Abstract:
An electrocoagulation system including a dosing unit, a mixing unit and a buffer tank is provided. The dosing unit receives a fluid from an external source and injects an electrochemically generated coagulant into the fluid using one or more pairs of electrodes. The mixing unit mixes the coagulant with the fluid and is separate from the dosing unit. The buffer tank holds the fluid until particles contained in the fluid grow to a predetermined size.

Description:
BACKGROUND 
       [0001]    The present exemplary embodiments relate generally to water treatment. They find particular application in conjunction with electrocoagulation, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiments are also amenable to other like applications. 
         [0002]    In water treatment, many different contaminants can be removed more efficiently by using a proper coagulant. The coagulant initiates aggregation of the contaminants to large enough particle sizes for easy removal. Coagulants include, for example, aluminum salts, iron salts, and natural or artificial polyelectrolytes. Typically, the inorganic coagulants are introduced into source water in the form of salts having low concentrations of the actual coagulant ions suspended therein. For example, FeCl 3 *6H 2 O is a typical coagulant used with salt water, and which contains less than 21% iron by weight. 
         [0003]    Another approach for introducing coagulants, which does not suffer from the above noted inefficiency, is electrocoagulation (EC). In EC, a coagulant is produced by electrochemical dissolution of one or more sacrificial electrodes, such as aluminum electrodes, iron electrodes, or the like, under an applied voltage. Dosing can be varied by changing the applied voltage or speed of source water flow past the electrodes. Other advantages of this method include, but are not limited to, reducing sludge generation, emulsion breaking, and the like. 
         [0004]    Even though EC has certain advantages over conventional options, it is not as widely used in the water treatment industry. One reason is the variety of electrochemical reactions that can occur depending on source water quality and applied voltage. Many electrochemical reactions do not affect coagulation, whereby energy is wasted unless the electrochemical reactions are controlled and/or limited. Another reason is the need to allow for a good and rapid mixing of the released coagulant ions into the bulk of the source water. For high salinity liquids, such as sea water or some produced waters, the high conductivity of these liquids causes a high dosing current even at low voltages that requires a highly turbulent flow regime to achieve sufficient mixing. 
         [0005]    As a result of the above noted challenges, water treatment systems employing EC are often highly adapted to a specific application and hard to adjust to work for other needs. For example, often times, EC systems include a combined dosing and mixing unit, where the shape of the mixing unit and the location of the electrodes are highly dependent upon the particular applications of the EC systems. 
         [0006]    The present disclosure contemplates new and improved systems and/or methods for remedying these, and other, problems. 
       INCORPORATION BY REFERENCE 
       [0007]    The following co-pending and commonly assigned applications, the disclosures of each being totally incorporated herein by reference, are mentioned:
   U.S. Published Application No. 2009/0050538, entitled, “Serpentine Structures for Continuous Flow Particle Separations”, by Lean et al.;   U.S. Published Application No. 2008/0128331, entitled, “Particle Separation and Concentration System”, by Lean et al.;   U.S. Published Application No. 2008/0230458, entitled, “Vortex Structure for High Throughput Continuous Flow Separation”, by Lean et al.;   U.S. Published Application No. 2009/0114601, entitled, “Device and Method for Dynamic Processing in Water Purification”, by Lean et al.;   U.S. Published Application No. 2009/0114607, entitled, “Fluidic Device and Method for Separation of Neutrally Buoyant Particles”, by Lean et al.;   U.S. Published Application No. 2010/140092, entitled, “Flow De-Ionization Using Independently Controlled Voltages”, by Armin R. Volkel et al.;   U.S. patent application Ser. No. 12/484,071, filed Jun. 12, 2009, entitled, “Method and Apparatus for Continuous Flow Membrane-Less Algae Dewatering”, by Lean et al.;   U.S. Published Application No. 2009/0283455, entitled, “Fluidic Structures for Membraneless Particle Separation”, by Lean et al.;   U.S. Published Application No. 2009/0283452, entitled “Method and Apparatus for Splitting Fluid Flow in a Membraneless Particle Separation System”, by