An electrocoagulation reactor is provided for treating waste water and removing contaminants therefrom. The reactor is typically a six-sided rectangular water-tight housing which has an inlet pipe and an outlet pipe. There are a multiplicity of charged plates located parallel to one another within the housing. Adjacent plates are typically oppositely charged and water will pass between the plates as it flows through the reactor. The electric field between the plates will help encourage coagulation of waste matter which then may be removed from the waste water downstream of the electrocoagulation reactor.
This application claims priority, is a continuation from, and incorporates herein by reference U.S. patent application Ser. No. 11/581,695filed Oct. 16, 2006, which claims priority and is a continuation from U.S. patent application Ser. No. 10/171,926, filed Jun. 14, 2002; which claims priority from U.S. Patent Application Ser. No. 60/318,730, filed Sep. 12, 2001; which is also herein incorporated by reference.
This application is related to U.S. patent application Ser. No. 08/976,695, filed Nov. 24, 1997, PCT/US98/24885, filed Nov. 23, 1998, U.S. patent application Ser. No. 09/554,975, filed Jul. 7, 2000, and U.S. patent application Ser. No. 09/961,524 filed Sep. 24, 2001, which are all herein incorporated by reference.FIELD OF THE INVENTION
Electrocoagulation reactors, more specifically, a electrocoagulation reactor with the plates in parallel to the flow of the water.BACKGROUND OF THE INVENTION
Wastewater, such as wastewater from factories or manufacturing plants, must be treated for contaminants before it is discharged into the environment. Water for use in industrial or other manufacturing process often requires treatment before use to alter its chemical or physical characteristics. Electrocoagulation is an electro chemical process that simultaneously removes heavy metals, suspended solids, organic and other contaminates from water using electricity instead of expensive chemical reagents. Electrocoagulation was first used to treat bilge water from ships. The Electrocoagulation process passes contaminated water between metal plates charged with direct current. While the term “wastewater” is often used herein, the term is to be understood to mean any water from which one may wish to remove a “contaminant” even though the contaminant may not necessarily be a material that would be harmful to ones health.
Additional background in the specifications regarding electrocoagulations may be found in U.S. Pat. No. 5,928,493, the specifications or drawings of which are incorporated herein by reference.
Applicant's provide, in the invention disclosed herein, an unpressurized electrocoagulation reactor, with plates in parallel to the flow of the water, which reactor has the capability of treating a higher flow of wastewater than has heretofore been available.SUMMARY OF THE INVENTION
Applicants provide for these and other objectives in a parallel flow reactor comprised of one or more reactor cells. Each cell typically includes a tank containing a cartridge, the cartridge having a frame with a multiplicity of aligned plates therein. Water flows through the tank, typically up from the bottom of the cartridge-held plates over a top wall of the cartridge in “water fall” (cascading) fashion and out the tank for further processing or use. Applicant provides an electrocoagulation cell with an open top, one that is unpressurized and obtains, at least in part, the flow of water under the impetus of gravity.
Applicants provide for these and other objectives in an electrocoagulation reactor comprising, in a preferred embodiment, two electrocoagulation cells placed “in series.” By “in series” applicant means that a molecule of wastewater will flow between two adjacent plate in the first cell of a reactor, out of the first cell of the reactor and between a second pair of plates in the second cell of the electrocoagulation reactor. Applicants provide, in a preferred embodiment of a two-cell electrocoagulation reactor, cells which are set in series. This is to be compared with the arrangement in a “series flow” reactor in which a single molecule of water would follow a serpentine path and pass between a multiplicity of plate pairs within a single cell.
Applicants provide for these and other objectives in a parallel flow, open top electrocoagulation reactor having one of more cells in series, wherein each cell typically contains a cartridge capable of being lifted out of the tank of the cell. In other words, applicants provide for a “cartridge” which is capable of receiving plates therein, and then dropped into, from the open top, the tank of a electrocoagulation cell, and, when the plates need replacement, the cartridge may be lifted out of the electrocoagulation tank so that the used up plates may be changed out with new plates at a point removed from the electrocoagulation tank. This and other advantages of applicant's cartridge will be apparent with reference to specifications and drawings contained herein.
