JPH01127096A - Water treatment apparatus of electric precipitator - Google Patents

Abstract

PURPOSE:To prevent the wasteful deterioration of a flocculant, by once storing the polluted water generated from an electric precipitator in a storage tank and providing an apparatus for preparing a flocculant solution in the predetermined amount corresponding to the amount of the polluted water when reaching a definite amount. CONSTITUTION:The polluted water generated by washing an electric precipitator 1 with water is once stored in a polluted water pit 4 through a drain pipe 3. When the amount of the polluted water in the pit 4 reaches a definite amount, said amount is detected by a level meter 5 and a flocculant dissolving apparatus 7 is turned ON on the basis of the detection signal of said meter 5 through a control apparatus 6 to charge a predetermined amount of a flocculant in the flocculant dissolving apparatus 7 and water is further added to the dissolving tank 7a thereof to prepare a flocculant solution. At the same time, a pump 8 is turned ON to transport the flocculant solution to a polluted water storage tank 9 from the polluted water pit 4 and turned OFF on the basis of the output signal of a level meter 10 turned ON when the amount of the polluted water in the tank 9 reaches a definite amount. At this time, a pump 12 is turned ON to inject the flocculant solution in the tank 7a in the tank 9.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electrostatic precipitator, and particularly to a water treatment device for treating waste water washed from an electrostatic precipitator installed to purify the air in a highway tunnel.

[Conventional technology]

Electrostatic precipitators are known as devices for cleaning air containing soot and dust. This electrostatic precipitator uses corona discharge to charge soot and dust particles in the air, applies Coulomb force to the charged particles, and collects them on a dust collecting electrode plate. Since the soot and dust accumulates in the dust collection passage, it is necessary to remove this soot and dust at regular intervals. As a means for removing soot and dust, an air cleaning method is generally used, and is disclosed in, for example, Japanese Patent Publication No. 16864/1983. This method blows air off the soot and dust that has accumulated on the electrode plates, and is widely used because the device is simple and the removed soot and dust can be easily discharged outside the machine. However, although the above-mentioned air cleaning method is effective in removing non-adhesive soot and dust, it has a drawback in that its cleaning power is weak in removing sticky soot and dust. On the other hand, as more and more cars are being fitted with spiked tires, concrete dust generated by scraping the road surface in winter has become a problem, and this also has an impact on electrostatic precipitators used in air purification equipment in expressway tunnels. is reaching. In other words, concrete dust becomes clay-like particles when combined with a snow melting agent such as calcium chloride, but when these sticky particles adhere to tires and are brought into the tunnel and collected by the electrostatic precipitator, the air It cannot be removed by cleaning methods. A water cleaning method is an effective cleaning method in such a case. This sprays pressurized water in place of the above-mentioned air spray, and the cleaning power of the fountain is far greater than that of air, and is also sufficiently effective against the above-mentioned adhesive particles. However, even the water cleaning method, which has excellent cleaning power, has many troublesome problems in other aspects, one of which is the treatment of wastewater generated during cleaning. Up until now, air cleaning has been the mainstream method for cleaning electrostatic precipitators, and water cleaning is difficult to treat afterward, so it has been particularly useful for air purification equipment in expressway tunnels where electrostatic precipitators are used on a large scale. It has not yet been put into practical use. Therefore, various aspects of the treatment of the above-mentioned sewage are unclear, including the selection of a flocculant for suspended soot, the separation of soot after flocculation, and the implementation of water cleaning for electrostatic precipitators, including subsequent dewatering of sludge. There are many issues that need to be solved.

[Problems to be solved by the invention]

Now, in conventional water treatment such as sewerage water treatment, the amount of wastewater is large and generally constant. Therefore, in many cases, a solution of the flocculant used in the flocculation step of water treatment is manually prepared by a worker for one to several days depending on the amount of waste water. However, in the case of cleaning an electrostatic precipitator, unlike in other cases, the amount of sewage generated is often not constant from day to day. In other words, the amount of sewage depends on the number of times the electrostatic precipitator is washed, and the number of times the electrostatic precipitator is washed depends on the amount of soot and dust in the air, and therefore varies greatly depending on the conditions of the day. For example, even in the above-mentioned electrostatic precipitator for highway tunnels, the number of times of cleaning, and therefore the amount of cleaning wastewater, is very irregular depending on the traffic volume of the day. On the other hand, it is difficult to keep workers permanently stationed inside the tunnel, so the flocculant solution is prepared in batches for several days, but for safety reasons, the maximum amount of wastewater expected to be generated is It was prepared accordingly. However, this results in a surplus of flocculant solution when the actual amount of sewage generated is small, especially when the sewage does not generate all of its heat. Once the flocculant is dissolved, its performance deteriorates within a few days, so the remaining solution had to be discarded, which was very wasteful. Therefore, this invention aims to constantly balance the amount of washed sewage from an electrostatic precipitator to be coagulated and the amount of a flocculant solution prepared for the water treatment, thereby efficiently coagulating sewage. The purpose of this invention is to provide a water treatment device using an electrostatic precipitator that can be used as an electrostatic precipitator.

