JPS60143888A - Circulating type pressure floatation concentration apparatus - Google Patents

Abstract

PURPOSE:To increase concentrating effect and to improve rate of recovery of solid matter by providing a device for operating the amt. of pressurized water, a device for correcting the value operated by said operating device with the amt. of water to be fed back, and a device for controlling a flow control valve by inputting a target amt. of pressurized water. CONSTITUTION:Data for the upper and lower limit values of the air/solid matter ratio (A/S) are obtd. from a practical plant, and the values are added to an operating device 12 for the pressurized water amt. using a setting device 11. The amt. of dissolved air Cs is given in the form corresponding to the concn. of the separated water C's at the moment by means of a correction circuit 14 of the pressurized water amt. for the concn. of the separated water, and the value of A/S is optionally varied within a range between the upper and lower limit by varying the amt. R of the pressurized water. Thus, the amt. R of the pressurized water to be fed back capable of maintaining A/S within the set range is operated basing on the measured value of the flow rate of introduced sludge, concn. of the sludge, and the concn. of separated water. The result is inputted to a flow rate controlling device 13, and the control valve 9 for the pressurized water amt. is controlled so as to obtain the target flow rate.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a circulation type pressurized flotation concentrator, and particularly to an improvement in decondensation efficiency and solid matter recovery rate in a process where the flow rate and concentration of inflow sludge largely fluctuate. The present invention relates to a suitable circulation type pressurized flotation concentration device.

[Background of the invention]

The following is known regarding the circulation type pressurized flotation concentrator.

The ratio of air to solids (gas-solid ratio A/S) is where: Cs = dissolved amount of air (CC/1), f - pressure P
fraction of bath denitrification at, P = positive pressure atm) =
(p+14.7)/14.7, p=instrument pressure (p
sig), Sm = inflow sludge concentration (mg/l), a =
Pressurized circulating water volume (mgd), Q-flow rate of sludge flow rate (n
lgd), the coefficient 1.3 is the air ICC (7) weight in m
It is indicated by g.

(Source: Translated by Takashi Asano, Wastewater Treatment Engineering 2 Metcalf&
Eddy Iguchi C0, Nishiharasei Cultural Foundation) Ceremony (1)
In this case, the A/S is determined based on the take obtained through experiments in advance, and is used as a design condition for this device.

As shown in Figure 2, the relationship between the applied pressure and the degree of floating matter x'a is that the higher the pressure, the higher the concentration of floating matter. Instead, it becomes saturated. However, it is also said that if the pressure is too high, the flocs may break.

In addition, as shown in Figure 3, even if the gas-solid ratio A/S exceeds a certain value, the amount of floating solids 1 tvt almost increases, and when this exceeds a certain value, the amount of suspended solids in separated water rapidly increases. The increase is shown in Figure 4.

In conventional circulation type pressurized RF-top equipment, the pressurization pressure, air Mi, + gas-solid ratio, etc. had to be adjusted on-site, so the properties of the inflowing sludge and the flow rate were adjusted when the equipment started operating. Fluctuations were often left uncontrolled. This is the inflow solids in
This shows that the current situation is that processing efficiency is greatly affected by x ajb.

In addition, in the Ot4 slope type pressurized flotation equipment, the separated water is circulated as pressurized water, so as shown in Figure 4, Al6
It is thought that the separation water tray suddenly deteriorated due to the decrease in water. In other words, when Al6 falls below a certain value, the separation water temperature increases by 4 degrees, but this lowers the live air dissolution rate of the pressurized return water and does not affect the floating of solids in the flotation tank. However, this caused a tragic cycle in which the separated water deteriorated to

Separated water sludge yield varies depending on the thickness and condition of the sludge settled in the tank. Currently, the level and thickness of the floss, and the adjustment of the sludge settled in the tank are being considered, but the A/S value, which is thought to be fixed and constant, is not actually realized due to an increase of 4 degrees of separated water. The problem was that we were not paying enough attention to the fact that the reduction rate was decreasing.

[Purpose of the invention]

One object of the present invention is to provide an automatic pressurized water circulation water flow rate control device that takes into account separation water sludge, in order to improve the deterioration of F1 separation water quality with low concentration efficiency.

[Overview of Kaimei-An]

The compression effect largely depends on the amount of inflowing solids, total air volume, pressure, amount of pressurized water, etc. As shown in Figure 4, when the A/S value falls below a certain value (α), the degree of separation water increases rapidly, so this is taken as the lower limit of Al6, and the A/S value is set as the lower limit of Al6 as shown in Figure 3.
Even if the S value exceeds the necessary value (β), the r';

In addition, the decrease in the live air dissolution rate due to an increase in the separation water temperature by 6 degrees is the fifth
Follow the diagram. Since the A/S value also increases in proportion to the decrease in the air injection rate, the amount of pressurized return water should be increased in proportion to the decrease in the live air dissolution rate in order to solve this problem and keep Al6 within a constant value. increase.