Applicants' unique cartridge also provides for the ability to accept plates of differing dimensions so, for example, a single cartridge may either receive plates with a given height, or, if the user requires less treatment capacity, to receive plates of a shorter or greater height. Thus, a user may, instead of using a reactor with a different size tank, simply use the same tank and same cartridge, but use, if the conditions require, plates with less or greater surface area.
Applicants provide for efficient treatment of wastewater in a parallel flow, open top, cartridge-receiving electrocoagulation cell in which there are a multiplicity of plates, at least some of the plates being alternately charged positive and negative, sometimes with an “intermediate” or uncharged plate (or plates) between adjacent positive and negative plates.
Applicants provide for these and other advantages and objects in an electrocoagulation reactor consisting of electrocoagulation cells in which, beneath the plate bearing cartridges and in fluid communication therewith is a solids sump with a drain attached thereto for removing from a tank of the electrocoagulation cell, waste sediment that has resulted from the electrocoagulation of waste particles and for removal of the collected sediment from a drain therein.
Applicants provide for these and other advantages and objectives, in an electrocoagulation reactor system comprising a unique stand for cooperatively engaging the tank and cartridge of the electrocoagulation cell to provide direct weight-bearing support of the plates in the cartridge of the electrocoagulation cell.
Applicants additionally provide a plate for use with any type of electrocoagulation reactor system, which plate contains cutouts in the walls there through, the cutouts for more effective treatment of wastewater passing adjacent the plate.
Applicants additionally provide, for use with any reactor, a recirculation pump and recirculation loop. The recirculation pump and loop takes some, but not all, of the water flowing out of a reactor and recirculates it through the reactor by, typically, routing it upstream of the intake of the reactor. This allows the user to maintain a greater flow of fluid through the reactor than the net flow of water treated.
Applicants also provide for a novel dissolved air floatation cell for the treatment of wastewater using an electrocoagulation reactor.
Attention will be first directed to
Turning now to sump portion 12J it is seen that this portion of cell tank 12 is located below open bottom 12R of cartridge receiving portion 12I so as to collect waste solids and suspended materials settling out from between plates 20 of first cartridge 14 (see
It is seen that first cartridge 14 is typically not mechanically fastened to cartridge receiving portion 12I or any other portion of cell tank 12, but merely rests along a portion of the bottom of cartridge receiving portion 12I here resting along the edges below rear wall 14A and front wall 14D on cartridge support ledge 12F and cartridge support and drain ledge 12G, respectively and on ledges below the sidewalls of the cartridge. First cartridge 14 is typically rectangular shaped and dimensioned for the receipt within cartridge receiving portion 12I of cell tank 12 so as to allow water coming in through inlet 13M to circulate up through a pair of adjacent plates 20 and to cascade over the weir 14J (or top lip) of front wall 14B into the transfer chamber 13 (See
Moreover, both rear wall of 14A and front wall 14B have vertical slots 14E on their inner faces for the acceptance of plates 20 in “slotting fashion.” Plates 20 are held along a pair of removed vertical edges and suspended between the front wall 14B and the rear wall 14A with the entire cartridge having an open top 14H and an open bottom 14I for water to pass up through the plates 20 as illustrated in
The function of first cartridge 14 is to provide structure to define and maintain a passageway for water entering through one or more inlet 3 13M such that the water will pass through a space between a pair of a multiplicity of pairs of plates 20 maintained between the front and rear walls of the cartridge 14, in such a manner that the water spills over weir 14J into transfer chamber 13 for leaving cell tank 12 through drain 12H. As the wastewater proceeds between the pair of oppositely charged plates 20 and any intermediate plates therebetween it will be subject to an electric field which will promote electrocoagulation processes known in the prior art.
