JPS6036835B2 - How to purify human waste water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for purifying treated human waste water, and more particularly to a method for purifying treated human waste water in which decolorization, sterilization, and denitrification of treated human waste water are effectively carried out by a combination of ozone addition and electrolysis. .

By law, effluent discharged from human waste treatment facilities is subject to 2
After dilution to 0 times, BOD3 is regulated to pm or less and SS70ppm or less, but in addition to this, pigment components and foaming components that cause visual pollution, and nitrogen and phosphorus that are thought to be the cause of eutrophication in the discharged water area. etc.

Furthermore, there are many bacteria including E. coli in the discharged water. These human waste treatment methods include an oxidation treatment method in which raw human waste is diluted and treated with aerobic organisms (activated sludge), and raw human urine is first subjected to anaerobic (digestion) treatment and then diluted or not diluted to aerobic treatment. Digestion and activated sludge treatment combined with biological (activated sludge) treatment.

After performing these treatments, various methods have been studied in which the ss content and phosphorus compounds are removed by coagulation and precipitation, and further decolorization and sterilization are performed by activated carbon adsorption or ozone oxidation treatment. Among the combinations of these various treatment methods, the combined coagulation treatment and ozone oxidation method is considered to be promising in terms of operability. However, a drawback of this treatment system is that when nitrite nitrogen is present, large amounts of ozone are required as it is consumed by oxidation to nitric acid. On the other hand, there are five representative methods for removing nitrogen components: ammonia stripping method, biological nitrification, denitrification method, selective adsorption of ammonium ions using natural zeolite, etc., and discontinuous point chlorination method. The first two methods are considered to be advantageous for nitrogen removal, but each method still has problems. Furthermore, as a method for removing nitrite nitrogen, only the biological nitrification-denitrification method has been put into practical use. The present invention has been made in view of the current situation, and its purpose is to:
It is an object of the present invention to provide a method for purifying treated human waste water which can enhance the decolorization and sterilization effects by ozone by removing in advance suspended matter and nitrite ions that impair decolorization by ozone.

To summarize the present invention, the method for purifying treated human waste water according to the present invention is {a} suitable for flotation and separation of suspended matter in human waste treated water in a flotation zone where hydrogen and oxygen bubbles generated by water electrolysis float. , 'b} The separated liquid is passed through an electrolysis zone filled with granular activated carbon between supporting electrodes consisting of one or more pairs of anodes and cathodes, and a direct current is applied to occlude and adsorb nitrite ions and organic substances. The method is characterized in that {c) ozone-containing gas is passed through the separated liquid to decolorize and sterilize the polymer coloring component by decomposing it.

In the present invention, in order to effectively oxidize and decompose organic substances such as polymer coloring components using ozone, suspended matter and nitrite ions (N
Ozone treatment is performed after removing nitrogen compounds such as 02-).

The raw water enters the flotation zone of the treatment tank, and suspended matter in the raw water floats up the treatment tank and is separated, accompanied by hydrogen and oxygen bubbles generated by water electrolysis in the flotation zone. This separated liquid then enters an electrolytic belt filled with granular activated carbon,
The organic matter contained in the raw water is adsorbed by activated carbon particles polarized by voltage application from a DC power source, and at the same time, nitrite ions are occluded by the activated carbon by electrical attraction.
If ozone-containing gas is bubbled into the raw water treated in this way, the ozone will not be consumed because the nitrate ions are stored in the activated carbon, and on the other hand, the ozone will be thoroughly dispersed between the activated carbon packed layers to improve gas-liquid contact. The coloring components contained in the raw water can be decomposed, and therefore the decolorization and sterilization of the raw water can be effectively achieved. According to the present invention, suspended matter, organic matter, nitrite ions, and colored components in raw water can be efficiently removed by the above-mentioned action, but when chlorine ions are dissolved in raw water at a rate of about 10 pm or more In this case, bacteria such as E. coli can be sterilized by the chlorine generated by the discharge at the anode part of the granular activated carbon particles in the electrolytic zone (granular activated carbon has a small overvoltage for chlorine ion discharge).

Further, the above-mentioned functions are thought to be exerted by the polarization of the granular activated carbon, and in order to utilize this polarization effect, in the present invention, the granular activated carbon with a particle diameter of about 5 or more is used.

Further, the shape of the granular activated carbon is not particularly limited, but a relatively spherical shape is generally effective. In the present invention, since the granular activated carbon in the activated carbon packed bed adsorbs and occludes organic substances and nitrite ions as described above, it is necessary to regenerate this.

