Cena, Aaron J. (304 Smith Street Mt. Shasta, CA, 96067, US)
Moore, Mark E. (200 Normandy Road Versailles, KY, 40383, US)
Stuerenberg, Mark J. (453 Lookout Court FT. Wright, KY, 41011, US)
Cena, Aaron J. (304 Smith Street Mt. Shasta, CA, 96067, US)
Moore, Mark E. (200 Normandy Road Versailles, KY, 40383, US)
Stuerenberg, Mark J. (453 Lookout Court FT. Wright, KY, 41011, US)
| 1. | An apparatus for treating a substance containing perchloroethylene, the apparatus comprising: a chamber for receiving the perchloroethylenecontaining substance, the chamber defining a first end and an opposite second end, the chamber including an inlet for the perchloroethylenecontaining substance adjacent the first end and an outlet adjacent the second end; and an ozone introducer coupled to the chamber adjacent the second end, wherein the perchloroethylenecontaining substance is received through the chamber inlet and sent out through the chamber outlet while the ozone introducer provides an ozone containing substance to the perchloroethylenecontaining substance to react with the perchloroethylene. |
| 2. | The apparatus of claim 1 wherein the perchloroethylenecontaining substance sent out through the chamber outlet is routed back into the chamber inlet for continual treatment until the amount of perchloroethylene in the substance is reduced to a desired level. |
| 3. | The apparatus of claim 1 further comprising a reservoir for storing the perchloroethylenecontaining substance, the reservoir coupled to the chamber for sending the perchloroethylenecontaining substance from the reservoir to the chamber. |
| 4. | The apparatus of claim 3 further comprising a pump interposed between the reservoir and the chamber for drawing the perchloroethylenecontaining substance out of the reservoir and into the chamber. |
| 5. | The apparatus of claim 3 wherein the reservoir includes an inlet and an outlet, and further comprising a first piping assembly coupling the outlet of the reservoir to the inlet of the chamber and a second piping assembly coupling the outlet of the chamber to the inlet of the reservoir. |
| 6. | The apparatus of claim 5 wherein the inlet of the reservoir is selectively couplable to either the outlet of the chamber or an output from a source of the perchloroethylenecontaining substance. |
| 7. | The apparatus of claim 5 wherein the outlet of the reservoir is selectively couplable to either the inlet of the chamber or to a sewer. |
| 8. | The apparatus of claim 5 wherein the reservoir defines an opening configured for insertion into, and withdrawal from the reservoir of a solid material containing perchloroethylene. |
| 9. | The apparatus of claim 8 wherein the reservoir further includes a removable lid over the opening. |
| 10. | The apparatus of claim 9 wherein the reservoir further includes an internal support configured for holding the solid material within the reservoir. |
| 11. | The apparatus of claim 5 further comprising a venturi injection apparatus for providing an ozonecontaining substance for reaction with the perchloroethylene containing substance, and wherein the outlet of the reservoir is selectively couplable to either the chamber inlet or the venturi injection apparatus. |
| 12. | The apparatus of claim 11 further comprising an ozone generator selectively couplable to either the venturi injection apparatus or to the ozone introducer. |
| 13. | The apparatus of claim 11 further comprising a catalyst introducer coupled to the venturi injection apparatus. |
| 14. | The apparatus of claim 1 wherein the chamber is arranged in a generally vertical configuration with the first end at an upper position and the second end at a lower position, and wherein the ozone introducer provides the ozonecontaining substance in a form that tends to rise within the perchloroethylenecontaining substance from the second end toward the first end. |
| 15. | An apparatus for treating a substance containing perchloroethylene, the apparatus comprising: a chamber for receiving the perchloroethylenecontaining substance, the chamber defining a first end and an opposite second end, the chamber providing for a flow of the perchloroethylenecontaining substance from adjacent the first end and generally toward the second end; and an ozone introducer coupled to the chamber adjacent the second end, wherein an ozonecontaining substance flows in the chamber in a direction generally opposite to the flow of the perchloroethylenecontaining substance. |
| 16. | The apparatus of claim 15 wherein the ozonecontaining substance is provided to the perchloroethylenecontaining substance in a form that tends to rise in the chamber. |
| 17. | The apparatus of claim 15 further comprising a reservoir for storing the perchloroethylenecontaining substance, and a pump interposed between the reservoir and the chamber for drawing the perchloroethylenecontaining substance out of the reservoir and into the chamber. |
| 18. | The apparatus of claim 17 wherein the reservoir includes an inlet and an outlet, and further comprising a first pipe coupling the outlet of the reservoir to the inlet of the chamber and a second pipe coupling the outlet of the chamber to the inlet of the reservoir. |
