CA2178258A1 - Method and apparatus for removing volatile organic compounds by cold oxidation - Google Patents

Abstract

A method and apparatus for reducing, abating, and destroying volatile organic compounds (V.O.C.s) contained in an air stream is disclosed. The air stream is mixed with a fog or mist of activated air in aqueous solution while the mixture is exposed to ultraviolet radiation in chambers along a tunnel. The activated air contains oxidants that are formed by exposing air to ultraviolet light. The activated air is generated under conditions that prevent prolonged existence of ozone and enhance the generation of highly active oxidants such as hydroxyl radicals. The aqueous solution is formed by dispersing the activated air into water in sparger tanks that include ultraviolet lamps to maintain a high oxidant level in the aqueous solution. The tunnel includes catalyst plates that act as scrubbers and that are exposed to the ultraviolet light in the tunnel to provide hydrogen to enhance generation of hydroxyl radicals. The tunnel includes coalescers that remove particulate water and V.O.C.s, which are collected in a supply tank and recirculated into the sparger tanks and thereafter back into the tunnel. The tunnel also includes carbon filters that collect V.O.C.s for surface reaction in the presence of further ultraviolet light.
Upon discharge from the tunnel, the air stream is delivered to a carbon bed system where remaining V.O.C.s are captured and further oxidatively destroyed. Two carbon beds can be used, with one carbon bed on-line while the other is regenerated using activated air.

Description

~ 21 78258 ME~r~OD AND APPARA~ru8 FOR R . ~
VOLATI~}: ORGANIC COMPO~IND~ ~Y COLD OXIDATION

FIFr n OF TTTF INVFNTION
This invention relates generally to controlling environmental pollution and, more 10 particularly, to a method and apparatus for reducing and destroying volatile organic compounds (V. O. C . s) .
BACKGROTJND OF TT~r' INVE~TION
V.O.C.s have long been a major source of air pollution as an inevitable contaminant exhausted from many industrial processes including, for example, large industrial paint shops used in the automotivc industry.
Legislative efforts have established emission standards 20 to control emission of V.O.C.s into the environment.
Current and future, 1 i~nre with such standards places a continuing demand on industry and creates an on-going need to reduce, degrade, and eventually destroy V.o.C.
emissions in a manner that is not cost prohibitive.
25 This is particularly critical for manufacturers in industrialized countries who compete against sources oper2ting in countries that do not have strict air pollution control laws.
3 o In automotive paint shops, large volumes of solvent (V. O. C. ) laden air must be removed from the paint spray booths and, to a lesser extent, from other paint shop operations, such as holding and quiet zones and paint bake ovens. For automotive paint shops, large 35 quantities of solvent-laden air mUst be processed.

P- 3 0 ~3 TRI ~ 2 Various techniques and combinations thereof have heretofore been used for V.o.C. abatement in paint shops .
Typically, scrubbers are used to capture inorganic chemicals and particulate paint from process exhaust air using liquids pumped through the scrubber.
Any rF-~; n i n~ paint particles are then removed from the exhaust air by filter banks with progressively increasing efficiencies. Less expensive filters are used in the initial stages to trap most of the larger paint particles. After filtering, the exhaust air stream is heated to reduce the humidity for a subsequent adsorbtion process. In the adsorption processes, solvent-laden air is concentrated into smaller quantities, typically 10% of the main exhaust airstream, and then processed. Typically, the concentration is accomplished by adsorbing the V. 0 . C. s into a carbon bed and then desorbing the carbon bed with hot air, hot inert gas or steam. The concentrated desorption product can then be finally processed through rl~Pm;c~l treatment, solvent recovery or incineration.
Various incineration apparatus can be used to oxidize the solvents in a concentrated solvent-air mixture taken from the carbon beds. ~owever, typically the mixture is heated to temperatures in excess of 1,400F. When held at these high temperatures, the solvents react with oxygen, with the final reaction 3 0 production products theoretically being harmless water vapor and carbon dioxide. Various types of thermal regeneration heat exchangers and the like are used to recoup heat from the incinerator exhaust to improve thermal efficiency. Direct incineration could be used 35 but it generally has a low thermal efficiency, p--308 TRI-MARX -- 3 --particularly for processing large volumes of V. 0 . C. -laden air. However, such prior art systems require large capacity carbon beds and have high energy costs f or incineration .
Except in the most advanced systems, some off-site treatment and/or disposal is frequently required. For smaller installations, as contrasted to large automotive assembly plants, off-site carbon bed lO desorption may be most cost effective. In general, carbon beds, when used alone, are not effective or cost efficient for processing large volumes of V.O.C.-laden air. Special systems are required to desorb the carbon beds and, for many applications, this is accomplished 15 off-site. Additionally, the desorption concentrate must still be treated for solvent removal and/or incineration. Incineration generally generates NOx or carbon - r~;dP and, without thermal recovery systems, has a direct thermal impact on the environment as well 20 as requiring off-site disposal. host importantly, prior art systems relying on high temperatures to complete oxidation are expensive to operate and may still require of f -site 1~ qpO~ 1 . These disadvantages, particularly when coupled with current and anticipated air and 25 environmental pollution control, create an on-going need f or improved V . 0 . C . abat~ment .
Another technique that has been utilized for abatement of V. 0 . C. s in industrial process air involves 30 the use of ultraviolet ~uv) light to break down the V.o.C.s directly and to form activated air containing oxygen in the form of ozone and other oxidants that also work to break down the V.O.C.s. As used herein, "activated air" should be understood to refer to air 3 5 that has been treated, whether by exposure to 2 ~ 78258 P--308 TRI-~ 4 --ultraviolet light or some other method, to increase the concentration of oxidants in the air. Commercial systems are available that utilize this technique for abatement of solvents contained in process air exhausted 5 from industrial paint booths, ovens, conformal coating areas, etc. A typical system includes a two-stage pre-filter, a photolytic reactor, an aqueous reactor, a coalescer, and a pair of granular carbon beds.
Particulates of one micron and greater in size are 10 collected and removed from the process air by the pre-filters. The air flow then passes through the photolytic reactor, where it is exposed to tuned ultraviolet light. Exposure of the process air to the ultraviolet light results in photochemical reactions 15 that form ozone from the oxygen contained in the air, as well as peroxides from the moisture content within the air .
Oxidative degradation begins in the photolytic 20 reactor due to both the newly formed oxidants and the direct exposure of the V.O.C.s to the ultraviolet light.
The air stream is then scrubbed with ozonated water in the aqueous reactor. The ozonated water is generated by subjecting air to the ultraviolet lights and then 25 injecting and mixing the activated air into the water.
At this stage, water soluble hydrocarbons will collect in the water and will thereby be removed from the air stream. After passing through the aqueous reactor, the water vapor contained in the air stream is removed by 3 o the coalsecer . The f inal stage in this process is to pass the air stream through a carbon bed f or adsorption of any remaining V. O. C . s . A second carbon bed i3 utilized so that while one carbon bed in on-line to adsorb the V. O . C . s, the other is in the process of being 35 regenerated using activated air containing ozone, P-308 TRI-MAR~C - 5 -hydrogen peroxide, and other oxidants produced photochemically by exposure of clean air to ultraviolet l ight .
The use of ultraviolet light to generate activated air containing ozone has also been implemented in various systems for treating water. For example, the following U. S . Patents are each directed to the use of ozone and other oxidants in the wash water of a laundry washing system: 3,065,620, issued November 27, 1962 to P.H. Houser; 3,130,570, issued April 28, 1964 to P.M.
Rentzepis; 3,194,628, issued July 13, 1965 to P. Cannon;
5,097,556, issued March 24, 1992 to R.B. Engel et al.;
and 5,241,720, issued September 7, 1993 to R.B. Engel et 15 al. In these systems, ozone is produced by exposing air to ultraviolet radiation that is produced by either a corona discharge or ultraviolet lamps. The activated air containing ozone and, in some cases, hydrogen peroxide is mixed with the wash water to improve the 2 o cleaning of laundry and reduce or even eliminate the need for detergents.
The literature also suggests that substantial laboratory efforts have been directed to using 25 ultraviolet radiation for other types of water treatment. See Legrini, Oliveros and Braun, "Photochemical Processes For Water Treatment, " Chem.
Rev. 1993 at pages 671 through 698, American Chemical Society Document No. 0009-2665/93/0793-0871.
30 Ultraviolet radiation for water treatment is potentially useful not only for treating drinking water, but also for treating contaminated surface water, ground water and waste water. However, based upon the 221 biographical references cited and reviewed, the authors 35 suggest that most such laboratory experimentation, with ~ 2 1 78258 P-3 08 TRI-M~ - 6 --a f ew noted exceptions, have not been evaluated on a prototype basis, much less commercially.
Althoug~ the Chemical Review article is 5 directed to water treatment as contrasted to V. O . C.
abatement in industrial process air, some of the mechanics of oxidative degradation considered therein may be useful as background for the present invention.
For example, Table I at page 674 ~reproduced as "TABLE
10 1" below) c~nf i rTnc the oxidation potential Or various oxidants believed to be available from the activated air and undoubtedly generated elsewhere in the system and process of the present invention as will be described.

oxidation Potent; A l ~ of Some ~ nts - S~ecies Oxidation Potçntial (V~
fluorine 3 . 03 hydroxyl radical 2 . 8 0 atomic oxygen 2 . 42 ozone 2 . 07 2 5 hydrogen peroxide 1. 7 8 P~LI1YdLU~Y1 radical 1.70 permanganate 1. 68 hypobromous acid 1. 59 chlorine dioxide 1. 57 30 hypochlorous acid 1. 49 hypoidous acid l . 45 chlorine 1. 3 6 bromine 1. os iodine o . 54 Each of the foregoing references, as well as 40 the literature describing the commercially available air treatment systems described above, all espouse the virtues Or ozone and the use of ultraviolet radiation to p-308 TRI-MARX - 7 _ 2 1 78258 generate that ozone. However, as shown in Table 1 above, ozone has a lower oxidation potential than hydroxyl radicals. Thus, ozone has less tendency to cause oxidation of the V. O . C . s than the hydroxyl 5 radical; that is, it is less active than the hydroxyl radical. U.S. Patent No. 4,214,962, issued July 29, 1980 to A.J. Pincon, sets forth other disadvantages of creating ozone in addition to other oxidants formed by ultraviolet radiation; namely, the increase in surface 10 tension of water with which it is mixed and the possible formation of carcinogenic substances. In that patent, an apparatus is disclosed for using ultraviolet light under 200 nanometers to generate an undisclosed activated oxygen product without the production of 15 o~one. When used for treating water for human consumption or swimming pools, the apparatus can include a polyvinyl chloride enclosure to permit liberation of free chloride to provide chlorination of the water.
Not unexpectedly, however, since the Pincon patent is directed to the use of ultraviolet radiation for water treatment, it does not address the problems associated with processing large guantities of industrial process air laden with V. o . C. s, much less offer any direct solution to the problems and disadvantages of the various commercial processes that rely at least in part on the presence Or ozone for V.O.C. abatement in the exhaust ~rom paint spray booths.