Lean et al.;   U.S. patent application Ser. No. 12/615,663, filed Nov. 10, 2009, entitled, “Desalination Using Supercritical Water and Spiral Separation”, by Lean et al.;   U.S. Published Application No. 2010/0072142, entitled, “Method and System for Seeding with Mature Floc to Accelerate Aggregation in a Water Treatment Process”, by Lean et al.;   U.S. patent application Ser. No. 12/484,038, filed Jun. 12, 2009, entitled, “Stand-Alone Integrated Water Treatment System for Distributed Water Supply to Small Communities”, by Lean et al.;   U.S. patent application Ser. No. 12/484,005, filed Jun. 12, 2009, entitled, “Spiral Mixer for Floc Conditioning”, by Lean et al.;   U.S. patent application Ser. No. 12/484,058, filed Jun. 12, 2009, entitled, “Platform Technology for Industrial Separations”, by Lean et al.;   U.S. patent application Ser. No. ______ [Atty. Dkt. No. 20100358-US-NP], filed ______, entitled, “Membrane Bioreactor (MBR) and Moving Bed Bioreactor (MBBR) Configurations for Wastewater Treatment”, by Lean et al.;   U.S. patent application Ser. No. ______ [Atty. Dkt. No. 20100997-US-NP], filed ______, entitled, “All-Electric Coagulant Generation System”, by Volkel et al.; and   U.S. patent application Ser. No. ______ [Atty. Dkt. No. 20100218-US-NP], filed ______, entitled, “System and Apparatus for Seawater Organics Removal”, by Meng H. Lean et al.   
 
       BRIEF DESCRIPTION 
       [0025]    The following description and drawings set forth certain illustrative implementations of the disclosure in detail, which are indicative of several exemplary ways in which the various principles of the disclosure may be carried out. The illustrative examples, however, are not exhaustive of the many possible embodiments of the disclosure. Other objects, advantages and novel features of the disclosure will be set forth in the following detailed description of the disclosure when considered in conjunction with the drawings, in which: 
         [0026]    According to one aspect of the present disclosure, an electrocoagulation system including a dosing unit, a mixing unit and a buffer tank is provided. The dosing unit receives a fluid from an external source and injects an electrochemically generated coagulant into the fluid using one or more pairs of electrodes. The mixing unit mixes the coagulant with the fluid and is separate from the dosing unit. The buffer tank holds the fluid until particles contained in the fluid grow to a predetermined size. 
         [0027]    According to another aspect of the present disclosure, a water treatment system including a dosing unit, a mixing unit, a buffer tank, and a filter and/or separator is provided. The dosing unit receives a fluid from an external source and injects an electrochemically generated coagulant into the fluid using one or more pairs of electrodes. The mixing unit mixes the coagulant with the fluid and is separate from the dosing unit. The buffer tank holds the fluid until particles contained in the fluid grow to a predetermined size. The filter and/or separator extracts particles of the predetermined size from the fluid. 
         [0028]    According to another aspect of the present disclosure, a method of treating water using electrocoagulation is provided. A fluid is received from an external source and injected with an electrochemically generated coagulant using one or more pairs of electrodes. The fluid and the coagulant are mixed independent of the injection. The mixed fluid is buffered until particles contained in the fluid grow to a predetermined size and the particles are filtered and/or separated from the fluid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a block diagram of a water treatment system in accordance with aspects of the present application; 
           [0030]      FIG. 2  is a detailed block diagram of an electrocoagulation (EC) system in accordance with aspects of the present application; 
           [0031]      FIG. 3  is a table of sample calculations for the required current for a seawater treatment system employing an EC system; 
           [0032]      FIG. 4  is a single planar spiral-type hydrodynamic separator according to aspects of the present disclosure; 
           [0033]      FIG. 5  is a multi-planar arc-type hydrodynamic separator according to aspects of the present disclosure; and, 
           [0034]      FIG. 6  is another multi-planar arc-type hydrodynamic separator according to aspects of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    One or more embodiments or implementations are hereinafter described in conjunction with the drawings, where like reference numerals are used to refer to like elements throughout, and where the various features are not necessarily drawn to scale. 
