JPH0248091A - Waste water treating device - Google Patents

Abstract

PURPOSE:To efficiently remove the flocs suspending in waste water to the outside of a cleaning tank by cascade-varying the amt. of the foam to be supplied into the waste water. CONSTITUTION:The compressed air supplied from an air compressor 5 is regulated by a regulator R1 to a desired air pressure. The air is connected to an air diffusion pipe 4 via a regulator R2 which reduces the pressure thereof and two pipelines; a pipeline 15 having a solenoid valve SV 1 and a pipeline 16 having a solenoid valve SV 2. The air reduced in pressure is, therefore, supplied to the air diffusion pipe 4 if the SV 1 is opened and the SV 2 is opened. The air of the desired pressure is supplied when the SV 2 is opened in this state. The more foam is generated when the air pressure is high than when the air pressure is low in this way. The switching of the amt. of the foam to be generated to two stages is possible by controlling the SV 1 and the SV 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention mainly relates to a wastewater treatment device for purifying car wash wastewater discharged from a car wash to a state where it can be reused.

[Conventional problems] Coin-operated car washes equipped with high-pressure spray type car wash machines,
Service stations equipped with gate-type car wash machines use a large amount of water, and in order to deal with water shortages in the summer and reduce running costs, there have been conventional wastewater treatment devices that purify car wash wastewater to a state where it can be reused.

By the way, most of these devices are of the so-called punch type, in which wastewater is once stored in a septic tank, purified, sent to another tank, and then purified again by the amount of purification. However, with conventional equipment, the time required for each process is relatively long, so when multiple car wash machines are operated at the same time or when cars are washed consecutively, the purification process cannot be completed in time. There was a problem.

[Objective of the Invention 1] The present invention aims to address the above-mentioned problems and shorten the time for wastewater purification treatment, by using a flocculating chemical to turn flocs of suspended solids precipitated in car wash wastewater into fine foam. The flocs floating in the wastewater are efficiently removed from the septic tank by varying the amount of foam (supplied air pressure) supplied into the wastewater in a series or several stages when the flocs are attached and removed by flotation. It is.

[Embodiment 1 of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system explanatory diagram of a wastewater treatment apparatus according to an embodiment of the present invention. Reference numeral 1 designates a drainage bit that collects and temporarily stores car wash wastewater discharged from a car wash, etc., and 2 designates a secondary storage tank that pumps up the wastewater with a pump and further stores it. The secondary storage tank is composed of a plurality of tanks communicating with each other, and has the role of precipitating impurities such as sand and dust contained in the wastewater and purifying the wastewater to some extent. 3 is a wastewater septic tank equipped with an aeration pipe 4 and having a funnel-shaped bottom. The air diffuser pipe 4 is connected to a compressor 5 and supplies fine bubbles into the tank. Reference numeral 6 denotes a flocculating chemical solution addition device that adds a flocculating chemical solution to wastewater during purification treatment, 14 a control device that controls the amount of foam generated from the aeration pipe and the flocculating chemical solution addition device, and 7 an outer tank that surrounds the septic tank 3. . Therefore, during the purification process, the flocs formed in the wastewater are floated by the foam generated from the aeration pipe 4, and are caused to overflow into the outer tank together with the flocs accumulated on the surface of the wastewater. 8 is a filter device that filters the remaining 70 ton of water contained in the treated water that is pumped from the septic tank;
10 is a treated water supply port, 10 is a fresh water supply port, and 11 is a water tank for storing treated water and fresh water. ] 2 is a floc dehydration tank which receives impurities precipitated at the bottom of the secondary storage tank 2, flocs received in the outer tank 7 during purification treatment, and impurities deposited at the bottom of the septic tank. brought back into focus.

Note that the wastewater purification treatment with the above system configuration is not carried out continuously, but once the septic tank 3 is filled with water, the injection of wastewater is stopped, and after purification, the wastewater is injected again. Punch processing is performed discontinuously in units of capacity, and treated water is sent to a water tank each time.