In a preferred alternate embodiment there may be more than one immediate or neutral plate between adjacent positively or negatively charged plates or, there may be no neutral plates at all between adjacent negatively and positively charged plates. However, it is seen that whatever configurations the sets may take they are disposed parallel to one another as set forth in
In first preferred embodiment in cartridge 14/18, the plates 20, as seen in
As a bit of background, reactors are typically rated in their ability to handle wastewater by the maximum amount of wastewater flow that can be treated by a given reactor. For example, a reactor may be designed to treat wastewater with a given conductivity/resistivity range at a flow of 500 gallons per minute. This rating for that given reactor is for a reactor with full plates as illustrated in 1A. However, the situation may arise where, for example, water with reduced flow rate is being treated and therefore the same applied voltage, say, for example, 48 volts may be used but the user may “size” the cartridge with smaller plates for easier handling and increased efficiency. It is found to be advantageous to use the same cartridge and provide a means for inserting shorter plates so as to efficiently handle wastewater with a lower flow rate than the maximum capability of the reactor cell. For example, a user may wish to purchase a cell of 500 gallons per minute maximum capacity even though the current demand of that user is only, say, 200 gallons per minute. It may be more economical to purchase a larger unit and use shorter plates and, when the requirements of the user increase to use the same cartridge and purchase longer plates. Applicants have provided for a mechanism in their unique cartridge system which will allow for the acceptance of shorter plates therein.
To “size” a reactor, one could build eight to ten different size tanks and cartridges to cover the different flow rate demands from, for example, 100 gallons per minute to 1500 gallons per minute. However, by using Applicant's design one can cover the entire range with only two different size tanks and cartridge by creating a flexible cartridge system allowing use of different size plates. In this way, a single cartridge design can be used to accommodate flow rate demands from 100 gallons per minute to 500 gallons per minute and another single cartridge design can accommodate flow rate demands of 500 gallons per minute to 1500 gallons per minute. This system is illustrated in
Moreover, with water being treated at less than the maximum rated capacity, it is beneficial to raise the height of weir 14J/16J to decrease the amount of “freeboard” or the amount of exposed plate above water level WL (exposed plate is “wasted” when the rest of the plate is being consumed). A method for increasing the height of weir 14J/15J is illustrated in
Applicant's concept of sizing the plates for a flow rate of less than the maximum capacity of the electrocoagulation cell at a given voltage for a given set of treatment parameters for water gives the user the possibility of using a single “universal” cartridge—that is, a cartridge whose plates or other variables can be sized so that it will effectively run water with requirements substantially less than the maximum capability of the unit, through the use of smaller plates. Smaller plates are, again, advantageous as they make handling of the cartridge which, loaded with plates, may weigh several thousand pounds, much easier. Applicants' provide for a universal cartridge with the ability to easily alter the cartridge to accept the plates with differing dimensions, while also being able to alter the weir 14J/16J height of the cartridge 14 to adapt to the smaller plates. Some of the electrocoagulation cells can use up to 7,000 pounds of steel plates in a single cartridge. Therefore, the decreased lift-out and handling requirement may be readily appreciated.
One could lift out Applicants' cartridge, which consists of a frame around the plates, and then, with the cartridge removed from the tank, change out the plates. In other words, plates don't have to be changed out directly from the tank. Indeed, one can withdraw one cartridge and immediately insert a second cartridge, full of plates and, at their leisure, remove the wasted steel plates from the first cartridge. In other words, the lift out cartridge provides that the plates can be removed “in mass” and “replaced in mass,” a system where the electrocoagulation reactor does not have to be shut down or be taken off-line while the plates are changed out.
Applicants provide yet another advantage in providing in
Applicants' open top, unpressurized parallel flow reactor may have a number of plate arrangements including: plus minus plus minus: plus n minus n plus n minus, etc. The recirculation loop may recirculate through one or more cells of the reactor. Typically, water will flow through each individual solid reactor from bottom to top, to assist in the escape of gases. Individual plates of each cell may be tabular in nature and made from iron, steel, aluminum or other material. They may include “cutouts” in various shapes (see
When bolted together the front assembly, rear assembly and two side assemblies form a rectangle which will vertically support the cell tank 12 at a point immediately below the lower perimeter of the cartridge 14 that is placed in the tank so as to avoid any sheer or flex loading on the bottom walls of the tank. That is, when bolted together the cell stand 40 will have upper perimeter walls that are dimensioned identical to at least a portion of the lower perimeter of the cartridge.