| 19. | The apparatus of claim 18 wherein the inlet of the reservoir is selectively couplable to either the outlet of the chamber or an output from a source of the perchloroethylenecontaining substance. |
| 20. | The apparatus of claim 18 wherein the outlet of the reservoir is selectively couplable to either the inlet of the chamber or to a sewer. |
| 21. | The apparatus of claim 17 further comprising a venturi injection apparatus for providing an ozonecontaining substance for reaction with the perchloroethylene containing substance, and wherein the pump is selectively couplable to either the chamber inlet or to the venturi injection apparatus. |
| 22. | The apparatus of claim 21 further comprising an ozone generator selectively couplable to either the venturi injection apparatus or to the ozone introducer. |
| 23. | The apparatus of claim 15 wherein the chamber includes an inlet adjacent the first end and an outlet adjacent the second end, and further wherein the perchloroethylenecontaining substance is pumped into the chamber at the inlet and flows out of the chamber at the outlet. |
| 24. | A system for treating a substance containing perchloroethylene, the system comprising : a reservoir for holding the perchloroethylenecontaining substance; a first ozone treatment apparatus for the perchloroethylenecontaining substance, the first ozone treatment apparatus including a chamber for receiving the perchloroethylenecontaining substance, the first apparatus further including an ozone diffuser for introducing an ozonecontaining substance to the perchloroethylene containing substance; and a second ozone treatment apparatus for the perchloroethylenecontaining substance, the second ozone treatment apparatus including a venturi injection apparatus for introducing an ozonecontaining substance to the perchloroethylene containing substance; wherein the first and second ozone treatment apparatuses are coupled to the reservoir for selective treatment of the perchloroethylenecontaining substance by either of the apparatuses. |
| 25. | The system of claim 25 wherein the chamber of the first ozone treatment apparatus defines a first end and an opposite second end and the chamber includes an inlet for the perchloroethylenecontaining substance adjacent the first end and an outlet adjacent the second end, wherein the perchloroethylenecontaining substance is received through the chamber inlet and sent out through the chamber outlet simultaneously with the ozone diffuser's providing the ozonecontaining substance to the perchloroethylenecontaining substance. |
| 26. | The apparatus of claim 25 wherein the first end of the chamber is an upper end and the second end of the chamber is a lower end. |
| 27. | The apparatus of claim 24 wherein the reservoir includes an outlet, and further comprising a pump coupled to the reservoir outlet, the pump selectively couplable to either the first ozone treatment apparatus or the second ozone treatment apparatus. |
| 28. | The apparatus of claim 24 wherein the reservoir includes an inlet that is selectively couplable to either the ozone treatment apparatuses or an output from a source of the perchloroethylenecontaining substance. |
| 29. | The apparatus of claim 24 wherein the reservoir includes an outlet that is selectively couplable to either the ozone treatment apparatuses or to a sewer. |
| 30. | The apparatus of claim 24 further comprising an ozone generator selectively couplable to either the first ozone treatment apparatus or the second ozone treatment apparatus. |
| 31. | The apparatus of claim 24 wherein the chamber defines a first end and an opposite second end, the chamber receiving the perchloroethylenecontaining substance adjacent the first end and providing for a flow of the substance generally toward the second end. |
| 32. | The apparatus of claim 31 wherein ozonecontaining substance flows in the chamber in a direction generally opposite to the flow of the perchloroethylene containing substance. |
| 33. | The apparatus of claim 24 further comprising a first pair of ganged valves for coupling the first ozone treatment apparatus to the reservoir and a second pair of ganged valves for coupling the second ozone treatment apparatus to the reservoir. |
| 34. | The apparatus of claim 24 wherein the reservoir defines an opening configured for insertion into, and withdrawal from the reservoir of a solid material containing perchloroethylene. |
| 35. | The apparatus of claim 34 wherein the reservoir further includes a removable lid over the opening. |
| 36. | The apparatus of claim 34 wherein the reservoir further includes an internal support configured for holding the solid material within the reservoir. |
| 37. | The apparatus of claim 24 further comprising a catalyst introducer coupled to the venturi injection apparatus. |
| 38. | A process for treating a substance containing perchloroethylene, the process comprising: providing a reservoir for holding the perchloroethylenecontaining substance; piping the perchloroethylenecontaining substance through an ozonediffusion tank for a first period, the ozonediffusion tank providing an ozonecontaining substance for reacting with the perchloroethylenecontaining substance; then, piping the perchloroethylenecontaining substance through a venturi injection apparatus for a second period, the venturi injection apparatus providing an ozonecontaining substance for reacting with the perchloroethylenecontaining substance. |