Next, the flow of the waste water purification process performed in the above configuration will be explained based on the $2 chart.

First, the car wash wastewater stored in the secondary storage [2] is transferred to the septic tank 3.
After pouring a specified amount of water into
Add a flocculating chemical solution that solidifies suspended solids in the wastewater into a floc-like form and stir ■. This flocculant solution is made up of three liquids: a flocculating aid containing an anionic surfactant, a flocculant containing tap water sulfuric acid, etc., and a polymer flocculant containing a nonionic surfactant, etc. The order of addition and stirring time are shown in Table 1 below.

At the beginning of Table 1, a coagulation aid is added, and at the same time, bubbles are continuously generated from the aeration pipe 4 for 30 seconds to stir the wastewater in the septic tank. After that, stop the generation of foam and
After leaving for 0 seconds, add the flocculant and stir in the same manner as above 9
0 seconds and leave for 30 seconds. Finally, a polymer flocculant is added and stirred for 60 seconds to complete the addition of the flocculant solution. When this third liquid polymer flocculant is added, the suspended solids in the wastewater begin to flocculate, and the flocculated particles repeatedly collide with each other in the water, significantly progressing agglomeration, and begin to precipitate as flocs. During the 15 minutes of standing time after addition of the polymer flocculant, almost complete growth occurs, leaving 70 inks floating in the transparent treated water. In this way, the flocculating chemical solution is added and stirred, and then foam treatment is performed to remove floating flocs. This foam treatment is carried out by generating foam in the treated water containing flocs from the aeration tube 4. The fine bubbles generated from the aeration tube located at the bottom of the septic tank adhere to the flocs floating in the water and remain as they are. It causes the flocs to float on the water surface, foams the detergent components contained in the treated water, and discharges the flocs accumulated on the water surface out of the septic tank.

After the floating flocs in the treated water are removed in this way, the treated water is pumped to the water storage tank 11 (1), and a series of wastewater purification treatment cycles are completed.

Next, foam processing will be explained in more detail. In the above foam treatment, the amount of foam supplied into the septic tank can be adjusted in two stages. As shown in the air piping diagram of FIG. 4, compressed air supplied from the air compressor 5 is first adjusted to an air pressure of 4 Kgf/cm2 by a regulator. After that, further increase the air pressure to IKgf/cm2.
It is connected to the diffuser pipe 4 through two pipes: a pipe 15 including a regulator R2 and a solenoid valve SVI, and a pipe 16 including a solenoid valve SV2. Therefore, SVI is opened and S
If V2 is closed, air is supplied to the diffuser pipe 4 at a pressure of IK) (f/cm2, and if SV2 is opened in that state, air is supplied to the diffuser pipe 4 at a pressure of 4Kgf/cm2. At this time, when comparing the amount of foam ejected from the air diffuser pipe, it is obvious that more foam is generated when the air pressure is high than when it is low, so by controlling SVI and SV2, the amount of foam generated can be reduced. It is possible to freely switch between two strong and weak stages and a state where foam generation is stopped.Figure 13 shows the two strong and weak foam generation states.(a) is ]Kgf/cm2
This is the state where the pressure is applied, that is, the weak state. When the amount of foam generated is small in this way, the effect of stirring the treated water is small, but the fine foam spreads evenly in the treated water and the bubbles that float to the surface cover the entire water surface. Under these conditions, the flocs floating in the treated water tend to adhere to the foam, and since there is little turbulence on the water surface, the floating flocs tend to accumulate in layers without being destroyed. . On the other hand 4
(b) shows the state in which a pressure of KHf/cm" is applied. At this time, a large amount of foam is generated with great force, so it pushes up the center of the water surface in a mountain shape and then descends toward the septic tank wall. A water stream is formed, and the foam flows around the area from the medium heat, and when the water stream collides with the septic tank wall, new bubbles are formed and the foam appears to be gathering along the inner wall of the septic tank. In other words, this means that the flocs attached to the foam are also washed away to the surrounding walls of the septic tank, and therefore, the flocs overflow out of the septic tank along with the foam that grows over time due to the strong water flow flowing from the center to the periphery. I will do it.

