liquid state for industry, agricultural, or other use. While any suitable condenser  182  may be used, in a preferred embodiment, the condenser  182  comprises an ambient passive condenser. The ambient passive condenser includes piping for transport of the steam and condensed water. The piping may be any suitable diameter. For example, the piping may be about 1 inch to about 10 inch, about 1 inch to about 5 inch, or about 3 inch in diameter. The piping may include thermally conductive structures having high surface areas for heat dissipation along the piping. For example, the piping may be coupled to fins (not shown). The condenser  182  may operate at any suitable pressure. In the illustrated embodiment, the condenser operates at a vacuum pressure. For example, the condenser may operate at about 6 psi, about 3 psi, about 1 psi or less. In another embodiment, the condenser  182  operates at ambient pressure or an above ambient pressure. 
     In some embodiments, the condenser  182  of the condenser unit  180  may include one or more condensers that may be actively cooled with refrigerant or cooled fluid. In one example, the condenser  182  includes an ambient passively cooled condenser and an actively cooled condenser. In some embodiments, ambient cooled condensers may be selectively operable to cool actively. In one example, fans may be used to direct air along piping and/or fins. 
       FIG. 7  illustrates a process flow, identified by broken lines, through the produced water treatment system  100 ′. At position  90 , produced water is supplied into the system  100 ′ at a system inlet  90  and is pumped to the float tank  121  by a pump  112 . The control unit  110  may perform pumping, metering, and level control functions as described above and elsewhere herein. Suspended solids and oil are assisted to the surface of the produced water by bubbling and are removed by the skimmer  124 . The produced water is indirectly heated in the float tank  121  via thermal transfer partition  128  that is heated by the process fluid in the bath vessel  161  that is heated directly and indirectly by the output of the burners  162 . The heat flashes VOCs and dissolved organics, which are pulled from the float tank  121  into the VOC gas suction line by the blower  163  and subsequently mixed with air and fuel for combustion and/or incineration at the burners  162 . 
     At position  91 , after passage through the skim oil unit  120 , the process fluid is flowed from the float tank  121  to the particulate removal unit  140 . The process fluid is then passed through particulate/element filters  142  at position  92  to remove particulates to preferably below 30 microns or more preferably 20 microns or less. At position  93 , the process fluid is supplied into the liquid/liquid separation unit  150  for removal of remaining hydrocarbons. The process fluid exits the liquid/liquid coalescer  152  and at position  94  is delivered to the flash concentration unit  160  where it is held within the bath vessel  161 . The separated skim and hydrocarbons captured from the skim oil unit  120  and liquid/liquid separation unit  150  may be collected for responsible disposal or recycling. In the bath vessel  161 , the process fluid is heated indirectly by contact with the fire tube  170 , riser tube  172 , return tube  174 , and distribution tube  178  and directly by a plurality of hot flue gas jets that emanate from a plurality of ports  179  in the distribution tube  178 . The heat transitions a portion of the process fluid to clean steam while concentrating the remaining fluid into a concentrated brine. Pumps may operate to control the inflow of process fluid into the bath vessel  161  and the outflow of brine from the bath vessel to maintain a desired salinity. Preferably, the salinity approximates saturation of the concentrated solution. For example, the brine may have a salt composition of about 230,000 ppm to about 250,000 ppm. The brine may be further treated as described with respect to  FIG. 1  or may be otherwise used or disposed of in an environmentally responsible manner. 
     At position  95 , the clean steam is flowed to an inlet  181  of the condenser  182  for condensing. The condenser  182  condenses the steam to water and the water is flowed from the condenser unit  180  and exits the system  100 ′ at an outlet at position  96 . 
     Table 1 provides an example analytical report comparing analyte composition of untreated produced water and treated produced water (condensed clean steam) treated according to the method described with respect to  FIG. 7 . The composition of the treated water is suitable for reinjection, agricultural, or industrial use. 
     It is to be appreciated that the produced water treatment systems, units, components, and methods thereof described herein may be utilized to treat water, such as waste water, and other liquids other than produced water and that the present application is not limited in this respect. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 ANALYTE 
                 UNTREATED 
                 TREATED 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Solids, Total Dissolved TDS @ 180° C. (mg/L) 
                 82,400 
                 391 
               
