Abstract:
Method and device for treating a liquid effluent, in which this effluent enters a vessel. An intermediate level of liquid in the vessel is detected; an influx of a dilution liquid into the vessel is instigated; a high level of liquid in the vessel is detected; the influx of dilution liquid is stopped and a discharge of the fluid is instigated; a low level of liquid in the vessel is detected; the discharge of the liquid is stopped; and, while it is being discharged, the discharged liquid is exposed to light radiation in at least one treatment channel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of the treatment of effluent with a view to discharging depollutant or decontaminated water into, for example, the waste water networks. 
     2. Description of the Relevant Art 
     Treatment of effluent is encountered when treating hospital waste from, in particular, human or animal biology analysis equipment or waste from, in particular, food product analysis equipment, the purpose being to destroy all kinds of pollutants such as bacteria, viruses, molds or fungi. 
     Patent FR-A-2 840 894 proposes to treat liquid effluent firstly using a filtration cartridge and secondly by exposing this effluent to irradiation with ultraviolet light, with the liquid effluent simply being stored in an intermediate tank from which the liquid effluent is discharged using a pump. 
     SUMMARY OF THE INVENTION 
     Embodiments herein describe an improved and more autonomous treatment of liquid effluent. 
     In one embodiment a method for treating a liquid effluent, in which this effluent enters a vessel, includes:
         detecting an intermediate level of liquid in the vessel;   upon detection of the intermediate level, instigating an influx of a dilution liquid into the vessel;   detecting a high level of liquid in the vessel;   upon detection of the high level, stopping the influx of dilution liquid and instigating a discharge of the fluid;   detecting a low level of liquid in the vessel;   upon or following detection of the low level, stopping the discharge of the liquid;   and, while it is being discharged, exposing the discharged liquid to light radiation in at least one treatment channel.       

     According to an embodiment, the method may include:
         discharging, via the treatment channel, any liquid that is at an overflow level above the high level and exposing the overflow liquid to light radiation.       

     According to an embodiment, the method may include:
         instigating a secondary influx of dilution liquid into the vessel from a low level;   detecting an intermediate low level of liquid in the vessel;   upon detection of the intermediate low level, stopping the secondary influx of dilution liquid.       

     According to an embodiment, the stopping of the discharge of the liquid may be offset by a set length of time in relation to the detection of the low level. 
     In another embodiment, a device for treating a liquid effluent includes a vessel; an influx pipe carrying the liquid effluent that is to be treated; an influx pipe carrying a dilution liquid under pressure and fitted with an electrically operated valve; a probe sensing a high level of liquid in the vessel; a probe sensing an intermediate level of liquid in the vessel; a probe sensing a low level of liquid in the vessel; a discharge pipe on which there are installed, from the upstream direction downstream, a flow regulating means and a means of exposing the discharged fluid to light radiation; an electronic circuit for controlling the electrically operated valve and the flow regulating means and subject to the signals from the level probes. 
     In an embodiment, the flow regulating means may include a pump and an electrically operated valve. 
     In an embodiment, the treatment device may include a probe for sensing an intermediate low level. 
     In an embodiment, the treatment device may include an overflow pipe the inlet of which is situated above the high level and which is connected directly to the inlet of the exposure means. 
     In an embodiment, the vessel may be fitted with a nonreturn valve allowing air to enter. 
     In an embodiment, the probes may be fixed to an upper wall of the vessel and include stems which run vertically. 
     In an embodiment, the exposure means may include at least two coaxial cylindrical tubes defining a treatment channel in which the discharged liquid can flow approximately longitudinally and at least one lamp emitting light radiation which runs longitudinally along the inner tube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be better understood from studying a device for treating effluent and the operation thereof, which are described by way of nonlimiting example and illustrated by the drawing in which: 
         FIG. 1  depicts a view in longitudinal section on I-I of  FIG. 2 , of a treatment device; 
         FIG. 2  depicts a view in cross section on II-II of the treatment device of  FIG. 1 ; 
         FIG. 3  depicts a view in horizontal section on of the treatment device of  FIG. 1 , under the vessel; and 
         FIG. 4  depicts an associated electronic control circuit. 
     