[Practice of the invention]

An embodiment of the present invention will be explained below with reference to FIG. 1
2 is a flow duration tank, 2 is a pressurizing pump, 3 is a pressurizing tank, 4 is a shallow-liquid ejector, and 5 is a gas-liquid ejector. In addition, 6 is the υbijin sludge v1 flow rate d1.7 is the inflow sludge once meter, 8 is the separated water concentration @Y19 is the pressurized water base control valve, 10 is the pressurized water flow meter, and 11 is the upper limit and limit setting of Al6. 12 is a pressurized water amount calculation device, 13 is a flow rate control device,
14 indicates a pressurized water amount correction circuit.

In the circulation pressurized flotation-sweeping method, air is dissolved in the inflowing sludge to a saturated state, then introduced into a pressurized tank and pressurized, returned to atmospheric pressure to precipitate air, generate air bubbles, and float the sludge.

In order to perform this levitation operation well, good air bubbles are generated to ensure sufficient adhesion to the S particles and to provide sufficient buoyancy on the Pt.

The specific implementation method will be explained below.

As shown in FIGS. 2 and 3, the upper limit of x/S.

The data of F' la (+i) is taken in an actual plant, and the upper and lower limit values are given to the pressurized water amount calculation device 12 by the setting device 11.

On the other hand, /A14!7I (one time pressurized water amount correction circuit 1
4, evaluate Cs" 1 / (K-8o + r). In this formula, So is the separation water ml [, i/r is the dissolution of air at the pressure P1 separation water 00, C, / is the separated water concentration S
Place your foot on the air R41Q child fIt when it is o. This result (2) value C11' is also given to the pressurized water amount calculation device 12.

In the pressurized water amount calculation device 12, A/S = Pressure P has an effect on floating substances at once, as shown in Fig. 1, but as long as it is above the threshold value, the degree of influence is small and remains constant. Therefore, use that value. Since the pressure P is one foot, f is determined to be a certain value. Air dissolution W4 scene C8 is given as Cs2 corresponding to the concentration of the separated water at that time by the pressurized water t+n positive circuit 14, so A/S can be improved by increasing the pressurized water volume.・Can be changed to tL within the lower limit range. Therefore, the inflow sludge flow rate.

Sludge function and separated water concentration [From the measured values, pressurized water is returned so that A/S is maintained within the optimum range.

do. This seal, the result is money flow'1 Lilil control device 13
The pressurized water amount EA control valve 9 is controlled so that the target flow rate is achieved.

According to Honjitsu 1M1+lI, the dose line effect increases and the floating sludge error number improves, while the separated water concentration stabilizes and the solids flotation efficiency in the tank deteriorates due to the deterioration of the number of separated water locations.
Minute P1 (it is possible to break the vicious cycle of deterioration of grain quality, reduce the load on subsequent sludge treatment, and further improve the impact on the water treatment process as a whole.

〔Effect of the invention〕

According to the present invention, the yielding effect is improved, and appropriate floating of solids is promoted by feedback control of the concentration of separated water, so that the recovery rate of solids is improved due to the weight loss effect due to shrinkage. This reduces the load on the subsequent sludge treatment process and the water treatment process in which the separated water is returned.

[Brief explanation of drawings]

Figure 1 is a custom-made diagram of positive pressure-4 material concentration, rA
The Z diagram is a characteristic diagram of the concentration of separated water and the gas-solid ratio. Figure 3 is a graph showing the percentage of floating objects (iso) group and live air bathing basin. Figure 4 is the bathing ratio of air lice to sludge retention. The characteristic diagram, FIG. 5, is a /1i8 standard diagram of an embodiment of the present invention. 7... Inflow sludge rock solidity count, 8... Separated water - number count, 9
... Pressurized water flow control valve, 10... Pressurized water current meter, 12
... pressurized water amount calculation device, 13... flow rate/control device,
14...Processing Industry Figure 1 2nd m Broom 3 Closed Broom 4 Kyo 5th Closed 6 7 4

Claims (1)

[Claims] 1. Consists of a flotation tank, pressurized water pump, air pressure feeder, liquid-liquid ejector, and gas-liquid ejector4.
In the JIim type pressurized flotation Isopongi device, a pressurized water amount calculation device is installed to keep the air-solid ratio within the appropriate band using a flow meter for inflow sludge, R, and ml port 1 for human sludge, and a separation water volume installed in a separation water tank. a device that uses a concentration meter to calculate the return amount to the pressurized water amount calculation device; and a flow control device that manually inputs a target value of the pressurized water amount from the pressurized water amount calculation device and controls the flow rate adjustment valve. Circulation type pressurized flotation concentration device that achieves %.