| 39. | The process of claim 38 wherein the first period is at least about five minutes. |
| 40. | The process of claim 38 wherein the second period is at least about five minutes. |
| 41. | The process of claim 38 wherein the first period is between about five minutes and about six hours. |
| 42. | The process of claim 38 wherein the second period is between about five minutes and about twentyfour hours. |
| 43. | The process of claim 38 wherein the first period is a time sufficient to reduce the viscosity of the perchloroethylenecontaining substance to a sufficient level to permit piping the perchloroethylenecontaining substance through the venturi injection apparatus substantially without clogging. |
| 44. | The process of claim 38 further comprising, after piping the perchloroethylene containing substance through the venturi injection apparatus to reduce the amount of perchloroethylene in the substance to a desired level, sending the substance to a sewer. |
| 45. | An apparatus for treating a substance containing perchloroethylene, the apparatus comprising: a chamber for receiving the perchloroethylenecontaining substance, the chamber including an inlet for the perchloroethylenecontaining substance, and an outlet, the chamber arranged in a substantially vertical configuration between the inlet and the outlet, the chamber providing for a flow of the perchloroethylenecontaining substance in a substantially downward direction in the chamber; and an ozone introducer coupled to the chamber to provide an ozonecontaining substance within the chamber, the chamber and ozone introducer configured for a flow of the ozonecontaining substance in a substantially upward direction in the chamber to react with the perchloroethylene. |
10/045,388, filed on November 9,2001, which is hereby incorporated by reference.
Background Ozone may be used to breakdown various chemicals from one compound to another, typically simpler compound. For example, perchloroethylene or perc, which is commonly used as a dry cleaning fluid and which is treated on disposal as a hazardous waste, can be treated with ozone to break the perchloroethylene down into carbon dioxide, water, oxygen in 02 form, and simple compounds of chlorine. The results of the ozone treatment are non-hazardous chemicals that can be disposed of more simply.
Summary A chemical treatment system is provided for treating a substance containing perchloroethylene with ozone. The system may include an ozone treatment apparatus with a chamber that provides for a flow of the perchloroethylene-containing substance within the chamber in a first direction and a flow of an ozone-containing substance in a second direction, generally opposite to the first. The system may also include an ozone treatment apparatus with a venturi injection apparatus for introducing an ozone- containing substance to the perchloroethylene-containing substance. The system may provide for selective treatment of the perchloroethylene-containing substance by either of the chamber and the venturi injection apparatus.
Brief Description of the Drawings Fig. 1 is a diagram of a system according to the present invention showing a
reservoir for containing a perchloroethylene-containing substance for routing through a pump to either a chamber treatment apparatus or a venturi injection apparatus, where an ozone-containing substance is introduced to the perchloroethylene containing substance.
Fig. 2 is a diagram showing further detail of the chamber treatment apparatus in the system of Fig. 1, including that the chamber is arranged generally vertical with an inlet for the perchloroethylene containing substance adjacent an upper end and an outlet adjacent a lower end and an ozone diffuser adjacent the lower end, providing a counterflow of the ozone-containing substance upwardly through the downwardly flowing perchloroethylene containing substance.
Fig. 3 is a diagram showing further detail of the venturi injection apparatus, including a pump to impel the perchloroethylene containing substance through a pair of venturi bodies for introduction of the ozone-containing substance.
Fig. 4 is an alternative embodiment of the present invention providing for a counterflow of the ozone-containing substance in the reservoir.
Detailed Description of the Preferred Embodiments The present invention provides for the treatment of a chemical with ozone. In the embodiments described below, the chemical is the liquid form of perchloroethylene, but it will be understood that the invention may be applied in the treatment of other forms and other compounds, in general to any material that is broken down by reaction with ozone. The present invention may be used with a source, such as a dry cleaning machine that periodically or continuously outputs a
perchloroethylene-containing substance. A typical dry cleaning machine used in a small dry cleaning establishment will produce about two to five gallons of perchloroethylene-containing substance per day. The substance also typically includes whatever other solid and liquid materials have been dissolved from the fabric in the dry cleaning process, such as oils and other organic and inorganic compounds.
