Abstract:
A pressure vessel ( 28 ) accumulates an aqueous stream at elevated pressure and feeds it through a pressure retaining array of passages ( 18 ) in the bottom wall of a modular reaction chamber ( 14 ) that operates at atmospheric pressure. Spaced electrodes ( 16 ) treat the stream during upward flow to the open top of the chamber, where the treated stream overflows the chamber and falls into an inter-wall volume between the chamber and an outside housing ( 12 ), washing foam from the housing and chamber as it exits. A housing cover ( 54 ) establishes headspace over the chamber to accommodate the overflow. The entire chamber ( 14 ) is removable from the housing ( 12 ) by loosening fasteners ( 39 ) in the bottom wall ( 20 ) and lifting it free, with no impediment due to clogging or corrosion outside the chamber.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention generally relates to electrolysis and to processes, compositions used therein, and method of preparing the compositions. More specifically, the invention relates to product, process, and electrolyte composition for electrolytic material treatment, where the material is water, sewage, or other waste water. In another aspect, the invention generally relates to the chemistry of electrical and wave energy. More specifically, the invention relates to electrolytic apparatus and to cells with electrolyte treatment means. 
         [0003]    2. Description of Related Art 
         [0004]    Electrocoagulation is a process of electrical destabilization of particles in water and is used to treat water to remove impurities. This process changes the surface charge of suspended particles, which allows suspended matter to form an agglomeration. Electrocoagulation is known to require no filters, no daily maintenance, and no additives. It is capable of removing any size of suspended solids, oil, grease and heavy metals. 
         [0005]    Electrocoagulation employs processing chambers that may contain one or more electrolytic cells. A housing typically defines a single chamber and contains one or more cells. Where a chamber is formed of multiple cells, each cell performs electrolysis according to its own characteristics. A single cell is formed of at least two electrodes in contact with an electrolyte solution. The electrodes are made of metal or carbon. An electrical charge is applied across a pair of electrode plates to cause a flow of ions within the electrolyte solution, resulting in redox reactions at the electrodes. According to conventional terminology, one electrode of an electrode pair is an anode, where oxidation occurs. The second electrode of the electrode pair is a cathode, where reduction occurs. In an electrolytic cell, the anode is positively charged and the cathode is negatively charged. The oppositely charged plates produce ions that move in the electrolyte. Positive ions move toward the negative electrode and negative ions move toward the positive electrode. 
         [0006]    An electrolytic cell is useful to decompose compounds in the electrolyte using electrical energy. For example, water in the electrolyte can be decomposed into hydrogen gas and oxygen gas. The practice of electrolysis upon aqueous solution containing other compounds can result in production of water plus an agglomerate. The latter can be separated from the water to produce residual clean water. This process and its chemistry are well known, and many types of apparatus are used in the practice of it. 
         [0007]    While electrolysis is highly effective in producing clean water, attempts to operate an electrolytic cell on a continuous, long term basis with a complex or variable electrolyte stream have encountered maintenance and operational difficulties. One of these limitations is with current flow paths. In an idealized, text book model of a cell, oppositely charged plates face each other across a gap filled with water, and the major facing surfaces of the plates generate ions or other charged particles in the water. In practice, plate wear can be much more accelerated than suggested by the model cell. Electrical current tends to travel along selected pathways of least resistance and often concentrates at specific areas of an electrode, such as the edges of the electrode. Concentrated current flow is undesirable because it quickly erodes the areas where it travels. Current can cut channels through a plate, erode away a plate from one edge, and even cut off a connection tab that is supplying power to the plate. In some chambers, the plates have been selectively eroded to the point of premature collapse. These problems result in interruption of water treatment and may require extensive and frequent maintenance of the electrocoagulation chamber. 
         [0008]    Electrocoagulation is effective for removing heavy metals, suspended solids, emulsified organics and many other contaminants from water. The contaminants are combined in a waste stream that produces floc, which is mainly insoluble oxides and hydroxides. A floc stream tends to settle for easy separation from the clear water. 
         [0009]    It would be desirable for an electrocoagulation chamber to be quickly and easily serviced when maintenance is needed. An aspect of maintenance is the ability to quickly and easily reconfigure a cell to meet new operational requirements. Thus, an object of the invention is to simplify cell reconstruction and reconfiguration by use of a modular cell design. 