In that case, the granular activated carbon can be regenerated by passing an electrolyte solution such as sodium chloride, calcium chloride, and sodium sulfate as a regeneration liquid through the granular activated carbon to diffuse and elute the adsorbed and occluded substances. Next, a specific example of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing a specific example of the apparatus used in the present invention, in which 1 is a treatment tank, 2 is a flotation zone, 3 is an electrolysis zone, 4 is a raw water inflow distribution pipe, 5 is an anode, 6 is a cathode,
7 is a recovery machine (scraper), 8 is a supporting electrode, 9 is granular activated carbon, 10 is an aeration pipe, 11 is a DC power supply, 12 is an ozone generator, 13 is a regeneration liquid storage tank, 14 is a dividing plate, and 15 is a storage 16 is a current plate, and 17 is a pent. The apparatus consists of a cylindrical treatment tank 1, the inner cylinder part of which is made up of a flotation belt 2 for suspensions caused by water electrolysis bubbles, and the outer periphery made up of an electrolytic belt 3 filled with activated carbon. . Levitation zone 2
, anodes 6 and cathodes 6 are arranged opposite to each other alternately at the upper part of the raw water inflow distribution pipe 4, and a recovery machine 7 for recovering floating floss is provided above the anodes 6 and cathodes 6. On the other hand, in the electrolytic zone 3, granular activated carbon 9 is filled between the supporting electrodes 8 so as to be in contact with each other. Ozone-containing gas can be bubbled into the lower part of the granular activated carbon packed bed from an aeration pipe 10. A DC power supply 11 necessary for electrolysis, an ozone generator 12, and a regeneration liquid storage tank 13 for regenerating activated carbon are attached to these devices. Raw water is inflow distribution pipe 4
The suspended matter in the raw water enters the flotation zone 2 and rises along with fine bubbles of hydrogen and oxygen generated between the anode 5 and the cathode 6, floats as froth, and is separated by the recovery machine 7. Ru.

Floating is effectively performed by the rectifying plate 16. The separated liquid passes through the dividing plate 14 and reaches the electrolytic band castle 3 along the path shown by the arrow.
to go into. The granular activated carbon 9, which is polarized by applying electricity to the granular activated carbon 9 filled in the electrolytic band 3, promotes the adsorption of organic matter in the separated liquid and also absorbs nitrite ions by electric attraction. Ozone-containing gas is ejected from a diffuser pipe 10 located at the bottom of the granular activated carbon packed bed, passes through the gaps between the granular activated carbon, and comes into contact with the separated liquid to decolorize colored components and sterilize bacteria. The treated water thus treated is discharged through the storage belt 15. In regenerating the granular activated carbon 9, a regenerating liquid is passed through the granular activated carbon 9 from the regenerating liquid storage tank 13, and adsorbed and occluded organic matter and nitrite ions are eluted. In addition, since the electrolytically generated gas contains hydrogen, the treatment tank 1 is of a closed type to prevent dangerous inspections.
It is made to dissipate from the pent 17 together with excess ozone and the like. The advantages of the present invention due to the configuration and operation described above can be summarized as follows.

{1) Suspended substances in raw water can be effectively separated by flotation due to the fine bubbles of hydrogen and oxygen generated during electrolysis.

'2} Nitrite ions, which prevent decolorization caused by ozone, are
It can be effectively occluded and removed by activated carbon polarized in a DC electric field, and it does not consume ozone.

{3' By dispersing ozone-containing gas between the activated carbon packed beds, it is possible to improve the gas-liquid contact and enhance the decolorizing effect.

'4- Compared to the conventional ozone decolorization method, the ozone injection rate can be lowered and the process can be performed within the same equipment.

{5} Nitrite ions occluded in activated carbon can be dissolved by simply soaking it in an electrolyte solution such as common salt.

Next, the present invention and its effects will be explained using examples.
The present invention is not limited in any way by this. Example In this example, an experiment was conducted using the apparatus shown in FIG.

FIG. 2 is a schematic cross-sectional view of this device, where 1 is a treatment tank, 8
Reference numeral 9 indicates a supporting electrode, 9 indicates a granular activated carbon, 1 indicates a diffuser tube, 11 indicates a DC power supply, and 12 indicates an ozone generator. The treatment tank 1 is vertically 7
It has a rectangular shape with 0 skin, 15 skin horizontally, and 5 cm inside, and a ferrite support electrode 8 with 15 vertical arcs, 20 arcs horizontally, and 0.5 skin thickness is provided on the lower side, and ozone is supplied to the bottom. Generator 1
Ozone gas can be ejected from the air diffuser 2 through the air diffuser 10.

Granular activated carbon 9 can be filled between the supporting electrodes 8,
A constant current is applied to the electrode from an external DC power source 11. Treated water from a human waste treatment plant was used as the test water.