         [0036]    With reference to  FIG. 1 , a water treatment system  100  according to aspects of the present disclosure is illustrated. The water treatment system  100  receives source water  102  from a base water source, such as a pond, a creek, a river, a lake, an estuary, a well, a holding tank, or other location. In certain embodiments, the source water  102  is initially passed through a filter and/or strainer  104 , where the filter and/or strainer  104  suitably includes openings sized to trap particulates above a certain size. For example, the openings may be sized to block particulates sized larger than 200 μm. The filter and/or strainer  104  is useful to avoid settling of large suspended particles in the water treatment system  100 . Additionally or alternatively, in certain embodiments, alkalinity  106  is added to the source water  102  in the form of a base to adjust the pH of the source water  102 . Any suitable base may be employed. 
         [0037]    The source water  102 , regardless of whether filtered and/or strained and/or dosed with the alkalinity  106 , flows to an electrocoagulation (EC) system  108  where a dosing unit  110  thereof doses the source water  102  with an electrochemically generated coagulant. Notably, the dosing unit  110  need not uniformly dose the source water  102  with the coagulant. To generate the coagulant, the dosing unit  110  suitably includes one or more individually addressable pairs of electrodes that can provide the correct amount of coagulant molecules to the source water  102  below the maximal desired voltage. It is contemplated that the independent pair(s) of electrodes are configured in series or in parallel. 
         [0038]    The maximal desired voltage is typically the voltage no higher than necessary to achieve the electrochemical reaction needed for generation of the coagulant. For iron, this is typically 1-1.5V, and, for aluminum, this is typically 2-3V. The maximal desired voltage is important from an efficiency standpoint. As the applied voltage across the independent pair(s) of electrodes increases, the number of electrochemical reactions generally increases. Hence, above the applied voltage necessary to achieve the electrochemical reaction needed for generation of the coagulant, unnecessary electrochemical reactions occur, thereby wasting energy. 
         [0039]    The dosing is suitably adjusted manually and/or automatically, on the basis of the source water  102 . For example, as the conductivity and/or the turbidity of the source water  102  increase, the dosing is adjusted. Dosing may be adjusted through modification of one or more of the flow rate through the dosing unit  110 , the applied voltage across each of one or more of the independent pair(s) of electrodes, which of the independent pair(s) of electrodes are activated, the pH of the source water  102 , and the like. As to which of the independent pair(s) of electrodes are activated, it is contemplated that, in certain situations, it may be appropriate to activate fewer than all the individual pair(s) of electrodes. 
         [0040]    The residence of the source water  102  within this dosing unit  110  is preferably as short as possible, but not more than 20 seconds, before it enters a mixing unit  112  of the EC system  108 . The mixing unit  112  efficiently distributes the coagulant through the source water  102  for floc conditioning. As noted above, the dosing unit  110  need not uniformly dose the source water  102  with the coagulant, whereby the mixing unit  110  is an important component of the EC system  108 . Suitably, the mixing unit  112  is a static or active in line mixing unit, such as a spiral mixer, but any type of mixing unit is contemplated. In certain embodiments, the flow regime through the mixing unit  112  is adjustable to control the turbulence and mixing of the source water  102 . As with the dosing unit  110 , the mixing unit  110  is typically controlled automatically and/or manually, on the basis of the source water  102 . 
         [0041]    In view of the discussion heretofore, it is to be appreciated that the dosing unit  110  and the mixing unit  112  are physically separate. This allows individual optimization of the dosing and the mixing and allows for the EC system  108  to be independent of the quality of the source water  102 . Further, this allows for easier flow rate scaling, as the different components of the EC system  108  follow different scale-up rules based on their core functionality. 