The perchloroethylene-containing substance from the dry cleaning machine is typically in a liquid form and may be piped out of the machine through ordinary <BR> <BR> plumbing, e. g. , PVC pipes. As shown in Fig. 1, a system providing an embodiment of the present invention, indicated generally at 10, includes a pipe 12 connected to a dry cleaning machine to receive a perchloroethylene containing substance 14. Typically the dry cleaning machine periodically outputs a quantity of the substance 14, but the invention may also be used where a continuous stream of substance 14 is outputted from the machine or other source.
The treatment process described below typically works best at temperatures from about 40° F to about 180° F. A typical temperature of substance 14 outputted from the dry cleaning machine may be as high as about 200° to 220° F, and thus a cooling system 160 may be added between the dry cleaning machine and treatment system. Cooling system 160 may be, for example, a cooling heat exchanger coupled to pipe 12 to lower the temperature of substance 14 as it flows through pipe 12. The cooling system may alternatively be provided elsewhere in the system.
A valve 16 controls the flow of substance 14 through a T-shaped pipe 18 into an inlet 20 of a reservoir 22. Valve 16 is depicted as a manual valve, including a
handle 24 for starting and stopping flow through valve 16, and valve 16 may alternatively be automatically controlled and can be any type of valve suitable for controlling fluid flow. During typical operation, valve 16 is opened to allow a quantity of substance 14 to flow or be pumped into reservoir 22 from the dry cleaning machine or other source. T-shaped pipe 18 also couples to a return line, to be discussed below, so that reservoir inlet 20 is shared between the return line and the dry cleaning machine pipe. Alternatively the dry cleaning machine pipe may be provided with a separate inlet to facilitate continuous flow from the source of the perchloroethylene- containing substance or for other reasons to segregate the input from the return piping.
Reservoir 22 is preferably a tank of about 20 gallon capacity, but the invention may be used with a reservoir of any size, preferably scaled to allow daily or weekly processing of the perchloroethylene-containing substance from the source. For example, with a 20 gallon tank coupled to a dry cleaning machine producing about 5 gallons of substance 14 per day, the treatment can be performed every second or third day, allowing excess capacity for the tank, it being preferable not to completely fill the tank in between treatments. Reservoir 22 is preferably a stainless steel container, although glass or ceramic may alternatively be used, particularly with a smaller container, or other material suitable for containing the chemicals involved.
Reservoir 22 includes a wall 26 defining an interior space 28 for storing substance 14. An internal support, such as rack 30 may be mounted in space 28. An opening 32, which may be located at any suitable location, such as an upper surface 34 of reservoir 22, may be covered with a removable lid 36, coupled by a hinge 38 to
reservoir 22 and including a manual knob 40 for selective lifting. Lid 36, which is preferably provided with appropriate sealing mechanisms, may be opened for the insertion into the reservoir and placing on rack 30 of one or more items 42 of a solid material. Items 42 may, for example, be filters used in the dry cleaning machine that have absorbed some of the perchloroethylene-containing substance. Items 42 may be placed in the tank for treatment and removal of the perchloroethylene. After treatment, the items may be withdrawn from the reservoir for further appropriate handling.
Reservoir 22 includes an outlet 44 for the perchloroethylene-containing substance. Outlet 44 and inlet 20 of reservoir 22 are both shown as being located adjacent a lower end 46 of reservoir 22, which provides for self-priming of the system in its operation to be described below, but the inlet and outlet may be at any location on reservoir 22. Outlet 44 is coupled through a pipe 48 to a valve 50 for controlling the flow of substance 14 out of reservoir 22. Valve 50 is depicted as a manual valve, including a handle 52 for starting and stopping flow through valve 50, and valve 50 may alternatively be automatically controlled and can be any type of valve suitable for controlling fluid flow. In typical operation, valve 50 is closed to allow reservoir 22 to fill, then is opened to allow treatment or dumping of substance 14 as will be described below.
