Compact high-throughput ultraviolet processing chamber

An ultraviolet processing chamber for treating contaminated waste water and the like. The processing chamber includes a chamber body defining a passageway through which the water under treatment flows. An enclosed volume is defined which contains an array of linear UV lamps and which includes a protective wall formed of a material substantially transparent to UV radiation. The protective wall is disposed with respect to the flow passageway so as to permit UV radiation to pass in substantial amounts into the flow passageway to irradiate the water or other substance under treatment. For ease of maintenance the array of UV lamps is contained in a module which is removable from the remainder of the processing chamber. More specifically, the lamps are mounted on a base portion, which may be secured in position on the chamber, and the plurality of lamps forming the array extend into the enclosed volume separated from the substance under treatment by the protective wall. Another assembly receives the ends of the lamps opposite the base portion. The base portion and the receiving assembly are formed to be in flow communication with the enclosed volume to permit circulation of coolant about the lamps within the enclosed volume to cool the lamps. Disposed within the passageway are a plurality of flow diverters, which direct the water under treatemnt to peripheral regions of the chamber passageway and to regions of the passageway proximate to the enclosed volume of higher UV intensity.

BACKGROUND OF THE INVENTION 
The present invention relates to the high-volume treatment of waste water 
or other aqueous (or gaseous) environments with ultraviolet radiation for 
the destruction of toxic organic compounds, microbial species, and the 
like. 
Various undesirable substances, such as heavy organic molecular compounds 
and microbial species, are often carried in waste water or other 
effluents, or in gaseous or other matrix environments, in which they may 
prove toxic in subsequent uses of the carrier material. 
One known process for sterilizing or disinfecting the carriers of these 
compounds is through irradiation with ultraviolet (UV) radiation. 
For treatment of waste water, for example, the water under treatment is 
mixed with ozone or peroxide and subsequently passed through a processing 
chamber where it is irradiated by a UV source typically in the form of one 
or more UV lamps as the water flows past. The most common form of lamp 
employed in such chambers has historically been the low-pressure linear 
mercury lamp. Recently much more powerful medium-pressure linear mercury 
lamps have been introduced. For the most part, however, these lamps have 
merely been used in place of the low-pressure lamps in processing chambers 
of conventional design intended for low-pressure lamps, and only limited 
attempts have been made to redesign the processing chamber to accommodate 
the medium-pressure lamps. Thus, known processing chamber designs for use 
with medium-pressure lamps share many characteristics--both positive and 
negative--in common with chambers for low-pressure lamps. 
The conventional UV processing chambers are subject to a number of 
deficiencies and drawbacks. The commonly employed low-pressure mercury 
lamps have a low power output in the deep UV region. Their radiation is 
used to create free radicals by photolytic action with ozone or peroxide, 
which in turn destroys toxic substances. Because of the low power of such 
lamps, however, the water has to travel relatively slowly through the 
processing chamber so that the travel time of the water through the 
operative portion of the chamber is often comparable to the diffusion time 
for contaminants through the water. As a result, contaminants in the water 
may foul the UV lamps and produce significant screening of the UV 
radiation. To solve this problem in the past, special devices have been 
used to scrub the buildup from the lamps while the lamps are operating, or 
water was continually mixed by propellers in the chamber, or else it has 
been necessary to shut the system down periodically to permit the lamps to 
be cleaned. 
To treat large volumes of water such as required in any industrial 
treatment facility, a matrix type array of such UV lamps is used, where 
each lamp of the array is immersed in the water under treatment. For large 
industrial systems as many as 200 low-pressure mercury lamps may be used. 
As a result, such systems tend to be bulky and may be so massive as to 
require a special concrete base to support the aggregate weight of the 
chamber and processed water, which can reach ten or more tons. 