         [0042]    After leaving the mixing unit  112 , the source water  102  enters a buffer tank  114  of the EC system  108 . The buffer tank  114  allows the floc particles to grow to the required size for efficient removal by a filter and/or separator  116  downstream from the buffer tank  114 . As such, the filter and/or separator  116  typically dictates the duration with which the source water  102  needs to remain within the buffer tank  114  and/or the size of the buffer tank  114 . Suitably, the buffer tank  114  is in line with the mixing unit  112  and/or provides a gently stirred environment to facilitate quick growth of the floc particles. 
         [0043]    The filter and/or separator  116  receives the source water  102  from the buffer tank  114  and removes the grown floc particles above a certain size from the source water  102  through one or more of sedimentation, filtering, hydrodynamic separation, and the like. As such, the filter and/or separator  116  is suitably one or more of a filter (barrier), a hydrodynamic separator (e.g., a spiral-type or arc-type hydrodynamic separator), and the like. Typically, the removal of floc particles yields effluent water  118  and waste water  120 . 
         [0044]    Additionally or alternatively, the effluent water  118  may be passed through a follow-on filter, e.g. to protect against abnormal periods of operation, such as flow pulsation or sudden spikes in turbidity of the source water  102 , or to remove dissolved solids using a reverse osmosis system. 
         [0045]    The waste water  120  is suitably disposed of in an appropriate manner. For example, the waste water  120  may be recirculated through the water treatment system  100  along a feedback line  122 . As another example, the waste water  120  may be passed to another water treatment or sludge treatment system. 
         [0046]    With reference to  FIG. 2 , detailed block diagram of an electrocoagulation (EC) system  200  according to aspects of the present disclosure is provided. The EC system  200  is a more specific embodiment of the EC system  108  of  FIG. 1 . Therefore, the discussion heretofore is equally amenable to the discussion to follow and components described hereafter are to be understood as paralleling like components discussed heretofore, unless noted otherwise. 
         [0047]    An optional first pump  202  receives source water, such as the source water  102  of  FIG. 1 , from an external source and pumps the water to a dosing unit  204 . The first pump  202  is suitably employed to manually and/or automatically control the flow rate of the source water through the EC system  200 . However, in certain embodiments, a pump external to the EC system  200  or placed elsewhere within the EC system  200 , such as a second pump  206 , is employed in lieu of the first pump  202  to facilitate the flow of the source water through the EC system  200 . 
         [0048]    The source water flows through one or more optional sensors  208  and an optional first valve  210  before being received by the dosing unit  204 . The sensor(s)  208  suitably measure one or more of the conductivity, the pH, the quality, and the like of the source water to facilitate manual and/or automatic dosing of the source water. The first valve  210  suitably allows the flow of the source water to the dosing unit  204  to be stopped and/or reduced. However, it is additionally or alternatively contemplated that the first valve  210  is employed to prevent backflow from the dosing unit  204 . The first valve  210  may be manually and/or automatically controlled. 
         [0049]    Upon entering the dosing unit  204 , the source water suitably flows vertically therethrough past one or more independent pairs of electrodes  212 , where a pump, such as the first pump  202 , suitably facilities such a flow. However, a horizontal configuration is contemplated. For example, it is contemplated that the source water enters the dosing unit  204  at one vertically oriented side, passes through the independent pair(s) of electrodes  212 , and leaves the dosing unit  204  on the opposite side. As illustrated, the individual pair(s) of electrodes  212  include a first pair of electrodes  212   a  and a second pair of electrodes  212   b.    
         [0050]    Each of the independent pair(s) of electrodes  212  includes a cathode (not shown) and an anode  214 ,  216  electrically coupled to a power supply  218 . The power supply  218  suitably allows individual control, manual or otherwise, over the applied voltage and/or current of the individual pair(s) of electrodes  212 . In certain embodiments, the power supply  218  is configured to switch between the independent pair(s) of electrodes  212  and/or between electrodes of the independent pair(s) of electrodes  212  at regular intervals for a more equal usage of the electrodes. For example, to switch between electrodes of one of the independent pair(s) of electrodes  212 , the polarity of the independent pair of electrodes may be switched. 