Valve 50 is coupled through a pipe 54 to an intake 56 of a pump 58, which includes an output 60 coupled to a piping assembly 62 for further redirection. Pump 58 provides for drawing substance 14 out of reservoir 22 and providing pressure to drive substance 14 into the attached treatment equipment. Substance 14 may be thick
and highly viscous, particularly when first drawn out of the dry cleaning machine prior to treatment, and pump 58 will be designed or selected appropriately to handle such conditions. Pump 58 may be alternatively located at other positions within the system to provide pressure for circulating substance 14 through the system, and additional pumps may be used as desired.
Piping assembly 62 connects output 60 of pump 58 to three valves for selective treatment or dumping of substance 14. A valve 64, controlled by a handle 66, couples from piping assembly 62 to a pipe 68 leading to a sewer drain 70. Valve 64 is preferably opened only for flushing the system with a cleaning solution, such as water, or when processing of the substance 14 is complete and it is appropriate under the applicable regulations to dump the substance into the sewer. Otherwise, valve 64 is ordinarily closed.
A valve 72, controlled by a handle 74, couples from piping assembly 62 to a pipe 76 leading to a first stage 78 for treatment of substance 14. Valve 72 is opened to allow treatment of substance 14 in first stage 78 and is typically closed for other operations, although it may also be opened under other circumstances, including flushing of the system.
A valve 80, controlled by a handle 82, couples from piping assembly 62 to a pipe 84 leading to a second stage 86 for treatment of substance 14. Valve 80 is opened to allow treatment of substance 14 in second stage 86 and is typically closed for other operations, although it may also be opened under other circumstances, including flushing of the system. The three valves 64,72, 80 are depicted as manual valves with
knobs for starting and stopping flow, and the valves may alternatively be automatically controlled and can be any type of valve suitable for controlling fluid flow.
As shown in Figs. 1 and 2, first stage 78 is an ozone treatment apparatus, indicated generally at 87, that includes a chamber 88 where much of the breakdown of the perchloroethylene occurs. Chamber 88 is preferably arranged generally vertically with an inlet 90 adjacent an upper end 92 of chamber 88. Pipe 76 is coupled to inlet 90 so that chamber 88 can receive the perchloroethylene-containing substance 14.
Chamber 88 may be arranged in configurations other than generally vertical, although in such case the ozone-containing substance within chamber 88 will tend to flow toward and accumulate on the high side of chamber 88, which is believed to provide less than optimal reaction between the ozone and the perchloroethylene.
Chamber 88 may be a tank or other container, or it may preferably be the same type of piping as is used in other piping in the system, albeit typically with a larger inner diameter. For example, pipe 76 may be 1-inch PVC pipe while chamber 88 may be 3-inch PVC pipe, and pipe 76 may be coupled to chamber 88 by a PVC coupler 94 that provides the conversion between the pipe diameters.
Chamber 88 may preferably have an inner diameter that is between about 1.5 and about 3 times the inner diameter of pipe 76. The larger diameter of chamber 88 may be used to provide for a lower velocity within chamber 88 for substance 14, if that is appropriate for the desired reaction rate between the perchloroethylene and the ozone. Chamber 88 may alternatively be of the same or smaller diameter as compared
to pipe 76 and other pipes.
Chamber 88 includes a lower end 96 and an outlet 98 adjacent the lower end.
An ozone introducer, such as ozone diffuser or sparger 100 is preferably located within chamber 88 adjacent lower end 96. Ozone diffuser 100 may alternatively be located elsewhere within chamber 88. Under pressure from pump 58, or by gravity or other pressurization, the substance 14 is fed into inlet 90 and flows through chamber 88, typically in a generally downward direction, and out through outlet 98 of chamber 88. At the same time, ozone diffuser 100 is introducing an ozone-containing substance 102, typically in the form of bubbles 104, and preferably in the form of micro bubbles.
Bubbles 102, or other gaseous forms of ozone-containing substances tend to rise in a generally upward direction within substance 14, in a direction generally opposite to the flow of substance 14.
The use of bubbles 102 is believed to be effective in particular for treatment of substance 14 when it is in a thick and highly viscous condition, which typically corresponds to a high concentration of perchloroethylene, as is the case when the substance is first treated after being received from the dry-cleaning machine. Such substance may also include a high concentration of large molecule organic and other compounds, some in clusters, and it is believed that the ozone diffusion treatment may also break down these molecules and clusters to provide a further thinning of substance 14. Bubbles 102, while tending in general to rise in substance 14, may, in some case, take more complex paths, for example, swirling, which is believed to promote increased ozone reaction in a type of ozone gas recirculation. Reaction
between the ozone is believed also to occur in the piping outside of chamber 88 as the ozone travels through the piping.