SUMMARY OF THE TNVENTIO~
The invention provides a method and apparatus for reducing, abating, and destroying volatile organic compounds on a continuous ~asis, wherein a V.O.C.-laden P-308 TRI-~ - 8 --air stream is mixed with and maintained in a fog or mist of activated air in aqueous solution while the mixture is repeatedly exposed to ultraviolet radiation in a series of chambers along a tunnel. The activated air 5 contains oxidants such as hydroxyl radicals, hydroperoxy radicals, and hydrogen peroxide. Preferably, some activated air is introduced into the tunnel in gaseous form. The activated air is generated by exposing humid air to ultraviolet radiation and the activated air is lO then dispersed in an agueous solution in sparger tanks.
The sparger tanks also include ultraviolet lamps to generate and maintain a high oxidant level in the aqueous solution and promote other reactions just before the aqueous solution is introduced into the tunnel as a 15 f og or mist .
Preferably, upon discharge from the tunnel, the air stream is still in a highly active state and is delivered through an expansion chamber to large carbon 20 beds where rr--;n;n~ V.O.C.5 are l:d~Lu~:d and further oxidatively destroyed. Clean air and water vapor and quite possibly harmless carbon dioxide are exhausted from the carbon beds to the atmosphere. Preferably two carbon beds are used so that one carbon bed is on-line 25 to capture any re~~;n;n~ V.O.C.s while the second carbon bed is being regenerated. Activated air is used to regenerate the carbon beds 50 that thc regeneration not only desorbs the carbon bed but also deposits and replenishes the carbon bed with oxidants from the 30 activated air. This regeneration as~ures that oxidants are available for surface reactions with any rr~-;nin~
V. 0 . C . s when the regenerated carbon bed is brought on-line. Preferably exhaust gases from the regeneration process are recirculated back through the tunnel, along 35 with activated air vented from the sparger tanks so that 2 1 7`8258 any reaction products generated in the carbon beds are continuously treated while being recirculated through the system.
The final end products from the cold oxidation process of the present invention are believed to be water (H20~ and carbon dioxide (C02~ as in an ideal incineration process. However, although some harmless water vapor and gaseous carbon dioxide is undoubtedly released to the environment, most of the water is retained in the system. As compared to incineration, less carbon dioxide than expected is exhausted from the carbon bed which is on-line. In any event, exhaust from the system to the environment is not a thermal pollutant.
While not ascribing to any one theory, it is strongly believed that the present invention destroys V. 0 . C . s by a combination of two phenomena, undoubtedly producing a synergistic effect. First, the activated air generated by ultraviolet radiation and further ultraviolet radiation of the active fog produces highly reactive oxidants which then subsequently oxidatively degrade and destroy the V.O.C.s. Secondly, direct ultraviolet photolysis of the V. 0 . C . s causes photochemical decomposition of the V.O.C.s with the resulting products interacting with oxygen, the oxidants and other intermediate radicals in the activated air and the activated air fog in the tunnel and preferably in 3 o the sparger tanks and the carbon beds .
These two phenomena occur alone and in combination in various degrees, not yet fully determined, in the various stages described hereinabove, principally:

~ 2 ~ 78258 P--308 TRI-N~RK - 10 -1. Reaction of the V . 0 . C . s, intermediates, and oxidants in the vapor stage occurring in the tunnel chambers;
2. Reactions with the V.O.C.s, intermediates, 5 and oxidants in the aqueous sparger oxidation tanks;
3. Sur~ace reaction and final destruction of V. 0 . C . s at the carbon beds; and 4. To a lesser extent, reactions o~
intermediates and oxidants in supply tanks and PVC
lO piping used throughout the system.
Enhancement of the activity level of the activated aLr is believed to occur by one or more effects that serve to decompose ozone generated by 15 irradiation from the ultraviolet lamps and thereby permit the liberated atomic oxygen to combine with available atomic hydrogen to form hydroxyl radicals.
These effects include photolysis of the ozone using ultraviolet light at a wavelength of 254nm, degradation 20 of the ozone as a result of creating and maintaining the activated air in a high humidity environment, and degradation of the ozone by radicals such as Cl- that are made available by ultroaviolet radiation of a PVC or other catalyst.
Regardless of precisely where and how total V. 0 . C . destruction occurs and how it progresses, no waste residue is generated, due in part to continuous recirculation of the aqueous solution through the 3 0 tunnel, the storage tank, the sparger tanks, and the circulation of the carbon bed regeneration exhaust air into the tunnel.
Components of the cold oxidation system, and 3 5 particularly the tunnel, are of modular construction to - 2 1 7~258 achieve economical original installation, future system expansion and retrofitting existing systems with a minimum capital expense and down time. Although particularly suited f or V . O . C . abatement of exhaust air 5 from paint spray booths for which they were designed, the method and apparatus of the present invention are potentially useful for V.O.C. destruction in exhaust air from many other laboratory and industrial processes, for example plating, phosphating and other bath-type 10 treatment processes and the manufacture of powdered resins and other resin processing operations. Moreover, the present invention is potentially useful for destroying a wide variety of V. O . C. s other than those used commercially in paint solvents, for example various 15 undesirable hydrocarbons and harmful carcinogens.
Objects, features and advantages of the present invention are to provide a method and an apparatus rOr V. O . C. air pollution abatement which 20 overcome the disadvantages of prior art techniques for V. O. C. pollution abatement in exhaust gases; which effectively and efficiently, both in cost and result, abate, reduce and/or destroy volatile organic compounds bef ore being exhausted into the environment; which 25 effectively destroy volatile organic compounds in exhaust gases to levels well below current accepted 6tandards; which facilitate installation, operation and maintenance at relatively low cost; which provide fast and cost-efficient installation, part replacement, 30 system expansion and retrofitting with low capital expenditures and short down times; which do not produce any detectable NOx, carbon monoxide, and/or ozone or other noxious gases exhausted to the atmosphere or undesirable final reaction products such as nitrogen 35 oxides and nitrous acid which would either remain in the ~ 2 1 78258 p-308 TRI-~RR - 12 --system and/or which would require off-site ~ pos~l treatment; which reduce carbon bed absorber size, capacity and cost, as contrasted to prior art carbon beds used either with or without subsequent 5 incineration; which operate on a continuous basis with high volumes of contaminated air and eliminate batch processing; which do not require high oxidation temperatures and are energy ef f icient; and which are particularly cost-effective and efficient for V.O.C.
10 pollution abatement in industrial processes involving large quantities of V.O.C.-laden exhaust air, particularly automotive and other large industrial paint shops and the like.

BRIEF DESCRIPTIQN OF THE DRAWINGS
A preferred exemplary ~rho~;r~nt of the present invention will hereinafter be described in 20 conjunction with the a~pended drawings, wherein like designations denote like elements, and:
Figure 1 is a schematic diagram of a V. O . C .
abatement system of the present invention that is useful 25 in carrying out the method of the invention;
Figure 2 is a diagrammatic view of a primary treatment tunnel of the abatement system of Fig. 1 showing the location and relative positioning of the 3 0 various components used in the tunnel;
Figure 2A is a perspective view of an ultraviolet lamp and deflector used in the tunnel of Fig. 2;

Figure 3 i5 a schematic diagram of a liquid subsystem used in the abatment system of Fig. 1 to generate activated fog and continuously recirculate liquid through the system;
Figure 4 is a sectional view through a sparger tank of the liquid subsystem of Fig. 3;
Figure 5 is a view, partly broken away and in 10 section, of a cell for generating activated air in the systcms of Figs. 1 and 3;
Figure 6 is a perspective view of a baffle plate subassembly of the generator cell of Fig. 5;
Figure 7 is a schematic view of an air f low system f or regenerating carbon beds and exhaust recirculation in the abatment system of Fig. 1; and 2 0 Figure 8 is a schematic view of regeneration piping for the carbon beds of Fig. 7.
DFTATTT~n DEs~`-RTpTIoN
Overview of the V~. Q . ~ . Ah~teme~t Svstem Fig . 1 schematically shows a pref erred Pmhnrl;r-rlt of a V.O.C. abatement system 10 of the present invention as it would be used for h~n~ll;ng large volumes of V.O.C.-laden process air exhausted from large automotive paint spray booths. As shown in Fig. 1, a V. O. C . -laden air stream 12 is drawn through a primary treatment tunnel 14 between an inlet 16 and an outlet 18 35 using a large centrifugal blower 20. Tunnel 14 - 2 ~ 78258 P--3 0 8 TRI-~ARK -- 14 continuously treats the air stream to destroy the V. 0. C. s within the air stream by oxidative deqradation and photolysis. In general, this is accomplished within tunnel 14 by mixing the air stream with activated air 5 and by direct exposure of the air stream to ultraviolet light. Blower 20 pushes the air exiting tunnel 14, along with any r --i nin~ V.O.C.s, into an expansion chamber 22 and then through a carbon bed absorber-reactor system 24 which exhausts to the 10 environment through exhaust stack 26.
As will be described below in greater detail, an activated air generator 28 produces activated air that is supplied via a second blower 30 to carbon bed 15 system 24 and the upstream end of tunnel 14. Carbon bed system 24 comprises a pair of separate and isolated carbon beds 32, 34 so that when one of the carbon beds is on-line in the process and treating exhaust air from tunnel 14, the other carbon bed is being regenerated 20 using the activated air from generator 28. The activated air from generator 28 contains a high level of oxidants which desorb and regenerate the off-line carbon bed .
PrimarY Treatment Tunnel Referring back to the primary treatment tunnel 14, activated air containing a high level of oxidants is fed from a second activated air generator 40 via pipe 42 30 to a sparger tank farm 44 which, using ultraviolet radiation, generates an aqueous solution laden with newly-generated and reactivated oxidants. The oxidant laden solution is then fed via pipe 46, solenoid operated valve 48 and header 50 to various selected 35 modular sections Sl through S15 where it is introduced -p--308 TRI-~$~RK - 15 -as an activated f og into various selected tunnel chambers C1 through C15 to maintain an oxidant-enriched, high-humidity environment within tunnel 14. This oxidant-enriched, high-humidity environment performs 5 various important functions, as will later be described in greater detail. Oxidant laden solution from sparger tank farm 44 is also fed via pipe 46, solenoid valve 52 and pipe 54 to an array of nozzles 56 which also provide an oxidant-enriched, high-humidity environment 10 downstream of a set of primary particulate filters 66 at the inlet 16 of tunnel 14. Also located downstream of inlet 16 is an array of activated air nozzles 68 that are connected to a tap 74 to receive partially spent activated air exhausted from the regeneration of carbon 15 ~ed system 24. In this way, any V.O~C.s contained in this regeneration exhaust gas will be recirculated through abatement system 10. These nozzles also receive activated air vented from sparger tank farm 44, as will be described below. Further, these nozzles are also 20 connected to a second tap 72 that can be used to provide newly generated activated air from generator 28 in the event greater oxidative activity is re~uired in tunnel 14 .
Activated aqueous solution introduced into tunnel 14 via nozzles 56 and nozzle header 50, which precipitates, condenses and/or is filtered out of the air stream 12, is collected in a supply tank 60 from which it can be recirculated via a pump 62 and a pipe 64 back to tank farm 44 where it is remixed with activated air from generator 40 and exposed to ultraviolet radiation to provide a continuous recirculating supply of oxidant enriched fog to tunnel 14.

.

Advantageously, each of the modular sections, S1-S15 can be fully or partially constructed off site.
The modular sections Lnclude framing, structural members, plumbing, fittings and some electrical wiring 5 for various functional components, i . e., ultraviolet lamps, mist nozzles, Viledon filters, carbon filters and catalyst plates, some of which can also be preassembled in the modules. Sparger tank farm 44 and carbon bed system 24 can also be partially assembled off site as 10 modules. External housing panels for tunnel 14 are fabricated and erected on site, preferably of stainless steel sheet metal to form chambers C1-C15. After completing all of the sheet metal fabrication and ductwork, the necessary piping, valving and electrical 15 wiring connections are made and the system cleaned and flushed before final installation of nozzles and ultraviolet lamps.
Although an understanding of the present 20 invention will be more fully apparent from the detailed descriptions to follow, in general, the V.O.C. air stream 12 entering tunnel 14 is filtered at filters 66 to remove particulate paint and other particles. It is then blended with the oxidant-enriched fog from nozzles 25 56 and with gaseous activated air from nozzles 68. The ~ixture then enters an expansion chamber 76 which allows the air stream to egualize and load the unit to a uniform flow. As the air stream continues moving from left to right as viewed in Fig. 1, it passes through the 30 series of treating chambers, C1 through C15, defined between corr~cpnn5in~ modular sections S1 through S15, where the V. 0 . C . s are at least partially destroyed by photodecomposition and oxidative degradation.