    
    
     While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The liquid effluent treatment device  1  depicted in  FIGS. 1 to 3  includes a parallelepipedal metal vessel  2  which has longitudinal walls  3  and  4 , transverse walls  5  and  6 , a lower wall or bottom  7  and an upper wall  8 . 
     Positioned beneath the vessel  2 , the treatment device  1  includes a treatment means  9  which includes two longitudinal treatment members  10   a  and  10   b , on each side of the lower wall  7 , and mounted in series. 
     The treatment members respectively include a metal outer tube  11  and a transparent coaxial tube  12  made of quartz, between them defining an annular exposure channel  13  and a longitudinal lamp  14  emitting ultraviolet light radiation, running cantilever fashion into the inner tube  12  and supported by an end plug  15  from which a power supply lead  16  emerges. 
     One of the lateral ends of the exposure member  10   a  is connected to the bottom  7  of the vessel  2  by a pipe  17  such that its annular exposure channel  13  is in communication with the vessel  2 , more or less at the middle thereof. 
     The corresponding end of the treatment member  10   b  is equipped with a lateral discharge pipe  18  linking its annular exposure channel  13  by natural flow to a waste water network for example. 
     The other ends of the treatment members  10   a  and  10   b  are connected laterally, by a transverse pipe  19 , placing their annular exposure channels  13  in communication and in series. 
     Underneath the vessel  2 , the treatment device  1  includes an influx pipe  20  carrying a dilution liquid into the vessel  2 , through the lower wall  7  thereof, this pipe  20  being, for example, connected to a pressurized domestic water supply network. 
     The treatment device  1  also includes a vertical overflow pipe  21  which runs vertically through the vessel  2 , which passes through the bottom  7  thereof and which is connected to the end of the treatment member  10   a  that corresponds to the end at which the pipe  17  is connected. The upper end of the overflow pipe  21  is located in the upper part of the vessel  2 . 
     The wall  3  of the vessel  2  is equipped with an influx pipe  22  carrying an effluent that is to be treated. 
     Provided on the pipe  17  are an electrically operated valve  23  and a pump  24 , from which electrical connection leads  25  and  26  emerge. 
     Provided on the pipe  20  is an electrically operated valve  27  from which an electrical connection lead  28  emerges. 
     The treatment device  1  includes four level sensing probes  29 ,  30 ,  31  and  32  which extend down into the vessel  2  from the upper wall  8  thereof and which respectively have stems  29   a ,  30   a ,  31   a  and  32   a  and washers  29   b ,  30   b ,  31   b  and  32   b  fixed to the exterior face of the upper wall  8  removably, for example using threaded fasteners, the probes being equipped with electrical connection leads  33 ,  34 ,  35  and  36 . 
     The lower end of the stem  29   a  of the probe  29  defines a low level  42  in the vessel  2 . 
     The lower end of the stem  30   a  of the probe  30  defines an intermediate low level  38  in the vessel  2 . 
     The lower end of the stem  31   a  of the probe  31  defines an intermediate level  39  in the vessel  2 . 
     The lower end of the stem  32   a  of the probe  32  defines a high level  40  in the vessel  2 , which level is located slightly below an overflow level  41  defined by the upper end of the overflow pipe  21 . 
     The effluent influx pipe  22  is positioned in such a way as to open into the vessel  2  at a level higher than the level of the overflow  41 . 
     As shown by  FIG. 4 , the treatment device  1  also includes an electronic circuit  42  which is connected to the level probes  29 ,  30 ,  31  and  32  by the electrical connection leads  33 ,  34 ,  35  and  36  and which is connected to the electrically operated valves  23  and  27  by the electrical connection leads  25  and  28  and to the pump  24  by the electrical connection wire  26 . 
     Moreover, the lamps  14  are connected to the electronic circuit  42  so that they can be powered with electricity. 
     The electronic circuit  42  is programmed in such a way as to operate the treatment device  1  as follows. 
     It is assumed that the electronic circuit  42  is in operation and that the lamps  14  are illuminated. 
     On start up, the electronic circuit  42  instigates the opening of the electrically operated valve  27  so as to carry an influx of dilution liquid into the vessel  2 . 
     When the level of liquid in the vessel  2  reaches the intermediate low level  38 , the electronic circuit  42  instigates the closing of the electrically operated valve  27 . 
     The effluent carried into the vessel  2  by the influx pipe  22  fills this vessel little by little and becomes mixed in with the dilution liquid. 
     When the level of liquid in the vessel  2  reaches the intermediate level  39 , the probe  26  detects this level and sends a corresponding signal to the electronic circuit  42 . The latter then orders the opening of the electrically operated valve  27  so as to introduce dilution liquid into the vessel  2 . 
     When the liquid contained in the vessel  2  reaches the high level  40 , the probe  27  detects this level and transmits a corresponding signal to the electronic circuit  42  which instigates closure of the electrically operated valve  27  followed by opening the electrically operated valve  23  and the starting of the pump  24 . 
     The liquid contained in the vessel  2  is then discharged from the vessel  2  via the pipe  17 , the channel  13  of the member  10   a , the connecting pipe  19 , the channel  13  of the member  10   b  and finally the end pipe  18 . 