The trend in the water treatment industry is now to switch to 
medium-pressure lamps instead of low-pressure ones. The power of the 
medium-pressure lamps exceeds the power of low-pressure lamps by a factor 
of about 100 to 150. More specifically, the medium-pressure lamps have a 
typical power rating of 200 to 250 watts per inch of lamp length and may 
be as high as 300 watts per inch. This is to be compared with a maximum of 
two watts per inch found in low-pressure mercury lamps. Thus, the number 
of lamps in systems of comparable throughput is reduced significantly. The 
medium-pressure lamps, however, also generate significantly more heat 
(about 50 percent of their output). Hence, these lamps have to be cooled. 
The use of these lamps is not yet widespread. When medium-pressure lamps 
are used, however, they are usually also disposed in arrays in 
conventional chambers as are the low-pressure lamps. Such systems are 
desired for processing large volumes of water (100 gallons per minute or 
more). Alternatively, a design is sometimes used which is especially 
adapted for medium-pressure lamps and high-volume processing, in which a 
plurality of long medium-pressure lamps, up to seven feet in length, are 
each contained in a cylindrical chamber, and the power for each such 
module can attain about 15 kilowatts. 
Although the use of medium-pressure mercury lamps eliminates some of the 
drawbacks of systems with low-pressure linear mercury lamps, such as their 
bulky size and excessive weight, other drawbacks of conventional UV 
treatment systems were merely carried over into systems with linear 
medium-pressure mercury lamps. Specifically, the medium-pressure lamp 
systems still employ unnecessarily complex matrix arrays for the lamp 
geometries and still require the whole system to be drained for 
replacement of each individual lamp. 
In fact, with the arrays of either the low-pressure or medium-pressure 
lamps, when a lamp must be replaced or cleaned, the whole system must be 
shut down and drained. This occurs on a periodic basis because lamp 
lifetime is well known and premature burnout is statistically 
insignificant. At that time the system is drained and the lamps are 
individually replaced, which is a tedious and time-consuming procedure. 
Thus, matrix arrays of lamps present two main drawbacks, notwithstanding 
their benefits. The fact remains that despite the known reliability of 
standard lamps, failures can occur due to such extraneous factors as 
improper cooling or electrical failure. In this case the action of the 
failed lamp in the array of lamps is not covered by the remaining lamps 
because in such systems the lamps are positioned to treat predetermined 
portions of the processing chamber. The UV radiation from the other lamps 
will not generally reach a particular portion of the chamber with 
sufficient intensity to substitute for a failed lamp. As a result, when a 
lamp fails, not all the water will be treated effectively if the system is 
permitted to continue operating. To guard against this, many systems have 
automatic controls which shut down the system when a failure in lamp 
performance is detected so as to prevent an outflow of untreated water. 
Another drawback of the standard lamp array geometry is the non-uniform 
distribution of radiation intensity in the processing chamber, which 
results from the lamps' complicated overlapping circles of action needed 
to insure that even the farthest reaches of the volumes allocated to the 
individual lamps are subjected at least to the minimum operative UV 
levels. Such an arrangement undesirably produces "pockets" of excess UV 
exposure mostly within close distances to the lamps, which results in an 
overall waste of UV energy, which may be as high as 30 percent. 
In some known systems the "pocket" effect is compensated somewhat by 
intensive mixing of the water under treatment so that portions of the 
water pass both through areas of higher and lower UV exposure, which 
enables one to decrease the UV intensities of the lamps (or to increase 
the throughput of treated water). Although the overall utilization of UV 
energy is improved in such case, in a chamber with complicated geometry 
and many lamps and in a chamber with a low speed of processed water 
through the chamber, the proper mixing of water is difficult to maintain 
throughout the chamber. Thus, this approach is not in widespread use, and 
usually the underutilization of UV in such systems is simply accepted. 
SUMMARY OF THE INVENTION 
The present invention provides an especially compact and lightweight 
processing chamber for use with powerful linear flashlamps or with 
medium-pressure linear mercury lamps, which overcomes many of the 
aforementioned disadvantages and tradeoffs of known processing chambers. 
