Patent Application
20130020501
The present invention relates to disinfecting contaminated water and, more specifically, disinfecting contaminated water using ultraviolet radiation.
Many homes and small businesses, particularly in rural and outlying areas which are not connected to rural treatment systems rely on septic tank systems, aerobic treatment systems, small package plants or other types of local treatment apparatus (collectively “packaged plants”) for wastewater treatment. These packaged plants generally use one or more tanks containing the treatment apparatus connected to a field drip system or drain field for ultimate disposal of the treated waters. Treatment entails degradation of waste in the water by the biological processes of bacteria and microorganisms. This “treated wastewater” generally contains bacteria and other microorganisms.
The fluid quality produced by packaged plants is usually regulated by one or more governmental agencies, most of which require that the discharged wastewater be disinfected to reduce the potential hazards caused by the bacteria/microbes in the treated effluent. One common type of disinfection treatment is chemical treatment with a chlorine type compound. Another common treatment is radiation with ultraviolet light (UV). What is known in the radiation of water with UV within the range from about 150 nm through about 300 nm is effective in destroying microorganisms. See for example U.S. Pat. No. 5,019,256; U.S. Pat. No. 5,256,299; U.S. Pat. No. 5,422,487; or U.S. Pat. No. 5,624,573. Prior art UV treatment systems are shown, for example, in U.S. Pat. Nos. 6,296,775, 7,250,610, 7,279,092, as well as U.S. Publication 2006/0163168, all of which are incorporated herein by reference for all purposes.
As evidenced by the patents and the prior art UV systems noted above, most UV disinfectant systems rely on flow of treated wastewater past a UV bulb which is positioned in an envelope, sleeve or the like of a material which is UV transparent. Typically these prior art UV disinfectant systems employ a quartz tube in which the UV bulb is disposed. However, the problem with a quartz housing or for that matter a housing over the UV bulb made of any type of UV transparent material is that over time a film of scum, particulates or the like forms on the chamber or sleeve and reduces the amount of UV radiation passing through to the point where the treated wastewater is not effectively disinfected.
In addition to treated wastewater there also exists a problem in disinfecting contaminated water from other sources. In many areas of the world infrastructure which provides potable water for human use, e.g., consumption, baths, etc. is inadequate. For example, in many parts of the world while municipal water may be delivered to residential or commercial sites, the pumping systems do not produce sufficient water pressure to service all of the household needs of the numerous residences attached or connected to the municipal system. In many instances, it is common to place a holding tank on the elevated portion of the residence, e.g., the roof, pump the water into the holding tank, and then use the head pressure of the water at the elevated location to accommodate normal household needs such as showers, faucets, etc. Still another problem with municipal water in these somewhat underdeveloped locations is that the water may become contaminated due to inadequate chlorination, leaking pipes, etc. Accordingly, even though the water is from a municipal system, it is still contaminated and can cause serious illness. Lastly, since the water in these environments is in the holding tanks as described above and may be quiescent for undesirable periods of time, there is a chance for the growth of microorganisms, bacteria and the like which would again contaminate the water prior to use.
In a general aspect, the present invention provides a UV disinfection apparatus for contaminated water wherein the UV light assembly is not in contact with the contaminated water.
In yet another aspect, the present invention provides a UV disinfection system comprising a tank or vessel for holding contaminated water and UV disinfection apparatus for disinfecting the contaminated water wherein the UV light assembly is not in contact with the contaminated water.
In one aspect the present invention provides a UV disinfection apparatus for contaminated water wherein the UV light assembly is not in contact with the treated wastewater.
In another aspect the present invention provides a UV disinfection apparatus for contaminated water which avoids deposition of deposits on the UV bulb of a UV disinfectant apparatus.
In still another aspect the present invention provides a UV disinfection system having a tank for holding contaminated water and a UV disinfection apparatus for disinfecting the contaminated water wherein the UV light assembly is not in contact with the contaminated water.
In still a further aspect of the present invention there is provided a UV disinfection system comprising a tank for contaminated water and a UV disinfection apparatus which avoids deposition of deposits on the UV bulb of the UV disinfection apparatus.
In yet a further aspect of the present invention there is provided a system for disinfecting contaminated water, such as described above which is used in conjunction with an alternative energy source to supply electric power to operate the UV bulb as well as any pumps.
