Abstract:
A method of remediating water contaminated by dissolved gases and liquids and suspended particles wherein the contaminated water is collected into a closed container without filling the container and heated to a temperature below the boiling point of water. Negative pressure is then drawn on the closed container without causing the water in the container to boil, whereby the dissolved gases and liquids in the contaminated water, having a boiling point lower than water, will evaporate out of the water into the head space above the water in the container. Finally, atmospheric air and/or oxygen are allowed into the container to push the vapors out of the head space of the container.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     One of the major problems facing future generations is polluted water. Increasing world population and rapid industrial growth combine to cause tremendous contamination problems in the world&#39;s rivers, lakes and oceans with an infinite variety of chemical and biological substances. Purification systems that can quickly and economically provide abundant amounts of fresh water from sewage or contaminated water will be and are in great demand. 
     2. Description of Related Art 
     A vacuum distillation system should be able to purify any contaminated liquid, such as water from a polluted river. While the prior art systems achieve this to a limited degree, there are significant commercial drawbacks. 
     To increase the efficiency of a distillation process, use of a vacuum has been tried. For example, U.S. Pat. No. 5,538,598 describes a distillation purifying system which creates a vacuum pressure that is transmitted throughout the system. 
     U.S. Pat. No. 5,441,606 discusses a distillation purifying system that uses an open tube bundle heat exchanger that heats the liquid (in this case, seawater) to facilitate vigorous evaporation resulting in the separation of salt and other contaminants from the water vapor. 
     Many of these inventions are unduly complex, uneconomical or not as efficient as the trade requires. The present invention overcomes these drawbacks to provide an advance to the art. 
     SUMMARY OF THE INVENTION 
     This invention relates to liquid purification systems that provide for inexpensive sterilization of water contaminated by liquid and/or solid matter, such as sewage or chemical waste. The invention is particularly effective in removing contaminants, such as, methyl tertiary butyl ethers (MTBE), hydrocarbons, alcohols, ethers, and any liquid with a greater volatility than that of water. The present invention enhances the removal of the contaminants by collecting the contaminated water into a closed container without filling it, heating the water in the container to a temperature below the boiling point of water and drawing a negative pressure on the closed container without causing the water in the container to boil. The dissolved gases and liquids in the contaminated water, having a boiling point lower than water, will evaporate out of the water into the head space above the water in the container. Further, by allowing atmospheric air into the container, vapors are pushed out of the head space of the container. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further aspects of the invention will be apparent when the description and claims set forth below are considered in conjunction with the accompanying drawings. 
     FIG. 1 is a fragmentary elevational view of an improved vacuum distillation system constructed in accordance with the present invention; and 
     FIG. 2 is a diagram of a distillation process. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes, contemplated by the inventor, for carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an easily implemented liquid purifying distillation process. 
     As shown in FIG. 1, pump  32  transports contaminated water from a source through a conduit  14 , into a container  2  via a valve  6  until it is filled to a desired level as regulated by a level control  8 . The contaminated water, heated by a heater  10  and monitored by a thermostat  12 , maintains a temperature below the boiling point of water. Contaminants dissolve in water at temperatures below their own boiling points and the boiling point of water. These contaminants may be any one or more of MTBE, glycerine, ethyl and methyl alcohol, and sulfuric, acetic, nitric acids and the like. As the vapor pressure of the contaminants rise with the temperature of the water, the tendency for the contaminants to escape into a vapor state increases. A vacuum pump  18  creates a partial vacuum in the ullage of container  2  and a condensate container  22 . The vacuum pump  18  attaches to the condensate container  22  via a conduit  20 . The level control  38  determines the level of the contaminants in the condensate container  22 . When the level of contaminants exceed the desired amount, a valve  24  opens and a pump  40  activates in order to remove contaminants. The contaminants may be removed manually as well. The amount of vacuum pressure and the temperature of the water are kept at a level so that the water does not boil. This temperature-pressure combination will ensure that contaminants in the water, having a boiling point lower than that of water, are evaporated, thus separating and permitting their extraction from the water. As these contaminants evaporate, their vapor fills the ullage space in container  2  until the ullage becomes saturated. Evaporation of the contaminants stop when the vapors and the liquid reach a state of equilibrium. 
     Since evaporation ceases as the ullage space becomes saturated, the process allows for the removal and replacement of the saturated vapors in the ullage with air, thus allowing evaporation to continue. This sequence is continuous. The rate of exchange of the ullage space may be determined by conducting tests to determine the time required to saturate the ullage space. The time required to process a “batch” in container  2  may be determined by testing and analyzing samples of the contaminated water. 