The processing chamber according to the invention takes advantage of 
powerful linear flashlamps having a typical length from 6 to 12 inches and 
total power output in all spectral regions from about 50 to 300 watts/inch 
of lamp length while avoiding common drawbacks of conventional UV 
processing chambers used with low-pressure or medium-pressure linear 
mercury lamps. The chamber design may be used with flashlamps or other 
linear lamps as well. 
Briefly, a processing chamber according to the invention includes a chamber 
body defining a passageway through which the water under treatment flows. 
An enclosed volume is defined which contains an array of linear UV lamps 
and which includes a protective wall formed of a material substantially 
transparent to UV radiation. The protective wall is disposed with respect 
to the flow passageway so as to permit UV radiation to pass in substantial 
amounts into the flow passageway to irradiate the water or other substance 
under treatment. For ease of maintenance the array of UV lamps is 
contained in a module which is removable from the remainder of the 
processing chamber. More specifically, the lamps are mounted on a base 
portion, which may be secured in position on the chamber, and the 
plurality of lamps forming the array extend into the enclosed volume 
separated from the substance under treatment by the protective wall. 
Another assembly receives the ends of the lamps opposite the base portion. 
The base portion and the receiving assembly are formed to be in flow 
communication with the enclosed volume to permit circulation of coolant 
about the lamps within the enclosed volume to cool the lamps. Disposed 
within the passageway are a plurality of flow diverters, which direct the 
water under treatment to regions of the chamber passageway with different 
UV exposures for the purpose of equalizing the exposure. 
In a particularly compact and effective embodiment of the invention, the 
enclosed volume is defined by a plurality of protective lamp shells, which 
may have a generally cylindrical form extending transversely through the 
central region of the flow passageway. Each individual lamp of the lamp 
array extends through its own cylindrical lamp shell, and coolant flows 
through each individual shell to cool the lamp within. 
Other aspects, advantages, and novel features of the invention are 
described below or will be readily apparent to those skilled in the art 
from the following specifications and drawings of an illustrative 
embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows an overall perspective view of an illustrative processing 
chamber, generally designated by reference numeral 10, according to the 
invention. Processing chamber 10 includes a chamber body 11, which 
includes an inlet port 12 and an outlet port 13. Chamber body 11 defines 
an internal passageway 14 communicating with inlet and outlet ports 12 and 
13 through which the water under treatment flows. FIG. 1 has been 
partially cut away to reveal the insides of the chamber. Running 
vertically through the chamber body are a plurality of generally 
cylindrical protective shells 16 arranged in a linear fashion along 
passageway 14. Although illustrated herein as running vertically, it will 
be apparent from the descriptions below that the shells may also be 
configured to run horizontally or at other dispositions. The shells are of 
such a shape and dimension that each may conveniently receive the envelope 
of a UV lamp. The shells are formed of a material such as quartz which is 
transparent to UV radiation. Positioned within the chamber passageway 14 
are a plurality of flow diverters 17 and 18, which serve to divert the 
flow of water under treatment in a manner described below. A plurality of 
UV lamps 19 are mounted in a removable cassette module 21 and are disposed 
within shells 16. 
As illustrated here the main portion of the processing chamber 11 has a 
square cross section, and the lamp shells 16 are spaced equidistant from 
one another in a linear array along the central longitudinal axis of the 
chamber. Chamber 11 is provided with entrance and exit funnels 23 and 24 
connecting the inlet and outlet ports with the main walls of chamber body 
11. Positioned in entrance funnel 23 at the inlet port is flow diverter 
17, which is provided by a generally conical member and which serves to 
spread the incoming flow as it enters the main part of chamber 11. To 
establish a flow of water through passageway 14 in a manner that maximizes 
the utilization of the UV radiation emitted by the centrally disposed 
lamps, a plurality of flow diverters 18 are positioned in the vicinity of 
the chamber sidewalls. Without such diverters, the water flow in the 
peripheral regions of passageway 14 will generally be of higher speed and 
will pass more quickly through the chamber than the flow in the central 
region of the chamber, and consequently will be underexposed. The lamps in 
the central region of the chamber present a hydraulic resistance to the 
flow so that the water here will move more slowly than in the free 
peripheral regions, absent the diverters, and the water will tend to be 
overexposed. The purpose of the flow diverters is to direct the peripheral 
and generally faster portion of the flow to the regions, designated at 
reference numeral 26 in FIG. 4, proximate to and between the linearly 
arranged UV lamp shells 16 where the UV light is of maximum intensity. 