First stage 78 includes a pipe 106 coupled to outlet 98 of chamber 88 for piping the substance 14 out of chamber 88. Pipe 106 is coupled through a valve 108, with a control handle 110, to a T-connector 112. Valve 108 is preferably ganged with valve 72 for simultaneous shutting off and opening up of both ends of first stage 78 for coupling and decoupling with reservoir 22. Valve 108 may be manual or automatically controlled.
T-connector 112 is coupled to a pipe 114 that routes the substance 14 back to reservoir 22. Pipe 114 is coupled to a valve 116, with a manual control knob 118 that couples through to T-shaped connector pipe 18 and the inlet to reservoir 22. Thus, the chamber outlet is routed back through reservoir 22 for continual treatment of substance 14 until the amount of perchloroethylene in the substance is reduced to a desired level. It can also be seen from Fig. 1 and the foregoing description that the inlet of the reservoir is selectively couplable to either the outlet of the chamber or an output from a source of the perchloroethylene-containing substance. Valve 116 may be either manually or automatically controlled along with the other valves to carry out desired system operations.
It can also be seen from Fig. 1 and the foregoing description that the outlet of the reservoir is selectively couplable to either the inlet of the chamber for ozone diffusion treatment or to the sewer.
As seen in Figs. 1 and 3, second stage of treatment 86 includes a venturi
injection apparatus 120, preferably include a T-connector 122, coupled to pipe 84, and a pair of pipes 124,126, each leading to one of a pair of venturi bodies 128,130. Any number of venturi bodies may be used. Fig. 3 also shows a pump 132, which may be understood to represent an additional pump to increase pressure for the venturi injection, or a schematic representation of the pressure produced by pump 58.
Venturi bodies 128,130 are selectively coupled to an ozone generator 134, which is in turn receiving oxygen from an oxygen concentrator 136, which are typically commercially available units selected for a desired system size and reaction rate. The more ozone is generated, the less time is required to remove a given amount of perchloroethylene from a given amount of substance 14.
Typically a single ozone generator and oxygen concentrator will be selectively coupled to both the venturi injection apparatus and to the ozone diffuser, so that ozone is available for only one stage at a time. However, additional ozone generator (s) and oxygen concentrator (s) may be used as desired and coupled for simultaneous reaction of ozone in both stages, or simply provided as independent sources of ozone.
The outputs of venturi bodies 128,130 are preferably connected to pipes 138, 140, which may be rejoined at T-connector 142, which is coupled to a pipe 144 for return to the reservoir. Pipe 144 is coupled through a valve 146, with a control handle 148, to T-connector 112, where the return flow from the venturi apparatus is rejoined to the return flow from the ozone diffusion apparatus. Valve 146 is preferably ganged with valve 80 for simultaneous shutting off and opening up of both ends of second stage 86 for coupling and decoupling with reservoir 22. Valve 146 may be manual or
automatically controlled. It can be seen from Fig. 1 that valve 72, valve 80, valve 50, and associated piping provide for selectively coupling the outlet of the reservoir to either the chamber inlet or the venturi injection apparatus.
Venturi injection apparatus 122 thus provides for reacting ozone-containing substance 102 with perchloroethylene-containing substance 14. The reaction is preferably furthered by addition of one or more catalysts, preferably a catalyst which promotes treatment of the perchloroethylene by promoting the decomposition of the ozone (03) into °2 and a free radical oxygen atom, which is particularly reactive with perchloroethylene and other chemicals. Catalysts may be introduced by dissolving in through the venturi bodies alongside the ozone containing substance 102. Such catalysts include iron ions, manganese ions, and hydrogen peroxide, and other suitable materials. Alternatively, the catalyst may be ultraviolet light, added by an ultraviolet lamp 150,152 located adjacent one or both of the outputs of venturi bodies 128,130 to radiate light on the substance 14 as it emerges from the venturi bodies mixed with ozone. A suitable ultraviolet lamp for use as a catalyst introducer is the Model No. IH- 1 S made by Ideal Horizons.