These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.
As used herein, the term “treated wastewater” generally refers to wastewater from a septic system which has been subjected to a pretreatment or settling tank to remove large solids and aerobic digestion to produce substantially clarified, treated wastewater. The term “contaminated water” refers to treated wastewater as well as water from other sources which is intended to be used as potable water or at the very least relatively bacteria and microorganism free water. Thus, in the description which follows, treated wastewater and contaminated water may be used inter-changeably.
Referring to
The UV disinfectant system 10 comprises a UV disinfectant apparatus shown generally as 24 comprising a housing shown generally as 26 having first and second end walls 28 and 30, respectively, a bottom wall 32 and first and second side walls (not shown). A removable cover 34 cooperates with housing 26 to form a chamber 28. Housing 26 has an inlet 36 located generally at first end wall 28 and an outlet 38 located generally at second end wall 30. As seen, inlet 36 is connected via a pipe 40 to a pump 42 disposed in tank or vessel 12 for pumping treated wastewater W into inlet 36 of housing 26. The bottom wall 32 of housing 26 forms a flow channel along which treated wastewater pumped via pump 42 flows toward the outlet 38 and via a down corner 40 back into tank 12.
An elongate UV bulb 42 extends between mounts 44 and 45 and first and second side walls 28 and 30, respectively. An electrical component box 46 is connected to a suitable source of power and houses necessary electronics, e.g., alarms, etc. for operating UV bulb 42. As seen, UV bulb 42 and the channel formed by bottom wall 32 are generally elongate and parallel to one another. UV bulb 42 is spaced above the level of treated wastewater W in chamber 28. It will be appreciated, that bulb 42 will be spaced above the level of the treated wastewater in housing 28, but sufficiently close to the level of treated wastewater in chamber 28 such that UV light from bulb 42 effectively irradiates the treated wastewater W flowing through housing 26 from inlet 36 to outlet 38. The spacing between UV bulb 42 and the level of treated wastewater W in chamber 28 will depend upon the size and strength of UV bulb 42. In operation, and with pump 42 activated, treated wastewater W is pumped out of tank 12 through housing 26 and returned to tank 12 via down corner 40. This constant recirculation of treated wastewater W through chamber 28 ensures the most effective UV irradiation of the treated wastewater W prior to it being discharged by gravity via riser 18 and outlet 16. In this regard it is known that in many UV disinfectant systems for treating wastewater, the wastewater generally makes a maximum of two passes past the UV bulb prior to being discharged. This is not always effective for the maximum kill rate of bacteria and microorganisms.
Since UV bulb 42 is spaced from the level of treated wastewater W in chamber 28, and unlike many prior art UV disinfectant systems, UV bulb 42 does not accumulate a film from scum, particulates or the like which are present in the treated wastewater W. Not only does this enhance the level of treatment but provides for more maintenance free operation. In the latter regard, many prior art UV disinfectant systems have the UV bulb in a substantially UV transparent envelope, sleeve or the like, the UV bulb being sealed from the treated wastewater by the sleeve. Because the sleeve is in direct contact with the treated wastewater W, it is prone to the build up of scum, particulates or the like which degrades the strength of the UV radiation reaching the treated wastewater. Accordingly, it is necessary to periodically remove the UV disinfectant system and clean the sleeve. Further, since even a quartz envelope, sleeve or the like can attenuate the UV radiation to some extent, by using the present invention either a weaker bulb can be employed or if a bulb typically used in the prior art UV disinfectant systems is employed, the treated wastewater W will receive greater UV irradiation.
Referring now to
Referring now to
Disposed in chamber 64 is a UV bulb 70, UV bulb 70 being connected by a socket 72 to end wall 58 and extending through an aperture 74 in end wall 56 into an electrical component box 76 containing electric power leads, alarms, etc. customarily used to operate UV bulb 70.
Optionally, although not necessary, there is a UV guard or splash plate 80 disposed between UV bulb 70 and the level of treated wastewater W in chamber 64, plate 80 resting on a peripheral ledge formed on the walls of housing 52. Splash plate or guard 80 serves the purpose of preventing any unexpected surges of treated wastewater W in chamber 64 from contacting UV bulb 70.
