Background of the Invention There are known devices for water treatment based on the use of plasma of an electric dis- charge the effect of which causes production of ions Q~, O2 O3 OH H2O, peroxide H2O2 and su- per-oxide H2O3 in an aqueous medium. The said reagents interact with matters contained in sew- age, and have a destructive effect on microorganisms.

There is a known device for water treatment, based on the use of an electrical corona d charge (JP, PN: 03181393, JP), which comprises a reaction chamber with two flat electrodes in- stalled horizontally in a case thereof so as to face each other, and connected to a source of high voltage. The device is provided with a means for feeding treated water into the reaction chamber.

The electric discharge plasma is produced between two said electrodes when a high voltage of at least 300 V is supplied..

There is a known device for water treatment based on the use of electric filamentary dis- charges (DE 4440813) which comprises a reaction chamber, two electrically isolated from each other electrodes, one of which, that belongs to a gaseous atmosphere, is made as a plate, is pro- vided with a dielectric and a cooling system, and is connected to a source of high voltage (8-12 kV) with a frequency of 200 kHz, and the other one, that ts covered by fluid in the course of the process, is grounded and presents the case. The device is provided with a means for feeding a treated fluid into the reaction chamber.

However this device also eootemplates operation. with. high voltages, and that is unsafe.

The closest prior art of the invention is a device intended for accomplishment of a method of sewage treatment by an electrical glow discharge produced above a thin sheet of fluid at a con= stant voltage of 0. 5-2 kV and an operating current strength of 50-100 mA under vacuum condi- tions and while a specific temperature is maintained (RU, 2043969).

The said device (RU, 2043969) comprises a reaction chamber with at least two annular elec- trodes, arranged in the case thereof coaxially (in alignment), one of which is an internal electrode in relation to the other, external. There is a clearance provided between the said electrodes for

Row of a treated fluid, and for an electrical glow discharge, produced between the said electrodes, one of which covered with the treated fluid in the course of the device operation. The device also comprises a means for applying an electric potential. to the said electrode,s which. incorporates a source of an operating constant voltage, electrically connected with the said electrodes, a cooling jacket, placed on the outer side of the said reaction chamber, a means for feeding the treated fluid into the said reaction chamber, and a means of vacuum development inside the said reaction chamber.

Is has been established that the basic operating factor affecting the efficiency of water treatment is the amount of applied energy per unit of a treated fluid per unit of the time of treat- ment. Therefore, to increase the process efficiency, it is necessary to increase the strength of the operating current of the glow discharge and to carry out the process of water treatment with the help of the non-self-mai glow discharge. However, no known device allows. to use a cur- rent, having a strength in excess of 0.1 A, since it causes a strong heat-up of electrodes, formation of an arc discharge and evaporation of the treated fluid.

It is an object of the invention to provide a device, allowing to carry out sewage treatment in a medium of a non-self-maintained glow discharge.

Another object of the invention is to provide, with the aid of additional ionization (excita- tion) discharge, applied to the same pairs the the unlike electrodes conditions for ionization and support of the operation discharge.

One more obJect of the invention is to provide conditions for contol and regulation d the value of strength of impulse operating current, it's clock frequency and duty cycle in the medium of operating glow discharge, as well as to regulate value of strength of the impulse current, clock frequency and impulse duration in the medium of additional ionization discharge.

Summary of the Invention These objects are accomplished by the provision of a Içnown-deliice for treatment ai dga contamination of sewage in a medium of an electrical glow discharge comprising a reaction chamber at least two annular electrodes (internal and external) arranged coaxially with a-clear- ance for initiation of the said glow discharge, a means for applying an electric potential to the said electrodes, which incorporates a source of an operating voltage, electrically connected with the said electrodes, a cooling jacket placed on the outer side of the said reaction chamber, a means for feeding the said water into the said reaction chamber, and-a means of vacuum development inside the said reaction chamber, according to the invention, is provided with a cooling system of inter- nal electrodes, whereas an external electrode presents a case of the said chamber, and the means

for applying an electric potential to the said electrodes comprises sources of an operating impulse voltage and ionization (excitant) impulse voltage having a split-type connection with each of the said electrodes with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage The internal electrodes therewith are made with through holes, increasing a cooling area, which are connected with the said cooling system of the internal electrodes.