As the V.O.C.-laden stream 12 passes through chambers S1 through S15, it is repeatedly exposed to ultraviolet radiation in the oxidant-laden, high-humidity environment. Activated air fog is 5 repeatedly replenished via header 50 in selected modular sections S1 through S15. As the V.O.C. laden air stream moves through various f ilters, precipitators and coalescers, particulate water, together with water-soluble compounds, are collected in supply tank 10 60. Preferably, selected coalescers are perforated plates coated with a catalyst, such as titanium dioxide, which provides hydrogen f or production of hydroxyl and other oxidants to thereby enhance the oxidative degradation of V.O.C.s. The perforated plates, and to 15 a lesser extent the filters, also act as scrubbers to mix and bring the activated air fog, oxidants and V . 0 . C. s in intimate contact with one another .
Pref erably, various other components in the system are made of PVC to serve as catalysts.
Water from supply tank 60 is recirculated into the sparger tank farm 44, mixed with the activated air from generator 40, exposed to further ultraviolet radiation, and reintroduced into tunnel 14 . Except f or 25 high humidity vapor discharged from the tunnel, together with r.or-in;n~ V.O.C.-laden air, water and any water-soluble in~prr~ ries from V.O.C. reactions are recirculated in a substantially closed system until all remaining intermediate reaction products are reduced to 30 water and/or carbon dioxide.
Activated Air -P-308 TRI-~ARK - 18 -As will be described in greater detail below, the activated air supplied by generzltor 40 is produced by exposing humid air to ultraviolet radiation to produce oxidant radicals, pref erably under turbulent 5 flow conditions and in the presence of a catalyst to enhance oxidant generation and produce additional oxidants. Normally, plant air is used as the fresh air supply for generator 40 with a humidity level of 85%
being typical. If necessary, humidity can be introduced 10 into the air at generator 40 by, for example, wicking water into the plant air. The ultraviolet light preferably includes 184.9nm and 254nm wavelengths, which can be achieved by enclosing an ultraviolet lamp in a suitable quartz lens, as will be described below.
Table 2 lists the relative percentages of the various oxidants and other constituents believed to be in the activated air. The percentages given indicate the relative amounts in the approximately 20% of the 2 0 activated air that includes oxygen and oxygen bearing compounds .
TAB~E: 2 Percent by Volume of Air Constituent ~xcludinq Nitroqen Nitrogen Dioxide (NO~,) 20 . 1%
Atomic Oxygen (I) 24 . 4%
3 o Hydrogen Peroxide (H22) 212 . 6%
Hydroperoxy Radical (HO2) 229 . 4%
Hydroxyl Radical (OH) 26. o%
Oxygen (2) 45 5%
Other Oxidants such as NO2, N2O <1. 0%
Other gases such as NH2, NH3, C2, N2, HCN, CI <1.0%
As Table 2 above indicates, even though the 40 ultFaviolet light includes the 184.9nm wavelength that ~ 2 1 782~8 P-308 TRI~ RK - l9 -is known to cause formation of ozone (03) in air, no ozone is present in the resulting activated air produced by generator 40. This is believed to result from the presence of humidity in the supply air which provides a 5 hydrogen rich environment that allows any ozone to almost immediately split and form hydroxyl radicals.
This is also believed to result from photolysis of the ozone caused by the 254nm ultraviolet light.
When the activated air is generated by exposure to ultraviolet radiation in the presence o~ a catalyst, such as polyvinylchloride, it is believed that the following additional radicals are produced:

RA~i;cals C2Cl-cl-Cl2 ClOH-H203Cl-H2Cl-HOCl-These radicals further help split the ozone, freeing up oxygen that can then combine with available hydrogen to form the highly active hydroxyl radicals.
3 0 Without wishing to be limited to any theoretical explanation, it is believed that, by splitting up the ozone almost as soon as it is generated, the oxygen from the ozone is available to f orm hydroxyl radicals that have a higher oxidation potential and are therefore more effective than ozone at destroying the V. o . C. s . In this way, the activity level of the activated air can be PnhAnf Pd. Furthermore, the oxidants produced are negatively charged, and this is ~ 21 78258 P--3 o 8 TRI-MARK - 2 0 believed to result in l~nhP~nr~rl degradation of the V.o.C.s. Preferably, the relative humidity of the plant or other fresh air used to generate activated air is at least 25% and, more preferably is within the range of 75-100% and, even more preferably is in the range of 90-100% .
The activated air is then dissolved as best as possible into an aqueous solution at sparger tank farm 44. The resulting activated aqueous solution is then introduced into tunnel 14 as an activated fog that mixes with the V.O.C.-laden air stream 12 passing through tunnel 14. The air stream is kept at a high level of activity via direct ultraviolet radiation in the high humidity environment. Photodecomposition initiates cleaving of the V.O.C.s and oxidative degradation begins in at least the f irst chamber, Cl . As the air stream moves through the tunnel, cleaving of the compounds and oxidative destruction continue at an accelerated rate as 2 0 reaction products in solution are f iltered and precipitated out of the air stream and returned to supply tank 60.
As indicated above, V. 0 . C. destruction according to the present invention is believed to occur by a combination of two phF~nn-~n~ ~ namely oxidative degradation of the V. o . C . s by oxidants contained in the activated air in gaseous and fog states, and by photolysis occurring simultaneously and undoubtedly synergistically, in tunnel 14 due to repeated exposure of the V. o. C . -laden air stream to ultraviolet radiation in a high-humidity environment. Consequently, tunnel 14 would be useful in and of itself to provide acceptable V. 0 . C. abatement without further treatment at carbon beds 32, 34.

~ 2 1 78258 p--308 TRI-MARK - 21 -Tunnel Chambers In general, tunnel 14 incorporates particulate filtration, misting or fogging, ultraviolet light 5 activation, coalescers, carbon filters for surface reactions, and preferably one or more catalysts. One or more of these functions is incorporated in each of the modular sections S1 through S15. Further, these functions are carried out in a predet~rm;n~d sequence so 10 that the processes and reactions occurring in chambers C1 through C15, individually and in se~[uence, optimize V. O . C . destruction occurring in tunnel 14 .
As shown in Fig. 2, the modular sections S1 15 through S15 in tunnel 14 are as follows:
Section S1: Mist nozzles, mixing cones, and ultraviolet lamps.
Section S2: Ultraviolet lamps and mist nozzles.
20 Section S3: Ultraviolet lamps and mist nozzles.
Section S4: Viledon filters and ultraviolet lamps.
Section S5: Carbon filters, ultraviolet lamps and mist noz z les .
Section S6: Ultraviolet lamps and mist nozzles.
25 Section S7: Perforated catalyst plates, ultraviolet lamps, and mist nozzles.
Section S8: Perf orated catalyst plates, ultraviolet lamps, and mist nozzles Section S9: Viledon filters and ultraviolet lamps.
30 Section S10: Carbon filters, ultraviolet lamps and mist nozzles.
Section S11: IJltraviolet lamps and mist nozzles.
Section S12: Ultraviolet lamps and mist nozzles.
Section S13: Perforated catalyst plates, ultraviolet lamps, and mist nozzles.

Section S14: Double Viledon filters and ultraviolet lamps .
Section S15: Carbon f ilters and ultraviolet lamps .
The illustrated Pmho~l;r^nt is based on an air stream flow rate of 22,500 ACFM to 36,000 ACFM at an average l,vt:la~y of 22 lbs. per hour to reduce V.O.C.
concentrations from upwards of lOOppm to no more than 12ppm per volume, which is less than half the current EPA standards of 25ppm. This system is manufactured in modular sections so that it can be easily sized for any flow rate or volume of V.O.C.s. For example, for smaller flows (22,500 to 36,000 ACFM), a single generator 40, tank farm 44, and tunnel 14 can be used.
For larger flows (50, 000 ACFM), a pair of tunnels 14 could be connected in parallel and run from a single generator 40 and tank farm 44. For very large flows (72 , 000 ACFM), a pair of tunnels could be used with a pair of generators 40 supplying activated air to tank 20 farm 44 at the rate needed to provide a suitable level of activated air within the water provided to the two tunnels. For a capacity of 36,000 ACFM, tunnel 14 is 12 ft. wide, 12 ft. high, and 56 ft. long, preferably made into two modular sections, each 28 ft. long. The walls 25 and roof are st:l;n~ steel, welded air tight.
Entrance sections are separ~tely fabricated to house filters 66, activated air nozzles 68, fog nozzles 56, and expansion chamber 76. In the ~rh~;r-nt 30 described, inlet 16 is designed so that the cross-sectional velocity does not exceed 450 ft. per minute and three separate f ilter sections are used to progressively filter out particulate paint, e.g., the average ef f iciency of the f irst f ilter is seventy-two 35 percent (72%) on paint particles of 4 micron size and greater, the second filter has an average efficiency of eighty-five percent (85%) on paint particles of 2 micron size and greater, and the third filter had an average efficiency of no more than ninety-six percent ~96%) on paint particles of 1 micron size and greater. All of the f ilters were made of synthetic organic f ibers to operate at one-hundred percent ~1009G) relative humidity withcut deterioration or chPr~r~;nq of the fibers. The filters can be built up of sections, about two feet by two feet, two to four inches deep, to fill the cross section of the tunnel, e.g., six filters across for a width of 12 ft. and six filters high for a 12 foot height. Suitable filters are available from Eaton Air Filter of 2338 Cole Street, Birmingham, Michigan 48009.
Similar filter sections are typically used in prior art carbon bed systems with incineration.
The array of activated air nozzles 68 consists of forty-eight nozzles capable of delivering up to about 150 cubic feet per minute of air from tank farm 44, tap 74, and/or generator 28 via tap 72. A normally open, electronically controlled valve 78 is used to control the flow of air to nozzles 68. The array of fogging nozzles 56 at inlet 16 is designed to instantly achieve high humidity in expansion chamber 76, for example by using 192 fog nozzles such as stainless steel nozzles with ruby orifice to produce a fog, ASI #006 at 0.033 gallons per minute at 1, 000 psi. Expansion chamber 76 may be about two feet long to allow the air stream 12 to equallze and load the system to a uniform air flow.
In each of the Ilwdular sections Sl through S15, the lamp portion of the modular section includes an array of 16 ultraviolet lamps 80, one of which is shown 35 in Fig. 2A. Each of the lamps include a lamp tube 80a -.
P-308 TRI-MAR~C - 24 -made from a high-output ozone ~ quartz that permits transmission of radiation in the wavelength range of from 184 . 9 nanometers to 254 nanometers. Lamps of this type are available from Voltrac Technologies, 186 Linwood Avenue, Fairfield, Connecticut 06420-0688. The lamps are ~our feet long and are mounted in a two-section frame, each frame section holding eight lamps extending in a vertical direction. Alternatively, lamps 8 0 can be mounted such that they extend in the horizontal direction, with access openings in the sides of tunnel 14 to allow the lamps to be changed from the outside of tunnel 14 wLthout having to shut down operation of abatement system 10. Each lamp 80 also has an upstream shield or deflector 82, cut from 3-inch PVC
pipe, leaving a 240 radiant section intact and a 120 window through which radiation is emitted into the downstream chamber. The PVC deflector operates as a catalyst, providing the various radicals listed previously in Table 3 that aid in the destruction of the V.o.C.s within air stream 12. Preferably, the PVC used is Schedule 80 which will provide the desired radicals, yet is dense and will not break down too quickly.
Section S1 includes an array of mixing cones 70 comprising 180 relatively small double-cone venturies to optimize mixing of the V.O.C.-laden air stream 12 with the aqueous fog from nozzles 56 and gaseous activated air from nozzles 68. These cones homogenize the V. 0 . C. -laden air stream with activated fog and activated air from nozzles 56 and 68, respectively, to form a homogenous mixture.
The nozzle portion of sections S1-S3, S5-S8, and S10-S13 each include thirty-five nozzles directed 3 5 downstream and mounted on seven vertical headers with P--308 TRI-~RK - 25 --five nozzles per header. The seven vertical headers are staggered between the eight vertical lamps, in the space between the lamp shields. As the air stream moves through tunnel 14, it is def lected around the lamps and 5 into the fog exiting from the nozzles. The nozzle section is made of stainless steel mounted on stainless steel struts. Again, the mist nozzles are of stainless steel with ruby orifice to produce a fog, ASI #006 at 0 . 033 gallons per minute at 1, 000 psi.