         [0051]    While the source water flows through the dosing unit  204 , the independent pair(s) of electrodes  212  are suitably controlled manually or automatically to properly dose the source water on the basis of source water quality. As noted above, dosing may be adjusted through modification of the applied voltage across the independent pair(s) of electrodes  212  and/or which of the independent pair(s) of electrodes  212  are activated. The applied voltage is suitably no greater than the maximal desired voltage, which is typically the voltage no higher than necessary to achieve the electrochemical reaction needed for generation of the coagulant. For iron, this is typically 1-1.5V, and, for aluminum, this is typically 2-3V. 
         [0052]    In certain embodiments, the dosing unit  204  may include a vent outlet  220  or the like to vent hydrogen gas generated at the cathodes of the independent pair(s) of electrodes  212  when the independent pair(s) of electrodes  212  are activated. Additionally or alternatively, the dosing unit  204  may include a skimmer (not shown) to remove floc floating to the top of the dosing unit  204 . Floc tends to incorporate hydrogen generated at the cathodes of the independent pair(s) of electrodes  212 , thereby causing the floc to float to the top of the dosing unit  204 . Additionally or alternatively, the dosing unit  204  may include a baffle  222  or the like to spread the source water entering the dosing unit  204  throughout the dosing unit  204 . Advantageously, this prevents stagnation points and/or counter vortices inside the dosing unit  204 , which prevent all coagulant ions generated at the independent pair(s) of electrodes  212  from being swept with the source water. 
         [0053]    After passing the independent pair(s) of electrodes  212 , the source water leaves the dosing unit  204  and enters a mixing unit  224 . Suitably, the source water is in the dosing unit  204  as short as possible, but no more than 20 seconds. To shorten the residence time inside the dosing unit  204 , many parallel electrode pairs can be arranged to increase throughput. That is to say, many parallel electrode pairs can be arranged along the length of the dosing unit  204  and simultaneously activated. 
         [0054]    In passing to the mixing unit  224 , the source water suitably passes through the optional second pump  206  and/or an optional second valve  226 . The second pump  206  suitably supplements the first pump  202  in controlling the flow of the source water through the EC system  200 . However, it is contemplated that the second pump  206  acts in lieu of the first pump  202  or the first pump  202  acts in lieu of the second pump  206 . The second valve  226  suitably allows the flow of the source water to the mixing unit  224  to be stopped and/or reduced. The second valve  226  and/or the second pump  206  may be manually and/or automatically controlled. 
         [0055]    The mixing unit  224  efficiently distributes the coagulant through the source water for floc conditioning. Notably, the dosing unit  204  need not uniformly dose the source water with the coagulant. Therefore, it is to be understood that the mixing unit  224  is an important component of the EC system  200 . In certain embodiments, the flow regime of the mixing unit  224  is manually and/or automatically adjustable to control the turbulence and mixing of the source water. In such embodiments, control is typically based on the source water. 
         [0056]    The mixing unit  224  is suitably a static or active in line mixing unit, but any type of mixing unit is contemplated. For example, in certain embodiments and as illustrated, a spiral mixer is employed to facilitate mixing. While the spiral mixer may take a variety of forms, in at least some forms, the spiral mixer operates as described in U.S. Ser. No. 12/484,005, filed on Jun. 12, 2009, and entitled “Spiral Mixing unit for Floc Conditioning”, incorporated herein by reference in its entirety. 
         [0057]    As described in the “Spiral Mixing unit for Floc Conditioning”, the spiral mixer provides a flash mixing where incoming source water is angled at the inlet to cause chaotic mixing when the source water impinges on a lower spiral channel wall of the spiral mixer. Further, a high shear driven fluidic flow rate in the channel is custom designed to achieve a shear rate which enhances the growth of dense and compact floc particles within a narrow, but uniform size range. In general, the higher the shear rate, the smaller the aggregated floc. 
         [0058]    After passing through the mixing unit  224 , the source water enters a buffer tank  228  so the floc particles can grow to a desired size before being removed from the source water. Suitably, the buffer tank  228  is in line with the mixing unit  224 . A filter and/or separator, such as a filter and/or separator  116 , used for removing the floc particles suitably dictates the duration with which the source water remains within the buffer tank  228  and the size of the buffer tank  228 . 