Without the flow diverters to "redistribute" the flow, the regions between 
the lamps would develop "pockets" of slow-moving water, which would be 
overexposed, while the peripheral streams of water would run through more 
quickly and would tend to be underexposed. Notwithstanding this retarding 
action, the linear lamp array is desirable for other reasons discussed 
below, and the flow diverters enable one to take full advantage of the 
linear array. The precise positioning of flow diverters 18 may vary from 
embodiment to embodiment, but in any case may readily be established by 
those skilled in the art to achieve the desired flow path. For example, 
for the configuration illustrated here diverters 18 are provided by 
rectangular strips positioned along, but spaced apart from, the sidewalls 
as shown in FIG. 4. Diverters 18 extend the full vertical height of the 
chamber and are angled at about 45 degrees to the direction of the water 
flow. It may also be advantageous to vary the angle of the diverters 
according to the flow rate. The optimal diverter angle and water passage 
parameters in any given chamber configuration as a function of flow rate 
may readily be determined empirically by those of ordinary skill in the 
art. The precise size of the conical member forming diverter 17 and its 
positioning in entrance funnel 23 may also be selected empirically so as 
to cooperate with flow diverters 18. 
The illustrated geometry for the processing chamber is particularly compact 
and effective. For example, an efficient chamber may be formed with the 
following dimensions: a square chamber cross section of 7 inches (roughly 
18 centimeters) on a side; four UV lamps spaced apart from one another by 
3.5 inches (9 centimeters); inlet and outlet ports with a 2-inch 
(5-centimeter) inside diameter; an overall length from inlet port to 
outlet port of 30 inches (76 centimeters); diverter 17 of conical shape; 
and diverters 18 in the form of rectangular strips about 1 inch wide (2.5 
centimeters) and running the vertical height of the passageway. With these 
dimensions and with UV lamps having a power rating of about 200 Watts per 
inch of lamp length, the chamber of the present invention is able to treat 
on the order of 10 to 100 gallons per minute of toxic effluent, depending 
on effluent initial concentration and degree of desired decontamination. 
To illustrate the processing efficiency of this embodiment specifically in 
cases where only minimal UV exposures are called for, which is the case 
for water disinfection where the exposure of 30 milliwatts per cubic 
centimeter of water under treatment is sufficient, the above-described 
configuration of the processing chamber with the same lamps can treat up 
to 3000 gallons per minute, and the flow may attain a speed of 3 meters 
per second. At these processing speeds and volumes the lamp's cooling 
shells and seals in the above configuration may experience a high 
hydrodynamic pressure which presently available commercial seals and 
lamp's shells will not withstand. For such cases an alternative 
configuration is preferred, in which the lamps are all positioned along 
one sidewall behind a common quartz window of a rectangular shape 
corresponding to the shape of the adjacent sidewall. This embodiment 
requires a different cassette module for mounting the lamps and achieves a 
lesser utilization of the UV output. To compensate for the reduced UV 
utilization, it is desirable to provide a UV mirror on the side wall 
behind the lamps to reflect a greater portion of the UV radiation into the 
processing chamber passageway. Although not as efficient as the embodiment 
of FIG. 1, such an embodiment is nevertheless useful in cases such as 
certain UV disinfection applications, in which a lower UV exposure will 
suffice. 