         [0010]    Rebuilding a typical chamber involves the cost of new plates in addition to loss of use of the chamber during down-time. Electrode plates often are arranged within a housing by use of a spacer, which can be a slotted edge guide. The slots receive the plates, while intermediate portions of the guide between slots serve as spacers that establish a predetermined gap between plates. Typically, two guides establish the plate spacing parameters of the cell, with the two guides arranged on opposite sides of the plates or on top and bottom of the plates. Repairing almost any problem with a typical cell requires at least partial disassembly of the chamber. 
         [0011]    Changing operational characteristics of a typical cell also requires at least partial disassembly of the chamber. For example, when treating certain electrolytes in a typical chamber, it may be necessary to change the plate gap that is currently established in a chamber. Typically, a change of plate gap is accomplished by switching the slotted guide for another with a more suitable intermediate dimension between slots. In addition, the accompanying loss of service time due to disassembly of a cell for any reason is undesirable. 
         [0012]    Rebuilding or reconfiguring a cell often is a difficult process. Simply stating that there is a requirement to change a plate or change a guide is deceptively simple. In practice, a cell needing maintenance can be so clogged or corroded that removing a single plate or removing a single guide is ponderous work. Such simply stated tasks may require hours of hard work with the help of heavy duty shop equipment. Hence, references to lost time and down time are serious matters and not to be taken lightly. 
         [0013]    It would be desirable for an electrolytic chamber to be rapidly serviceable, even when disassembly or replacement is required. 
         [0014]    Further, it would be desirable for an electrocoagulation cell to be constructed in such a manner that clogging and corrosion are minimized. 
         [0015]    To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following. 
       BRIEF SUMMARY OF THE INVENTION 
       [0016]    Against the described background, it is therefore a general object of the invention to provide an electrocoagulation chamber formed of a housing that contains a modular or removable reaction chamber. The component reaction chamber is configured to support a plurality of electrode plates at preselected mutual spacing and oriented in a vertical position within the reaction chamber. A manifold grid or array of inlet openings is formed in a bottom, manifold wall of the reaction chamber. The array is configured to place the openings, or at least a preselected portion of such openings, to communicate with the spacing between electrode plates, such that a liquid feed stream passing upwardly through the openings is fed into the spacing between the electrode plates. Preferably the number and position of the inlet openings feeding each spacing is substantially identical so as to create a uniform feed between each spaced pair of plates. In any event, the manifold array establishes a flow of liquid into the reaction chamber via the spaces between the electrodes. 
         [0017]    The reaction chamber forms an outlet for discharging the treated liquid feed stream. The outlet may be an open top of the reaction chamber, where the treated feed stream is allowed to overflow the side walls of the reaction chamber. The housing may be taller and wider than the reaction chamber, such that the overflowing feed stream falls into or within the housing. The electrode plates may have a functional height of about the height of the reaction chamber so that the feed stream is treated for substantially the entire height of the reaction chamber. A portion of each electrode plate may extend above the top of the reaction chamber. These extending portions may be ears or tabs that provide a dry electrical connection point for applying selected polarity to each plate. 
         [0018]    The housing and modular reaction chamber engage one another to establish two modes of operation for processing the liquid feed stream. In the first mode of operation, upstream of the manifold, the feed stream is handled under pressure. As a portion of the housing, or as a separate chamber located below the housing, a pressure vessel receives the feed stream below the reaction chamber. The pressure vessel defines an inlet for receiving the feed stream under pressure. Thus, the inlet may be deemed to be relatively small and is sized for connection to a conduit from a pump or other source of pressurized liquid. Conveniently, the inlet may be located on the bottom wall of the pressure vessel. A top wall of the pressure vessel defines an outlet window. The dimensions of this outlet window are similar to the dimensions of the manifold grid or array of inlet openings on the bottom or manifold wall of the reaction chamber. As compared to the relatively small inlet to the pressure vessel, the outlet window is relatively large. The term, “window” refers to a large opening. This window is juxtaposed to the manifold wall of the reaction chamber, where the array of inlet openings to the reaction chamber limits flow from the pressure vessel to the reaction chamber. In one possible configuration, the top wall of the pressure vessel extends centrally from the periphery of the pressure vessel to a position underlying side walls of the reaction chamber, and then defines a central outlet window beginning inside the side walls of the reaction chamber. This suggested configuration allows the pressure vessel to support the reaction chamber while leaving open the large central window for transmitting the pressurized feed stream into the reaction chamber through the array of inlet openings, which overlie the outlet window. 
