RU2522599C1 - Device for filtration of sewage waters with reverse osmosis membrane purification system - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: device contains a receiving reservoir, the main forcing pump, an input three-way high-speed valve, a connecting pipe for input of water to be purified, a membrane unit, a connecting pipe for output of the purified sewage, an output three-way high-speed valve and a reservoir of the purified sewage, successively connected to each other by a pipeline for operation in a sewage purification mode. In their turn, the reservoir of the purified sewage, an additional pump, the output three-way high-speed valve, the connecting pipe for output of the purified sewage, the membrane unit , the input three-way high-speed valve and a settling tank are successively connected by an additional pipeline to operate in a mode of reverse osmosis membrane purification. The membrane unit is connected to an ultrasonic generator. A control unit, provided in the device, is connected to the input and output three-way high-speed valves, additional pump and ultrasonic generator.

EFFECT: increased efficiency of periodic purification of filtering elements and increase of their service term.

1 dwg

Description

The invention relates to environmental protection technology using reverse osmosis filtering membranes for wastewater treatment, for example, the filtrate of solid waste landfills.

Known recovery reverse osmosis wastewater treatment (RU 2088537 C1, published. 08.27.1997). In a known solution, the wastewater from the washing stage of the galvanic production is subjected to mechanical filtration, then subjected to reverse osmosis to obtain the filtrate and concentrate, and then the filtrate is returned to the washing stage and the concentrate is directed to the metal extraction stage by the electrochemical method.

A disadvantage of the known solution is the reduction in plant productivity due to the constant recovery flow.

A known system for the automatic cleaning of the filter element (RU 212855810 C1, published. 04/10/1999) The invention provides an increase in the efficiency of cleaning the filter element by eliminating its gradual, slightly noticeable clogging by means of constant or periodic cleaning of the latter without violating the main cleaning mode by this element which Any medium (gas or liquid). The system cleans the filter element with at least a pressure medium. At least one concentrated medium having a higher pressure and / or speed than the medium being cleaned by the filter element is used as a cleaning medium. At the same time, at least one other medium, different in composition and / or state from the first, is used separately or together with a cleaning medium. The system comprises at least one pipe for supplying a cleaning medium, at least one support for securing the filter element.

The disadvantage of the system is the need to use such a high pressure drop across the membrane to clean it that there is a real risk of damage to the polymer material of the membrane. This is explained by the very small size of the cell membranes for reverse osmosis and their low mechanical strength.

The invention achieves the technical result, which consists in increasing the efficiency of periodic cleaning of filter elements - reverse osmosis membranes and increasing their service life.

The specified technical result is achieved in the invention as follows.

A device for filtering wastewater with a reverse osmosis membrane treatment system includes a receiving tank, a main injection pump, an inlet three-position quick-acting valve, a nozzle for inputting a cleaned drain, a membrane unit, a nozzle for discharging a cleaned drain, an outlet three-position quick-acting valve and a tank for cleaned drain, connected in series a pipeline for operation in drainage treatment mode.

In turn, the tank for cleaned drain, an additional pump, an outlet three-position quick-acting valve, a fitting for outputting a cleaned drain, a membrane unit, an inlet three-positioned quick-acting valve and a sump are connected in series by an additional pipeline for operation in the reverse osmosis membrane cleaning mode.

The membrane unit is connected to an ultrasonic generator.

The control unit, which is equipped with the device, is connected to the input and output three-position quick-acting valves, an additional pump and an ultrasonic generator.

The invention is illustrated in the drawing, which schematically shows the proposed device.

The device comprises a pipe 1 for operating in the drain cleaning mode, a receiving tank 2, a main injection pump 3, a three-position inlet quick-acting valve 4, a membrane unit 5, a nozzle 6 for entering the cleaned drain, an additional pipe 7 for operating in the reverse osmosis membrane cleaning mode, the cleaned tank 8 drain, nozzle 9 for the output of the cleaned drain, an output three-position quick-acting valve 10, an additional pressure pump 11, a settling tank 12, an ultrasonic generator 13, a control unit 14, control lines 15 I am.

The device operates as follows.