The internal electrodes cooling system is made as a tube, passing through the said elec- trodes, or as two, arranged in alignment tubes, passing through the said electrodes The clearance between the internal and external electrodes is 4=20 mm.

It is preferred that there are at least two internal electrodes, electrically isolated from each other.

The number of the internal electrodes is determined by the degree of contamination and volume of water, subject to treatment and/or decontamination per unit of time.

The provision is further made for magnets, installed on the outside of the said reaction chamber opposite the internal electrodes, with the provision for the removal thereof.

The magnets. therewith-are made of an annular shape.

The said reaction chamber is made of a cylindrical shape, for example, with the inside di- ameter of 25-250 mm and the height of 150-1500 mm, and is installed upright.

The said means for water delivery into the said reaction chamber is made with a provision for feeding, the said. medium onto. the internal surface of the external electrode in a turbulent flow, for example, as injectors having a tangential arrangement along a circle at an angle, preferably of 5-30° relative to the horizontal plane of the reactor.

The said sources of an operating impulse voltage and ionization impulse voltage have a split-type connection with each of the said electrodes, with the provision made for simultaneous supply thereto of the operating impulse voltage and ionization impulse voltage.

The internal electrodes are made of a metal, having a thermal conductivity factor of at least 100 W/(mK).

The outside surface of the internal electrodes is covered with a refractory metal, for example, tungsten or nickel-chromium alloy, The magnets are made so, that to provide a magnetic field with a value of magnetic induction of at least 0. 01 T (Tesla).

Brief Description of the Dpawmgs The essence of the invention will now be illustrated by graphics, where Fig. 1 is a block diagram of the device for sewage treatment and decontamination ; Fig, 2 is a longitudinal sectional view of a reaction chamber, where proper treatment and/or decontamination of water occur ; Fig. 3 is a cross-sectional view of the said reaction chamber, taken along line A-A.

Detailed Description of the Invention A device for sewage treatment and decontamination (Fig. 1) comprises a reactor 1, where a non-self-maintained glow discharge is produced and proper treatment and decontamination of sewage occur, a reservoir 2 for accumulation of sewage, before it is fed to the reactor 1, means providing for vacuum development in the reactor 1 and comprising a water-jet ejector 3 and a pump 4 that keeps the ejector 3 operating, a unit 5 for monitoring selected vacuum parameters in the reactor 1, a unit 6 for feeding fluid from the reservoir 2 into the reactor 1, units 7 and 8 for cooling the reactor 1, a reservoir 9 for collection of a purified fluid connected with the reactor 1, a pump 10 for pumping out the purified fluid from the reservoir 9, a filter 11 connected with the pump LO,. an electrical. power supply source 13-for energizing the reactor 1 and a means 13 pro- viding control over and monitoring of operation of the entire device.

The means 13 can be made, for example, as a processor.

A device as claimed in the invention can be made with one reactor 1 or more.

The reservoir 2 is equipped with a float valuve 1,4 providing a required level of the treated fluid.

The unit 5 for monitoring the selected vacuum parameters in the reactor 1, comprises a pres- sure transmitter 15 connected with the reactor 1, and a controller 16 of the pressure transmitter 15, and a solenoid-operated valve 17.

A pipeline 18 connects the ejector 3 to the reactor 1 and the reservoir 9 for vacuum devel- opment therein.

The unit 6 for feeding fluid from the reservoir 2 into the reactor 1 comprises a coarse Biter 19, a solenoid-operated valve 20 and a pipeline 21 connecting the reservoir 2 with the reactor 1, The unit 7 for cooling the reactor 1 is essentially a jacket, placed around the reactor 1 con- nected with the means (not specified on the drawing) for pumping a liquid coolant through the jacket.

The unit 8 for cooling. the reactor I comprises heat exchanger 22, an oil pump 23 and means for cooling oil in the heat exchanger 22.

The means for cooling oil in the cooler 22 can be provided by cooled water.

The pump 4 is connected to the ejector 3 by a pipeline 24.

The pumps 4 and 10, the power supply source 12, the controller 16 of the pressure transmit- ter 15, and the solenoid-operated valve 17, the solenoid-operated valve 20, the oil pump ? 3 are connected with the contfel-means 13 (the connection is not specified on the drawing).