         [0019]    In the second mode of operation, the feed stream enters the reaction chamber at atmospheric pressure through the manifold array of inlet openings. In the reaction chamber, the feed stream is treated at atmospheric pressure. The feed stream rises in the reaction chamber until reaching the top where the treated stream overflows the top edge of reaction chamber. In this mode of processing, the relationship between the reaction chamber and the housing is controlling. The housing is wider and taller than the reaction chamber. The reaction chamber fits into the housing in a predefined position where there is spacing between the respective sidewalls of the two components, creating an inter-wall volume between the sidewalls of the reaction chamber and housing. This spacing allows the treated feed stream to be removed from the housing without leaving behind any substantial trapped liquid in the inter-wall volume. In a preferred arrangement, the housing is cylindrical and has a predefined transverse diameter. The reaction chamber is a rectangular box or rectangular cuboid, where transverse diagonals between corners are shorter than the predefined transverse diameter of the housing cylinder. The reaction chamber may fit symmetrically into the housing at a preselected position, such that no side wall of the reaction chamber is in contact with a side wall of the housing. 
         [0020]    The housing carries a discharge means, such as a chute that feeds the overflowed liquid feed stream from the inter-wall volume to an external facility such as a settling pond or tank. The chute is located at the bottom level of the housing, at approximately the same level as the bottom wall of the reaction chamber. Liquid from the overflowed feed stream is able to drain from all sides of the reaction chamber through the chute. This drainage is desirable because electrocoagulation produces a top foam. The upflowing liquid in atmospheric processing washes the foam out of the reaction chamber and into the inter-wall volume. That liquid, including top foam, exits the housing through the chute. 
         [0021]    The reaction chamber is configured to ensure symmetrical or centered fit within the housing. One suitable configuration is for the bottom, manifold wall of the reaction chamber to closely fit the inside transverse shape of the housing, inside the side walls. When the housing is cylindrical, this is achieved by configuring the bottom wall of the reaction chamber to be a disk with diameter approximately equal to the inside diameter of a cylindrical housing. This bottom wall is mounted to the side walls of the reaction chamber to carry the side walls where desired, which typically is in a centered relationship. Likewise, the array of manifold holes in the bottom wall is formed with respect to the mounting of the side walls, which in turn locates the electrode plates and interplate spacings. 
         [0022]    In a modified version of the described bottom wall, one edge of the bottom wall is cut straight, outside and parallel to a side wall of the reaction chamber. This straight edge is in a position corresponding to the mounting location of the exit chute in the housing. Thus, the exit chute is mounted at an opening in the side wall of the housing, with a support base extending into the housing and fitting against the straight edge of the reaction chamber&#39;s bottom wall. This fit between the base of the chute and the bottom wall of the reaction chamber establishes a transition area for guiding treated liquid out of the housing. The base of the exit chute may be thinner than the bottom wall of the reaction chamber, establishing a downward step at the start of the chute to help feed liquids from the inter-wall volume out of the chute. Together, the housing, chute, and reaction chamber form a coordinated structure that ensures full drainage of overflow liquid. 
         [0023]    The reaction chamber is coordinated in size with the housing. Similarly sized reaction chambers can be exchanged in the same housing, and limited differences in the configuration of similarly sized reaction chambers allow a certain amount of variation in processing performance while maintaining the same housing. As described, the reaction chamber is formed of a bottom, manifold wall, and a rectangular box structure that defines four side walls. An opposite pair of the side walls is configured to support electrode plates of a preselected thickness at a preselected interplate spacing, forming a series of plates that is a full set for the reaction chamber. These supporting side walls may be grooved in a coordinated pattern to establish vertical reception slots that each receive and support an electrode plate. Ungrooved lengths between the grooves establish an interplate spacing. The first and last plates in the series are located against the opposite side walls, which are non-supporting side walls, and which are normal to the supporting side walls. The manifold apertures in the bottom wall lie generally in alignment with the ungrooved lengths. Typical configurations for a reaction chamber that processes ten gallons per minute are ten electrode plates with three-eighths inch spacing or eleven electrode plates with one-quarter inch spacing. 
