JPS5864194A - Method for operating cell for aerating active sludge - Google Patents

Abstract

PURPOSE:To accurately control the concentration of purified liquid and to enhance the effect of purification, by treating liquid to be purified, which is prepared by diluting raw water with preheated hot water and diluting water containing a controlled amount of unpreheated water, with active sludge in an aerating cell. CONSTITUTION:Gas liquor reserved in a gas liquor tank 3 is supplied to an aerating cell 5 by a pump 4, and its supply amount to the aerating cell 5 is maintained at a predetermined value by a controlling valve 6, which is operated in connection with a flow rate-controlling adjustor 6', provided in a supply pipe line. As diluting water to dilute the gas liquor, cold sea water of about 10-32 deg.C directly gathered from the sea and warm sea water above 30-45 deg.C heated by using it for cooling in a factory are conjunctly used. A controlling means 13 calculates the mixing ratio of the cold sea water C to the warm sea water H so that the mixed sea water becomes at a predetermined temperature, and instructs the opening rate of each controlling valve 10, 11 so as to obtain a predetermined amount of the mixed sea water.

Description

[Detailed Description of the Invention] The present invention relates to a method for operating an activated sludge aeration tank, and in particular,
This invention relates to a method for simultaneously controlling the concentration and temperature of treated water by devising a method for supplying dilution water that is mixed to adjust the concentration of wastewater (raw water) to be treated.

As is well known, activated sludge treatment is a method of decomposing harmful components contained in wastewater using bacteria to render them harmless, and has been developed primarily as a sewage purification technology.

However, recently it has been used in the general chemical industry with good results.

For example, in coke manufacturing plants, cyanide and phenol are present in the spray water waste (generally called gas liquid) used to cool the gas in the coke oven. Activated sludge method is used.

FIG. 1 is a process diagram illustrating this gas liquid activated sludge treatment method. The gas HA collected in the gas liquid bit 1 is first sent to the gas liquid tank 8 by the pump 2 and stored. It is sent to the aeration tank 6 by the cylinder 4. Reference numeral 6 designates a flow rate control valve, whose opening degree is adjusted according to the signal from the flow rate controller 6', and is configured to obtain a set, round flow rate. Supplied. Further, a predetermined amount of dilution water such as seawater is supplied to the aeration tank 6 through a flow control valve 7 and a flow rate regulator τ in order to dilute the gas liquid to a predetermined concentration and adjust its temperature.

Activated sludge, which is a collection of bacteria, is cultivated in the aeration tank 6 I/C, and by mixing it under aeration with the stirring device 19, harmful components in the gas liquid are biologically decomposed and rendered harmless. After that, it is discharged outside. In the figure, 5' is a thermometer υ for detecting the temperature inside the aeration tank 6, and arrow S indicates a test steam injection for temperature control, which will be described later.

By the way, it has been recognized that the removal ability of harmful substances in such activated sludge treatment is significantly influenced by the living environment of batataeria, which are rutting organisms, and especially by the temperature and concentration of the treated water, and high treatment effects can be obtained. For this purpose, temperature and concentration must be strictly controlled.

Furthermore, the concentration of the substance to be treated in the gas liquid (#water) is:

Since the variation is only within a normally permissible range and can be considered as a nuisance, the concentration can be controlled by controlling the concentration of the gas liquid, which is the raw water in the treated water. The concentration below refers to the a degree of raw water in the treated water. However, in the conventional method as described above, only a flow rate control method is used in which the temperature of the aeration tank 5 is monitored with a thermometer 5' and the flow rate of dilution water is set. If diluted water with a large dilution is used, temperature control cannot be performed accurately. Moreover, if control is centered on the tm degree, concentration control will be insufficient), and in any case, it is difficult to obtain optimal biological reaction conditions. In order to deal with this problem, there is a method of controlling the temperature by blowing steam into the aeration tank 5, but the economical burden required for piping and steam generation equipment for this purpose is quite large. Moreover, this method can only be applied when the temperature of the treated water is low, such as in winter.
In summer, when both the dilution water and the aeration static electricity are at high temperatures, the optimum temperature for aeration is often exceeded, as will be described later, so injecting steaming water is rather counterproductive. Therefore, there is a need for the development of a technique that can accurately control the degree and temperature of the gas liquid in the treated water without relying on such auxiliary means.

The present inventors have focused on the above-mentioned circumstances and have conducted research to develop a method that can simultaneously control gas liquid concentration and temperature with a relatively simple configuration. Considering the fact that in addition to general industrial water that is not heated in normal treatment plants, there is also a large amount of industrial water that is used for cooling in various facilities and heated by heat exchange. I got the idea that if both were used together as dilution water, the temperature could be easily controlled.