TheThe reactor 1 (Fig. 2) is made as a chamber and comprises a case 25 being an electrode that is covered, during the operation, with the treated fluid. There are electrodes 26 installed in the case 25 of the reciprocal, relative to the electrode 25, potential, which are in a gaseous atmos- phere during operation of the reactor l. and a. system-27 for. cooling the electrodes 26. The reactor 1 is equipped with the means for delivering and forming a stream of the treated fluid made, for example, as injectors 28. Magnets 29 are installed on the outer side of the case 25 opposite the electrodes 26 with the provision for the removal thereof The electrodes 26 (Fig. 3) are made of annular shape with through holes 30 connected with the cooling system 27, made as two coaxial pipes, connected with the unit 8 (Fig. 1) for cooling the reactor 1 by the feed and lateral pipelines (not specified on the drawing).

The magnets 29 are both the the permanent magnets, and electromagnets, made of annular shape and installed with the provision for the removal thereof The jet injectors 28 have mainly a tangential arrangement along a circle at an angle of 5- 30° (at an angle of 15° in this device) relative to the horizontal plane of the reactor 1, and are con- nected by the pipeline 2. to to the reservoir 2.

The case 25 being an electrode and the electrodes 26 are electrically connected to the power supply source 12, The electric power supply source 12 comprises sources of the operating impulse voltage and ionization impulse voltage, each being individually connected to the electrodes 25 and 26.

The case 25, being an electrode, of the reactor 1 is made in a form of a hollow cylinder (tube) with the inside diameter from. 25 up to 250 mm and the height from 150 up to 1500 mm, The case 25 is made of a material, having no catalytic effect on the treated fluid such as stainless steel, and is installed spatially upright. In a particular embodiment, the reactor 1 is made with the inside diameter of 80 mm and the height of 900 mm.

The electrode 26 can. comprise one or more electrode members. To treat and decontaminate large volumes of fluids, containing a heavy waste load, it is necessary to have a large surface area of the active electrode. Therefore, the electrode 26 can be a cluster electrode. The number of the

members thereof is determined by the time required ior the treated Suid to stay in the reaction zone in order the selected efficiency of the process can be achieved.

In a particular embodiment of the invention the electrode 26 consists of 6 members.

A separate conductor 31 connects every electrode 26 to the electric power supply source 12.

There is a galvanic isolation between the electrodes 26 and the case 25 (being an electrode) of the reactor 1 and between the electrodes proper provided by dielectric hollow inserts 33 made of ce- ramies.

The electrodes 26 are installed, so that they have a clearance relative to the electrode 25, in a particular embodiment of 8mm.

The electrodes 26 are made of a metal, aluminum ; having a thermal conductivity of at least 100 00 W/(mK). The outside surface of the electrodes 26 is covered with a refractory metal for ex- ample, tungsten.

The magnets 29 are made so that to provide a magnetic field with a value of magnetic in- . duction of. at least 0. 02 T.

The device according ta t-invention functions. in the following manner : In response to control signals of the control means 13 (processor) a reduced atmospheric pressure from 30 up to 29* from 4*103 to 3. 3*104 Pa), ie. vacuum, is developed in the case 25 of the reactor 1 with the-aM of the water-jet ejector 3 through the pipeline 18. In this case, used as an. operating fluid, which. develops depression, is sewage subject to treatment, which is fed to the ejector 3 with the aid of the pump 4. While passing through the ejector 3, the water is oxygen- ated from air, since the ejector provides for vigorous mixing of the water and air. The selected vacuum parameters are monitored with the aid of the pressure transmitter 15, the controller 16 of the pressure transmitter 15, and the solenoid-operated valve 17. In so doing, the controller 16 of the pressure transmitter 15 digitizes data received from the pressure transmitter 15 and feeds this information to the processor 13.

Simultaneously, the liquid coolant is pumped through the unit 7, i. e. the cooling jacket of the reactor 1, and the cooling transformer oil is pumped through the unit 8 connected with the cooling system 27, thus ensuring maintenance of the required temperature of the electrodes 25 and 26, and the treated water below the natural boiling point.