The arrangement of the UV lamps as illustrated herein achieves an optical 
coupling of the lamps, which provides for minimal nonuniformity of the UV 
radiation within the processing chamber. The lamps are disposed along the 
processing chamber center line with a separation between adjacent lamp 
centers equal to the distance between the center line and the neighboring, 
i.e., parallel, sidewall of the chamber. (In the embodiment in which the 
lamps are disposed behind a quartz window along one sidewall, the distance 
between the lamp centers is equal to the distance to the opposite 
sidewall.) The magnitude of that distance to the neighboring sidewall is 
preferably selected as the distance from the lamps at which the UV losses 
in the water under treatment reach about 70 percent. 
The sidewalls opposite the lamp array may advantageously be provided with a 
UV-reflective surface to enhance the intensity of the UV radiation in the 
vicinity of the sidewalls. For example, for use in processing water a 
UV-reflective surface yielding about 50-percent reflection in the deep UV 
region may be provided by polished stainless steel coated with chrome. A 
better, although more expensive, reflective surface in the deep UV range 
may be achieved with aluminum coated with magnesium fluoride 
(Al+MgF.sub.2) which is in turn coated with a coating such as TEFLON to 
prevent dissolution or degradation of the (MgF.sub.2 +Al) mirror. With 
this arrangement reflections in the deep UV range can reach as high as 80 
percent. 
It should be apparent that uniform UV irradiation of the water throughout 
the processing chamber as it is presented in FIG. 1 (with a lamp array 
along the chamber center) cannot be achieved through the optical design of 
the lamp illumination pattern in and of itself. In the present invention 
the uniformity of UV irradiation is enhanced by the mixing produced by the 
flow diverters, which compensates appreciably for the nonuniformities 
inherent in the lamp illumination pattern. Irregularities in the lamp 
illumination pattern are also smoothed out in the illustrated embodiment 
by the positioning of feedthroughs for the electrical cabling associated 
with the lamps. A maximum intensity of UV radiation in the lamp 
illumination pattern will lie in the spots between two adjacent lamps. 
Feedthroughs 27 in the form of vertical tubes (diameter of 0.5 inch), 
which carry return high voltage wires from the bottom of the processing 
chamber to the top, are located at the positions of maximum UV radiation 
intensity. See FIGS. 1 and 4. This reduces overexposure and at the same 
time assures a well balanced electrical circuit with a low impedance and 
balanced electromagnetic plasma action in the lamps. Thus the spots of the 
maximum UV intensity are utilized in the chamber for necessary electrical 
hardware while some broader areas of elevated UV intensity in UV circles 
overlapping from adjacent two lamps accommodate a higher than average 
water flow due to the actions of the diverters. 
Another advantage of the linear array of lamps is the ability to cover the 
action of a failed lamp through increased action of the remaining lamps 
without shutting down the whole system. This is apparent from the 
illustrated embodiment, in which the water under treatment necessarily 
flows through the region treated by each lamp. In this way if a lamp 
should burn out and the processing chamber be permitted to continue 
operating, all portions of the flow of water will still be exposed to the 
appropriate intensity of UV radiation, although the duration of the 
exposure will of course be diminished. This is to be contrasted with known 
matrix arrays of UV lamps for treating comparable volumes of water at 
comparable rates. In such arrays each lamp is assigned to the treatment of 
a designated subvolume of water. If a lamp should fail, then some of the 
water in the subvolume associated with that lamp will simply fail to be 
exposed to UV radiation of the desired intensity. 
Yet another advantage of the present design is the easy replacement of all 
the lamps by means of a replaceable lamp cartridge. As illustrated here 
the UV lamps are mounted in the processing chamber by means of a removable 
cartridge or cassette module designated generally by reference numeral 21 
in FIG. 5. Module 21 includes a base portion 28 for holding lamps 19. Each 
lamp 19 is secured in an appropriate socket in base portion 28 and 
provided with electrical connections for the lamp's ground and ignition 
wire. In the FIG. 5 the ground connection is shown at 30 and ignition 
wires 31 are fed through the base portion 28. Surrounding each lamp socket 
and mounted on the base portion is a coupling member and seal, which makes 
sealing contact with an entrance aperture at the lower extremity of the 
associated shell 16 in the chamber body. As illustrated in FIG. 5, the 
seal is provided by a deformable gasket and surrounding hose clamp which 
are mounted over a flange protruding from the bottom of the chamber body 
at the entrance aperture of each shell. Other suitable seals and clamps 
for accomplishing this purpose are well known to those skilled in the art 
and need not be described here in any detail. 