         [0024]    Each electrode plate is configured with a lower portion or processing portion to treat the liquid feed stream and that fits within said reaction chamber. Each electrode plate also is configured with an upper or superstructure portion that remains above the reaction chamber and is adapted for possible attachment to a polarizing source. The superstructure portion is an upstanding ear or tab that is a narrow extension of the lower portion of the electrode plate and is located near one edge of the electrode plate. The housing is fitted with a top cover that contains the treated water from overflowing the top of the housing while permitting passage of the tab through the cover. The cover is slotted in positions and number that align with the tabs, according to the position and number of plates in the reaction chamber. As an example, with ten electrode plates, the plates in successive slots would have tabs located at opposite sides of the reaction chamber. Only one design of electrode plate is necessary because any plate can be turned to vary the relative side edge where the tab lies. With the single design, each successive plate is reversed so that the tabs in each pair of consecutive slots are at opposite lateral sides of the reaction chamber. Accordingly, the cover would have aligned slots that are coordinated with the alternating side alignments of the successive plates. With ten plates in a single reaction chamber, the cover would have two columns of five slots each. The slots in each column are staggered with respect to slots in the other column, to match the staggered positions of the tabs. A seal such as an o-ring is applied to each tab at a suitable height to seal against a slot, thus making the top cover water-tight when attached to the top of the housing. 
         [0025]    The dry exterior of the cover is a convenient location for attaching polar leads. A pair of oppositely polarized mounting bars is attached to the cover in spaced apart locations. The mounting bars may be located near opposite side edges of the cover. For example, a mounting bar may be located near each column of slots, outside the position of the column of slots. This positioning of the mounting bars conveniently places a different polarity in proximity to the tabs in each column of slots. Both the mounting bars and the tabs are configured to accept jumper wires at attachment holes. Jumper wires may be used to connect each mounting bar to each tab that is to carry the same polarity. Jumper wires from each mounting bar are conveniently used to connect to the juxtaposed column of tabs. This arrangement is flexible and allows selected plates to not be directly polarized, if desired. Likewise, it is a simple matter to extend a jumper wire to a tab in the opposite column, if desired, or to otherwise create novel patterns of polarized electrodes. 
         [0026]    To allow direct viewing of chamber performance, the housing or top cover may have viewing windows installed. As an example, the top cover has adequate room for a viewing window in a central position, between the two columns of slots. A viewing window is helpful to monitor foam removal, plate wear, and other dynamic conditions that might develop during operation of a cell. 
         [0027]    The housing and cell are assembled to allow ready disassembly, when needed. The housing, cover, and pressure vessel are assembled on vertical rods located outside the housing, in dry locations. To remove a reaction chamber, the cover is removed by removing top fasteners from the vertical rods. The reaction chamber is removed from within the electrocoagulation chamber by loosening fasteners that secure the manifold wall and into the top wall of the pressure vessel. These fasteners are located in the inter-wall volume and outside the plate area of the reaction chamber. In this inter-wall position, these fasteners are not prone to corrosion. The reaction chamber then can be lifted from the housing. Because the entire reaction chamber is removed as a unit, clogging or corrosion within the chamber does not slow down maintenance. A new reaction chamber, with new manifold and new plates, can be set into the housing to resume service. Where the new chamber is configured the same as the old chamber, the old top can be reused, if desired. If the new reaction chamber is configured differently from the old one, it will be originally equipped with a manifold of coordinated design, and a new top is applied with slots matching the new positions of the plate ears. 
         [0028]    According to a method of the invention, a liquid feed stream is treated by electrocoagulation. First, the feed stream is pressurized above ambient levels and accumulated in a pressure vessel. Second, the liquid feed stream of the pressure vessel is continuously fed through a matrix of pressure limiting openings into a reaction chamber at atmospheric pressure, wherein the reaction chamber contains a vertically oriented array of spaced apart electrode plates, and the matrix of openings is arranged to feed the incoming liquid stream into vertically oriented interplate spaces. Third, the array of electrode plates electrolytically treats the liquid stream in the interplate spaces while the continuously fed liquid stream elevates the treated liquid to the top of the reaction chamber. Fourth, elevated liquid of the feed stream together with any product foam is further elevated to overflow the top of the reaction chamber and fall into a collection area outside the reaction chamber. 
         [0029]    According to a further aspect of the invention, the matrix of pressure limiting openings is configured by sizes and positions to provide uniform upward flows in the reaction chamber. 
         [0030]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with the description, serve to explain the principles of the invention. In the drawings: 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0031]      FIG. 1  is a front elevational view of the housing of the electrocoagulation chamber. 
           [0032]      FIG. 2  is a vertical cross-sectional view of the electrocoagulation chamber taken on the plane through line  2 - 2  of  FIG. 1 . 
           [0033]      FIG. 3  is a horizontal cross-sectional view of the electrocoagulation chamber, taken on the plane of line  3 - 3  of  FIG. 2 . 
           [0034]      FIG. 4  is a top plan view of the electrocoagulation chamber showing the lid. 