It is seen that electrocoagulation cell stand 40 has a number of vertical support legs 42 for providing a vertical support to tank support perimeter members 44A, 44B and 44C. The tank perimeter support member 44A provides support to the left and right side of the tank, 44B provides support to the tank directly beneath the rear wall of the cartridge and vertical support perimeter 44C provides vertical support to the tank directly below the front wall of the cartridge. Fasteners 45A are used to fasten the stand together by engaging bolt holes 45B. Note that both the rear assembly of the stand and the front assembly of the stand include cross braces 46 and 48, with cross brace 46 on the rear assembly of the stand including a vertical support leg 42 for reaching all the way to the floor. (See
Typically, a reactor is rated at a given flow rate and works most efficiently at that flow rate. For example, a 350 GPM parallel flow electrocoagulation reactor is preferably not run at less than 50 gallons per minute. Applicants provide, in
A recirculation loop may be used with any of Applicant's embodiments disclosed herein, in fact with any other electrocoagulation reactor or system. It provides a fairly simple and inexpensive means to maintain a given flow rate through a reactor while increasing the residence time of the water in the reactor (compared to a single pass) and, for decreasing the net flow of water treated but maintaining a higher flow rate through the reactor. For example, assume upstream pump (100) is pumping 100 gallons a minute from a water source (WS). Reactor (102) may be a 350 gallon per minute reactor. At this flow rating, there is sufficient flow through the reactor to properly scrub the plates and efficiently treat the water. One can use a recirculation pump (104) providing flow at the rate of 250 gallons per minute to provide a flow rate through a reactor of 350 gallons per minute. Yet the net treatment rate is 100 gallons per minute of waste water flow downstream from a recirculation junction (106). In fact, Applicant's may increase the flow rate through a reactor providing a flow rate greater than the rating for the reactor, which flow rate may provide additional water velocity to scrub the plates. For example, a flow rate of 400 gallons per minute may be provided through the reactor while the net waste water treatment may be 100 gpm or less.
Turning now to
The upstream pump (100) may be used to flood the reactor and provide for water fluid flow through the reactor or the “head” of the water source may serve the same function. The reactor also has an outlet port (114) and outlet pipe sections (114A and 114B). Water leaves the electrocoagulation reactor at outlet port (114). Some of the water will be recirculated by exiting the outlet pipe at recirculation junction (106), being drawn by a recirculation pump (104) through a recirculation loop (116). Recirculation loop (116) may include pipe section (116A) upstream of recirculation pump (104) and a recirculation pipe section (116B) downstream of recirculation pump (104). Recirculation pipe section (116B) joins the intake pipe downstream of upstream pump (100) (if any) and upstream of intake port (112), here at junction (110).
One of the purposes in the parallel flow reactor of providing a recirculation loop is to increase the probability of an ion of waste composition being adjacent an oppositely charged plate. In pressurized reactors (such as Applicants' series flow reactor), sufficient velocity of liquids through the reactor must be maintained for proper removal or scrubbing of the plates of the reactor. On the other hand, in Applicants' parallel flow reactor, which is typically run at atmospheric pressure, sufficient flow is necessary to increase the opportunity of a charged ion to be adjacent an oppositely charged plate.
One way in which a recirculation loop may be used is to replace the requirement for multi-cell electrocoagulation reactor. For example, if a treatment job may require 200 g.p.m. through two cells, one following the other (see
Applicants discloses in
Applicants' novel apparatus, a gas-assisted flotation cell, is provided which has a conical upper chamber that tapers into a neck portion, which neck portion may include a manifold with gas intake jets to assist in lifting and propelling floated solids residing above a liquid level, out of a removed end of the neck for discarding or for further treatment, as liquid is drawn off the bottom of the main chamber for either reuse or further treatment.