To guide the lamp module into position on the chamber body, base portion 28 
is formed with two guide holes 32 and 33, and the chamber is provided with 
a pair of guide shafts in registration with the guide holes of the base 
portion. (Only one such guide shaft 34 is visible in FIG. 1.) In the 
illustrated embodiment the lamp module is held in position by turn screws 
36. Other conventional means may also be used and other custom 
configurations may also be devised for removably holding the lamp module 
in position on the chamber. These are well within the ordinary skill in 
the art and need not be described here. 
When module 21 is mounted on the chamber body, lamps 19 extend through 
shells 16 to a receiving assembly 29 on chamber body 11, which receives 
the upper extremities of the lamps. The lamps may be formed with the upper 
extremity terminating in a flexible wire 37 of typically 14 or 16 gauge 
which serves as the power connection to the upper lamp electrode, which 
will generally be the anode. Terminating wires 37 are secured in 
appropriate sockets in receiving assembly 29 and serve to provide the 
mounting connection to the receiving assembly and the requisite 
high-voltage connections for the lamps. Forming the receiving connections 
for the lamps from the flexible wires in this manner is highly desirable 
in that, unlike conventional clamping sockets, no stress is introduced on 
the lamp at the upper extremity by the receiving assembly. As illustrated 
in FIG. 1, the chamber is provided with feedthroughs 27 by each lamp shell 
to bring the high voltage electrical power lines for each lamp to the 
underside of the chamber. This serves to simplify the electrical cabling, 
to maintain a low impedance for the lamp circuits, and to balance the lamp 
plasma within the center of the lamp bore. This is accomplished through 
stainless steel tubes roughly 0.5 inches in diameter, which do not occupy 
much of the valuable space between lamps and, as explained above, are 
advantageously positioned in spots of maximum UV intensity so as to 
prevent overexposure at these spots. Other arrangements could, of course, 
be used as well. 
The high-voltage connections are preferably made in this manner separately 
for each lamp and are fixed in receiving assembly 29 and hence in the 
processing chamber. Receiving assembly 29 may also include seals as needed 
to produce a water-tight seal with shells 16. 
As in any high-power lamp system, the processing chamber also includes a 
lamp cooling system. The base portion 28 is formed with an internal 
coolant passage leading to each lamp, which is provided with a coolant 
port for connection to tubing 39 for carrying the coolant. Corresponding 
coolant outlet ports are provided at the top of the chamber by each shell 
as part of receiving assembly 29 for connection to tubing 40, as shown in 
FIG. 1. The coolant enters the system through inlet tubing 39 and travels 
through the coolant flow passageways formed in base portion 28 to shells 
16. The diameter of the shells is sufficiently greater than that of the 
lamps to permit sufficient coolant to flow past the lamps to maintain the 
lamps at their recommended operating temperature. The gap between a shell 
16 and its enclosed lamp communicates with the corresponding coolant 
outlet port in receiving assembly 29. The coolant circulates through 
coolant outlet tubing 40. 
This arrangement eliminates several problems. To remove lamps, the cassette 
module 21 may be removed without having to shut down the system. A new 
cartridge with new lamps can be readily mounted in place of the removed 
cartridge making lamp replacement quick and easy. The lamps may be 
pre-mounted on the cassette cartridges at the time of manufacture and may 
simply be replaced as a unit so that the system experiences little down 
time and the user spends little time on maintenance. Spent lamp cartridges 
may be returned to the manufacturing facility for repair and recycling. 
Note that the lamp cooling is independent of the water under treatment 
because of the closed cooling system. The flow rate of the coolant is 
independent of the flow rate of the water under treatment and may thus be 
adjusted to optimize the lamp cooling. The coolant may be kept relatively 
free of contaminants, thus greatly reducing fouling of the lamp envelopes. 