           [0035]      FIG. 5  is a side elevational view of a reaction chamber with near side removed to show a set of electrodes therein, with inlet openings and fastener openings in the manifold plate shown in phantom. 
           [0036]      FIG. 6  is a top plan view of a reaction chamber fitted with a set of electrode plates therein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    With reference to the drawings, the invention is an electrocoagulation chamber  10  that is adapted for treating an influent liquid stream moving substantially vertically from bottom to top. The chamber  10  is formed of a housing  12  that contains a modular or removable reaction chamber  14 . The reaction chamber  14  contains a set of electrode plates  16 . In this context, a set of electrode plates is those that occupy predetermined available spots or slots in the reaction chamber, with no requirement that the individual plates match one another, although typically a set of plates will be a set of identical plates. The reaction chamber is configured to carry the electrode plates  16  in predetermined positions, at a preselected interplate spacing, and in substantially vertical orientation. The plates may be vertically elongated in order to provide an elongated, vertical processing pathway within the reaction chamber  14 . 
         [0038]    A means for infeeding a liquid stream to the reaction chamber is located at the bottom of the reaction chamber  14 . The infeed means may be a grid, array or matrix of nozzles or net openings  18  acting as a manifold. Suitably, these net openings  18  may be formed in a manifold wall positioned at the open bottom of the reaction chamber. For convenience, accuracy, and modularity, the manifold wall may be attached as a bottom wall  20  of the reaction chamber  14  by suitable fasteners  41 . The manifold wall is positioned with respect to the reaction chamber to place the array of net openings  18 , or at least a preselected portion of such openings, where they are aligned to communicate with the interplate spacings  22  of a set of plates, such that the liquid feed stream passing upwardly through the openings  18  is fed into the interplate spacings. Preferably the number and position of plural net openings feeding each spacing is substantially identical so as to create a feed of similar or uniform volume between each spaced pair of plates  16 . In any event, the array of openings establishes a flow of liquid into the reaction chamber via the interplate spaces  22 . The combination of coordinated positions of the electrode plates, the interplate spacings, the manifold wall, and the array of net openings in the manifold wall establishes the modular characteristics of the reaction chamber, such that a reaction chamber  14  is readily removed and replaced with another in the housing  12 . For example, reaction chambers  14  can be replaced or substituted for one another within the same housing  12  even when the replacement has a different number of plates or different spacing between plates. 
         [0039]    The reaction chamber  14  defines an outlet for discharging the treated liquid feed stream. The outlet may be an open top  24  of the reaction chamber  14 , where the treated feed stream is allowed to overflow the sides of the reaction chamber  14 . This means for discharge requires no significant attachment to other structures of chamber  10 , further contributing to the ease and speed of replacing a reaction chamber. The housing  12  may be taller and wider than the reaction chamber  14 , such that the overflowing feed stream falls into the housing  12 . The electrode plates  16  may have a functional height of about the height of the reaction chamber  14  so that the feed stream is treated for substantially the entire height of the reaction chamber  14 . A portion of each electrode plate  16  may extend above the open top  24  of the reaction chamber  14 . These extending portions may be ears or tabs  26  that provide a dry electrical connection point for applying selected polarity to each plate  16 . 
         [0040]    The housing  12  and modular reaction chamber  14  engage one another to establish two modes of operation for processing the liquid feed stream. In the first mode of operation, the feed stream is maintained under elevated pressure. As a portion of the housing, or as a separate chamber located below the housing, a pressure vessel  28  located below the reaction chamber  14  receives the feed stream. The pressure vessel defines an net  30  for receiving the feed stream under pressure. Thus, the net  30  may be relatively small and is sized for connection to a conduit from a pump or other source of pressurized liquid. Conveniently, the net  30  may be located on the bottom wall  32  of the pressure vessel  28 . A top wall  34  of the pressure vessel  28  defines a relatively large outlet window  36 . The dimensions of this outlet window  36  are similar to the dimensions of the portion of bottom wall  20  carrying the grid or array of net openings  18  at the bottom of the reaction chamber  14 . By comparison, the net  30  is relatively smaller, while the outlet window  36  is relatively larger, The term, “window” refers to a large opening, This window  36  is juxtaposed to the bottom wall  20  of the reaction chamber  14  and aligned with the grid or array of net openings  18  to the reaction chamber, which limit flow from the pressure vessel  28  to the reaction chamber  14 . In one possible configuration, the top wall  34  of the pressure vessel extends centrally from the periphery of the pressure vessel  28  to a position underlying side walls of the reaction chamber, and then defines a central outlet window from the side walls of the reaction chamber  14 . This suggested configuration allows the pressure vessel  28  to support the reaction chamber  14  while leaving open the large central window  36  for transmitting the pressurized feed stream into the reaction chamber through the array of net openings  18 , which overlie the outlet window  36 . 