After the selected vacuum value has been attained in the reactor 1 and the receiving reser- voir 9, the solenoid-operated valve 20 opens in response to a control signal of the processor 13, <BR> <BR> <BR> and sewage is fed for treatment in a turbulent flow 0. 3-5 mm in depth from the inlet reservoir 2 through the pipeline 21 and the injectors 28 into the reactor 1. The filter 19 therewith allows to

prevent suspension particles in the treated fluid from getting on the injectors 28. After that, the operating impulse voltage of no more than 500 V with the clock frequency of 0. 1-100 kHz, and duty cycle no less than 1. 3 and the ionization impulse voltage featuring the value of 2-10 kV, the current strength of 3 0-5 000). tA. and the pulse duration of 0.01-20 µs, are simultaneously applied to the electrodes vs and 26, thus producing a non-self-maintained glow discharge with an adjust- able operating current of 0. 1-20 A on each pair of the unlike electrodes, the operating voltage of no more than 500 V, the clock frequency of Q. 1-100 kHz and the duty cycle of at least 1.3.

Such conditions of producing the glow discharge allow to implement the process at an aver- age in time value of impulse current strength of up to 20 A and a voltage of no more than 500 V with the provision for adjustment of the clock frequency and duty cycle of the current impulse.

The fluid is treated by the non-self-maintained glow discharge in presence or in absence of a magnetic field.

The fluid treated by the non-self-maintained glow discharge, drains into the reservoir 9, from where it is delivered to the filter 11 by the pump 10 for extraction of insoluble sludge that coagulates, during the fluid treatment.

The device according to the invention, was used for sewage treatment and decontamination according to the allowing embodiments : Embodiment 1.

Subject to treatment was sewage containing 22 mg/l of ions Fe2+ ; 55. 5 mg/l of Cr6+ ; 14. 3 mg/1 of Ni2+ ; 8.0 mg/1 of Mo4+, 6.0 mg/l of Co2+, having pH=6. 5.

The efficiency of treatment of this water was examined in-relation-to the depth of the treated fluid sheet, and the average in time value of the impulse operating current of a non-self-maintained glowdischarge.

The sewage sample was treated by plasma of a non-self-maintained glow discharge, produced with the aid of the above-described device.

The sewage sample was treated by the non-self-maintained glow discharge, having the average in time value of strength of impulse operating current of 2A, 3A, 5A on two pairs of the unlike electrodes, the voltage of 450V, the clock frequency of 400Hz, the relative pulse duration of 2.

The operating impulse voltage of 450V with the clock frequency of 400Hz was applied to the electrodes 25 and 26, and the non-self-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of SkV of 2mA with the pulse duration of 10 pts and clock fre- queney of 20 kHz which was applied to the same electrodes 25 and 26.

The distance from the surface of liquid to the electrode 26 in gaseous media was 8mm.

The pressure in the reactor 1 was maintained at the level of 50Torr, the inlet fluid temperature at the reactor 1 was T=293 K.

The treated fluid was passed through the non-self-maintained-, low discharge plasma. in a. stream 0. 55mm, 0. 65mm and 0. 75mm in depth.

Simultaneously, the non-self-maintained glow discharge plasma was further affected by a mag- netic field, with the value of magnetic induction being 0. 02 T.

The treatment results are presented in Table 1.

Table 1 #Strea Im-Fe Cr Ni Mo Co Powercon- m puls sumption : depth, e Content Effi- Content Effi- Content Effi- Content Effi- Content Effi-kW. KW h/ mm cur- after cienc after cienc after cienc after cienc after cienc h rent, treat- y, % treat- y, % treat- y, % treat- y, % treat- y, % ment, ment, ment, ment, ment, mg/l mg/l mg/l mg/l mg/l 1 0,55 2 0.014 99.94 0.08 99.85 0.006 99.96 0.045 99.44 0.008 99.86 0,9 1.38 2 O, 65 3 0.022 99.9 0.22 99.61 0.007 99. 95 0. 09 98.88 0.022 99.64 1,35 3 0, 75 5 0. 035 99.85 0.36 99,56 0. 009 99. 94 0. 23 97. 13 0. 032 99.47 2,25 1.55 The analysis of data, presented in Table 1 shows that the degree (efficiency) of the sewage treat- ment from ions of heavy metals depends on the average in time value of the strength of the sum- marized operating impulse current and the depth of the treated fluid.

