SU865829A1 - Unit for waste water purification - Google Patents

Description

(54) INSTALLATION FOR SEWAGE TREATMENT

The invention relates to chemical technology and can be used for wastewater treatment. A known water treatment unit comprising a filter and a diaphragm electrolyzer 1 connected thereto. However, since in the diaphragm electrolyzer the waste water is not purified with, but only acidified when it is treated in the anode chamber and alkalized when it is treated in the cathode chamber, heavy metal ions that are not extracted on the filter are discharged together with the catolite and anolyte. This requires the use of additional facilities for cleaning kato / lita and anolyte. Closest to the invention, in technical terms, is a plant comprising a series-connected diaphragm electrolyzer and a filter 2 connected to its cathode chamber. A disadvantage of the known setup is that the crude anolyte is removed from the anode chamber of the diaphragm electrolyzer. If it is mixed with catholyte purified on a filter, the latter is contaminated with heavy metal ions, which reduces the quality of purification of the entire volume of treated water and limits the capacity of the unit. The purpose of the invention is to increase plant performance by eliminating contaminated production emissions. The goal is achieved by the fact that in an installation containing a series-connected main diaphragm electrolyzer, a filter connected to its cathode chamber and an auxiliary diaphragm electrolyzer, the cathode and anode chambers are independently connected to the filter, the output of the cathode chamber of the auxiliary chamber and the anode output of the main diaphragm electrolyzers are connected between each other and are connected by return pipe to the input of the cathode chamber of the main diaphragm electrolyzer. The drawing shows the scheme of the proposed installation. The installation includes a source water piping 1, equipped with valves 2 for controlling the flow of water supplied to the anode 3 and cathode 4 chambers of the main diaphragm electrolyzer 5. A filter 6 is connected to the cathode chamber of the electrolyzer 5. 9 n cathode 10 camera auxiliary diaphragm electrolyzer I. The output of the cathode chamber

10 auxiliary electrolyzer

11 and the output of the anode chamber 3 of the main electrolyzer 5 are connected to the mixer 12 and connected via a return pipe 13, equipped with a pump 14, to the inlet of the cathode chamber 4 of the main electrolyzer 5.

The installation works as follows.

The source water containing heavy metal ions is supplied via conduit 1 to the anode 3 and cathode 4 chambers of the main diaphragm electrolyzer 5. The flow of water supplied to the electrode chambers is controlled by valves 2. Electrochemical pH is raised in the cathode chamber 4 of the electrolyzer 5 catholyte to the values necessary to convert heavy metal ions into insoluble (hydroxide) compounds. In the anode chamber 3, an anolyte is electrochemically acidified at the same time.

The catholyte leaving the cathode chamber 4 enters the filter 6, where insoluble compounds of heavy metal ions are separated from the aqueous phase.

The purified catholyte, which has alkaline reaction, is directed through pipeline 7 to the anode 9 and cathode 10 chambers of the auxiliary electrolyzer 11. The flow of water supplied to the electrode chambers is controlled by means of valves 8.

In the anode chamber 9 of the auxiliary electrolyzer, the pH of the purified water decreases to its value in the untreated water. In the cathode to $ 1 measure 10, the pH of the water is further increased.

Water from the anode chamber 9 is diverted either to the sewage system or to a povN 6.4-6.6 Zinc, mg / l 0.1-0.3 Nickel, mg / l 0.3-0.4 Copper, mg / l 0 3-0.8

to use. Heated water (catholyte) from the cathode chamber 10 g. Auxiliary electrolyzer 11 is smashed in mixer 12 with an acidic anolyte from the anode chamber 3 of the main electrolyzer 5, neutralizing its excess acidity. Since the anolyte of the main electrolyzer was not otcice from heavy metal ions, the catholyte mixture from the cathode chamber 10 and the anolyte from the anode chamber 3 is guided by a pump 14 through conduit 13 to the cathode chamber 4 of the main electrolyzer 5 for cleaning.

The ratio of flow rates supplied to the anode and cathode chambers of diaphragm electrolyzers is determined from the condition of the maximum flow of water in the cathode chamber of the main and anode chamber of the auxiliary electrolyzers without disturbing the process of electrochemical pH change.

When purifying water from heavy metal ions, the ratio of the costs of catholyte and anolyte in the main electrolysis cell and the ratio of the costs of anolyte and catholyte in the auxiliary electrolyzer can be in the range of (0.83-0.88) :( 0.17-0.12 ).

Example. Wastewater from the electroplating shop is made from heavy metal ions. The initial -water water has a pH of 7.4, the concentration of the cycle ions is 65, copper — 38, nickel — 44 mg / l.

As the filter loading material, polystyrene foam granules are used, as the material of the diaphragm 4y of the electrolyzers - chlorinated fabric in two layers. with

Processing parameters: the current consumption for the processing of the catholyte of the main and anolyte of the auxiliary electrolyzers - 760 Cl / l) The electrolysis voltage - 24 V; current density on the electrodes - 30 A / m; cost ratio of catholyte and anolyte 0.96: 0.14; filtration rate 2 m / h.

The concentration of heavy metal ions and pH in purified water are given. in the table.

10.1-10,22,6-2,96,9-7,2

0.1-0.442-567.2-9.8

0.2-0.428-396.6-10.0

0.4-0.830-348.6-12.7

Thus, the use of the proposed plant prevents the production emissions of contaminated and acidic water, which occurs during the purification of water in a known plant, and thereby increase the productivity of the plant.

Claims (2)

1. USSR Author's Certificate No. 454180, cl. C 02 B 1/00, 1974. 2. Authors certificate of the USSR 583099, cl. C 02 B 1/82, 1977 5 (prototype).