JP2854388B2 - Water control method for dewatered sludge - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for controlling the moisture content of dewatered sludge of the present invention, and more particularly, to dewatered sludge capable of continuously and constantly controlling the water content of dewatered sludge by a simple operation. Water control method.

[Conventional technology]

2. Description of the Related Art Conventionally, an automatic moisture meter using far ultraviolet rays has been used for moisture measurement of dewatered sludge obtained by concentrating and dewatering sludge. However, this measuring instrument measures the sludge by drying the sampled sludge by the gravimetric drying method.The response time is long, and continuous measurement cannot be performed because sampling is required. There was a problem that they could not follow.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a method for controlling the water content of dewatered sludge that can continuously and highly accurately measure the water content of the dewatered sludge and control the water content of the dewatered sludge to a constant value.

[Means for Solving the Problems] The present inventor has proposed a rotating electrode (Japanese Patent Application No. 2-9837) filed earlier.
No. 6, Japanese Unexamined Patent Publication No. 3-295460) found that the above object can be achieved by applying moisture control of dewatered sludge.
The present invention has been reached.

The present invention relates to a method for producing dewatered sludge by introducing sludge stored in a sludge tank into a chemical mixing tank, injecting and mixing a drug, and then dehydrating the dewatered sludge by a dehydrator. A negative electrode and a positive electrode are provided with a rotating electrode provided on a rotating terminal in parallel at an interval of 1 mm or less, a constant voltage is applied to the rotating electrode, and an electrolytic current is measured so that the measured value falls within a certain range. The present invention also relates to a method for controlling the water content of dewatered sludge, wherein the water content of dewatered sludge is controlled to be constant by adjusting the rotation speed of the dehydrator, the amount of sludge supplied to the chemical mixing tank, or the amount of injected chemical.

The rotating electrode used in the present invention, at least one pair of cathode and anode is 1 mm or less, preferably 0.75 mm to 0.1 mm, more preferably provided on the rotating terminal at intervals of about 0.5 mm to 0.3 mm in parallel. is there. By providing the cathode and anode parallel to the rotating terminal at an interval of 1 mm or less, it is possible to reduce the amount of water in the sample without installing a fixed pole in the sample and without being restricted to a sample in which a diffusion tank is easily obtained. Since a proportionally stable electrolysis current can be generated, the amount of water in the sample can be calculated from the current value. In addition, by using such a rotating electrode, it is possible to prevent sludge from adhering to the electrode surface, so that continuous current measurement is possible. When calculating the water content from the electrolytic current value, it is preferable to perform temperature correction in order to improve measurement accuracy.

FIG. 4 is a perspective view of an example of a rotating electrode used in the present invention. The rotating electrode 6 is composed of a pair of cathodes 12 and anodes 13 provided in parallel at an interval of 1 mm or less, fixing the cathodes 12 and anodes 13 and exposing only their tips, and other components. An insulating portion 16 for insulating the cathode 12
And a current collecting brush 14 and a power supply ring 15 for connecting the anode 13 to a power supply and a measuring unit, respectively.

Noble metals such as platinum are used as the materials constituting the cathode and the anode, and copper, SUS, and the like can also be used for the cathode. Although the exposed positions of the cathode 12 and the anode 13 are provided at the bottom of the rotating electrode 6, they may be provided at the sides or may be comb-shaped electrodes. For the insulating portion 16, resins such as epoxy resin, vinyl chloride resin, and phenol resin, ceramics, and the like are used. The length of the electrode is preferably shorter from the viewpoint of measurement accuracy, preferably 20 to 10 mm or less, and more preferably about 5 mm.

The present invention utilizes the fact that the electrolysis current changes due to the change in the properties of the sludge (change in the amount of water). The electrolysis current value is measured directly and continuously by the rotating electrode,
Since the properties of the sludge can be grasped instantaneously, the water content of the dehydrated sludge can be adjusted by adjusting the amount of sludge supplied to the chemical mixing tank, the amount of the chemical injected, or the rotation speed of the dehydrator according to the change in the properties. It can be controlled constantly.

 Hereinafter, the present invention will be described in detail with reference to the drawings.