The most effective, as regards the degree of treatment and power consumption, is the treatment of fluid passed in a stream 0.55mm in depth through plasma of a non-self-maintained glow dis- charge, having the average in time value of strength of the summarized impulse operating current of 2A, the voltage of 450V, the frequency of 40QHz and the relative pulse duration of 2. The power consumption during such treatment of sewage from ions of heavy metals is only 1.38 kW.h per 1 m3, while the known method-of water purification with the aid of a glow discharge (RU, 2043969, Table) requires 1.6-1.9 kW. h for treatment of 1 m3.

Embodiment 2.

Subject to treatment was an aqueous solution of sodium thiosulfate, containing 1.0 g/l of silver and having pH==7, The efficiency of the solution treatment was examined in relation to the value of the operating current, and the relative pulse duration of a non-self-maintained glow discharge.

Aqueous solution was treated with plazma of non-self-maintained glow discharge, produced with the aid of device described above.

The sewage sample was treated by the non-self-maintained glow discharge, having the average m time value of strength of the summarized impulse operating current of 1A, 3 A, 6 A and 10 A on four pairs of the unlike electrodes, with the relative pulse duration of 2.0, 3.0 and 4. Q, the voltage of 490V, the clock frequency of lOOOHz and the relative pulse duration of 2.

The operating impulse voltage of 490V with the clock frequency of lOOOHz was applied to the electrodes 25 and 26, and the non-self-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of 10kV current strength of 2mA, clock frequency 40 kHz, with the pulse duration of 10pu, which was applied to the same electrodes 25 and 26.

The pressure in the reactor 1 was maintained at the level of 50Torr, the inlet fluid temperature at tWr 1 was T=293 K.

The treated fluid was passed through the non-self-maintained glow discharge plasma in a stream 0.8 mm in depth.

The distance from the fluid surface to the electrodes in gaseous atmosphere was 8 mm.

Simultaneously, the non-self-maintained glow discharge plasma was further affected by a mag- field with the value of magnetic induction being 0.02 T.

The treatment results are presented in Table 2. Table 2. # Impulse Pulse duration 2 Pulse duration 3 Pulse duration 4 current, A Silver con- Efficiency, Silver con- Efficiency, Silver con- Effi- tent after % tent after % tent after ciency, % treatment, treatment, treatment, mg/1 mg/1 mg/1 1 1A 98 90.2 124 87,6 185 81,5 2 3A 42 95,8 62 93,8 96 90,4 3 6A 7 99,3 13 98,7 74 92,6 4 1QA 0 100 0 1-00 26 97. 4 Theanalysis of data presented in Table 2 shows that treatment by a non-self-maintained glow dis- charge having the average in time value of strength of the summarized impulse operating current of 10 A and the relative pulse duration of 2. 0 or 3.0 at the frequency of 1000Hz and the voltage of 490V results in an increase of the treatment efficiency by up to 100%.

Besides, this embodiment substantiates the possibility of selection of the non-self-maintained glow discharge parameters for accomplishment of the most effective treatment from a particular kind of contamination.

Application of the operating current with the relative pulse duration of 4,diminishes the treatment efficiency. Thus, the optimal duty cycle of the operating current for sewage treatment from ions of silver is determined within the range from 2. 0 to 3.0.

Embodiment 3.

Subject to treatment was a conducting solution containing 500 mg/1 of a surfactant DC-10 (oxyethylated spirit).

The aqueous solution solution was treated by plasma of a non-self-maintained glow discharge, produced with the aid of the above-described device.

The sewage sample was treated by the non-self-maintained glow discharge having the average in time value of strength of the summarized impulse operating current of 0. 6 A, 2 A, 4 A on two pairs of the unlike electrodes, voltage 470V,clock frequency 100Hz and 400Hz and the relative pulse duration of 2.

The operating impulse voltage of 470V with the clock frequency of 100 and 400 Hz was applied to the electrodes 25 and 26, and the non-self-maintained glow discharge plasma was produced with the aid of ionization impulse-voltage of 10 kV, with average value of strength of impulse current of 4mA with the pulse duration of 5 µs, which was applied to the same electrodes 23 and 26.

The distance from the surface of liquids to the electrode 26 in the gaseous medium was 8mm.

The pressure in the reactor 1 was maintained at the level of 50Torr, the inlet fluid temperature at the reactor 1 was T=293 K.