A cleaned effluent, for example, a filtrate of a landfill for solid domestic waste, is piped 1 to a receiving tank 2. Then, using the main injection pump 3, the effluent is fed to an inlet three-position quick-acting valve 4.

If the differential pressure across the membrane block 5 is exceeded by less than 10% of the nominal value, the valve 4 introduces a cleaned drain through the nozzle 6 into the membrane block 5, in which the drain is cleaned. The cleaned drain through the nozzle 9 and the output three-position quick-acting valve 10 enters the tank 8.

In the process of cleaning the drain on the surface of the reverse osmosis membrane of block 5, a precipitate layer is formed that prevents filtration.

If the differential pressure across the membrane unit 5 is exceeded by more than 10% of the nominal value recorded by the pressure sensor, a corresponding signal is sent to the control unit 14 and, according to the signal from the control unit 14, the valve 4 blocks the input of the cleaned drain to the membrane unit 5.

After this, the membrane is cleaned as follows. From the tank 8, with the help of an additional pump 11 through the pipeline 7 for operation in the reverse osmosis membrane cleaning mode, the cleaned drain through the valve 10 and the nozzle 9 enters the membrane unit 5. The membrane is flushed and the flushing products are discharged into the sump 12.

Thus, the membrane unit 5 is periodically cleaned with a reverse flow of purified effluent with the discharge of flushing products into the sump 12.

To reduce the pressure created by the additional pressure pump 11 when flushing the membrane unit 5 and to avoid damage to it, the membrane unit 5 is connected to the ultrasonic generator 13.

The generator 13 creates oscillations on the membrane with a wavelength and amplitude not less than the average cell size of the membrane. In accordance with the theory of nonlinear oscillations, superimposed oscillations with a wavelength corresponding to the characteristic size of the body to which they are applied cause oscillatory processes on its surface in a layer corresponding to the amplitude of the oscillations in thickness.

As experiments on cleaning the filtrate of the solid waste landfill show, the thickness of the sediment layer on the membrane at which the filtration stops is 22-26 microns. The dependence of the layer thickness on the operating time of the membrane block is linear.

The most rational practice turned out to be the application of ultrasonic vibrations to a layer 10-12 microns thick. Moreover, the decrease in the flow rate of the filtrate through the membrane block was 20% -25% of the nominal value.

The application of ultrasonic vibrations with a frequency from 3.0 to 22.0 kHz for 30-50 seconds once in 10 days of operation made it possible to maintain the constancy of the volume of the treated stream with an accuracy of 1.5%.

The service life of the filtering reverse osmosis membranes for cleaning the filtrate without periodic washing of the membrane block 6 with a reverse flow of purified runoff 9 was 92-96 days.

The service life of filtering reverse osmosis membranes for cleaning the filtrate with periodic washing of the membrane unit 6 with a reverse flow of purified effluent 9 was 205-215 days.

The service life of filtering reverse osmosis membranes for cleaning the filtrate with periodic washing of the membrane block 6 with a reverse flow of purified drain 9 and the application of ultrasonic vibrations with a frequency of 3.0 to 22.0 kHz was 725-760 days.

When ultrasonic vibrations are applied, the sediment on the surface of the fragments is destroyed, forming a visually well-visible fluidized bed, which is removed by a reverse flow.

The economic efficiency of the invention is determined by a significant reduction in the need for membrane blocks in wastewater treatment

Claims (1)

A device for filtering wastewater with a reverse osmosis membrane purification system, comprising a receiving tank, a main injection pump, an inlet three-position quick-acting valve, a nozzle for inputting a cleaned drain, a membrane unit, a nozzle for discharging a cleaned drain, an outlet three-position quick-acting valve and a tank for cleaned drain connected in series with a pipeline for work in the mode of effluent treatment, while the reservoir of purified effluent, an additional pump, an output three-position high-speed a control valve, a fitting for the outlet of the cleaned drain, a membrane block, an inlet three-position quick-acting valve and a sump are connected in series with an additional pipeline for operation in the reverse osmosis membrane cleaning mode, a membrane block is connected to an ultrasonic generator, and a control unit is connected to an inlet and outlet three-position quick-acting valves, additional pump and ultrasonic generator.

Images