In the f ilter and lamp sections S4, S9, and 514, the filter can be made up of 25 sections, approximately 24" x 24" x 1" thick, mounted in stainless steel frames and backed on both sides by stainless steel 15 wire mesh. A suitable filter material is Viledon, sold commercially by Eaton Air Filter of Birmingham, ~ichigan. Preferably, the Viledon filters remove particulate water and other particles down to at least five microns in size and, even more preferably, down to 20 about one micron in size. The ultraviolet lamp portions of these sections can be identical to the lamp array previously described, and can be located immediately downstream of the f ilters .
In each modular section 55, 510, and 515, twenty-five coconut carbon filters approximately 24" x 24" x 1-7/8" thick are installed in a st~inlPcs steel framework so that all of the air moving through the tunnel 14 must pass through the carbon f ilters .
3 0 Pref erably the f ilters have interior cross-bracing and are backed at the downstream side by a perforated stainless plate that supports the coconut carbon filters and ensures that all of the air moving in tunnel 14 passes through the carbon f ilters . In modular sections s5 and 510, the ultraviolet lamp portion and the mist -` 2 ~ 782~8 nozzle portions are immediately downstream of the carbon filters and have the construction previously described.
The perforated catalyst plate portions of sections S7, 58, and S13 are each fabricated from 6iX
standard ferrous punch plates, each approximately 4 ' x 6', 16 gauge, perforated with %" holes, %" off center and mounted in a frame to fill the tunnel. The perforated plates are heavily coated with a high hydrogen shift catalyst, for example, titanium dioxide applied with an ultraviolet-resistant adhesive. Other catalysts can be used, including a titanium-ferrous catalytic mix, a copper zinc catalytic mix, a copper silver catalytic mix, and copper zinc-silver catalytic mix. The lamp and nozzle portions of sections S7, S8, and S13 are of the same construction as set forth hereinabove and are located just downstream of the perforated catalyst plates. Preferably, only the upstream surface of the plates are coated with the catalyst, leaving the ferrous material of the inner surface of the perforations and the backside of the plates exposed . By providing an exposed f errous surface, the ultraviolet light and peroxide radicals can react with the iron in the plates to liberate hydrogens needed to produce the highly active hydroxyl radicals.
With the arrangement of tunnel 14 described hereinabove, as soon as the V.O.C.-laden air stream 12 enters tunnel 14, wetting of the V. O . C. s and the 3 0 oxidants and some oxidative degradation begins immediately upon air stream 12 hPrn~;ng mixed with the activated air from nozzles 68 and the activated fog from nozzles 56. This step may be viewed as a pre-treatment for further oxidative degradation and photolysis in tunnel 14 and may not be required for some applications.

2 1 782~8 In the illustrated embodiment, this initial step provides a convenient and preferred location for recirculating some of the active solution in supply tank 60 in a closed loop through sparger tank farm 44 and tunnel 14. Similarly, inlet 16 of tunnel 14 provides a preferred location for introducing vented activated air from tank farm 44 and also for continuously recirculating partially spent activated air exhausted from carbon bed system 24.
As the air stream progresses through chambers C1 through C15, it is progressively and continuously treated by direct exposure to ultraviolet light and oxidant laden fog. The ultraviolet radiation in chamber Cl not only continues to activate the fog by regenerating oxidants, but it also begins photolysis of the V.o.C.s, at least initiating wetting, cleaving, and photod~~ osition of the V.o.C.s. Simultaneous oxidative decomposition of the V.O.C.s occurs due to the high level of oxidants in the activated fog. Further oxidative degradation and photolysis occurs as air stream 12 moves through chambers C2 and C3.
As the stream passes out of chamber C3 and through the Viledon filters in section s4, the filters remove particulate water, together with water-soluble int~ te radicals, compounds and the like, and the filtrate is collècted in supply tank 60. The Viledon filters allow only humidity, gaseous V.o.C.s, and activated air in gaseous form to pass into chamber C5 where the air stream is again irradiated by ultraviolet radiation still in a high-humidity environment but without dense activated fog. This is believed to enhance more direct irradiation of the V. 0 . C. s due to reduced scattering and absorbtion of the radiation as -` - 2 1 78258 .
P--308 TRI~ - 28 --compared to a dense fog environment. However, the humidity in chamber C5 is sufficiently high (95-10096 relative humidity) to cause formation of new hydroxyl radicals from any ozone generated therein by the 5 ultraviolet lamps. ~loreover, it ls believed that oxidants are continuously deposited on the carbon filter surfaces in Section 55 at the downstream end of chamber C4 for surface reaction with photod~ osed V.o.C.
products. To some extent, these surface reactions may 10 be influenced by ultraviolet radiation reaching the carbon filters.
In chambers C5 and C6, the air stream again moves through a high-humidity, dense fog environment 15 with prolonged activation by ultraviolet radiation.
This causes further oxidant generation and photochemical and oxidative ~ - 2 ition of the V . o . C . s . As the air stream reaches section s7 at the downstream end of chamber C6, the catalytic plates serve as scrubbers to 20 force activated fog, oxidants, and V.O.C.5 into intimate contact with one another. Activated fog also condenses on the catalytic plates to remove water-soluble compounds, intermediate radicals and the like. The reactions occurring have been found to be ~nh~n~ed by 25 the catalysts present. It is belicved that the catalysts cause a high hydrogen shift which promotes breakdown of the V.o.C.s, oxidative degradation and/or oxidant generation.
3 o Chambers C7 and C8 are also highly active due to ultraviolet radiation combined with additional infusions of activated fog. Cleaving, wetting and photochemical and oxidative decomposition continue, probably at an accelerated rate, before being f iltered 35 at section S9. In chamber C9, as in chamber C4, the air stre2m enter6 in a high-humidity condition but without dense active fog. As in chamber C4, ultraviolet irradiation of the V.o.C.s is more direct and efficient.
Fresh oxidants are produced, photochemical and oxidative 5 decomposition continues, but ozone production is still inhibited. Carbon filters at the upstream end of section S10 perform as in section S5, followed by a high level of activity in chambers C10-C12, as in chambers C5 and C6, due to replenished activated dense fog and 10 repeated ultraviolet radiation . As the V. 0 . C.
concentration levels continue to drop, photoche_ical and oxidative decomposition undoubtedly are more effective and efficient as the V.O.C.s migrate through the activated f og and are exposed to ultraviolet radiation 15 and oxidants in chambers C10-C12.
At section S13, as at section 57, the air stream, oxidants and fog are scrubbed and coalesced in the presence of a catalyst by perforated catalyst plates 20 with any crn~pnq~tion flowing into tank 60. Extended exposure to ultraviolet radiation and dense active fog is repeated in chamber C13, as in chamber C8, progressively achieving still further photorh~mir~l and oxidative V.O.C. destruction before filtering at section 25 S14.
At section S14, particulate water is removed by Viledon filters, along with water-soluble reaction radicals, compounds and the like. In chamber C14, as in 3 0 chambers C4 and C9, the air stream is exposed to ultraviolet radiation in a high humidity environment, but without dense fog before passing through the carbon filter in section S15. Chamber 14 therefore provides a direct and efficient irradiation of the r~;nin~
35 V. o . C . s, not only in the air stream but also on the 2 1 782~8 P--308 TRI-MAR~ - 30 --surface of the carbon filters in section 515.
Reactivation of the air stream in chambers Cl4 and C15 by ultraviolet radiation continues V. 0 . C . destruction and provides additional oxidants that aid in any further 5 V. 0. C. oxidative destruction required at the carbon bed system 24.
As will be apparent from the above process description, repeated ultraviolet radiation of the 10 V. 0 . C . laden air stream 12 occurs in a high-humidity environment, whether as a dense fog, as in chambers C1-C3, C5-C8, and C10-C13, or as a gaseous humidity, as in chambers C4, C9, C14, and C15. This insures a continuously replenished supply of oxidants for reaction 15 with photochemically decomposed V. 0. C. products .
Additionally, the sustainable formation of ozone, as would be expected with dry air, does not occur in the high humidity environment maintained throughout tunnel 14. Experimental analysis has not revealed any 20 detectable ozone exiting from tunnel 14. Analysis conf irmed that the exiting gas from chamber Cl5 does not contain ozone. It is believed that any ozone produced is quickly decomposed by one or more of a variety of rhGn' -n~, including the presence of high humidity, 25 photolysis by the 254nm ultraviolet radiation, and cleavage due to chlorine and other radicals that were liberated from the catalysts as a result of being exposed to the ultraviolet light.
It has been de~tnn;ne~l empirically that the present invention effectively and efficiently destroys V. o . C. s to levels well below the current accepted standards as indicated in Table 4.