            
           
           
               
            
               
                 Major Ions (mg/L) 
               
            
           
           
               
               
               
            
               
                 Alkalinity, Total as CaCO 3   
                 459 
                 246 
               
               
                 Bicarbonate as HCO 3   
                 560 
                 300 
               
               
                 Chloride 
                 45,600 
                 25 
               
               
                 Sulfate 
                 389 
                 42 
               
               
                 Calcium 
                 3620 
                 59 
               
               
                 Magnesium 
                 508 
                 13 
               
               
                 Potassium 
                 1130 
                 5 
               
               
                 Sodium 
                 29,800 
                 53 
               
            
           
           
               
            
               
                 Nutrients (mg/L) 
               
            
           
           
               
               
               
            
               
                 Nitrate 
                 0.06 
                 4.94 
               
               
                 Ammonia 
                 69 
                 9.8 
               
            
           
           
               
            
               
                 Metals, Dissolved (mEq/L) 
               
            
           
           
               
               
               
            
               
                 Calcium 
                 181 
                 2.93 
               
               
                 Magnesium 
                 41.8 
                 1.05 
               
               
                 Sodium 
                 1,300 
                 2.29 
               
            
           
           
               
            
               
                 Metals, Total (mg/L) 
               
            
           
           
               
               
               
            
               
                 Mercury 
                 0.00006 
                 Not Detected 
               
               
                   
               
            
           
         
       
     