〔Example〕

FIG. 1 is a process diagram of an apparatus for producing dehydrated sludge showing one embodiment of the present invention. This apparatus comprises a sludge tank 1 for storing sludge 9, a medicine mixing tank 2 for injecting a medicine into sludge 9 supplied from the sludge tank 1 and mixing the mixture with a stirrer 8, and mixing in the medicine mixing tank 2. A dehydrator 3 for dehydrating the mixed liquid,
A belt conveyor 4 for transporting the dewatered sludge 10 dehydrated by the degreasing machine 3, a rotating electrode 5 installed in the dewatered sludge 10 and continuously measuring an electrolytic current at a constant voltage; And a computing unit 6 for controlling the rotation speed of the dehydrator 3 so that the measured value of the dehydrator 3 is within a certain range.

In such a configuration, the sludge 9 stored in the sludge tank 1 is introduced into the medicine mixing tank 2 by the pump 7, and a certain amount of medicine (polymer coagulant, inorganic coagulant, etc.) is injected into the stirrer 8 And then introduced into the dehydrator 3,
The dewatered sludge 10 is dewatered and conveyed by the belt conveyor 4. On the other hand, a constant voltage is applied to the rotating electrode 5 installed in the dewatered sludge 10, the electrolytic current of the dewatered sludge is measured and input to the calculator 6, and the dehydrator is set so that the measured value is within a certain range. The rotation speed of the dewatered sludge is calculated and transmitted to the degreasing machine 3, and is controlled so that the water content of the dewatered sludge is constant.

FIG. 2 is a process diagram of a dewatered sludge producing apparatus showing another embodiment of the present invention. The difference between FIG. 2 and FIG. 1 is that instead of controlling the rotation speed of the dehydrator 3, a chemical supply control valve 11 is provided, and the chemical supply amount is adjusted according to a signal from the arithmetic unit 6 so that the dewatered sludge is adjusted. Is controlled to be constant.

FIG. 3 is a process diagram of a dewatered sludge producing apparatus showing still another embodiment of the present invention. The difference between FIG. 3 and FIG. 1 is that instead of controlling the number of rotations of the degreasing machine 3, the amount of sludge supplied to the chemical mixing tank 2 by the pump 7 is adjusted to keep the water content of the dewatered sludge constant. It is to control.

In the device shown in FIGS. 1, 2 and 3,
There is no need to sample the dewatered sludge, and the properties of the dewatered sludge can be grasped continuously and instantaneously, operating conditions can be set according to the properties of the sludge, and the moisture content of the dewatered sludge can be controlled to a constant value.

〔The invention's effect〕

According to the method for controlling the moisture content of dewatered sludge of the present invention, a cathode and an anode use a rotating electrode provided on a rotating terminal in parallel at an interval of 1 mm or less, and the electrolytic current value in the sludge is directly and continuously measured with high precision. It is possible to measure and set the power supply conditions so that the current value falls within a certain range. Therefore, even when the properties of the sludge change rapidly, the moisture content of the dewatered sludge can be easily controlled to be constant. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram of an apparatus for producing dehydrated sludge showing one embodiment of the present invention, and FIG. 2 is a process diagram of an apparatus for producing dehydrated sludge showing another embodiment of the present invention. FIG. 3 is a process diagram of a dewatered sludge producing apparatus showing still another embodiment, and FIG. 4 is a perspective view of an example of a rotating electrode used in the present invention. 1 ... sludge tank, 2 ... chemical mixing tank, 3 ... dehydrator,
4 ... belt conveyor, 5 ... rotating electrode, 6 ... arithmetic unit, 7 ... pump, 8 ... stirrer, 9 ... sludge, 10 ...
Dewatered sludge, 11 ... Chemical supply control valve, 12 ... Cathode, 13 ...
Anode, 14: Power supply brush, 15: Current collecting link, 16: Insulating part.

Continuation of the front page (56) References JP-A-3-295460 (JP, A) JP-A-3-180747 (JP, A) JP-A-4-42046 (JP, A) JP-A-3-274448 (JP) , A) Real opening 58-163865 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 27 / 30,27 / 416 G01N 27/00-27/24 C02F 11/14

Claims (1)

(57) [Claims] A sludge stored in a sludge tank is introduced into a chemical mixing tank to inject and mix a medicine, and then dewatered by a dehydrator to produce dewatered sludge. A pair of cathodes and anodes are provided with a rotating electrode provided at a rotating terminal in parallel at an interval of 1 mm or less, a constant voltage is applied to the rotating electrode, and an electrolytic current is measured, so that the measured value is in a certain range. A method of controlling the water content of the dewatered sludge, wherein the water content of the dewatered sludge is controlled to be constant by adjusting the rotation speed of the dehydrator, the amount of sludge supplied to the chemical mixing tank or the amount of injected chemical.