         [0059]    An optional electronic control system  230  suitably optimizes operation of the EC system  200 . The control system  230  monitors the sensor(s)  208  to determine the source water quality. Based on this determination, the control system  230  controls the dosing and/or mixing using one or more of the first pump  202 , the second pump  206 , the first valve  210 , the second valve  226 , the power supply  218 , and the like. Advantageously, the control system  230  can respond to changes in, for example, source water quality faster and more reliably than a manual operator. Additionally, the control system  230  can perform one or more of monitoring the usage of each of the pair(s) of electrodes  212 , switching the polarity of one or more of the pair(s) of electrodes  212  in regular intervals, suggesting replacements of the pair(s) of electrodes  212  when needed, and the like. 
         [0060]    A processor (not shown) of the control system  230  suitably carries out computer executable instructions stored on a non-transient computer readable medium (not shown) of the control system  230  to control and optimize the EC system  200 . The processor includes one or more of a microprocessor, a microcontroller, a graphic processing unit (GPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and the like. The memory includes one or more of a magnetic disk or other magnetic storage medium; an optical disk or other optical storage medium; a random access memory (RAM), read-only memory (ROM), or other electronic memory device or chip or set of operatively interconnected chips; an Internet server from which the stored instructions may be retrieved via the Internet or a local area network; or so forth. In certain embodiments, a computer embodies the control system  230 , as illustrated. 
         [0061]    With reference to  FIG. 3 , a table  300  of sample calculations for the required current for a seawater treatment system employing an EC system, such as the EC system  108  of  FIG. 1 , is provided. The calculations are done as if the seawater treatment system treats 12,000 gallons of seawater per day with an equivalent dose of 10 mg/l FeCl 3 . Residence time within a dosing unit of the EC system is calculated assuming the dosing unit includes a volume of 0.0025 m 3 . 
         [0062]    With reference to  FIG. 4 , a single planar spiral-type hydrodynamic separator  400  is illustrated. In certain embodiments, the separator  400  is employed within the water treatment system  100  of  FIG. 1  as the filter and/or separator  116 . The separator  400  has an inlet  402 , at least one curved or spiral portion  404  and an outlet  406 . This separator  400 , in one form, may be cut from plastic. The type of plastic may vary as a function of the specific application and the environment in which it is implemented. In one variation of the separator  400 , the center region of the separator  400  near the inlet  402  may be removed to allow access for an inlet coupler to be described hereafter. The spiral portion  404  of the separator  400  may take a variety of forms. For example, the spiral portion  404  may be converging or diverging. As a further example, the outlet  406  and inlet  402  locations may be interchanged to suit the application (e.g., for increasing or decreasing centrifugal forces). 
         [0063]    The single planar spiral-type hydrodynamic separator  400  uses the curved channel of the spiral portion  404  to introduce a centrifugal force that generates a flow field in the fluid, e.g., water, that will sweep suspended particles to one side of the channel, including neutrally buoyant particles (e.g., particles having substantially the same density as water, or the fluid in which the particles reside). Separation efficiency depends on many parameters, including, for example, geometry of the channel and flow velocity. Forces on the particles include centrifugal forces and pressure driven forces, among others. 
         [0064]    With reference to  FIG. 5 , a multi-planar arc-type hydrodynamic separator  500  is illustrated. In certain embodiments, the separator  500  is employed within the water treatment system  100  of  FIG. 1  as the filter and/or separator  116 . The separator  500  operates as described in connection with the single planar spiral-type hydrodynamic separator  400  of  FIG. 4  and comprises multiple planar curved arc segments  502  (e.g., fractional arc segments) that are vertically stacked as parallel channels to increase throughput. These planar curved arc segments  502  do not complete a loop for any one arc segment, although the characteristics and functions of a spiral-type hydrodynamic separator, such as the single planar spiral-type hydrodynamic separator  400  of  FIG. 4 , nonetheless apply to the arc segments  502 . The arc segments  502  comprise an inlet  504 , curved or arc section  506  and an outlet  508 . 