     In any of the above or another example, and with further reference to  FIGS. 8 &amp; 9 , the produced water treatment system  100 ,  100 ′ includes a control unit  1000 . In some embodiments, the control unit  1000  may include or incorporate a metering system as described above. The control unit  1000  includes a controller  1010  operable to control unit operations  1015 , e.g., processes and parameters. For example, the controller  1010  may be operable to actuate valves to control fluid flow, levels, or pressure or initiate, modify, or cease operations of pumps, burners, fuel flow, oxidant or air flow, fans, heaters, coolers, agitators, or other system operations  1015 . 
     In various embodiments, the control unit  1000  may include or communicate with one or more sensors  1020  to obtain produced water treatment data  1030  from which the controller  1010  analyzes to determine various control operations. The produced water treatment data  1030  may be transmitted from the one or more sensors  1020  to the controller  1010  via wired or wireless communication port. For example, the communication port, which may include multiple communication ports each associated with one or more sensors  1020  may include a transmitter or transceiver to transmit the produced water treatment data  1030  to communication port  1040 , which may include or communicate with a receiver or transceiver to receive the transmitted produced water treatment data  1030 . In some embodiments, the one or more sensors  1020  include thermal sensors, pressure sensors, optical sensors, video or image sensors, proximity sensors, flow sensors, proximity sensors, motion sensors, moisture sensors, weight sensors, sound or electromagnetic wave sensors (transmitter, receiver, or transceivers), capacitance sensors, or other sensors. 
       FIG. 8  provides an overview of the control unit  1000  for controlling system operations  1015  as described herein. The control unit  1000  comprises a flexible platform from which various tasks or functions related to the operations of the produced water treatment system, e.g., controlling or monitoring the operations of the system. 
     The control unit  1000  may include a controller  1010  configured to perform various monitoring and control tasks with respect to the produced water treatment system. As introduced above, the controller  1010  may be configured to operatively associate with one or more sensors  1020  positioned to sense, detect, or measure conditions of the produced water treatment system in real-time. The controller  1010  may be configured to route or make available operation data to one or more operation databases  1060  or user interfaces  1050 . The operation database  1060 , for example, may be accessed by the controller  1010  to retrieve, store, or archive control unit data, which may include raw, processed, or analyzed operation data, events, as well as parameter definitions, including rules, statistics, tables, algorithms, or other data used to process or analyze data including generating or identifying operational conditions. Sensors  1020  may collect operation data comprising produced water treatment data and transmit, either wireless or by wired connection, the produced water treatment data to the controller  1010 , as introduced above. The operations database  1050  may include files comprising instructions executable by the controller  1010  to perform one or more aspects of a control program. The controller  1010  a processing unit  1070  as shown in  FIG. 9  for executing the instructions. The controller  1010  may execute the control program and be configured to interface the functionalities of the controller  1010  with users via one or more user interfaces  1050 . The control program  120  may define various administrative parameters, e.g., definitions or settings, of the control unit  1000  such as operational and administrative decision rules including set points, operational condition identification, and analysis parameters, any of which may include customizable definitions to fit a desired application. For example, the controller  1010  may be operatively associated with one or more processes of the system to monitor, collect, analyze, process, and/or communicate data indicative of operational conditions, events, or states as defined by the control program. In various embodiments, the control program includes selectable processing protocols including set points definitions, threshold definitions, trigger event definitions, and/or response definitions. 
     The controller  1010  may also be configured to process the operation data. For example, the controller  1010  may analyze the operation data to determine operational conditions, format the operation data into a desired format or generate reports, e.g., enter select data or analyzed data into predefined forms or according to requests received from users interfaces  1050 . 
     In various embodiments, the controller  1010  may be programmed to activate, deactivate, or modulate one or more system actuators  1115   a , motors  1115   b , pumps  1115   c , valves  1115   d , burners  1115   e , blowers  1115   f , skimmer  1115   g , or combination thereof. The controller  1010  MAY perform the above operations according to programed sequences according to a formula for example, upon receiving an instruction from a user interface  1050 , or in response to produced water treatment data  1030  received from one or more sensors  1020 . Sensors  1020  may include temperature sensors  1020   a , pressure sensors  1020   b , flow sensors  1020   c , salinity sensors  1020   d , volume sensors  1020   e , position sensors  1020   f , as well as any other sensor, including those described elsewhere herein. As introduced above, sensors  1020  may transmit produced water treatment data  1030  via wired or wireless connection to the controller  1010 . On or more sensors  1020 , for example, may include a communication port  1020  configured to send electronic communication signals. For example, sensors  1020  may include a transmitter or transceiver for two-way communication with a communication port  1040  comprising a transceiver in data communication with controller  1030 . For example, the controller  1010  may initiate collection of produced water treatment data  1030  from a sensor. The controller  1010  may then activate, deactivate, or modulate a system operation  1115  based on the produced water treatment data  1030  collected by the sensor  1020  and transmitted to the controller  1010 . The controller  1010  may analyze the produced water treatment data  1030  communicated from one or more of the sensors  1020  operatively associated with various sub-process equipment and compare the data to thresholds and parameters provided by a predefined program selected by user and then actively modulate system operations  1115  to conform the selected program. 