The treated fluid was passed tithe non-self-maintained glow discharge plasma in a stream 0.65mm in depth.

Simultaneously, the treated fluid was further affected by a magnetic field-with the value. of mag- netic induction being 0. 02 T. The solution treatment results are presented in Table 3.

Table 3. # Impulse Frequency 100 Hz Frequency 400 Hz current, A Content after Efficiency, % Content after Efficiency, % treatment, mg/l treatment, mg/l 1 0.6 55 89 49 90,2 2 22 22 95, 6 19 96, 2 3 4. 0 0 100 0 100

The analysis of data presented in Table 3 shows that the treatment efficiency depends on the value and frequencyof the operating current. Thus, the efficiency of the treatment process increases with an increase of the value and frequency of the operating current.

Embodiment 4 Subject to treatment was water, containing various microorganisms in a concentration of 1012 unit/l.

The aqueous solution was treated by plasma of a non-self-maintained glow discharges produced with the aid of the above-described device.

The sewage sample was treated by the non-self-maintained glow discharge, having the average in time value of strength of summarized impulse operating current of 5A and 10A, on two pair of the unlike electrodes the voltage of 475V, the clock frequency of 2 kHz and the relative pulse duration of 2.

The operating impulse voltage of 475V with the clock frequency of 2kHz, was applied to the electrodes 25 and 26, and the non-seW-maintained glow discharge plasma was produced with the aid of ionization impulse voltage of 10kV, with impulse current strength of 200 µA, clock fre- quency 40kHz with the pulse duration of 5ps, which was applied to the same electrodes 25 and 26 The distance between surface of liquid and electrode 26 in the gaseous media was 8mm.

The pressure in the reactor 1 was maintained at the level of 5 103 Pa, the inlet fluid temperature at the reactor 1 was T=293 K.

The treated fluid was passed through the non-self-maintained-glow discharge. plasma in a stream Q. 5 and 1. 0 mm in depth.

Simultaneously, the non-self-maintained glow discharge plasma was further affected by a mag- netic field with-té value of magnetic induction being 0. 02 T. The treatment results are presented in Table 4 Table 4 Microorganism species Initial Fluid treatment time (sec) before complete inactiva- concentra-tion of microorganisms at fluid depth, mm tion, unit/I 0, mm 1,0 mm Impulse cturent, A Impulse cuirect, A 5 10 5 10 Colon bacillus 1012 0,45 0,7 0,8 1,2. E.Coli Yeast-like fungi of loIZ 0, 35 0,55 0,65 1,05 Candida genus Pathogenic staphylo- 1012 0,35 0,55 0,65 1,05 coccus

The analysis ot a presented tn lable 4 shows that the rate of decontamination (treatment time before complete inactivation of microorganisms) depends on the average in time value of the summarized impulse operating current of a non-self-maintained glow discharge, and a treated fluid depth in the stream, passed through the non-self-maintained glow discharge plasma. As can be seen from this Table, the maximum time of inactivation of E.Coli is 1.2s, for yeast-like fungi of the Candida genus and for pathogenic staphylococcus it is 1.2 s, whereas during a fluid treat- ment by a glow discharge (see RU, 2043975, Table0 the minimum time of inactivation of E.Coli is 7 s, and for yeast-like fungi of the Candida genus and for pathogenic staphylococcus it is 6 s.

Thus, the device according to the invention allows to carry out treatment and decontamination of water in a medium of a non-self-maintained glow discharge, and to provide for adjustment of the value, clock frequency and relative pulse duration of the impulse operating current, thereby allow- ing to select the most optimal conditions of water treatment and/or decontamination.

The above embodiments of the device according to the invention, confirm that it can be effec- tively used for treatment and decontamination of industrial and domestic sewage containing criti- <BR> <BR> cal concentrations oftoxiferous components to a level of the hygiene and sanitary standards and lower, for supplementary purification of sewage, after prior treatment by known methods.

Thus, the device according to the invention allows to carry out the treatment process at a high (20A) average in time value of strength of current and a relatively low voltage of 300V and be- low. The proposed invention makes it possible to increase the efficiency of sewage treatment and decontamination, and thus to reduce the power costs of treatment per volume unit of treated flu- ids.