~ 2 1 7825 P--308 TRI-~IARK -- 31 _ 8 T}~3LE 4 SYSTEIS INLET' BEFORE CMBON BED2 OUTLET
F<EDUCTION CARBON
BED
5 SWlthout tunnel 14 56 ppm 56 ppm 50,000 ppm3 14 ppm ('3:1) 25,000 ppm3 With tunnel 14 10 Xylene s6 ppm 30 ppm 0 130 ppm3 0.688 ppm ~ Mea~3ured by Photorae loni3ation Lnstrument averaged over A 33 hour run.
l~easured by an ~ r9~ 1 lal oratory, Swanson Environmental Inc.
samplen were removed after 8 hours of V.O.C. spray prLor to regeneratLon. The amounts ~3hown therefore reprenent the re~ldual ~Imount left on carbon before the regeneration process.
Although the present invention preferably utilizes further oxidative degradation in carbon bed sy5tem 24, it will be apparent from Table 4 that the treatment in tunnel 14 alone resulted in a reduction from 56 parts per million to 30 parts per million which, even without subsequent treatment in the carbon bed system 24, may be more than adequate to meet applicable standards.
Liauid Svstem Referring now to Fig. 3, fresh water, preferably filtered tap water, is supplied to tank 60 through a solenoid valve 102 and inlet pipe 104. Valve 102 is opened and closed by a suitable liquid level control, including a float-operated liquid level sensor 106 to initially fill tank 60 and maintain a liquid level between an upper limit 108 and a lower limit 110.
The upper limit 108 is established by an overflow outlet pipe 107 which is also connected to a normally-closed solenoid valve 109 so that tank 60 can be drained.
Fresh water can also be supplied to tank 60 via a manual P--308 TRI-~ C - 32 -valve 112. Liquid from tank 60 is supplied to four low-pressure sparger tanks 114, 116, 118, and 120 in tank farm 44 by pipe a 122, pump 62, normally-open solenoid valves 126, 128, a low-pressure filter 130, 5 normally-open solenoid valve 132 and pipes 64 which discharge liquid into the top portion of tank 114.
Filter 130 can be bypassed by a normally-closed solenoid valve 138 and drained into supply tank 60 via a normally-closed solenoid valve 140. Tank 114 can also 10 be supplied directly with fresh tap water via a normally-closed valve 141 to f lush out the system .
Liquid pumped into tank 114 is transf erred by gravity to tank 116 by a pipe 142, from tank 116 to tank 118 by an overflow pipe 144, and from tank 118 to tank 120 by a pipe 146. Pump 62 is a low ~LeS2~UL~:, high capacity pump. Overflow from tank 120 is returned to tank 60 via overflow pipe 152 and a normally-open solenoid valve 154. Each sparger tank 114-120 has a sight tube 156 so that an operator can visually monitor the liquid level in each of the tanks. Sparger tanks 114-120 can be drained into tank 60 via drainpipe 189 and normally-closed valves 190, 192 when it is desired to purge or f lush the system .
Liquid from tank 120 is delivered to nozzle array 56 and nozzle header 50 through piping 172, filter 176, pump 182, and normally open valves 170, 174, 178, 180, 184, 48 and 52. Filter 176 can be bypassed via a normally-closed valve 186 and drained into tank 60 via normally closed valve 188. Preferably, filter 176 traps particulates larger than l micron to ensure that particulates do not enter tunnel 14 and prevent clogging of the nozzles. Header 50 feeds nozzles Nl-N3, N5-N8, 35 and N10-N13 in corresponding modular sections, Sl-S3, P--3 o 8 TRI -MARK -- 3 3 55-S8, and S10-S13, as previously described ln connection with Figs. 1 and 2, to maintain a high humidity environment throughout tunnel 14.
S As generally described in connection with the overall system of Fig. 1, the liguid supplied to nozzle header 50 and nozzle array 56 is an aqueous solution containing dispersed bubbles of oxidant-laden activated air from generator 40. As shown in greater detail in Fig. 3, compressed air is delivered to generator 40 from a source of fresh plant air 194 through a filter and coalescer 196, a compressor 198, a variable Venturi flow regulator 200 and normally-open solenoid valve 202.
Filter 196 is used to remove particulate moisture and oils down to 0. 01 microns in size. Air entering generator 40 passes serially through a series of individual activated air cells 210 (Figs. 3, 5 and 6) where it is exposed to ultraviolet radiation to generate the various oxidants. Activated air from generator 40 2 0 is then delivered via header pipe 42 to each of the sparger tanks 114-120 via an associated variable flow regulator 212. Regulators 212 control the activated air entering each tank and balance the distribution to all of the tanks.
Since tanks 114-120 are of similar construction, only tank 116 will be described in detail.
Compressed activated air, at relatively low volume and low pressure, enters the lower portion of tank 116 through an inlet tube 214 and a spider of sparger pipes 216. Sparger pipes 216 cause the activated air to be dispersed in minute bubbles and agitate the liquid in tank 116. As shown in broken lines in Fig. 3 and in cross section in Fig. 4, four ultraviolet lamps 218 are mounted on the top of tank 116 and extend downwardly through a major portion of the tank, terminating just above the spider sparger tubes 216. Lamps 218 also consist of an ultraviolet lamp tube, protected from the liquid in tank 116 by a separate quartz lens tube 217 5 and can be identical to lamps 80 used in tunnel 14.
Each of the quartz lens tubes 217 are preferably made from the same high-output ozone LEI material used to make lamps 218. For purposes of simplification, an electrical power source 219 is illustrated with 10 connections to only two of the lamps 218 in each of the tanks 114, 116, it being understood that source 219 is connected to all of the lamps in all of the tanks.
As the activated air from spider sparger tubes 15 216 bubbles somewhat violently and migrates upwardly through tank 116, the activated air bubbles are exposed to further ultraviolet radiation to generate and reactivate oxidants. Oxidant generation and reactivation occurs not only as fresh activated air is 20 introduced into each tank, but also as activated liquid moves progressively through the tanks. Additionally, ultraviolet radiation of the aqueous solution in tanks 114-120 is also believed to contribute to total V. O. C .
destruction by promoting further int~rr~ ry and 25 radical reactions which occur after photochemical degradation of the V . o . C. s in tunnel 14 .
As mentioned above, relatively large quantities of water are required to maintain high 30 humidity in tunnel 14. In the illustrated (~mho~;r-nt~
tank 60 holds 1,028 gallons, with pump 62 providing 60 gallons per minute at low pressure and pump 182 delivering 12.7 gallons per minute at 1,000 p.s.i. For supplying about 12 . 7 gallons per minute to pump 182, 35 tanks 114-120 may have capacities of about 113-200 P - 3 0 8 TRI -~ARK - 3 5 gallons per tank, with compressed activated air from generator 4 0 being introduced into each tank at a rate of 1.5 cubic feet per minute at ten to fifteen psi per minute. Progresslve circulation through tanks 114-120 as described herein insures an adequate supply of freshly activated, oxidant-laden liquid required to maintain the dense activated air fog and the high humidity in tunnel 14. Most of the piping in the low pressure portions of the system of Fig. 3 is made of PVC
which is believed to provide a catalytic action for reactions occurring in the liquid as the liquid recirculates from tank 60 through tank farm 44, resides in tunnel 14 as a fog, and then is precipitated back into tank 60.
As shown in Figs. 1 and 3, activated air that collects at the top of each of the sparger tanks 114-120 is vented to a pipe 79 that supplies the activated air to air nozzles 68 along with regenerated exhaust air that is supplied from carbon bed system via tap 74.
Preferably about 100-120 cubic feet per minute is delivered to nozzles 68, with tanks 114-120 supplying about 12-16 cubic feet per minute at lOpsi and about 90-100 ACFM through tap 74.
Activated Air Generator Cell ~
Referring to Figs. 5 and 6, there is illustrated in greater detail one of the generator cells 210 in generator 40. Each cell includes an ultraviolet lamp 220, which can be the same as lamps 80 in tunnel 14 and lamps 218 in tank farm 44. Each lamp 220 is generally concentrically retained in a tubular outer casing 221 of its associated cell 210. Compressed air 35 from generator 40 enters cell 210 through an inlet fitting 226 on an end cap 222 and is exhausted from cell 210 through an outlet fitting 228 on an end cap 224.
Lamp 220 is carried on a subassembly 230, slidably received in casing 221 and comprising a plurality of 5 baffle plates 232 which provide a serpentine flow path that introduces turbulence into the air stream f lowing through cell 210. Baffles 232 are mounted on three rods 234 that are spaced apart and extend axially within casing 221 about lamp 220. Each baffle 232 is generally 10 a circular disk having a cutaway flat edge 236 and the baffles are mounted on rods 234 with alternating flats 23 6 facing in opposite directions to provide the serpentine f low path . All of the baf f les 2 3 2, except one end baffle 232 ', have a central clearance hole 238 15 through which lamp 220 is received, with one end of lamp 220 being received in and supported by a socket 240 on end baffle 232 ' . Lamp 220 is energized at its other end via t~rm;n~l~ 242, 244, wires 246, 248 and socket 250.
Casing 221 has an inside diameter-to-axial length ratio of between 1 to 8 and 1 to 16, and preferably about 1 to 12. To insure turbulent flow, preferably the baffles 232 are equidistant and at a distance of between one-half and one-times the inside diameter of the casing 221. Preferably the area of the cutaway flaps 236 is not greater than about 1096 of the baf f le plate area to enhance turbulent f low and to provide a scrubbing action. Preferably casing 221, end caps 222, 224, baffles 232 and retainer rods 234 are 3 0 made of PVC f or the reasons set f orth above to resist oxidation and also, it is believed, serve as a catalyst.
With this construction, the baffles 232 are cemented to rods 234 and the subassembly 230 tacked to casing 221 with PVC cement.

P--308 TRI~ 37 --In one practical construction of the generator cell 210, casing 221 is made from commercially available PVC tubing having a nominal outside diameter of six inches and, with end caps 222, 224 an overall length of 5 about 5-1/2 feet. The baffle s~h~c~mhly, also made of PVC, had 14 baffles having a diameter of about six inches and a thickness of 3/16 of an inch. About 3/8 of an inch was removed to form flaps 236. A suitable ultraviolet lamp tube having an overall length of about 10 61 inches is commercially available from Voltarc Technologies of Fairfield, Connecticut.
A generator 40 of twelve of these cells connected in series had an output of about 42 standard 15 cubic f eet per minute when operated with a compressed air inlet pressure of about 20 psi. The activated air produced by this generator is believed to typically have same the oxidants as other radicals in the proportions set forth in Tables 2 and 3. No bacterial maintenance 20 is required because of the biological treatment by ultraviolet radiation by lamps 220 in cells 221, lamps 218 in tank farm 44, and the numerous ultraviolet lamps in chamber 14.
Carbon Bed Reqeneration In prior applications using carbon beds for V.O.C. abatement, when low concentration, high volume air is passed through the carbon bed, the V.O.C.s are 3 o absorbed into the bed. The bed is later desorbed by steam, etc., yielding a higher concentration, smaller volume effluent which must then be further processed by incineration or other solvent removal techniques. For some prior applications, carbon bed desorption must be 35 performed offsite, and other prior applications require " 2178258 offsite disposal of waste products. Moreover, when using the method and apparatus of the present invention, carbon beds may not be required for all applications where treatment in tunnel 14 has reduced V . 0 . C . s 5 sufficiently meet applicable standards. When carbon beds 32, 34 are utilized according to the present invention, they may be constructed in a manner similar to that of prior art carbon beds. However, the utilization and function of carbon beds according to the 10 preferred omhoA;r^nt of the present invention differs significantly from prior art carbon beds used only as an absorber .
Referring back to Fig. 1, it will be 15 r ^-hP~ed that in the preferred Pmho~i -nt, the air stream exiting tunnel 14 has just been reactivated with ultraviolet radiation in chambers C14 and C15 and filtered by carbon filters in modular section 15. The air stream entering expansion chamber 22 is still highly 20 active with oxidants, together with some V.O.C.s and, most likely, int~ te compounds resulting from photochemical and oxidative degradation in tunnel 14.
Continued oxidant activity at a high level can be maintained by using additional ultraviolet lamps in 25 expansion chamber 22.
Preferably two c2rbon beds 32, 34 of modular construction and assembled off-site are used. During final on-site as6embly, beds 32, 34 are enclosed by a 30 suitable external housing, generally designated at 266 and isolated from each other by an internal partition 267. An inlet chamber 268 for bed 32 is connected to expansion chamber 22 via an inlet duct 270 and an inlet damper 272. Exhaust from bed 32 to an exhaust stack 26 35 is through an outlet duct 274 and outlet damper 276.