The present invention has been made as a result of intensive research to realize such an idea, and its configuration is that when yA water is diluted with dilution water and supplied to the tank for activated sludge treatment,
i% preheated as dilution water! The gist lies in controlling the raw water concentration and 1M degrees in the treated water by using fan water and non-preheated water together and controlling the ratio of the two used.

The structure and effects of the present invention will be explained below based on the drawings showing examples, but FIG. 2 is a representative example and does not limit the present invention.

Figure 42 is a schematic process diagram showing an example of the present invention.

For gas liquid, etc., use the gas liquid bit l,
It is sent to the gas tank 8 via the bonder 2 and stored there. The figure shows a 14Fi heat exchange type cooler.

This is provided to cool the gas liquid to a predetermined temperature in advance, and a flow rate control valve 15 is provided in the flow path of the cooling water for heat exchange to detect the gas liquid temperature behind the cooler 14. By the action of the indicator controller 15' for indicating the opening degree of the flow rate control valve 15, the flow rate of the cooling water is adjusted so that the gas liquid decreases to a predetermined ors degree. This heat exchange is an auxiliary means for lowering the temperature of the gas liquid in advance and narrowing the temperature control range in the gas liquid dilution step that will be performed later, and is especially effective when the temperature of the dilution water is high, such as in the summer. It can be omitted in winter when the dilution water is low in humidity.

The gas liquid stored in the gas liquid tank 8 is supplied to the aeration tank 6 by the bonder 4, and the supply pipe is provided with a control valve 6 which is operated by being connected to a flow rate control regulator 6'. The amount of gas liquid fed to the aeration tank 6 is set in advance and kept constant.

In the present invention, the dilution water for diluting this gas liquid is 1, for example, cold seawater taken from the sea (about 10 to 2℃) and warm seawater (sO to 41S'C) that has been heated and used for cooling in the factory.
(above) are used together. In addition to seawater, lake water,
The most economical water can be selected depending on the location conditions, such as river water or industrial water. The temperature of each of the baseboards described above varies depending on the season and operating conditions, etc., but under no circumstances should the temperature of 4-cold seawater be higher than that of 1-cold seawater.

Therefore, by adjusting the ratio of cold seawater and warm seawater used, the temperature can be freely adjusted while keeping the total seawater flow rate (iD, dilution rate of gas liquid) constant K11i.

That is, each of the supply pipes for cold seawater C and warm seawater H is provided with a flow rate control valve 10.11, and the opening degree of these valves is adjusted according to an instruction from a control device 111'l as described later. In addition, each supply pipe is arranged to join downstream of the control valves 10 and 11, and is supplied to the aeration tank 5 through a soft part that is adjusted to a predetermined temperature and flow rate. It is also possible to supply the gas to the aeration tank 5 after merging it into the supply pipe and mixing it with the gas liquid.

The control device flt1B calculates the mixing ratio of cold seawater C and warm seawater H so that the mixed seawater has a predetermined temperature, and operates each control valve 10 and 11 so that a predetermined mixed seawater temperature is obtained at the mixing ratio. It has a function to indicate the opening degree of the oA degree indicating controller 51'. When the temperature inside the aeration tank 5 is higher than 11 degrees, the opening degree of the cold seawater flow control valve 10 is increased and the opening degree of the warm seawater flow control valve 11 is decreased to lower the temperature of the mixed seawater. On the other hand, aerated cypress 6
When the temperature in the mixed seawater is lower than the set temperature, the opening degree of the cold seawater flow control valve 10 is decreased, and the opening degree of the VC warm seawater flow control valve 11 is increased to increase the temperature of the mixed seawater. . In this case, a predetermined mixed seawater flow rate is set in the mixed seawater flow rate control valve 12, i? ], the openings of the control valves 10 and 1] are adjusted so as to satisfy this flow rate.
In the end, the temperature and flow rate of the mixed seawater supplied to the aeration tank 5 are set to values that meet the target values.

As a result, the temperature of the treated water and the gas liquid concentration within the ii1[4115] can always be maintained within the optimum range.

High processing efficiency is guaranteed.

FIG. 8 is a partial process explanatory diagram showing another embodiment of the present invention, which is particularly suitable when the capacity of the aeration tank 6 is extremely large. That is, when a large-capacity aeration tank 6 is used, if the gas liquid and mixed seawater are directly supplied, it will take time to disperse the two.
@Temperature distribution and concentration distribution may occur in the air tank 5. However, as shown in Figure f4 (@mixing tank 8 before battery tank 5)
Place.