Applicants' gas-assisted flotation cell provides advantages not found in the prior art, including U.S. Pat. No. 5,055,184 (Carpenter, et al. 1991), the specifications and drawings of which is incorporated herein by reference. The Carpenter reference discloses generally a gas-assisted flotation apparatus for separating solids from liquids in a slurry. It comprises a main chamber, an inlet channel from which a liquid slurry may enter, and an upper tapered portion. Gas bubbles attached to solids and particles will tend to float upward in the main chamber and reside above a liquid line. When the level of liquid is sufficiently high in the chamber, the material floating above the liquid line will either drop off through a side exit pipe above the tapered chamber or, if a gas, will rise upward as through a chimney. Thus, the Carpenter reference discloses two exits ports for expelling material rising above a liquid surface and, in addition, requires a valve mechanism to control the level of liquid in the main chamber.
Among the advantages of Applicants' present invention over the Carpenter reference is the positive removal, as by compressed gas, of floating solid material out of a removed end of a neck that is in fluid communication with the opening at the apex of the tapered walls of the upper chamber. Further, Applicants provide a simple method of maintaining a liquid level in the main chamber sufficient to present material floating above such level to the compressed gas injected into the neck of the main chamber. Further, Applicants provide a novel tapered lower chamber for collection of sediment therein and, further, for a novel stilling chamber suspended within the main chamber. This and other novel features of Applicants' gas-assisted flotation process and apparatus will be apparent with reference to the drawings below.
The figures illustrate a main chamber 202 including a tapered upper chamber 204. Main chamber 202 includes vertical sidewalls 206. Applicants provide a tapered lower chamber 208 which descends below the vertical sidewalls 206 and terminates in a drain 210 that may have a plug, removable therefrom, for the draining of sediment that may collect thereon. Tapered upper or lower chambers may be conical or polygonally shaped.
Turning back to the upper chamber, it is seen that tapered upper chamber 204 reaches an apex that is open and in fluid communication with a neck 212. In
Applicants' novel gas-assisted flotation apparatus 200, 200A may include a stilling chamber 220, the stilling chamber including an inlet tube 222 for carrying a liquid, typically with a flocculant or precipitant suspended therein into the stilling chamber. Applicants' inlet tube 222 may be seen to have an open removed end 222A, and, adjacent a removed end an angled portion 222B for directing the flow of liquids into the stilling chamber so as to generate a slow, non-turbulent flow within the chamber. Upstream of the point at which the inlet tube enters the main chamber, there may be a degas vent or pipe 224 from which the larger gas bubbles may escape from the liquid before it enters the main chamber. Entering the stilling chamber 220 through a dissolved air delivery tube 226 is a compressed gas liquid composition. The dissolved air delivery tube includes a removed end 226A which may include an angled portion 226B in an effort to assist in the circulation of the fluid in the main chamber to avoid turbulence. Indeed, the function of stilling chamber 24 is to reduce the velocity of liquid entering the chamber to a point of slow, smooth flow. Stilling chamber 220 also is intended to increase retention time to allow further coagulation, flocculation and gas bubble precipitation as well as a growth of flocculant solid particles. Note that stilling chamber 220 may include a flanged lip 228 adjacent an upper opening thereof and a sloped bottom wall 232, the flanged lip and sloped bottom wall connected by vertical sidewalls 230. The effect of the flanged lip and/or sloped bottom wall is to promote a smooth, slow flow of the liquid and thus provide increased efficiency. Notice that open bottom 234 of stilling chamber 220 may be located above drain 210 so as to “allow” any precipitates descending therefrom to travel toward the drain. Note also that the sidewalls of the stilling chamber may include an interior baffle 236 projecting into the stilling chamber so as to reduce the flow of liquids therein to, again, promote a smooth non-turbulent slow flow of liquid. Furthermore, the stilling chamber may be supported within the main chamber, above the floor of the main chamber by chamber support baffles 238 extending from an inner surface of the vertical sidewalls of the main chamber to the sidewalls of the stilling chamber, the support baffles having an exaggerated width (vertical dimension) so as to help minimize currents in the main chamber.
