Method and apparatus for purifying water.

The invention relates to a method for purifying water and an apparatus for carrying out the method according to the invention.

The object of the invention is to provide a method of the type mentioned, which provide effective cleaning, especially of fatty acid-containing wastewater, allows with simple means.

The object is achieved by the features of claim 1.

In the method according to the invention are separated from the electrodes 2 or 3-valent metal ions in a simple manner by means of electrolysis, which cause flocculation within the water to be purified. It is believed that these flakes comes about by formation of colloidal oxide hydrates of the deposited metal ions. The flakes formed bind themselves more in the contained water to be purified impurities and thus serve as a vehicle for their separation from the water to be purified. made possible the continuous production of ions for flocculation by the automatic cleaning of the electrodes by means of solid particles of the moving bed. These are kept in motion depending on the nature of the bed from the water flowing through. They thereby move in various directions and speeds towards the surface of the electrodes and along them. This results in the desired cleaning effect. Further purification effect is achieved that the solid particles move past cleaning by back move by driving through the water at the electrodes.

As 2- or 3-valent metals for the electrodes are preferably iron or aluminum can be used.

In a preferred embodiment of the method according to the invention, a plurality of, ie, at least three electrodes are provided which are polarized alternately by applying a direct current voltage. Here, it is advantageous to change the polarity of the individual electrodes periodically, for example every 10 minutes, so that not only constantly positively charged electrode will be consumed, but a uniform consumption of the electrodes and also occurs simultaneously a certain amount of electrode cleaning.

The inventive method is particularly suitable for the purification of fatty acids containing water. In the presence of fatty acids in the water to be purified, the deposited by electrolysis metal ions combine with the fatty acids to water-repellent metal soap flakes. These flakes turn prevent further contamination, especially organic colloidal particles and carry them with you.

The features of the claims 5 to 7 relate respectively to a further development of the process for improving the flocculation.

Provided that the electrolysis is carried out with a current source connected to electrodes, in particular for electrodes made of the same material, can be controlled by the feature of claim 8, the intensity of the process, or when little polluted water energy can be saved.

A simple process step in this direction is the shopping times of the claim. 9

The invention also provides apparatus for performing the method according to the invention, characterized by the features of claim 12th

That the electrodes are arranged in a moving bed of solid particles, resulting in a simple way, the above already described automatic cleaning of the electrodes. Their constant effectiveness is guaranteed. The flaring of Ausflockungsgehäuses brakes to rapid Weiterfluß and allows entrained out of the bed solid particles the return movement in the electrolysis chamber.

For the flocculation advantageous materials of the electrodes are addressed by the features of claims 14 and 15. FIG.

An energy-saving way of electrolysis indicates the feature of claim 16, since an ion release can be achieved to a power source without connecting the electrodes when the electrodes are made in accordance with concerted different metals. For highly corrosive water, the electrodes can be even a battery, so supply voltage.

This can surrounding the electrode moving bed, as indicated in the features of claim 17 be of various types, particularly as regards the movement of the solid particles in the bed. The type of bed depends to a large extent on the nature of the solid particles, for example, granite, sand or plastic pellets, as well as the number, size and arrangement of the electrodes. As solid, non-conductive particles of the moving bed are particularly suitable Granitteilchen. An economic control of the electrolysis is made possible when lying on voltage electrodes in a simple manner by the feature of claim 21st Thus, in heavily polluted water the effectiveness of cleaning increased in low polluted water to save energy.

A particularly simple device this is addressed by the feature of claim 22nd

The housing of the electrolysis chamber is always negatively charged at carrying out the process, since in a repolarisation otherwise corrosion would occur. As the metal for the electrolysis chamber housing, for example, is steel.

Hereinafter, an apparatus for performing the method according to the invention and the method carried out therewith will be described with reference to the single drawing figure.

Water to be purified 1 is introduced via a supply line 3 from the bottom in an electrolysis chamber. 4 Adjoining the electrolysis chamber 4 upwardly a conically expanding Ausflockungsgehäuse 2 on which merges into a cylindrical top. 9

The electrolysis chamber 4 contains a bed 5 of solid particles. At the bottom, from the supply flared portion 4a of the electrolysis chamber 4 an air blower 6 is introduced. In the cylindrical part of the electrolysis chamber 4 electrodes 7 and 8, supported on a manner not shown, immersed in the bed. 5 They may be, each electrically connected in ways not shown here.

At the top, the cylindrical part 9 of the Ausflockungsgehäuses 2 an open-topped annular channel 10 is appropriate for receiving from there escaping foam 11. The annular channel 10 is connected with a discharge channel 12th This includes a tissue or cloth filter 13. The forwarding there emergent water-repellent substances 14 is not shown.

In the cylindrical part 9 of Ausflockungsgehäuses a discharge line 16 is connected for clean water below the annular channel 10th

To the supply line 3, a light source 17 and on the other hand, a light sensor is prior to its entry into the electrolysis chamber 4 to a transparent portion 3a arranged on one side 18. The light sensor 18 controls depending on its actuation the voltage at the electrodes if they are connected.

With the device described is water, in particular waste water, purified as follows:<ul><li>The water to be purified 1 flows through the supply line 3 for electrolysis chamber 4. When passing through the transparent portion 3a represents the light sensor based on the turbidity of the water pollution levels and regulates then the voltage supply to the electrodes 7 and 8. Upon entering the electrolysis chamber receives water, a flow rate, which moves in the order of magnitude of the moving speed of the solid particles of the bed. 5 This rate is approximately one tenth of the free-fall velocity of the particles in the water. By the air blower 6, air is pale in the electrolysis chamber below the electrodes, in addition, which amplifies the movement in the electrolysis chamber.</li><li>The electrodes, preferably of aluminum or iron, are precipitated ions. These combine with impurities, in particular with fatty acids to water-repellent flakes, for example, metallic soaps. These flakes in turn prevent further contamination, especially organic colloidal particles and carry them with you. On emerging from the electrolysis chamber 4, the flow rate is reduced so that the binding of further contamination by the flakes electrolytically formed can proceed further through the flaring of Ausflockungsgehäuses. 2 Furthermore, the entrained out of the bed solid particles can move back in consequence of their higher specific gravity in the electrolysis chamber. 4 They move while also cleaning the electrodes along.</li></ul>

The flocculated impurities form a foam layer 11, which overflows into the annular channel 10 on the surface of Ausflockungsgehäuses. You passes from there through the discharge channel 12 through the cloth filter 13. A therein arising water-repellent product 14 is excreted in not shown manner.

The purified Waser 15 passes through the discharge line 16 from the Ausflockungsgehäuse and is further purified through a sand filter not shown.

The effectiveness of the electrodes 7 and 8, that is, the current release of ions to flocculate, is ensured by the solid particles of the bed. 5 They move both in the electrolysis chamber under the action of the water and the air stream against the electrodes and along them, and during the return movement from the Ausflockungsgehäuse if they have been carried along out of bed. This automatic cleaning of the electrodes is necessary not only for heavily polluted waste water, but also in the cleaning of relatively clean raw water. The cleaning of the electrodes is used to remove oxide films that otherwise coat the electrodes and can prevent the release of ions.

The light source 17 and its opposite light sensor 18 measure the water pollution by which turbidity, ie, the obstruction of the light beam. The sensor accordingly controls the energization of the electrodes and thus the intensity of the electrolysis.

In the context of the invention, electrodes of different material can be used without producing an electrical voltage ions. For highly corrosive water, especially in the use of aluminum anodes, the electrolysis chamber may even be to the battery.