     As introduced above, the controller  1010  may be configured to communicate signals to one or more interfaces, e.g., programs, control system or external devices, user access devices or applications, or indicators which reflect a condition, event, state, activity, or function of the produced water treatment system. For example, one such indicator may include a notification, which may include activation of a warning light, an audible alert, or a message sent to and displayed on a graphical display associated with a local or remote user interface such as a system control panel, computer, or personal electronic device, such as a smart phone. 
     Analysis of operation data may include the controller  1010  utilizing administrative parameters comprising analysis tools to determine, calculate, or classify an operational condition, event, or state and then performing or initiating a predefined response or action in accordance with administrative decision rules specified in the control program. For example, the controller  1010  may compare raw or processed operation data or an operational condition determined using such data to predefined set points. Set points may include measurable standards identified or specified by a user or otherwise defined in the control program. Set points may include, for example, pressures or temperatures, salinities, agitation rates, flow rates, volumes, levels, filter unit flow, fuel rate, blower rate, fuel/air ratio, valve states, filter efficiencies, expected remaining life of filters, etc. 
     When a set point comparison identifies an occurrence of a trigger event, the controller  1010  may respond in a predefined way. For example, the controller  1010  may transmit to one or more interfaces  1050  a notification, alert, or alarm. Additionally or alternatively the controller  1010  may perform or initiate a control operation specified by a decision rule, e.g., modulate an operation of the produced water treatment system to address a trigger event. In various embodiments, set points or the predefined response to a trigger event may be statically or dynamically defined and, thus, may be beneficially configurable to adapt to different operational conditions or circumstances within any given application. In one embodiment, an authorized user may define the statically or dynamically defined response to one or more trigger events. 
       FIG. 9  illustrates various hardware units of a controller  1010  according to various embodiments. In general, the controller  1010  may include one or more processors, servers, databases, networks or network devices, and peripherals configured to obtain and transmit data and initiate control operations configured to perform in whole or in part the operations of the control program. As shown, the controller  1010  comprises a processing unit  1070 , e.g., one or more electronic data processors or central processing units having logic control functionalities. The controller  1010  further comprises a memory unit  1075  comprising one or more electronic data storage mediums such as recording media, read-only, volatile, non-volatile, semi-conductor based, or other data storage mediums known in the art. The memory unit  1075 , for example, includes one or more data storage mediums having stored thereon one or more programs or applications comprising software, firmware, or other instructions stored in one or more files executable by the processing unit  1070  to perform the various operations and functions of the controller  1010 . The memory unit  1075  may further include database  1060 . The instructions may include the control program  1080 , which may include interaction with additional applications or services. 
     The controller  1010  may also include a communication unit  1090  configured to transmit and receive data. The communication unit  1090  may include one or more data ports, communication ports  1040 , transmitters, receivers, transceivers, network cards, modems, gateways, routers, switches, firewalls, local, virtual, wide area, cloud/internet area, or internet-based distributed networks, Ethernet, wireless or wired digital communication devices, telecommunication devices, monitors, speakers, lights, buttons, knobs, or peripherals. The controller  1010  may also include or be operationally associated, e.g., via communication with associated communication ports coupled with sensors or system operations, with control and monitoring components such as sensors, actuators, valves, pumps, power switches, etc. for controlling or monitoring operational conditions of the produced water treatment system. 
     This specification has been written with reference to various non-limiting and non-exhaustive embodiments. However, it will be recognized by persons having ordinary skill in the art that various substitutions, modifications, or combinations of any of the disclosed embodiments (or portions thereof) may be made within the scope of this specification. Thus, it is contemplated and understood that this specification supports additional embodiments not expressly set forth in this specification. Such embodiments may be obtained, for example, by combining, modifying, or reorganizing any of the disclosed steps, components, elements, features, aspects, characteristics, limitations, and the like, of the various non-limiting and non-exhaustive embodiments described in this specification. 
     The grammatical articles “one”, “a”, “an”, and “the”, as used in this specification, are intended to include “at least one” or “one or more”, unless otherwise indicated. Thus, the articles are used in this specification to refer to one or more than one (i.e., to “at least one”) of the grammatical objects of the article. By way of example, “a component” means one or more components, and thus, possibly, more than one component is contemplated and may be employed or used in an application of the described embodiments. Further, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of the usage requires otherwise. Additionally, the grammatical conjunctions “and” and “or” are used herein according to accepted usage. By way of example, “x and y” refers to “x” and “y”. On the other hand, “x or y” refers to “x”, “y”, or both “x” and “y”, whereas “either x or y” refers to exclusivity. 
     Any numerical range recited herein includes all values and ranges from the lower value to the upper value. For example, if a concentration range is stated as 1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, 1% to 3%, or 2%, 25%, 39% and the like, are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values and ranges between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this application. Numbers modified by the term “approximately” are intended to include +/−10% of the number modified. 
     The present disclosure may be embodied in other forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be had to the following claims rather than the foregoing specification as indicating the scope of the invention. Further, the illustrations of arrangements described herein are intended to provide a general understanding of the various embodiments, and they are not intended to serve as a complete description. Many other arrangements will be apparent to those of skill in the art upon reviewing the above description. Other arrangements may be utilized and derived therefrom, such that logical substitutions and changes may be made without departing from the scope of this disclosure.