[Means to solve the problem]

In order to achieve the above object, this invention adds a flocculant to the waste water generated by washing an electrostatic precipitator with water, and collects and separates the suspended soot and dust in the waste water. In the treatment equipment, there is a sewage storage tank that temporarily stores sewage generated from the electrostatic precipitator, a level meter that detects when the sewage in this sewage storage tank has reached a certain amount, and a signal from this level meter that collects the sewage. A flocculant dissolving device for preparing a predetermined amount of flocculant solution corresponding to the amount of wastewater in the storage tank shall be provided.

[For use]

According to this invention, the preparation of the flocculant solution is started only after the amount of sewage reaches a certain amount, and since the amount of the solution corresponds to this amount of sewage, fluctuations in the amount of sewage generated can be avoided. Regardless of the situation, it is possible to always prepare a necessary and sufficient amount of flocculant solution.

【Example】

The present invention will be described in detail below based on the drawings. FIG. 1 is a system diagram showing the configuration of the main parts of the water treatment apparatus of the present invention. In FIG. 1, pressurized cleaning water is supplied to an electrostatic precipitator 1 through a cleaning pipe 2, and this cleaning water is sprayed through a fountain nozzle (not shown) into a dust collection passage where soot and dust have accumulated. The washing water that has washed away the soot and dust becomes sewage in which soot and dust are suspended, and is temporarily received in the sewage pit 4 at the bottom of the dust collector through the drain pipe 3. Approximately 4 rrr of water is used each time to clean the electrostatic precipitator, and the capacity of the sewage pit 4 is 5 bottles. The sewage pit 4 is provided with a level meter 5 that detects the water level of the sewage, and when the amount of water in the sewage pit reaches a certain level, a signal from the level meter 5 turns on the flocculant dissolving device 7 through the control device 6. be done. As a result, a predetermined amount of flocculant is charged into the flocculant dissolving device 7 from a flocculant storage box (not shown), water is further added, and a flocculant solution is prepared in the dissolution tank 7a. Furthermore, the pump 8 of the sewage pit 4 is turned on at the same time by the signal from the level needle, and the sewage is transported to the sewage storage tank 9. The sewage storage tank 9 has almost the same capacity as the sewage pit 4, but when the sewage in the sewage pit 4 is transferred and the amount of sewage in the sewage storage tank 9 reaches a certain amount, the level meter IO is activated. . The signal from the level meter 10 turns off the pump 8 through the control device 11, and at the same time turns on the pump 12, so that all of the coagulant solution in the dissolution tank 7a is drained into the wastewater storage tank 9.
injected into the body. In the wastewater storage tank 9, the wastewater and the flocculant are mixed under stirring by the stirrer 13. When a predetermined period of time, for example about 10 minutes, has passed and the soot and dust have sufficiently coagulated and formed flocs in the wastewater storage tank 9, the pump 14 is turned on by the operation of a timer (not shown), and the to-be-treated wastewater in the wastewater storage tank 9 is turned on. The liquid is sent to the next solid-liquid separation step. In the above embodiment, the flocculant dissolving device 7 is turned ON by the operation of the level meter 5 of the sewage pit 4, but the flocculant dissolving device 7 is turned ON by the operation of the level meter 13 of the sewage storage tank 9, and then the timer is activated. It is also possible to turn on the pump 12 after a certain period of time and inject the flocculant solution into the wastewater storage tank 9 by the operation of the above. In particular, a plurality of electrostatic precipitators 1 and sewage pits 4 attached thereto are installed,
When one sewage storage tank 9 is provided in common to these devices, when the sewage that flows from each electrostatic precipitator 1 into the sewage storage tank 9 reaches a certain amount, the level meter 13 operates. It is preferable to turn on the flocculant dissolving device 7.

【Effect of the invention】

This invention includes a sewage storage tank that temporarily stores sewage generated from an electrostatic precipitator, a level meter that detects when the sewage in this sewage storage tank reaches a certain amount, and a signal from the level meter that detects whether the sewage is A flocculant dissolving device is installed to prepare a predetermined amount of coagulant solution corresponding to the amount of sewage, and when the amount of sewage reaches a certain amount, a predetermined amount of coagulant solution corresponding to the amount of sewage is prepared, and the sewage is coagulated. Since this flocculant solution is used up each time during treatment, wasteful deterioration of the flocculant can be prevented, and wastewater washed from an electrostatic precipitator can be efficiently treated.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of main parts showing an embodiment of the present invention. 1; Electrostatic precipitator, 2; Cleaning pipe, 3: Sewage drain pipe,
4: Sewage pit, 5 double level meter, 7: Coagulant dissolving device,
9: Sewage storage tank, 10 level meter.

Claims (1)

[Claims] 1) In a water treatment device for an electrostatic precipitator, in which a flocculant is added to the wastewater generated by washing the electrostatic precipitator with water, and the suspended soot and dust in the wastewater is coagulated and separated, from the electrostatic precipitator. A sewage storage tank that temporarily stores the generated sewage, a level meter that detects when the sewage in this sewage storage tank reaches a certain amount, and a signal from this level meter that corresponds to the amount of sewage in the sewage storage tank. 1. A water treatment device for an electrostatic precipitator, comprising: a flocculant dissolving device for preparing a predetermined amount of flocculant solution.