2 ~ ~8258 Similarly, an inlet chamber 277 for bed 34 is connected to expansion chamber 22 via a duct 280 and damper 282 and bed 34 is exhausted to stack 26 through an outlet duct 284 and outlet damper 286. Bed 32 is brought on-line by opening dampers 272, 276 and closing dampers 282, 286 and bed 34 is brought on-line by opening dampers 282, 286 and closing dampers 272, 276. Each of the carbon beds 32 and 34 include a respective template 290 and 292 located just upstream of dampers 276 and 286, respectively. Each of the templates 290 and 292 provides a restriction in the flow path that results in a backpressure within its associated carbon bed. This backpressure equalizes the flow through the carbon filters to help maximize the effectiveness of the carbon beds. Each of these templates can be implemented using a pair of perforated plates with the degree of alignment of the perf orations being varied as necessary to obtain the desired backpressure.
Referring also to the schematic of Fig. 7, blower 30 draws fresh plant air 300 through a filter 302 and into generator 28 through a five-port manifold 304.
Each port of manifold 304 feeds a respective row of seven serially-connected activated air cells 306 whose exhaust streams flow through respective solenoid operated valves 308 to a five-port exhaust manifold 310 and then through piping 312 to the inlet of blower 30.
Blower 30 delivers compressed air at about 300 ACFM to activated air tap 72 via delivery piping 314 and solenoid valve 316; to perforated tube arrays 320, 321 in carbon bed 34 via piping 314 and respective solenoid valves 3I8, 319; and to perforated tube arrays 326, 328 in carbon bed 32 through piping 314 and respective solenoid valves 322, 324. Preferably, each of the 35 perforated tube arrays 320, 321, 326, and 328 has 2 ~ 78258 multiple rows of perforated outlet tubes, for example arranged in a vertical array of three tubes 330, 332, 334, as shown in Fig. 8 for the array 328. This arrangement uniformly disperses activated air into the carbon beds during regeneration. In the exemplary embodiment being described, each carbon bed 32, 34 can be fabricated in two modular sections, each about 30 ft.
long x 10 ft. wide x 10 ft. high and finally assembled on site end to end into a 60 ft. unit. The carbon bed base material can be 500 cu. ft. of natural grain coconut activated carbon shell.
As ~;~rll~s~cl above in connection with generator 40, the generation of activated air is preferably carried out using humid air. Thus, humidity can be added to the fresh plant air 300 used by generator 26. Optionally, the cleaned process air exiting carbon bed system 24 can be used in lieu of plant air 300 and can therefore be taken directly from stack 26 via a supply line 336 shown in Fig. 1. This cleaned process air is well filtered and rises to a humidity level of approximately 95% after only three minutes of operation of abatement system 10. Thus, the cleaned process air neither requires added humidity nor filtering and filter 302 can therefore be eliminated.
As shown in Figs. l and 7, regeneration eYhaust gases from carbon bed 34 are delivered to supply tap 74 through a pair of solenoid valves 340, 342, exhaust header 344, piping 346 and solenoid valves 348, 350. Regeneration exhaust gases from bed 32 are similarly delivered to tap 74 through a pair of solenoid valves 352, 354, manifold 344, piping 346 and solenoid valves 348, 350. Exhaust manifold 344 may also be 35 directly connected to stack 26 through piping 346, valve ~ 2 1 78258 348 and a solenoid valve 356 for applications where the regeneration exhaust is sufficiently clean for exhausting it directly into the environment.
Advantageously, activated air supplied to the carbon beds 32, 34 during regeneration not only desorbs the carbon beds but also deposits oxidants on carbon bed surfaces for further V.O.C. destruction by surface reactions when the regenerated carbon bed is brought on-line. Consequently, it is also desirable to recirculate the regeneration exhaust gas from carbon beds 32, 34 through tap 74 and back into tunnel 14 to promote continuing int~ ry reactions and destroy any re--; n; n~ V. O . C . S and V. o . C. decomposition products .
Cells 306 in generator 28 can be constructed substantially as described in connection with cells 210 in generator 40. Cells 306 are serially connected in six respective rows so that the number of cells on-line can be selected via valves 308 according to the system demands for regenerating either cell 32 or 34 and also supplying activated air via port 28 to activated air nozzles 68 in tunnel 14. Blower 30 has a variable speed control (vfd~ 370 so that the output from blower 30 can be varied in accordance with 6ystem demands.
Photochemical and Oxidation Reactions and Results Based on testing of abatement system 10, it 3 o has been demonstrated that the present invention ef f ectively destroys V . o . C . s of the type encountered in an automotive paint spray booth exhaust system. Much of this testing was done to simulate a percentage ratio based on a commercial unit which could handle 72,000 cfm 35 at 45 lbs. of V.O.C.s per hour. In order to get 2 ~ 78258 P - 3 0 8 TRI ~ K - 4 2 representative results for paint spray solvents, the results shown in Table 4 are for a ratio of two parts methylamylketone (l~AK) to one part Xylene. Although the pathways of oxidative degradation and V.O.C. destruction 5 have not been completely elucidated, the various reactions occuring for these solvents are known and the results of Table 4 show that the present invention can successfully reduce or destroy V. O . C. s .
As one example of V.O.C. degradation, the following reactions show methane (CH4) reduction by hydroxyl (Ho ) . As shown, this is accomplished by replacement of each hydrogen atom. ~he first step i5 formation of methyl alcohol (CH30H or H-CH20H), followed 15 by formation of formaldehyde (HCl(OH)2) which, by 10s5 of water gives CHlO or H CHO, and, finally, formation of formic acid (CH(OH)3) which, by loss of water gives CHO (OH) 2, HO-COOH, or H2CO3.
CH4 + HO -- C^H3 + H20 C^H3 + HO' - CH,OH
CH,OH + HO' -- C^H20~0H) + HzO
C^ H2 ( OH) + HO - C^ H2 ( OH) 2 + H20 C^H2(0H)2 + HO - CH~2 + H20 CH,02 + HO ~' CHZO + H20 CH20 + HO - C HO + H20 C^HO + HO' - HzCO2 H2CO2 + HO - HC^ 2 + H20 -~ 2 l 782~8 P-3 0 8 TRI -~ARK - 4 3 HC^ Oz + NO' - N2 CO3 N2CO3 + HO- ~ HzO + COz It should be noted that the a~ove reactions are representative of hydroxyl intrusion only and that they do not consider any reactions or ~nhAnr -nts of reactions that may occur due to intrusion of the ultraviolet light, other radicals and oxidants in the activated air, as well as electron/photon transfer. A
similar process of chemical reduction to water and carbon dioxide is believed and expected to occur with similar compounds, such as: N-butyl alcohol; aromatic hydrocarbons; mineral spirits; 1,1, 1 trichloroethylene;
BTX's in light ppm; methanol; MEK; V, I~, and P, Naptha;
N-butanol; perchloroethylene; and butyl ether.
As indicated earlier, it is strongly believed that V. 0. C. destruction into harmless water and carbon dioxide is achieved by the combination of two ~ht~nt -n undoubtedly producing a synergistic effect. First, ultraviolet radiation produces highly active oxidants which then subsequently oxidatively degrade the V.O.C.s.
The oxidants are generated not only in the activated air from generators 28, 40 but they are reactivated, regenerated and freshly generated by ultraviolet radiation in the sparger tank farm 44 and within the numerous chambers in tunnel 14 having ultraviolet lamps.
Generation of the activated air is carried out in a high humidity environment and using ultraviolet wavelengths of 184 . 9nm to produce ozone and 254nm to help quickly break down the ozone so that the liberated oxygen can form highly active hydroxyl radicals. The generation of activated air is also carried out in the presence of a catalyst to help liberate hydrogen for hydroxyl radical 2 ~ 78258 production. oxidants in the activated air from generator 28 are deposited on surfaces in carbon beds 32, 34 during carbon bed regeneration and for surface reaction with V. 0 . C. s when the carbon beds are brought 5 on-line in the process. These surface reactions can be enhanced by additional ultraviolet radiation in expansion chamber 22, ~ust before any ro~-;n;n~ V.O.C.s in the air stream are passed through carbon beds 32, 34.
Secondly, direct ultraviolet photolysis of the V.O.C.8 10 causes a photochemical decomposition of the V.O.C.s, with the resulting products interacting with the oxidants and chemical intor~o~ tes constantly being generated, reactivated and reacting throughout the system.
It should also be apparent that ultraviolet radiation for phot~do(-~~rosition and for oxidant generation takes place under a variety of conditions.
In tunnel 14, ultraviolet radiation occurs in the 20 various heavily fogged chambers and also in chambers where, after particulate water is filtered, only high gaseous humidity is present in the chambers just before the carbon filters. Residence time varies in different chambers. Ultraviolet radiation impinges directly on 25 catalyst plates and other PVC components and on carbon filters where surface reaction can occur. ~eavy homogeneous mixing occurs at cone array 7 0 and heavy scrubbing occurs at the perf orated catalyst plates .
Varying degrees of turbulence also exist in tunnel 14 30 due to the different filter arrangements and particularly the perforated catalyst plates, as well as the effect of the nozzle sprays and diversion around the lamp shields. Experimentation has shown that oxidant production, as well as V.O.C. destruction, is onh~nce~
35 by catalytic action provided, in the example described 2 ~ 782~8 hereinabove, by the PVC. In addition to the lamp shields and catalytic plates, various other internal supports that are exposed to the ultraviolet lamps within tunnel 14 can be made of catalytic materials.
5 For example, PVC pipe can be used in the frame structure that supports the ultraviolet lamps and can be used for piping of the activated air and the oxidant-laden aqueous solution created in tank farm 44. Due to the high level of oxidants present in the system, slight 10 oxidation of the PVC may also be occurring, with some reaction products entering the system. Indeed, analysis has yielded some reaction products confirming this and, after extended use, a slight surface erosion can be detected at some of the PVC components.
When either carbon bed 32 or 34 is on-line, oxidants are continuously deposited onto the surface of the carbon bed for continued destruction of any V.O.C.s r~-;n;n~ in the air stream passing through the carbon 20 bea. During regeneration, oxidants produced by activated air generator 2~3 are not only deposited on the carbon bed for V.O.C. destruction when the carbon bed is brought on-line but, additionally, regeneration exhaust is recirculated back into tunnel 14 for further 25 reactivation. At sparger tank farm 44, an aqueous solution is irradiated as the air bubbles through the sparger tank and the solution moves from tank to tank and then into tunnel 14 so that the f og or mist delivered into tunnel 14 is highly active with oxidants.
3 0 Particulate water f iltered out of tunnel 14 and otherwise precipitated into tank 60 is believed to still be suf f iciently active to contribute to reactions occurring in tank 60. Dissolved oxidants and intermediary compounds are recirculated through sparger - 2 i 78258 tank farm 44 to be exposed to ultraviolet radiation and recirculated into tunnel 14.
some of the oxidants produced by ultraviolet radiation at generators 28, 40 and in sparger tanks 44 and in tunnel 14, are potent oxidizing agents but their life as a radical, for example the hydroxyl radical, may be relatively short, liPr~n~l; ng on the competition for reaction and recombination throughout the system.
lo Hence, for high-volume industrial processes, oxidant production is continuous throughout the system by repeated exposure to ultraviolet radiation and by the introduction of fresh oxidants from generators 28 and 40. Also, the various oxidants available in abatement system 10 are available not only for direct reaction with photod~r~roce~l V. 0 . C. s, but they serve as intP -';Ate radicals in radical to radical reactions as various chain reactions occur in the system. In any event, the desired end result of total destruction of V.O.C.s is achieved, yielding final end products of carbon dioxide and water.
Since water is a neco~sAry part of the system operation and processes, generation of water has a beneficial result, leaving only the relatively harmless carbon dioxide to be dealt with, at least from a theoretical standpoint. Analysis to date has not det~rm;ni rl the fate of carbon dioxide, if any, generated by abatement system 10. Although some experimentation has shown expected increases of C02, anticipated increased presence of C02 at exhaust stack 26 cannot effectively be detected. This would be desirable for direct comparison of the V.o.C. destruction efficiency by the present invention relative to V. o . C. destruction efficiency by incineration, whose end products are also P--308 TRI-~IARK - 47 -carbon dioxide and water. However, with the system of the present invention, the absence of a detectable expected increase in Co2 at exhaust stack 2 6 has sever~l possible explanations. First, it is possible, but 5 unlikely, that no carbon dioxide is produced by the system. Secondly, in an oxidant-enriched environment, carbon dioxide might well react ;~ccording to the following reaction scheme as suggested in the aforementioned t`h~mi cal Review article:
HO- + C2 - HCO3 HO' + HCO3 - H20 + CO3 HO- + HCO32 - HO- + CO3 15 In a hydroxyl radical enriched environment, any bicarbonate or carbonate which is formed by the interaction of water or hydroxide with C02 can react with the hydroxyl radical to give a carbonate radical anion.
This radical anion is itself an oxidant, although of 20 less oxidation potential than the hydroxyl radical.
Thirdly, carbon dioxide is readily absorbed into the carbon beds 32, 34 and this absorbed carbon dioxide is not easily displaced but it will slowly release over time. Finally, because of the large amount of water 25 present in and passed through sparger tank farm 44, carbon dioxide may be made "solubleized" into the aqueous phase and never appear at exhaust stack 2 6 .
As discussed above, no detectable levels of 30 ozone are present in the activated air produced by generators 28 and 40. Moreover, no ozone is gene+ated in sparger tank 4 4 because the air is dissolved in an aqueous solution and no ozone is generated in tunnel 14 --` 2 1 782~8 P-308 TRI-M~RK - 48 -due to the f og and high humidity present throughout the tunnel. This is believed to result from one or more of the following rh~nl -n~: decomposition of ozone due to the presence of high humidity; selection of ultraviolet light wavelengths, and ~he presence of radicals from the PVC catalysts. It is generally believed that, in a dry environment, ultraviolet radiation at wavelengths shorter than about 220 nanometers will produce ozone and decompose l into O~. It is also believed that ultraviolet radiation at a wavelength of 184 . 9 nanometers is particularly effective in producing ozone.
It is further believed that ultraviolet radiation at wavelenght of 254 nanometers decomposes ozone. The ultraviolet lamps used in practicinq the present invention have a spectral wavelength distributed between 184 and 254 nanometers, with the 184.9nm light helping to generate ozone and the 254nm light helping to break down that ozone. The lamps are relatively low wattage, for example 0 . 425 amps at 120 volts for each lamp in each of the cells 306 in generator 28 and cells 210 in generator 240. Similarly, each of the lamps used in tunnel 14 and sparger tank farm 44 is relatively low wattage .
It is expected that the process of the present invention can be optimized for a wide range of V.O.C.s and V. O . C. s other than those expected in paint spray booth applications by varying the amount (higher wattage) and radiation wavelengths, either distributed over different wavelength ranges or possibly even monochromatic radiation at selected wavelengths. By using modular sections such as sections S1 through S15, when new technology is developed, it can easily be retrof itted to an existing system . Exposure time to ultraviolet radiation in tunnel 14 can be varied by P--3 o 8 TRI-MARK -- 4 9 varying the number and length of chambers included in the tunnel and by varying the turbulence in various chambers .
The present invention effectively and efficiently achieves the desired end products, namely water and undoubtedly some CO2. No nitrous oxides, ozone and other objectionable pollutants, including thermal pollution, are exhausted into the environment. Original installation costs are competitive with competitive systems for a variety of reasons. System components and system design do not have to meet the demands of high temperature systems such as incinerators. Smaller carbon beds can be used because substantial V . O . C .
reduction and destruction occur in the tunnel and V.O.C.
destruction continues in the carbon bed by surface reactions with oxidants from the generator. The apparatus of the present invention is constructed with relatively ;nP~ ncive materials including extensive use of low-cost, commercially available PVC pipe.
Operating and maintenance costs are also reduced as compared to competitive systems. No special ~h~ are required as might be used for chemical V.o.C. destruction. Indeed, the only "starting~
materials are tap water and plant air. The oxidants utilized, for example as shown in Tables 1 and 2, represent 20g~ of the atmosphere. Carbon bed regeneration time is reduced by using activated air, 3 o regeneration is done on site and no large quantities of waste by-products need to be hauled away for offsite treatment and/or ~;qposAl. In this regard, with the present invention it has been noted that some small granules about the size of a grain of f ine sand eventually collect in tank 60, but the quantity produced 2 ~ 78258 P--3C8 TRI-~$~RK - 50 -is insignificant and possibly due to some incidental mineralization occurring in the process. Energy efficiencies are expected to compare favorably with incineration, even though that comparison has not been 5 quantif ied to date .
It will thus be apparent that there has been provided in accordance with the present invention a method and apparatus f or abatement of volatile organic 10 compounds which achieve the aims and advantages specified herein. It will of course be understood that the foregoing description is of a preferred exemplary embodiment of the invention and that the invention is not limited to the specif ic Plnhorl; 1- ~t shown . Various 15 changes and modifications will become apparent to those skilled in the art and all such variations and modif ications are intended to come within the scope of the ~rpPnr~Prl claims.