     When the level of liquid in the vessel  2  reaches the low level  37 , the electronic circuit  42  instigates the stopping of the pump  24  and the closing of the electrically operated valve  23 , with a temporal offset of a duration such that the level of liquid in the vessel  2  reaches a bottom low level  43  near the lower wall  7  or is completely discharged. 
     The electronic circuit  42  then instigates the opening of the electrically operated valve  27  so as to bring about a secondary influx of dilution liquid into the vessel  2 . 
     When the level of the dilution liquid reaches the intermediate low level  38 , the electronic circuit  42  instigates the closing of the electrically operated valve  27 . 
     When effluent is carried into the vessel  2 , the level of liquid contained in this vessel rises and the cycle that has just been described recommences starting from the level  38 . 
     When the liquid discharged from the vessel  2  passes through the exposure channels  13  of the treatment members  10   a  and  10   b , it undergoes a decontamination treatment through being exposed to the ultraviolet light radiation from the lamps  14 . 
     In an alternative form, the lamps  14  may be permanently illuminated. 
     In another, more economical, alternative form, upon detection of the intermediate level  39 , the electronic circuit  42  instigates the illuminating of the lamps  14  and, when the low level  43  is reached, the electronic circuit  42  instigates the switching-off of the lamps  14 . Of course, the time spent conveying the dilution fluid that raises the level from the intermediate level  39  to the high level  40  must be long enough for the lamps  14  to warm up. To ensure that, the length of time for which the dilution fluid is supplied may be set by setting the electrically operated valve  27  or by providing a flow limiter on the influx pipe  20 . 
     Moreover, the treatment device may include a safety probe  44  including a vertical stem  44   a  and a washer  44   b  for mounting on the wall  8  and defining a safety level  45  situated between the high level  40  and the overflow level  41 , this safety probe  44  being connected to the electronic circuit  42  by a line  46 . 
     When the fluid in the vessel  2  reaches the safety level, the electronic circuit  42  may trigger an audible and/or luminous alarm and force the closing of the electrically operated valve  27 . 
     The treatment device just described has the following advantages. 
     The influx of dilution liquid between the levels  39  and  40  allows the effluent to be diluted and therefore allows more effective treatment thereof via the members  10   a  and  10   b.    
     The pump  24  is able to regulate the rate at which the liquid is discharged and thus ensure a controlled length of exposure in the members  10   a  and  10   b.    
     The electronic circuit  42  may be programmed to regulate actuation of the pump  24  to ensure different rates of flow suited to the particular effluent that is to be treated. 
     Because of the way in which they are mounted, the probes  29  to  32  can be changed, independently of one another, so as to define different associated levels, for example according to the particular effluent that is to be treated. 
     In particular, the probe  31  can be interchanged to adapt the intermediate level to suit the particular effluent to be treated. As was seen above, it is this probe  31  that determines the dilution ratio, according to the relative positions of the intermediate level  39 , of the high level  40  and of the low level  43 . 
     Specifically, the dilution ratio defined by the probes  39 ,  40  and  43  and the discharge flow rate defined by the pump  24  need to be adapted to ensure that the treatment of the effluent to be treated is as effective as possible and destroys the pollutants. It may be seen that, depending on the effluent that is to be treated, the dilution ratio, defined as being a ratio between the volume of water added between the levels  39  and  40  and the volume of effluent poured into the vessel between the levels  38  and  39  may range between 0 and 50, more specifically between 0.2 and 30. 
     If the level of liquid in the vessel  2  exceeds the high level  40  and reaches the upper level  41 , the overflow is discharged through the overflow pipe  21  directly through the members  10   a  and  10   b  without passing through the pipe  17  governed by the electrically operated valve  23  and the pump  24 , undergoing decontamination treatment through these members  10   a  and  10   b  under the effect of the lamps  14 . 
     The fact that there is a bottom low level  38  and influxes of dilution liquid more or less ensures cleaning of the ends of the probes. 
     Furthermore, the electronic circuit  42  may be programmed also to carry out treatment cycles that are imposed at predetermined, possibly adjustable times, for example every three or four hours, in case the amount of effluent admitted to the vessel  2  should become scarce. Should this happen, the electronic circuit  42  would instigate the influx of the dilution fluid up to the high level  40  even if the level in the vessel was below the intermediate level  39 , and would then instigate discharge, as described earlier. 
     An imposed treatment cycle may also be scheduled in the event of a loss of power, as soon as this power is reinstated. 
     As shown by  FIG. 1 , the wall  8  of the vessel  2  may have an inspection hatch  47  fitted with a nonreturn valve  48  to allow air to enter the vessel  2  while preventing gases contained in the vessel from being discharged to the outside. 
     As  FIG. 2  shows, the wall  3  of the vessel  2  may be provided with a horizontal external support  49  to accept a cartridge  50  for chemical treatment and/or filtering of the effluent, before the effluent is carried into the vessel  2 , this cartridge being positioned above the level of the inlet  22  to prevent backflushing with effluent. 
     Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.