         [0041]    In the second mode of operation, the feed stream enters the reaction chamber  14  through the array of net openings  18  and thereafter is treated at atmospheric pressure. Passage through the many openings  18 , as the stream transitions from higher pressure to atmospheric pressure, establishes turbulent flow between the plates  16 , which is favorable for processing the stream. In the reaction chamber  14 , the feed stream is treated at atmospheric pressure. The feed stream rises in the reaction chamber  14  until reaching the top where the treated stream overflows the top edge  24  of reaction chamber  14 . In this mode of processing, the relationship between the reaction chamber  14  and the housing  12  is controlling. The housing  12  is wider and taller than the reaction chamber  14 . The reaction chamber fits into the housing  12  in a predefined position where there is spacing between the respective sidewalls of the two components, creating an inter-wall volume  37 . This spacing allows the treated feed stream to be removed from the housing  12  without leaving behind any substantial volume of trapped liquid in the inter-wall volume  37 . In a preferred arrangement, the housing  12  is shaped as an upright cylindrical and has a predefined transverse diameter, The reaction chamber  14  is shaped as a rectangular box or rectangular cuboid formed of a side closure, such as four side walls  48 ,  52  meeting at right angles. Transverse diagonals between corners are shorter than the predefined transverse diameter of the cylindrical housing sidewall. The reaction chamber  14  may fit symmetrically into the housing  12  in a preselected position, such that no side wall of the reaction chamber  14  is in contact with the side wall of the housing  12 . 
         [0042]    The housing carries a discharge means, such as a conduit or an exit chute  38  that feeds the overflowed liquid feed stream from the inter-wall volume  37  to an external facility such as a settling pond or tank. The chute  38  is located at the bottom level of the housing  12 , at approximately the same level as the bottom wall  20  of the reaction chamber. Liquid from the overflowed feed stream is able to drain from all sides of the reaction chamber  14  through the chute  38 . This drainage is desirable because electrocoagulation typically produces a top foam, which in a pressurized cell tends to remain in the cell and reduce available volume for processing the liquid stream. The upflowing liquid in atmospheric processing chamber  14  washes the foam out of the chamber and into the inter-wall volume  37 . That liquid, including top foam, exits the housing  12  through the chute  38 . 
         [0043]    The reaction chamber  14  is configured to ensure a symmetrical or centered fit with respect to the cylindrical wall of housing  12 . A guide or spacer operates between the reaction chamber  14  and housing  12  to establish relative positioning. One suitable configuration is for the manifold wall  20  to be attached by fasteners  41  as the bottom wall of the reaction chamber  14  and to closely fit the inside transverse shape of the cylindrical housing side wall  12 , thereby establishing a predetermined position for the reaction chamber  14  inside the housing  12 . The manifold wall  20  is wider than the walls of reaction chamber  14  and provides a laterally wider peripheral wall portion that extends between the reaction chamber walls and the housing wall, The peripheral wall portion is fastened to the top of the pressure vessel by fasteners  39 . These fasteners are readily reached through the inter-wall volume by normal took for installing or removing a reaction chamber  14 . Reaction chambers  14  are readily removed and replaced for maintenance of for a change in performance, due to guidance by a guide wall  20 , which results in the replacement chamber precisely fitting into the proper, predetermined position. 
         [0044]    When the housing  12  is cylindrical, the predetermined fit is achieved by configuring the bottom, manifold wall  20  of the reaction chamber  14  as a disk with diameter approximately equal to the inside diameter of a cylindrical housing  12 . The diameter of the disk-shaped portion of wall  20  is wider than the side walls of the reaction chamber  14 . Fastening bolts  39  can fix manifold wall  20  in preselected position with respect to top wall  34  of pressure vessel  28  to carry the side walls  48 ,  52  of the reaction chamber  14  in a desired position, which typically is in a centered relationship within housing  12 . External vertical alignment rods  40  further ensure that the housing and pressure vessel maintain theft alignment with respect to manifold plate  20 . Likewise, the array of manifold holes  18  in the manifold wall  20  is formed to coordinate with the interplate spacings  22 . The mounting position of the reaction chamber&#39;s side walls on the manifold wall  20  locates the electrode plates  16  and locates the interplate spacings  22 . In a single modular reaction chamber  14 , the use of an integral manifold wall  20  ensures that the manifold holes  18  are suitably located to feed into the interplate spacings  22 . 