         [0065]    Also shown in  FIG. 5  is an inlet coupler  510  that allows for an inlet of fluid from a common source to all of the separate arc segments  502 . It should be appreciated that the inlet coupler  510  may take a variety of forms. In one form, the inlet coupler  510  is a cylinder and has perforations or a continuous slot corresponding to the inlet of each layer. At least one outlet coupler (not shown) may also be implemented. The outlet coupler(s) could resemble the inlet coupler. 
         [0066]    With reference to  FIG. 6 , another multi-planar arc-type hydrodynamic separator  600  is illustrated. In certain embodiments, the separator  600  is employed within the water treatment system  100  of  FIG. 1  as the filter and/or separator  116 . The separator  600  operates as described in connection with the single planar spiral-type hydrodynamic separator  400  of  FIG. 4  and comprises stacked channels (not shown individually). The curved structure  602  has an inlet  604  (which may include an inlet coupler), curved portions  606  and  608 , and at least one outlet  610  or  612 . As shown, there is an outlet  610  for selected particles such as particles of a particular size or density (e.g., buoyant particles). The outlet  610  is positioned midway around the curve between the curved portion  606  and the curved portion  608 . The second outlet  612  for selected particles of a second size or density (e.g., neutrally buoyant particles) is positioned at an end of the curve  608  opposite the inlet  604 . In general, these outlets  610  and  612  can be used to remove particles of varying sizes or densities from the fluid flow. As above, at least one outlet coupler may also be utilized. 
         [0067]    For more information pertaining to  FIGS. 4-6 , attention is directed to U.S. Ser. No. 12/120,093, filed on May 13, 2008, and entitled “Fluidic Structure for Membraneless Particle Separation”, incorporated herein by reference in its entirety. Further, for additional forms of hydrodynamic separators suitably employed as the filter and/or separator  116  of  FIG. 1 , attention is directed to U.S. Ser. No. 11/606,458, filed Nov. 30, 2006, and entitled “Serpentine Structures for Continuous Flow Particle Separations”; U.S. Ser. No. 11/606,460, filed Nov. 30, 2006, and entitled “Particle Separation and Concentration System”; U.S. Ser. No. 11/725,358, filed Mar. 19, 2007, and entitled “Vortex Structure for High Throughput Continuous Flow Separation”; U.S. Ser. No. 11/936,753, filed Nov. 7, 2007, and entitled “Device and Method for Dynamic Processing in Water Purification”; U.S. Ser. No. 11/936,729, filed Nov. 7, 2007, and entitled “Fluidic Device and Method for Separation of Neutrally Buoyant Particles”; U.S. Ser. No. 12/328,682, filed Dec. 4, 2008, and entitled “Flow De-Ionization using Independently Controlled Voltages”; U.S. Ser. No. 12/484,071, filed Jun. 12, 2009, and entitled “Method and Apparatus for Continuous Flow Membrane-Less Algae Dewatering”; U.S. Ser. No. 12/120,153, filed May 13, 2008, and entitled “Method and Apparatus for Splitting Fluid Flow in a Membraneless Particle Separation System”; U.S. Ser. No. 12/615,663, filed Nov. 10, 2009, and entitled “Desalination using Supercritical Water and Spiral Separation”; U.S. Ser. No. 12/234,373, filed Sep. 19, 2008, and entitled “Method and System for Seeding with Mature Floc to Accelerate Aggregation in a Water Treatment Process”; U.S. Ser. No. 12/484,038, filed Jun. 12, 2009, and entitled “Stand-Alone Integrated Water Treatment System for Distributed Water Supply to Small Communities”; and, U.S. Ser. No. 12/484,058, filed Jun. 12, 2009, and entitled “Platform Technology for Industrial Separations”, all of which are incorporated herein by reference in their entireties. 
         [0068]    The disclosure has been made with reference to preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the preferred embodiments be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.