After introducing a predetermined amount of gas liquid and mixed seawater into the mixing tank-8 and controlling the temperature and concentration of the treated water at this stage, if this is supplied to the aeration tank 5, the temperature Jf and concentration as described above can be achieved. It is also possible to eliminate non-uniformity. In this case, the humidity and gas liquid concentration in the mixing tank 8 may be controlled in exactly the same manner as in the example shown in FIG.

The present invention is roughly constructed as described above, and by using both cold water and hot water as dilution water, the temperature and concentration of treated water can be accurately controlled to ensure optimal conditions for biological reactions by activated sludge. As a result, processing efficiency was stabilized at a high level. However, there is no need for heating steam O blowing equipment, etc., which is an auxiliary temperature control means installed in the 4b cypress, and heat exchange water is discharged after being used for cooling at each bridge facility in the factory. Since it is a method of effectively using water as hot water, there is almost no economic burden.

This is an extremely practical method.

Next, examples of the present invention will be shown.

Example 1 In the case of diluting 35 m/hr of gas liquid with 120 w/hr of mixed seawater to obtain 175 m/hr of treated water and performing activated sludge treatment while maintaining the temperature in the aeration tank at 80°C,
The temperature and concentration during treatment were controlled according to the method shown in FIG. 8, and FIGS. 4(a) and 4(b) are system diagrams showing the temperature balance in this case.

In the summer when the outside air temperature is high, both the warm and cold seawater temperatures are relatively high (/I! Source water: about 45℃, cold water: FJ
8! The target temperature in the aeration tank 5 cannot be set to 80°C even if the gas liquid (gas liquid pipe 1 has an outlet temperature of approximately 70°C) is diluted with the above-mentioned mixed seawater of warm seawater and cold seawater. Therefore, the gas liquid temperature is lowered to 80° C. by the cooler 14. Next, set the temperature indicator b”O set temperature on the mixing tank 8 to 81.6°C, and set the t!1 mixing tank 8 K 65
In addition to supplying gas liquid at yy//hr, the control device 1
120tri/hK mixed seawater was supplied to 111g while adjusting the opening degree of cold/hot water flow control valve 10.11. In this case, the temperature of the mixed seawater was 82°C, and the temperature of the water to be treated in the mixing tank 8 was a stable value of approximately 81.6°C. When this treated water was introduced into the aeration tank 6 and activated sludge treatment was carried out while supplying an aeration static electricity of about 29°C, the temperature of the treated water was always stable at 80°C. The temperature balance at this time is the current shown in FIG. 4 U).

Next, in winter when the outside IC temperature is low, warm seawater has a temperature of about 80%
℃, and cold seawater is about 10℃, which is a low temperature of about 70℃.
℃ gas liquid was supplied to the mixing tank 8 as it was without being cooled by the cooler 14, and the temperature was controlled. In this case, the temperature of the static electricity for aeration is low ((approximately 5 degrees Celsius)) and the temperature of the water to be treated in the aeration tank 5 drops considerably, so the set temperature of the temperature indicator controller 5# in the mixing tank 8 is set to 42 degrees Celsius. By setting the temperature higher, the temperature of the water to be treated in the aeration tank 5 could be maintained at a constant 80°C.The humidity balance at this time was
As shown in Figure (b).

In the above, examples of control in summer and winter were shown.

When the outside electric temperature is at an intermediate value such as in spring or autumn, the treated water in the aeration tank 5 can be controlled by appropriately determining whether or not the cooler 14 should be operated and the set temperature of the temperature indicating controller 5''. m degree can be maintained at 80°C.Also, even when the temperature of the gas liquid fluctuates, it can be maintained at 80°C according to the above method.
m degrees in the air tank can be easily set as desired. The method of the present invention can be used in any activated sludge method that targets high-temperature raw water.

[Brief explanation of drawings]

Fig. 1 is a process diagram showing an example of controlling treated water in conventional activated sludge treatment, Fig. 2 is a process diagram showing an embodiment of the present invention, and Fig. 8 is another embodiment of the present invention. A partial process explanatory diagram showing the process, FIG.
・Aeration tank 6, 7, 10.11-...Stoichiometric control valve 5"...Temperature indication adjustment needle 8...Mixing tank 9...
Mixing device applicant Kansai Thermal Chemical Co., Ltd.

Claims (1)

[Claims] tllll [When water is diluted with dilution water to become treated water and supplied to an aeration tank for activated sludge treatment, preheated high-temperature water and non-preheated water are used together as dilution water, and both A method for operating an activated sludge aeration tank characterized by controlling the concentration and temperature of raw water in treated water by controlling the usage ratio of (2. A method for operating an activated sludge aeration tank in which seawater is used as dilution water in claim 1.