Claims (70)

1. A method for degrading volatile organic compounds (V.O.C.s) contained in exhaust air from industrial processes and the like by a continuous flow treatment in an enclosed tunnel having multiple chambers therealong comprising the steps of:
continuously introducing a stream of said exhaust air with V.O.C.s therein into an entrance of said tunnel, exposing a supply of air to ultraviolet radiation to produce a supply of activated air having reactive oxidants therein, including at least hydroxyl radicals, forming an aqueous solution having said activated air dispersed therein, misting said aqueous solution into a first chamber of said tunnel to maintain an activated fog environment in said first chamber, and passing said air stream through said first chamber and exposing said air stream to ultraviolet radiation to oxidatively and photochemically degrade said V.O.C.s in said air stream.

2. The method set forth in Claim 1 further comprising introducing said aqueous solution into said first chamber as a mist having aqueous particulate in the range of from 1 to 5 microns.

3. The method set forth in Claim 1 further comprising extracting particulate water with dissolved reaction products from said air stream as it leaves said first chamber while passing gaseous V.O.C.s, gaseous activated air and aqueous vapors in said air stream into a chamber downstream of said first chamber.

4. The method set forth in Claim 3 further comprising exposing said air stream to ultraviolet radiation while said air stream moves through said downstream chamber.

5. The method set forth in Claim 4 wherein said downstream chamber is a second chamber downstream and contiguous to said first chamber, and wherein said method further comprises:
maintaining said air stream substantially free of particulate water as said air stream enters said second chamber so that said gaseous V.O.C.s, activated air and aqueous vapors are exposed to ultraviolet radiation in a high humidity but substantially unfogged environment in second chamber.

6. The method set forth in Claim 5 wherein said second chamber is maintained at a relative humidity in the range of about 95 to 100 percent.

7. The method set forth in Claim 5 wherein water is extracted from said air stream and said second chamber is maintained substantially free of particulate water by filtering said air stream as it leaves said first chamber and enters said second chamber.

8. The method set forth in Claim 6 wherein said air stream is filtered through a filter medium which removes particulate water greater than about 5 microns.

9. The method set forth in Claim 5 further comprising extracting V.O.C. reaction products from said air stream as it leaves said second chamber.

10. The method set forth in Claim 9 wherein V.O.C. reaction products are extracted from said air stream as it leaves said second chamber by passing said air stream through a carbon filter.

11. The method set forth in Claim 10 further comprising exposing said carbon filter to ultraviolet radiation.

12. The method set forth in Claim 5 further comprising:
passing said air stream through a third chamber upstream of said first chamber;

continuously misting said aqueous solution into said third chamber to maintain an activated fog environment therein, passing said air stream through said third chamber while simultaneously exposing said air stream and said fog to ultraviolet radiation in said third chamber, and agitating said fogged air stream in said third chamber while simultaneously contacting said fogged air stream with a catalyst.

13. The method set forth in Claim 12 wherein said fogged air stream is agitated and contacted with a catalyst as said air stream leaves said third chamber.

14. The method set forth in Claim 12 wherein said air stream is passed through said third chamber and then through at least one first chamber and then immediately through said second chamber.

15. The method set forth in Claim 14 wherein said air stream leaving said third chamber is then passed sequentially through a plurality of first chambers contiguous to each other and then passed immediately from a last one of said sequential first chambers into said second chamber.

16. The method set forth in Claim 5 further comprising:

passing said air stream through another first chamber downstream of said second chamber, and then passing said air stream through another second chamber downstream of said other first chamber.

17. The method set forth in Claim 1 wherein water and V.O.C. reaction products extracted from said air stream moving through said tunnel are recirculated back into said tunnel and misted into said airstream.

18. The method set forth in Claim 17 wherein extracted water and V.O.C. reaction products are recirculated back into said air stream by dispersing activated air in said extracted water and V.O.C.
reaction products to form said aqueous solution.

19. The method set forth in Claim 18 further comprising exposing said aqueous solution to ultraviolet radiation while simultaneously dispersing activated air therein.

20. The method set forth in Claim 5 further comprising passing air exhausted from said tunnel through a carbon bed system to adsorb any remaining V.O.C.s from said air stream.

21. The method set forth in Claim 20 further comprising:

passing activated air through said carbon bed system to desorb said carbon bed system and disperse oxidants in said carbon bed system for surface reaction with V.O.C.s in said air stream, and then passing said tunnel exhaust air through said carbon bed system.

22. The method set forth in Claim 21 wherein desorption activated air exhausted from said carbon bed is introduced into said tunnel.

23. The method set forth in Claim 22 wherein said desorption exhaust air is introduced into an activated fog environment in said tunnel.

24. The method set forth in Claim 20 further comprising the step of providing a restriction to the flow of air through said carbon bed system.

25. The method set forth in Claim 3 wherein said downstream chamber is another first chamber immediately contiguous to said first mentioned first chamber and said method further comprises:
introducing a fog of said aqueous solution into said other first chamber to create an activated fog environment therein, passing said V.O.C. air stream through said contiguous first chamber while simultaneously exposing said air stream and said fog to ultraviolet radiation in said other first chamber, and extracting particulate water with dissolved reaction products from said air stream as it leaves said other first chamber.

26. The method set forth in Claim 25 wherein said air stream is repeatedly exposed to ultraviolet radiation in an activated fog environment as said air stream moves sequentially through a plurality of first chambers and particulate water with V.O.C. reaction products are extracted from said air stream in each first chamber.

27. The method set forth in Claim 26 wherein said air stream is also repeatedly exposed to ultraviolet radiation in a high humidity environments substantially free of activated fog.

28. The method set forth in Claim 27 wherein water vapor and gaseous V.O.C.s in said air stream are exposed to ultraviolet radiation in an environment substantially free of activated fog immediately after particulate water and V.O.C. reaction products have been extracted from said air stream at at least one of said first chambers.

29. The method set forth in Claim 26 wherein said air stream is repeatedly exposed to ultraviolet radiation in an activated fog environment at least several times and filtered at least several times.

30. The method set forth in Claim 29 wherein said air stream is exposed to ultraviolet radiation in an activated fog environment with intermediate extraction of water and V.O.C. reaction products. at least five times.

31. The method set forth in Claim 28 wherein water vapor and gaseous V.O.C. s exposed to ultraviolet radiation are then passed through a carbon filter before said air stream is again exposed to ultraviolet radiation in an activated fog environment in at least one of said first chambers.

32. The method set forth in Claim 26 wherein said air stream is contacted with a catalyst before repeated exposure to ultraviolet radiation in said first chambers.