Referring now to
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Tube 102 has a slot 114 generally diametrically opposite the channel for treated wastewater formed in tube 102. Accordingly, in use, apparatus 100 would be oriented with slot 114 up and the bottom of tube 102 down. Overlying slot 114 is a cover 116, cover 116 being a segment of a plastic, e.g., PVC pipe which has an ID substantially equal to the OD of tube 102. Attached to cover 116 are a pair of spaced brackets 118 and 120 which carry sockets, only one of which (socket 120) is shown in
Referring now to
Tank 152 has a neck portion 158 with a removable cover 160 whereby the interior of vessel 152 can be accessed as necessary. A pair of L-shaped mounting brackets 162 and 164 are attached in a suitable manner to a cylindrical extension 164 of neck portion 158. Brackets 162 and 164 serve to hold a UV disinfecting apparatus shown generally as 166 and comprising a housing or body, generally rectangular in shape, 168 which has a bottom wall 170 forming a flow channel extending from a first end wall 172 of housing 168 to a second end wall 174 of housing 168. Housing 168 is provided with a removable cover 176. Attached to the underside of cover 176 are sockets 178 and 180 in which is received a UV bulb 182. Electric power lines 184 extend through an electronic component box 186 mounted on the top of cover 160. The air lift pump comprises a compressor or the like 190 which pumps air through a line 192 to a gas sparger 194 located between a tube 196 having an intake 198 and a gas sparger 194. Tube 196 has an L-shaped top 200 opening into the chamber 168A formed in housing 168. In operation, and while pump or compressor 190 is running, air is pumped through line 192 and sparger 194 and, as it bubbles upward through mouth 198 of tube 196, it lifts treated wastewater W, in a well-known manner, through outlet 200 into UV chamber 168A. The treated wastewater flowing through chamber 168A is irradiated by UV bulb 182 and exits housing 168 through a down corner 202 where it is returned to the treated wastewater W in vessel 152. Again, there is, so long as pump 190 is in operation, continuous UV irradiation of the treated wastewater W in vessel 152. In this regard, and with respect to the other embodiments discussed above, regardless of the pump system employed, the treated wastewater W can be passed through the UV treatment apparatus 166 as often as desired, i.e, pump 190 could be set to run continuously.
One of the many advantages of the UV disinfectant apparatus and system of the present invention, over and above its ability to ensure greater disinfection of treated wastewater is the ability to ensure that this enhanced disinfectant treatment occurs regardless of the load placed on the system. For example, in the typical residential environment, a toilet flush will send about 1.6 gallons of water to the septic system, e.g., an aerobic wastewater treatment system. In prior art systems where there is a maximum of about two passes of treated wastewater past the UV bulb prior to disposal, this relatively small amount of water from a toilet flush can be fairly effectively disinfected by the prior art systems. However, in cases where there is a large charge of wastewater, e.g., from an emptying bath tub, washing machine or the like, the rate of discharge of water through the prior art UV disinfecting systems is too great to allow ample irradiation. However, using the apparatus or system of the present invention wherein the treated wastewater can be passed multiple times, e.g., as long a pump system is designed to run, a greater kill rate of bacteria and microbes is achieved.
In the description above, reference is made to a pump, e.g., pump 42 for introducing treated wastewater from tank 12 into UV disinfecting apparatus 24. It will be understood that the term “pump system” as used herein refers not only to a submersible pump, of whatever type, but also to gas lift systems which can be used to introduce treated wastewater W from tank 12 into the UV disinfecting apparatus, whether the UV disinfecting apparatus is disposed interiorly of the tank or exteriorly thereof.
Referring now to
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Turning now to the embodiment shown in
It will be appreciated that UV disinfectant system 226 need not be disposed at an elevated position relative to a user accessible outlet, e.g., a shower, faucet, bath tub or the like. Indeed, much like the embodiment shown in
The term “alternative energy source” refers to an energy source which is not dependent on the burning of fossil fuel, solar power and wind power being prime examples. Further, as is well known, solar panels and smaller wind turbines can be installed near the UV disinfectant system of the present invention and be small enough to only supply to the electronic components of the UV disinfectant system, and/or on a slightly larger scale to the dwellings where the UV disinfectant system is located.
One of the features of the present invention is that because of recycling water past the UV bulb assembly, a smaller UV bulb can be employed minimizing the power needs of that component.
Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.