Reaction of ozone with the perchloroethylene is also promoted by the alkalinity of substance 14. This is believed to be the case because the higher pH supports the creation of hydroxyl radicals (OH-), which promote ozone and perchloroethylene decomposition. The catalysts also promote the creation of hydroxyl radicals to the same effect. The pH of the substance 14 can be increased, for example, by adding sodium hydroxide to substance 14 in reservoir 22, or at any location in the piping prior
to ozone treatment in either the diffusion chamber or the venturi injection apparatus.
A summary of valve control settings for typical modes of operation of the system is provided in the following table: Stage 1 Counterflow of Ozone Valves 72,108 Open Valves 80,146 Closed Valve 50 Open Valve 116 Open Valve 16 Closed Valve 64 Closed Stage 2 Venturi Injection of Ozone Valves 72,108 Closed Valves 80,146 Open Valve 50 Open Valve 116 Open Valve 16 Closed Valve 64 Closed Draining to Sewer Valves 72,108 Closed Valves 80,146 Closed Valve 50 Open Valve 116 Closed Valve 16 Closed Valve 64 Open Filling from Dry cleaning Machine Valves 72,108 Closed Valves 80,146 Closed Valve 50 Closed Valve 116 Closed Valve 16 Open Valve 64 Closed In operation the system is typically used to first pipe the perchloroethylene- containing substance 14 into reservoir 22, at which time substance 14 is typically thick, viscous, and black or near black or dark brown in color, and includes a
relatively high concentration of perchloroethylene. The thickness and viscosity of substance 14 at this time typically prevents it from being effectively treated through a venturi injection apparatus because of the tendency towards clogging in a venturi body of a suitably small dimension for ultimately satisfactory treatment of perchloroethylene.
Thus, the substance 14 is first piped through the ozone-diffusion chamber or tank for a first period, the duration of which may be determined by any of several criteria. For example, the system may incorporate an oxidation reduction potential (ORP) sensor or a conductivity sensor, which may be located at the outlet of reservoir 22, or at another suitable location. The ORP or conductivity sensor can measure the amount of perchloroethylene in substance 14 to provide an indication for when to use ozone diffusion, when to use venturi injection, and when to dump into the sewer, or other holding basin.
A suitable ORP sensor is incorporated in the process control meter of the Great Lakes Instruments Model 33 ORP Controller. A suitable conductivity sensor is incorporated in the process control meter of the OakTon Series 1000 Conductivity/Resistivity Controller. These meters include a sensor that can be placed into the flow of substance 14 in the piping or elsewhere in the system of the present invention, and a receiver/controller that receives a signal from the sensor. The meters may be programmed to compare the signal to a set point (or user programmed target value) and provide control signals for the valves for appropriate operation.
The color of substance 14 may also be used as a criteria for determining
process flows because the substance typically changes from a darker color, a brown, near-black, or black color, to a lighter brown, through a milk color, and finally to a clear color, as the amount of perchloroethylene is reduced. A preselected time period in minutes or hours for each stage of treatment may be used, alternatively or in combination with the other criteria.
After the substance 14 is treated in the ozone diffusion chamber for the first period, the valves may be set to pipe substance 14 through the venturi injection apparatus for a second period, which also may be determined by the various foregoing or other criteria. The venturi injection apparatus is typically more capable of reducing the perchloroethylene amount to an environmentally acceptable degree for discharge into the sewer. It is believed that the first period may range from at least about five minutes to no more than about 6 hours and that the second period will range from at least about five minutes to no more than about twenty-four hours. In general, the switch from ozone diffusion to venturi injection of ozone may be desirable at about the time that the first stage treatment has reduced the viscosity of perchloroethylene- containing substance 14 to a sufficient level to permit piping the perchloroethylene- containing substance through the venturi injection apparatus substantially without clogging.
Fig. 4 shows an alternative embodiment for an ozone treatment system including a reservoir 222, similar to that of Fig. 1, but with an inlet 290 at an upper end 292 and an outlet 298 at a lower end 296, as in chamber 88. Outlet 298 is coupled to a pipe 306, leading to a pump 258, which pumps substance 14 up a pipe 276. Inlet
290 is coupled to pipe 276 for recirculation of substance 14. Inside reservoir 222, substance 14 flows in a generally downwardly direction, while an ozone diffuser 100 inside reservoir 222 adjacent the lower end provides a counterflow of an ozone- containing substance 102 in a generally upward direction, substantially opposite to that of the perchloroethylene-containing substance.
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