33. The method set forth in Claim 26 further comprising:
collecting particulate water extracted from said air stream in said tunnel, and dispersing said activated air in said collected water to form said aqueous solution before said aqueous solution is misted into said air stream to thereby continuously recirculate said collected water back through said tunnel.

34. The method set forth in Claim 26 further comprising:
exhausting gaseous V.O.C.s and water vapor from said tunnel, and passing said tunnel exhaust gases through a carbon bed system to adsorb remaining V.O.C.s from said air stream.

35. The method set forth in Claim 34 further comprising:
passing activated air through said carbon bed system to desorb said carbon bed and disperse oxidants in said carbon bed system for surface reaction with V.O.C.s in said tunnel exhaust gases, and then passing said tunnel exhaust gases through said carbon bed system.

36. The method set forth in Claim 35 further comprising:
exhausting desorption activated air from said carbon bed system, and introducing said carbon bed exhaust air into said tunnel.

37. The method set forth in Claim 35 further comprising:
providing at least a pair of carbon beds in said carbon bed system, passing exhaust air from said tunnel through a first one of said carbon beds to adsorb V.O.C.s from said exhaust air while simultaneously passing activated air to the other of said beds to desorb said other bed and recharge said other bed with a fresh supply of oxidants for surface reaction with said V.O.C.s, and then passing said tunnel exhaust air through said other carbon bed to adsorb V.O.C.s from said tunnel exhaust air while simultaneously passing activated air through said first carbon bed to desorb said first carbon bed and recharge said first carbon bed with a new supply of oxidants for surface reaction with said V.O.C.s.

38. The method set forth in Claim 1 wherein activated air is introduced into said tunnel in gaseous form.

39. The method set forth in Claim 1 wherein prior to exposing said air stream to ultraviolet radiation, said method further comprises:
spraying aqueous solution into said air stream, and then vigorously blending said air stream and said aqueous solution spray to intimately contact V.O.C.s in said air stream with said aqueous solution.

40. The method set forth in Claim 1 wherein said air stream moving through said tunnel is contacted with a catalyst.

41. The method set forth in Claim 40 wherein said air stream is contacted with polyvinylchloride in an activated fog environment.

42. The method set forth in Claim 1 wherein said V.O.C.s include methylanylketons (MAK), Xylenes , and ortho-xylens.

43. The method set forth in Claim 1 wherein said exposing step further comprises exposing air having a relative humidity of at least 85% to ultraviolet radiation to produce said supply of activated air.

44. The method set forth in Claim 1 wherein said air stream is passed through said tunnel at a rate that is in the range of 22,500 to 50,000 ACFM.

45. The method set forth in Claim 1 wherein said aqueous solution is misted into said tunnel at a rate in excess of five gallons per minute at about 1,000 psi.

46. The method set forth in Claim 1 wherein said air stream is exposed to ultraviolet radiation in the range of from 184 to 254 nanometers.

47. The method set forth in Claim 1 wherein said aqueous solution containing activated air dispersed therein is formed by mixing activated air with a liquid to disperse bubbles of activated air in said liquid while simultaneously exposing said aqueous solution to ultraviolet radiation.

48. The method set forth in Claim 1 wherein a plurality of first chambers are maintained at one hundred percent relative humidity and said air stream is heavily saturated to provide said activated fog environment, and at least one other chamber is maintained at a high relative humidity and substantially free of particulate water from upstream chambers.

49. Apparatus for removing volatile organic compounds (V.O.C.s) from industrial process exhaust air and the like on a continuous basis by photochemical and oxidative degradation, comprising:
a generator providing a source of activated air, said generator having a plurality of electrically energized lamps therein producing ultraviolet radiation, with said generator being arranged and constructed to receive clean air, expose said clean air to ultraviolet radiation and deliver activated air having reactive oxidants therein, a mixer arranged and constructed to disperse bubbles of activated air from said generator into a liquid to form an activated aqueous solution, a walled tunnel having an inlet for receiving air having V.O.C.s therein, a plurality of chambers spaced along said tunnel, and an outlet for discharging exhaust air after treatment in said tunnel, said tunnel being arranged and constructed to confine said exhaust air into an air stream moving along a path through said tunnel, at least one of said chambers comprising a plurality of nozzles receiving activated aqueous solution from said mixer and spraying said aqueous solution into said one chamber to introduce an activated fog into said airstream, a plurality of electrically energized ultraviolet lamps carried in said one chamber to expose said air stream and activating fog to ultraviolet radiation in said one chamber, and a liquid extractor for removing particulate water from said air stream as it moves out of said one chamber and into a downstream contiguous chamber.

50. The apparatus set forth in Claim 49 wherein said plurality of chambers includes a plurality of first chambers including said one chamber, and all of said first chambers have nozzles for introducing activated fog into said air stream, ultraviolet lamps for exposing said air stream and said fog to ultraviolet radiation and liquid extractors for removing particulate water from said air stream when said air stream moves out of each first chamber.

51. The apparatus set forth in Claim 50 further comprising:
a first partition extending transversely of said tunnel across said air stream path and separating said one first chamber from said contiguous chamber, and wherein:
said extractor comprises filters mounted on said partition so that said air stream flows through said filters into said contiguous chamber, and a plurality of electrically-energized lamps are mounted on said partition downstream of said filters to radiate ultraviolet radiation into said contiguous chamber.

52. The apparatus set forth in Claim 51 wherein said contiguous chamber is a first chamber and said apparatus further comprises a plurality of nozzles carried on said partition downstream of said filter for receiving activated aqueous solution from said mixer and introducing activated fog into said downstream contiguous chamber.

53. The apparatus set forth in Claim 51 wherein said filters have filter characteristics selected to block particulate water and pass gaseous V.O.C.s and water vapor so that said air stream moves into said contiguous chamber substantially free of particulate water and said plurality of lamps on said first partition expose gaseous V.O.C.s and water vapor to ultraviolet radiation in said contiguous chamber.

54. The apparatus set forth in Claim 53 further comprising:
a second partition extending transversely of said tunnel and across said air stream path at an outlet of said contiguous chamber; and second filters mounted on said second partition so that said air stream must flow through said second filters.

55. The apparatus set forth in Claim 54 wherein said second filters are carbon filters.

56. The apparatus set forth in Claim 55 wherein:
a plurality of second chambers, including said contiguous second chamber, are spaced along said tunnel, each of said second chambers is downstream immediately contiguous to a first chamber to receive gaseous V.O.C.s and water vapor, each of said second chambers has ultraviolet lamps to expose gaseous V.O.C.s and water vapor to ultraviolet radiation, and each of said second chambers has carbon filters mounted on second partitions at outlet ends of said second chambers.

57. The apparatus set forth in Claim 50 further comprising:
a third chamber in said tunnel immediately upstream of a first chamber, nozzles connected to said mixer and operatively associated with said third chamber to introduce activated fog into said air stream in said third chamber, electrically-operated ultraviolet lamps operatively associated with said third chamber to expose said fogged air stream to ultraviolet radiation in said third chamber, and a third partition in said third chamber extending transversely of said tunnel across said air stream path, and scrubbers mounted on said third partition to create turbulence in said air stream and intimate contact between V.O.C.s in said air stream and oxidants in said activated fog.

58. The apparatus set forth in Claim 57 wherein said scrubbers include a catalyst.

59. The apparatus set forth in Claim 57 wherein said scrubbers are perforated plates having said catalyst on at least one surface thereof.

60. The apparatus set forth in Claim 49 further comprising:
a collection tank arranged and disposed to receive liquid removed from said air stream by said extractors, and a pump system connected to said collection tank and said nozzles to recirculate liquid from said tank back into said air stream in said tunnel.

61. The apparatus set forth in Claim 60 wherein said pump system comprises:
a first pump operatively connected between said tank and said mixer to deliver extracted liquid to said mixer, and a second pump operatively connected between said mixer and said nozzles to deliver said aqueous solution from said mixer to said nozzles.

62. The method set forth in Claim 61 wherein said mixer further comprises:
a housing having a liquid inlet connected to said first pump to receive liquid from said tank, a bubbler operatively connected to said activated air generator and arranged and disposed in said housing to disperse bubbles of activated air in liquid in said housing to form said activated aqueous solution, and a plurality of ultraviolet lamps mounted inside said housing to expose said aqueous solution and said activated air bubbles to ultraviolet radiation while said activated aqueous solution is being formed.

63. The apparatus set forth in Claim 49 wherein said mixer comprises:
a housing in which bubbles of activated air are dispersed in a liquid to form said activated aqueous solution, and a plurality of ultraviolet lamps operatively mounted inside said housing to expose said aqueous solution and said activated air bubbles to ultraviolet radiation while said activated aqueous solution is being formed.

64. The apparatus set forth in Claim 49 wherein said tunnel comprises:

a plurality of first chambers spaced along said air stream path, each of said first chambers having activated fog nozzles and ultraviolet lamps operatively associated therewith to expose said air stream and activated fog to ultraviolet radiation, and liquid extractors to remove particulate water as said air stream moves out of respective first chambers, a plurality of second chambers spaced along said air stream path with respective second chambers being contiguously downstream of respective first chambers, filters extending transversely of said tunnel across said air stream path between contiguous first chambers and second chambers, said filters having filter characteristics selected to extract particulate water from said air stream leaving first chambers and pass gaseous V.O.C.s and water vapor from a first chamber to a contiguous second chamber, said second chambers having ultraviolet lamps operatively associated therewith to expose said gaseous V.O.C.s and water vapor to ultraviolet radiation as said air stream moves through said second chambers, and at least one third chamber in said tunnel upstream from one first chamber and its contiguous second chamber, said third chamber having:
ultraviolet lamps and activated fog nozzles operatively associated therewith to simultaneously expose said air stream and activated fog in said third chamber to ultraviolet radiation, and catalytic perforated plates extending transversely of said tunnel in said third chamber across said air stream path.

65. The apparatus set forth in Claim 64 wherein at least two contiguous first chambers are located in said air stream path upstream of said contiguous second chamber.

66. The apparatus set forth in Claim 49 further comprising:
a carbon bed system enclosed in a housing, first ducting connecting said tunnel outlet to said carbon bed housing to deliver air discharge from said tunnel to said carbon bed system for adsorption of any remaining V.O.C.s.

67. The apparatus set forth in Claim 66 further comprising:
damper means to selectively interrupt delivery of tunnel discharge air to said carbon bed system through said first ducting, a carbon bed desorption system comprising:
a source of activated air, said source having a plurality of electrically energized lamps therein producing ultraviolet radiation and being arranged and constructed to receive clean air, expose clean air to ultraviolet radiation to produce activated air containing oxidants, piping operatively connecting said activated air source to said carbon bed system, and valve means for selectively passing activated air through said piping to said carbon bed system during carbon bed desorption.

68. The apparatus set forth in Claim 67 wherein:
said carbon bed system includes at least first and second carbon beds, said damper means is operative to deliver said tunnel discharge air through said first ducting to one of said carbon beds and interrupt delivery of tunnel discharge air to the other carbon bed, and said valve means is operative to deliver activated air from said source through said piping to said other carbon bed to desorb said other carbon bed while said one carbon bed is receiving tunnel discharge air through said ducting.

69. The apparatus set forth in Claim 67, further comprising: a return piping system connected at one end to an exhaust of said carbon bed system and at its other end to said tunnel to introduce carbon bed exhaust into said air stream.

70. The apparatus set forth in Claim 66, wherein said carbon bed system defines a path extending between an inlet and an outlet of said carbon bed system, and wherein said carbon bed system includes an airflow restriction located in said path proximate said outlet, whereby said airflow restriction creates a backpressure within said carbon bed system.