The foam treatment process thus sets the foam ejection amount in three stages: strong, weak, and stopped, and Table 2 below shows an example of the combinations.

As shown in the upper table of Table 2, first start the foam treatment process at low temperature, first generate fine foam evenly in the treated water,
The entire surface of the water is covered with floating foam. As a result, a large amount of flocs floating in the treated water rises to the surface together with the foam, adheres to the foam and accumulates on the water surface. Thereafter, there is a short pause (30 seconds), and the bubbles that have not surfaced completely rise to the surface, and the flocs gather on the water surface. After this stopping time has passed, it is turned back to high and generates foam. Then, the above-mentioned water flow is generated in the septic tank, and the flocs that had been quietly accumulating on the water surface along with the foam are pushed up by the bubbles that grow one after another due to the strong water flow change and overflow outside the septic tank. At this time, the flocs floating in the treated water are attached to the foam and floated, of course.
Detergent components remaining in the treated water that cannot be removed by the flocculating chemical solution are also removed from the tank by foaming.

After this state continues for 5 minutes, foam is generated again at low temperature. This is to float the flocs remaining in the treated water that could not be removed even with the above treatment to the water surface, and also to remove the flocs that adhered to the inner wall of the septic tank during overflow.
The purpose is to float the 70 ink that comes into contact with the treated water and returns to the water.

Thereafter, in the same manner as described above, the residual flocs and residual detergent components in the treated water are almost completely removed under the "strong" foam generation state, and the foam treatment process is completed.

The results obtained by the method of the present invention and the results obtained by the method in which the amount of foam generated is fixed at a constant level are shown below.

Table 3 Note) However, the amount of treated water is 2001, and the transparency is not over 30 degrees.

Comparing the results of the method of the present invention and the method of treating the amount of foam at a constant level, we find that the water quality is sufficient for washing J17 water, with a transparency of 30 degrees or higher, and a high-low hexane extraction amount of 5.
It can be seen that the method of the present invention requires only half the time to purify the foam to ppm compared to the case where the amount of foam is kept constant.

[Effect 1 of the Invention Since the present invention is configured as described above, the following effects can be obtained.

In this type of wastewater purification equipment, which performs batch processing discontinuously in units of septic tank capacity, the foam processing time, which accounts for most of the time required for purification, is reduced to about half that of when the foam volume is treated at a constant rate. Since the Md is applied, the time required for the second purification process is shortened, the amount of purification treatment per unit time is increased, and the purification treatment efficiency is greatly improved. Therefore, even when multiple car wash machines are operated at the same time or when washing is carried out continuously, there are fewer cases where the purification process becomes inadequate and the problem is compensated for with building blocks.

[Brief explanation of the drawing]

FIG. 1 is a system explanatory diagram of a water treatment device according to an embodiment of the present invention. FIG. 2 is a 70-sheet showing the flow of wastewater purification treatment according to an embodiment of the present invention. FIG. 3 is an explanatory diagram showing a state in which foam is generated in the treated water. Figure 4 is an air piping diagram. 3 is a septic tank, 4 is an aeration pipe, 6 is a flocculating chemical addition device, 7 is an outer tank, and 14 is a control device.

Claims (1)

[Claims] An aeration pipe that is connected to an air supply source and generates foam in the treated water, a means for changing the amount of foam generated by switching the air pressure supplied to the aeration pipe, a septic tank that is equipped with the aeration pipe inside, and The septic tank is equipped with an outer tank for covering, a flocculating chemical addition device that adds a flocculant chemical into the septic tank, and a control device that controls the amount of foam generated from the aeration pipe and the flocculating chemical adding device. A wastewater treatment device characterized in that the foam is floated and removed using foam, and the amount of foam supplied to treated water containing flocs after addition of a coagulating chemical solution is varied.