The sample water had a yellowish brown color, the suspended matter concentration was 45 ppm, the chromaticity was 170 degrees, the total nitrogen concentration was 33 pm, and the nitrite ion concentration was 41 ppm. In addition, these analyzes, including the experimental results described later, were carried out using a gravimetric method to determine suspended solids concentration, a colorimetric method using cobalt chloride coloration to determine chromaticity, and an instrumental analysis method to detect total nitrogen concentration by ammonia coulometric titration using hydrogen gas. The nitrite ion concentration was determined by the OR reagent coloring method based on JIS. Furthermore,
Regarding the bactericidal effect, the number of coliform bacteria was measured using a desoxycholate method specified by JIS.
In this example, for comparison, an experiment using ozone alone was conducted as a control, and this will be described first. Using the above apparatus, the effect of gas-liquid contact between sample water and ozone gas was investigated in batch operations.

The liquid volume was set to 5 (liquid depth 52), and ozone-containing gas (03 concentration 0. group volume %) was blown from the bottom to an injection rate of 170 ppm. The results are shown in FIG. FIG. 3 is a graph showing changes in chromaticity and nitrite ion concentration with respect to ozone injection rate. As you can see from this graph, coloring components and nitrite ions each react with ozone,
Nitrite ions are consumed to be oxidized to nitrate ions as shown in the following equation. N. Summer ten. 31N.

Mi ten. 2. Therefore, the amount of ozone required for oxidative decomposition of the original coloring component is 200 ppm or more.

On the other hand, as for the bactericidal effect, sufficient effect could not be exhibited because suspended matter was included. Separately, the above device was filled with 500 liters of granular activated carbon 9 with a particle size of about 5 (liquid volume 4 liters), a constant current of IA was passed between the supporting electrodes 8, and an ozone-containing gas (03 concentration 0) was applied from the bottom. .5 volume%) at an injection rate of approximately 5
It was blown in to 0 ppm.

The results are shown in FIG. FIG. 4 is a graph showing changes in chromaticity and nitrite ion concentration with respect to the ozone injection rate and the amount of current applied. As can be seen from this graph, nitrite ions were almost completely removed at 6000 coulombs/sleeve, and the color was also decolorized by ozone at 5 pm. This means that nitrogen-containing ions including nitrite ions are effectively occluded in the granular activated carbon 9, and suspended matter is also floated and separated by electrolytic bubbles, so that ozone absorbs coloring components from the granular activated carbon 9. This indicates that it was effectively decomposed between the packed layers.
On the other hand, Escherichia coli was also sterilized to the point that it could not be detected by separating the suspended matter. Note that the granular activated carbon 9 is regenerated in steps 1 to 5.
It was confirmed that this can be achieved simply by immersing the bond in an electrolyte solution such as % saline solution. From the above experimental results, it is clear that ozone can effectively decompose colored components when nitrite ions and suspended matter are removed.

It was confirmed that ozone decomposition by activated carbon hardly occurs in spherical activated carbon and in liquid. Furthermore, since the molecular weight of the colored components in the human waste treated water was as high as tens of thousands or more, they were hardly adsorbed on the activated carbon. Moreover, similar results have been obtained in distribution processing as well. As explained above, according to the present invention, by removing in advance suspended matter and nitrite ions that interfere with the decolorization and bactericidal action of ozone, it is possible to effectively decolorize colored components in human waste treated water and to sterilize the same. The effect can be increased.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing a specific example of the device used in the present invention, Fig. 2 is a schematic cross-sectional view of an experimental device in an example of the present invention, and Fig. 3 is a color versus ozone injection rate in a comparative experiment. Graph showing changes in temperature and nitrite ion concentration,
FIG. 4 is a graph showing changes in chromaticity and nitrite ion concentration with respect to the ozone injection rate and the amount of current applied in an example of the present invention. 1...Treatment tank, 2...Floating zone, 3...
... Electrolysis zone, 4 ... Raw water inflow distribution piping, 5.
...Anode, 6...Cathode, 7...
Recovery machine, 8... Support electrode, 9... Granular activated carbon, 10... Diffusion tube, 11... DC power supply, 12... Ozone generation Container, 13... Regeneration liquid storage tank, 14... Splitting plate, 15...
Reservoir belt castle, 16... Rectifier plate, 17...
Bento. 3rd figure, 0 figure, 2nd figure, 2nd figure

Claims (1)

[Scope of Claims] 1 (a) The suspended matter is separated by flotation by passing the human waste treated water through a flotation zone where hydrogen and oxygen bubbles generated by water electrolysis float, and (b) The separated liquid is separated by flotation of one or more pairs of separated liquids. The separated liquid is passed through an electrolytic zone filled with granular activated carbon between the anode and the cathode, and a direct current is applied to occlude and adsorb nitrite ions and organic substances, and (c) ozone is added to the separated liquid. A method for purifying human waste water, characterized by decolorizing and sterilizing it by decomposing a polymeric coloring component through a gas contained therein. 2. The method for purifying human waste water according to claim 1, wherein the granular activated carbon is regenerated by passing an electrolyte solution through the granular activated carbon packed bed. 3. The method for purifying human waste treated water according to claim 1 or 2, wherein the particle diameter of the granular activated carbon is 5 mm or more.