The main chamber must be provided with a means to remove a liquid therefrom, the liquid here being removed by outlet channel assembly 240 which may consist of a single pipe, having multiple branches 240A, 240B and 240C (see
Applicants may also provide a standing pipe 242 with a catch vessel 244 from which liquid removed from the main chamber through outlet channel assembly 240 may be contained, for the control of the level of liquid in main chamber 202 and as a source of water for the air dissolving mechanism.
So long as fluid to be treated is allowed to enter chamber, the fluid will rise to the level of the top of standing pipe 242. This level may be adjusted to coincide with the level of the bottom of the sideport 214 or to a level just below jets or pressure ports 218D, or to any both appropriate for the density of the floating phase.
Thus, Applicants provide a novel gas-assisted flotation process and apparatus that achieves at least the following results: reduction of turbulence; effective removal of gas/solid material through a removed neck opening; effective maintenance of fluid level adjacent a gas or compressed air transport tube; an effective drain to remove precipitates; the angled injection of fluid into a stilling chamber and gas dissolved air from a separate tube into a stilling chamber, the stilling chamber being effectively designed to help reduce turbulence. Dissolved gas is injected through dissolved air delivery to be 226. Water is drawn off the bottom of catch vessel 244. Air pump 244A will inject air into the stream of fluid injected into the stilling chamber. Outlet port 244B will pass water on for further treatment or use.
Thus, applicants provide a method of transporting a quantity of water from a removed location to an electrocoagulation reactor, moving the water through the electrocoagulation reactor while subjecting the water to an electric field, then discharging the waste water from the electrocoagulation reactor through a discharge port. Downstream the discharge port and inline with discharge piping is a recirculation loop that includes a pump for recirculating a portion of the water back into the electrocoagulation reactor by reintroducing the waste water that is already passed through the reactor at least once upstream of the inlet port of the reactor.
1. A system for treating water, the system comprising:
- a multiplicity of reactor plates;
- a cartridge adapted to removably receive a multiplicity of the plates therein and maintain the plates in parallel alignment;
- a cell tank adapted to receive the cartridge with reactor plates loaded therein such that the cartridge is substantially inside the cell tank when received, wherein the cartridge may be removed from the cell tank to replace one or more reactor plates, the cell tank having an intake pipe and a discharge pipe;
- a pump adapted to convey a quantity of water from a distant location to the intake pipe and into the cartridge; and
- an electrical conduit adapted to convey an electrical signal to the reactor plates to subject water moving between the plates to an electric field.
2. The system of claim 1, wherein the cartridge is configured such that water flowing therethrough moves upwards between the plates.
3. The system of claim 2, wherein the cartridge has first wall and a second wall, the first wall shorter than the second wall such that water flows over the top of the first wall after moving upwards between the plates.
4. The system of claim 3, wherein the cell tank includes a portion for receiving the water flowing over the top of the first wall.
5. The system of claim 1, further comprising a recirculation loop for taking a portion of the water in the output pipe and reintroducing it to the inlet pipe.
6. They system of claim 5, wherein the recirculation loop comprises a positive displacement pump.
7. The system of claim 5, wherein the recirculation loop includes a pipe for joining the outlet pipe and for joining the inlet pipe downstream of the pump.
8. The system of claim 1, wherein the pump is a positive displacement pump
9. The system of claim 1, wherein the cell tank has an open top and the receipt and removal of the cartridge are accomplished through the open top.
10. The system of claim 1, further comprising a second cell tank in series with the first cell tank.
11. The system of claim 1, wherein the cartridge includes a multiplicity of slots dimensioned to receive a reactor plate.
12. The system of claim 1, wherein the cell tank includes a sump portion adapted to gather waste from the water.
13. The system of claim 1, further comprising handling straps adapted to engage the cartridge and to assist in handling of the cartridge.
14. The system of claim 1, wherein some of the plates have a shorter height than others of the plates.
15. The system of claim 1, further comprising a water clarifier adapter to clarify the water discharged from the cell tank.
16. The system of claim 1, further comprising an electrocoagulation reactor downstream of the cell tank, the electrocoagulation reactor adapted to subject the water discharged from the cell tank to an electric field.