     If valve  4 , which is open to the atmosphere, is opened, a stream of air is forced into container  2  through an inlet pipe  30  because of the partial vacuum generated by the vacuum pump  18 . The air stream displaces the saturated vapor in the ullage, and transports it to the condensate container  22  through conduit  16 , where the vapors are condensed and collected as contaminants. After a predetermined time, valve  4  may be closed and the evaporation of contaminants is allowed to continue, saturating the ullage space again. The air stream may be introduced in a specific sequence of allowing saturation of the ullage space, and thus removal of the saturated vapors, this sequence being repeated throughout the entire remediation process. Unexpectedly good results have been obtained also by simply allowing the air stream to be continuous and uninterrupted. 
     In an alternate embodiment, the removal of contaminants in the water is enhanced introducing air, in the form of bubbles, and oxygen, in the form of hydrogen peroxide or ozone, into the contaminated water. The bubbles, after coming into contact with the contaminants, adsorb the contaminants with other adsorbed contaminants and rise to the surface of the water. When the air bubbles reach the surface of the water, they release the adsorbed contaminants. The combination of the presence of oxygen in the form of hydrogen peroxide and/or ozone and the higher temperature of the water increases the oxidizing process of MTBE, hydrocarbons, alcohols and ethers. Ozone and/or hydrogen peroxide is introduced into the container  2 . 
     When the contaminated water in processing tank  2  has been remediated to a desired level, some of the water (the desired batch size) in container  2  is removed through an outlet conduit  26  and discharged to a desired location by a pump  34 . Container  2  is then again filled with contaminated water from a contaminated source through conduit  14  via pump  32 , and the process is repeated. The contaminated exhaust of vacuum pump  18  must be controlled, remediated and released to the atmosphere as required by local environmental regulations. This can be done in a manner well known in the trade. 
     As shown in FIG. 2, a distillation process commences with a functional box, step  48 , that closes valves  4 ,  6 ,  24  and  28 . Decisional box, step  50 , requires the checking of level switch  8 . If check level switch  8  indicates that the level is high, step  50  will skip to step  56  where valve  6  closes and pump  32  stops. If check level switch  8  shows that the level is low, step  50  advances to functional box, step  52  where valve  6  is opened and pump  32  starts. Step  52  proceeds to decisional box, step  54  which continues to functional box, step  56  if check level switch  8  confirms that the level is high. Until check level switch  8  indicates that the level is high, step  54  will result in a loop. Step  56  closes valve  6  and stops pump  32  and proceeds to decisional box, step  58  which checks thermostat  12 . If the temperature is less than the set temperature, step  58  advances to functional box, step  60  which turns a heater  10  on. Step  60  proceeds to functional box, step  62  which starts vacuum pump  18 . If the temperature is above the set temperature, step  58  progresses to step  62 . Step  62  advances to functional box, step  64  which closes valve  36 . Step  64  continues to functional box, step  66  which starts air stream cycling sequence time. Step  66  proceeds to functional box, step  68  that opens and closes valve  4  as set on sequence timers. Step  68  advances to functional box, step  70  which starts a batch timer. Upon completion, decisional box, step  72  checks batch timing. If the time is less than the set batch time, a loop will result until the time is greater than the set batch time. When the time is greater than the set batch time, step  72  advances to functional box, step  74 , which opens valves  28  and  36  and starts pump  34 . Step  74  proceeds to decisional box, step  76  which checks level control  38 . If level control  38  indicates that the level is high, a loop will result causing functional box, step  77  to open valve  24  and start pump  40  until level control  38  confirms that the level is low, which results in the closing of valve  24  and pump  40  to stop (shown in functional box, step  78 ). Step  78  progresses to decisional box, step  80  which checks level control  8 . When the level control indicates that the level is high, a loop will result until level control  8  shows the level is low. If level control  8  confirms that the level is low, step  80  advances to functional box, step  82  which closes valve  28  and stops pump  34 . Step  82  proceeds to functional box, step  84  that opens valve  6  and starts pump  32 . Step  84  progresses to decisional box, step  86  which checks level control  8 . When check level control  8  indicates that the level is low, a loop results until check level control  8  shows that the level is high. When the level is high, step  86  advances to functional box, step  88  which closes valve  6  and stops pump  32 . Step  88  skips to step  58  to complete the distillation process loop. 
     Having illustrated and described a preferred embodiment as well as variants of this invention, it will be obvious to those skilled in the art that further changes and modifications may become apparent. Such changes and modifications are to be considered within the scope and essence of this invention. 
     The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. 
     Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.