Fouling of the lamp shells may be reduced through the self-cleaning effect 
of an elevated flow rate through the chamber. It has been demonstrated 
with this design that at greater water speeds on the order of 20 
centimeters per second or above fouling does not occur due to the 
self-cleaning action of the fast-moving water. The present invention, 
especially in the case when the lamp module is placed along the side wall, 
includes such self-cleaning action as an added benefit when the UV 
exposure time is small and consequently the water flow is high, i.e. above 
20 cm per sec. However, when processing highly contaminated waste water, 
the water flow may fall in the range of a few centimeters per second even 
with the highest available lamp UV power (200 watts per inch). 
To maintain the self-cleaning action in the processing chamber regardless 
of UV exposure conditions, the present invention provides two optional 
water storage tanks, each of the same size as the processing chamber 
(about 4 Gallons in the illustrated embodiment). The small size of the 
processing chamber and storage tanks makes for a compact overall system. 
This arrangement is shown in FIG. 6, which includes processing chamber 10 
and first and second buffer storage tanks 41 and 42. The flow through the 
system is controlled by water valves V1, V2, V3 and V4. When valve V1 is 
closed, valve V2 is open and the waste water fills the tank 42. Tank 41 is 
already filled from the previous cycle in which valve V1 was open and 
valve V2 was closed. While tank 42 is filling, valve V3 from tank 41 is 
open and allows water to be pumped through processing chamber 10 by water 
pump 43. The water passes through filter 44 and through the open valve V5 
into the tank 41 while valve V6 on this return line is closed. The 
processing cycle for buffer chamber 42 starts when valves V4 and V6 open 
(automatically) and pump 43 starts circulating water from this tank 
through processing chamber 10. These cycles alternate automatically one 
after another to assure an uninterrupted flow of water through the whole 
system. The water may be recirculated as many times as needed to reach the 
desired amount of UV exposure. One tank is filled at the projected water 
flow rate for the system, while the second tank, which was already filled 
in the previous cycle, is used for the water circulation from this tank to 
the processing chamber. This circulation is supported by a backup water 
pump, so that water can move through the chamber at a constant rate 
regardless of the water flow on the line. The flow rate is adjusted to be 
high enough to support the self-cleaning action by the circulating water 
so as to prevent fouling. The return lines between the processing chamber 
and the buffer tanks may also include a filter for collecting accumulated 
byproducts washed from the quartz and mirror surfaces within the chamber. 
When the water has been recirculated the desired number of times, the 
purified water is drained from the buffer tanks 41 and 42. The water in 
tank 41 is released through output valve V7 under the action of gravity or 
by a second pump on the output line if a gravity flow is not sufficient. 
During this time valves V1 and V3 are closed to prevent mixing of treated 
water with untreated water. Draining of such a compact buffer chamber (4 
Gallons) does not take more than about 15 seconds using standard two-inch 
pipes and valves. The drain valves V7 and V8, of course, are always closed 
except when draining the associated tank 41 or 42. It is clear from the 
above description that the recirculation of waste water through the buffer 
tank does not slow down the overall system throughput. In fact, the 
throughput remains the same as if water would move only through the 
processing chamber at the original low speed. The implementation of 
hydraulic apparatus according to the above descriptions is well within the 
ordinary skill in the art and need not be described here in further 
detail. 
The above provides a description of an illustrative embodiment of the 
invention. Given the benefit of this description, various modifications 
and alternate configurations will occur to those skilled in the art, not 
all of which can be conveniently described herein. For example, those 
skilled in the art will appreciate from the above descriptions that 
arrangements of this processing chamber can also be used for treatment of 
contaminated air as well with little or no modifications or adjustments. 
This is due to the similar hydrodynamic nature of air and water and due to 
similar action of UV on undesirable organic waste or bacterial species in 
either environment. 
Accordingly, the invention is not intended to be limited only to the 
specific examples and embodiments disclosed herein, but is defined by the 
appended claims.