         [0045]    With reference to  FIG. 3 , in a modified version of the described manifold  20 , one edge  42  of the bottom wall  20  is cut straight, at a position that will be outside and parallel to a side wall  48 ,  52  of the reaction chamber. This straight edge  42  is in a position corresponding to the mounting location of the exit chute  38  in the housing  12 . Thus, the exit chute  38  is mounted at an opening  44  ( FIGS. 1 &amp; 2 ) in the side wall of the housing  12 , with a support base  46  extending into the housing  12  and fitting against the straight edge  42  of the reaction chamber&#39;s bottom wall  20 . This fit between base  46  of the chute  38  and the bottom wall  20  of the reaction chamber  14  establishes a transition area for guiding treated liquid out of the housing. The base  46  of the exit chute  38  may be thinner than the bottom wall  20  of the reaction chamber  14 , establishing a downward step at the start of the chute  38  to help feed liquids from the inter-wall volume  37  out of the chute  38 . Together, the housing, chute, and reaction chamber form a coordinated exit structure that ensures full drainage of overflow liquid, including any foam. 
         [0046]    The reaction chamber  14  is coordinated in size with the housing  12 . Similarly sized reaction chambers  14 , together with any coordinating top cover that is needed, can be exchanged in the same housing  12 , and limited differences in the configuration of similarly sized reaction chambers  14  allow a certain amount of variation in processing performance while maintaining the same housing  12 . As described, the reaction chamber  14  is formed of a bottom wall or manifold wall  20  and a rectangular box structure that defines four side walls  48 ,  52 . An opposite pair of the side walls  48  may be referred to as plate supporting walls. These are configured to support electrode plates  16  of a preselected thickness at a preselected interplate spacing  22 , forming a series of plates that is a full set for the reaction chamber  14 . These plate supporting side walls  48  form vertical grooves  50  on theft inside faces in a coordinated pattern to receive plates between opposed grooves at fixed positions. Other portions of side walls  48  may be referred to as ungrooved lengths but simply are areas between the plate carrying grooves  50  that establish the interplate spacing  22 . The first and last plates in a set are located against opposite side walls  52  that are not plate supporting walls. These walls  52  are normal to the plate supporting side walls  48 . The apertures  18  in the bottom wall  20  lie generally between opposite ungrooved portions of walls  48 . Typical configurations for a reaction chamber  14  that processes ten gallons per minute are ten electrode plates with three-eighths inch (9.53 mm) spacing or eleven electrode plates with one-quarter inch (6.35 mm) spacing. 
         [0047]    As best seen in  FIGS. 4-6 , each electrode plate  16  in a set is substantially identical in shape, with a lower portion sized to fit in the reaction chamber to treat the feed stream and with an upper or superstructure portion that remains above the reaction chamber and is configured for possible attachment to a polarizing source. A suitable superstructure configuration is an upstanding tab  26  that is a upward extension of the processing portion of the electrode plate with a width that is less than the processing portion of a plate  16 . The housing  12  is fitted with a watertight top cover  54  that contains the treated water from overflowing the top of the housing  12  while still permitting passage of the tabs  26  through the cover. The cover defines a suitable number of slots  56  in positions that align with the tabs  26  of plates  16  in the reaction chamber  14 . The configuration of the cover  54  and reaction chamber  14  are coordinated. As an example using a set of ten electrode plates, the plates  16  in successive grooves  50  would have tabs positioned near opposite sides of the reaction chamber  14 . A single design of electrode plate  16  can provide a tab at either edge of the plate because any plate can be turned to reverse the relative side edge where the tab lies. With the single design for plates  16 , each successive plate is reversed so that the tabs in each pair of consecutive grooves are at opposite lateral sides of the reaction chamber. Accordingly, the cover  54  has aligned slots  56  that are coordinated with the alternating tab positions of the successive plates in the set. With ten plates in a single reaction chamber, the cover defines two columns of five slots each. The slots  56  in each column are staggered with respect to the slots  56  of the other column, thereby matching the staggered positions of the tabs  26 . A seal such as an o-ring  58  is applied to each tab  26  at a suitable height to establish a tight seal against a slot  56 , making the top cover  54  water-tight when attached to the top of the housing  12 . 
