JPH0346182B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic separation treatment method, and more specifically, a method for coagulating non-magnetic suspended matter in a liquid into a magnetic floc in the presence of a magnetic substance, a flocculant, etc., and then subjecting the same to magnetic separation treatment. The present invention relates to a magnetic separation treatment method that can effectively and sufficiently separate and remove non-magnetic suspended matter from a liquid by using a magnetic material uniformly dispersed by sound waves. Municipal sewage, industrial wastewater, various manufacturing process waste liquids, and activated sludge treated water, etc., contain organic or inorganic non-magnetic suspended substances (hereinafter simply referred to as
(abbreviated as SS) are often mixed together. If these are released into the environment as they are, they become a source of pollution, so they must be disposed of by some means. In recent years, magnetic separation processing has been used to treat liquids containing such SS (hereinafter simply referred to as raw water). In this case, the magnetic separation treatment involves co-agglomerating the SS in the raw water in the presence of an appropriate magnetic material and coagulant to form a magnetic floc that can be subjected to magnetic separation treatment, and then magnetically separating this. ,
Typically, for example, an electromagnetic filter is used as the magnetic separation device, and powder particles of magnetite, which is a ferromagnetic material, are used as the magnetic material. However, in conventional magnetic separation treatment in such cases, generally, a stirred mixture of magnetic powder particles obtained by mechanically stirring with a blade stirrer etc. is poured into raw water, a flocculant is added, and the raw material is separated. This method coagulates SS in water with magnetic powder particles to form magnetic flocs, which is then sent to a magnetic separation device.
In reality, according to such conventional methods, a non-negligible amount of SS is still suspended in the treated water, and it is still insufficient, especially in today's world where removal of SS is extremely demanding in terms of quality and quantity. There is a desire for more efficient and sufficient separation and removal of SS through separation treatment. From the above-mentioned viewpoint, the present invention provides
The present invention provides a magnetic separation treatment method that can efficiently and sufficiently separate and remove SS. Hereinafter, the structure of the present invention will be explained in detail by using an electromagnetic filter as a magnetic separation device and magnetite powder as an example of the magnetic material, and comparing it with a conventional method based on the drawings. FIG. 1 is a schematic system diagram illustrating the processing procedure of the conventional method. In the middle of the piping through which raw water is sent by the pump 11, a mixed liquid 31 of magnetite powder particles stirred by a blade-type stirrer 21 and a diluted solution 44 of flocculant by a blade-type stirrer 22 are pumped to the pumps 12 and 1, respectively.
3, and then passed through an electromagnetic filter 51 to obtain treated water. The electromagnetic filter 51 captures and accumulates magnetic flocs of SS and magnetite powder coagulated by a flocculant, and these are discharged from the system by backwashing in a conventional manner after continuous treatment for a certain period of time, for example. In addition to the examples shown in the drawings, such conventional methods include separately providing a mixing tank for raw water and magnetite powder, a co-flocculating tank using a coagulant, or adding magnetite powder and a coagulant to raw water. In some cases, SS is added at the same time, but in actual magnetic separation treatment using either method, a non-negligible amount of SS still floats in the treated water. When the present inventors investigated the cause of this problem, they found that in the conventional method, the magnetite powder particles introduced into raw water were not uniformly dispersed, and that the magnetite powder particles were agglomerated between each other. Since one of the SS is not in a state where it can adsorb SS in the raw water, the SS is either supplied to the electromagnetic filter in the form of a floc by a flocculant without forming a magnetic floc, or the SS is supplied to the electromagnetic filter in the form of a floc without forming a magnetic floc. However, it has been found that the tightness between SS and magnetite powder particles is weak and the magnetic flocs are supplied to the electromagnetic filter, and the SS in such flocs is not captured by the electromagnetic filter and is entrained in the treated water. Ivy. Therefore, the inventors of the present invention conducted further intensive research in order to solve this problem, and found that if the magnetite powder particles to be introduced into raw water are dispersed in the liquid using ultrasonic waves in advance, each magnetite powder particle will appear as if it were a single particle. When the magnetite particles are in a uniformly dispersed state, and the dust that often adheres to the surface is removed at the same time, the magnetite particles in this state are put into raw water. It was confirmed that SS in water is efficiently, tightly and strongly adsorbed to each magnetite powder particle, and these form magnetic flocs by the flocculant, and these magnetic flocs are reliably captured by an electromagnetic filter. This finding led to the completion of the present invention. 2 and 3 are schematic system diagrams showing different embodiments of the present invention. In the case of FIG. 2, a uniform dispersion of magnetite powder particles 7 is generated by an ultrasonic oscillator 61 in the middle of the piping where raw water is sent by the pump 14.
1 and a diluted solution 42 of the flocculant produced by the blade stirrer 23 are added by pumps 15 and 16, respectively, and then passed through an electromagnetic filter 52 to obtain treated water. In the case of FIG. 3, a mixed liquid 32 of magnetite particles is stirred by a blade-type stirrer 24 in the middle of a pipe for feeding raw water by a pump 17, and is uniformly dispersed as described above in a dispersion container 81 equipped with an ultrasonic oscillator 62. The liquid 72 and the diluted flocculant solution 43 produced by the blade stirrer 25 are pumped into the pumps 18 and 43, respectively.
19, and then passed through an electromagnetic filter 53 to obtain treated water. In all of the illustrated embodiments, magnetite powder particles are added to raw water as uniform dispersion liquids 71 and 72 in an activated state as if they had been separated one by one as described above, and magnetic flocs captured by electromagnetic filters 52 and 53 are added to the raw water. is discharged out of the system by backwashing as in the conventional method. In the present invention, the magnetite powder particles are typical examples of a magnetic material, and the electromagnetic filter is a typical example of a magnetic separation device, and other well-known magnetic materials and magnetic separation devices can be used. The flocculant is one or more types selected as appropriate depending on the properties of the target raw water, and usually anionic or nonionic polymer flocculants, such as polyaluminum chloride, may be used. . In order to make the effects of the present invention explained above more concrete, the following Table 1 is illustrated. In the table, the conventional example is shown in FIG. 1, Example 1 is shown in FIG. 2, and Example 2 is shown in FIG. 3, respectively.

【table】

[Table] As is clear from the results in Table 1, in each example, the SS concentration in the treated water was significantly lower than in the conventional example, and the magnetite powder particles used were exposed to ultrasonic waves. Therefore, it can be seen that it is functioning efficiently and satisfactorily. According to the present invention, SS in raw water can be separated and removed more efficiently and sufficiently in the magnetic separation process, and there is no phenomenon of adhesion and accumulation of magnetite powder particles in a tank or in the middle of piping, which occurs in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram illustrating the processing procedure of the conventional method, and FIGS. 2 and 3 are schematic system diagrams illustrating different embodiments of the present invention. 11-19...Pump, 21-25...Blade type stirrer, 31,32...Stirring mixed liquid, 41-43
... Diluted solution, 51-53 ... Electromagnetic filter,
61, 62... Ultrasonic oscillator, 71, 72... Uniform dispersion liquid, 81... Dispersion container.

Claims (1)

[Claims] 1. When a magnetic substance and a coagulant are appropriately added to a liquid containing a non-magnetic suspended substance to form a magnetic floc from the non-magnetic suspended substance, and when this is subjected to magnetic separation treatment, the magnetic material is uniformly dispersed by ultrasonic waves. A magnetic separation processing method characterized by adding a body.