         [0048]    The dry exterior of the cover  54  is a convenient location for attaching polar leads. A pair of mounting bars  60  is attached to the cover  54  in spaced apart locations near opposite edges of the cover  54 . For example, a mounting bar  60  may be located near each column of slots  56 , outside the position of the column of slots. The mounting bars are insulated from one another and each carries an opposite charge, such as by connection the an external power supply. This positioning of the mounting bars  60  conveniently places a source of different polarity in proximity to the tabs  26  in each column of slots. Both the mounting bars and the tabs are configured to be selectively, temporarily interconnected to power any tab with any selected polarity. For example, the interconnection may be by jumper wires  62  connected between a mounting bar and a tab at any selected pair of attachment holes  64 . Jumper wires  62  may be used to connect each mounting bar  60  to each tab  26  that is to carry the same polarity. Jumper wires  62  from each mounting bar  60  are conveniently used to connect to the juxtaposed column of tabs, This arrangement is flexible and allows selected plates  16  to not be directly polarized, if desired. Likewise, it is a simple matter to extend a jumper wire  62  to a tab in the opposite column or otherwise create novel patterns of polarized electrodes. 
         [0049]    To allow direct viewing of chamber performance, the housing  12  or top cover  54  may have viewing windows  66  installed. As an example, the top cover  54  has adequate room for a viewing window  66  in a central position, between the two columns of slots. A viewing window  66  is helpful to monitor foam removal, plate wear, and other dynamic conditions that might develop during operation of a cell  10 . 
         [0050]    Cover  54  is secured to housing  12  by dry connectors  40 , which are secured by fastening nuts  68  that can be loosened to remove the cover. The dry connectors may be vertical tension rods  40  located outside housing  12  and pressure vessel  28 , where the rods interconnect the cover with the stacked elements of the housing  12  and pressure vessel  28 . Separate fasteners may secure the top wall  34  and bottom wall  32  of the pressure vessel to the rods  40  in positions that maintain the integrity of the pressure vessel. Seals  74  are used between cover  54  and housing  12 , between pressure vessel top wall  34  and housing  12 , between top wall  34  and sides of the pressure vessel, and between pressure vessel bottom wall  32  and sides of the pressure vessel. 
         [0051]    Rapid maintenance is made possible by the modular design of the reaction chamber  14 . The reaction chamber is held in place within the housing  12  by fasteners  39 , which may be bolts that extend through the bottom wall  20  and into underlying top wall  34  of the pressure vessel in positions external of side walls  48 ,  52  of the reaction chamber  14 . Due to theft positions, these fasteners  39  are not subject to corrosion or electrolytic action from the electrocoagulation process. Removing fasteners  39  allows the reaction chamber  14  to be readily lifted from the housing  12  and replaced with another. Because the manifold wall  20  is part of the reaction chamber structure, each new chamber  14  comes equipped with a suitable manifold wall  20  and properly positioned inlets  18  for the number and spacing of the electrode plates  16  in the new set. A new, coordinated top cover  54  is needed when the replacement reaction chamber  14  is of a new configuration. 
         [0052]    In addition to the invention of cell  10 , the liquid feed stream is treated by electrocoagulation according to steps that constitute a novel method. As described above and illustrated in the drawings, the liquid feed stream is treated by, first, pressurizing the stream to above ambient level. The pressurized stream is accumulated in a pressure vessel  28 , where it is available for further treatment. Second, the liquid feed stream in pressure vessel  28  is continuously fed into a reaction chamber  14  through a means for restricting pressure loss. The matrix of pressure limiting openings  18  functions in this manner by feeding the liquid stream from the pressure vessel into the reaction chamber. The openings are small enough and few enough in number that the liquid in the pressure vessel is maintained at a pressure above atmospheric. In the reaction chamber, the liquid stream is at atmospheric pressure. The reaction chamber  14  contains a vertically oriented array of spaced apart electrode plates  16 . The matrix of openings  18  are arranged to feed the incoming liquid stream into vertically oriented interplate spaces  22 . Third, the array of electrode plates  16  electrolytically processes the liquid stream within the interplate spaces  22  while the continuously fed liquid stream elevates the treated liquid to the top  24  of the reaction chamber  16 . Fourth, elevated liquid of the feed stream together with any product foam is further elevated to overflow the top  24  of the reaction chamber and fall into a collection area  37  outside the reaction chamber. 
         [0053]    According to a further aspect of the invention, the matrix of pressure limiting openings  18  is configured by sizes and positions to provide uniform upward flows in the reaction chamber  14 . 
         [0054]    The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be regarded as falling within the scope of the invention.