RU2328450C2 - Processing line for disinfecting sewage water and natural water - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention pertains to disinfection of sewage water and natural water without use of chemical reagents, such as chlorine, fluorine, ozone, and can be used in treating water in household and industrial systems, in chemical and pharmaceutical, drinking and meat processing, medical and other industries. The processing line consists of five stages of cavity processing, each of which contains a container and a hydro-dynamic cavitator in form of rotary cavitator. The installation is equipped with a clarification line and a discharge line for sludge into the sewer system. Cavitation action in the five cavitators provides for not only inhibition of bacteria, on partial precipitation of salts of heavy metals.

EFFECT: stepwise increase in pH in five stages of cavitational treatment of water provides for killing pathogenic microflora.

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Description

Technical field

The invention relates to a device for cavitation disinfection of natural and wastewater without the use of chemicals, such as chlorine, fluorine, ozone, and can find application in the preparation of water in drinking water and industrial systems, as well as for disinfecting sewage from enterprises in meat and dairy industry and other agricultural facilities.

The wastewater and natural water treatment methods used in modern wastewater treatment plants cannot cope with the increasing anthropogenic pollution of water supply sources and, as a result, there is a deterioration in the quality of drinking water, including bacteriological indicators.

Disinfection or disinfection is the treatment of water, which should ensure the destruction of pathogens in it. Degree of disinfection within the limits of 99.99 ÷ 99.999% is considered satisfactory.

Among the chemical methods of disinfection, the most common at the moment is chlorination, since chlorine is a relatively inexpensive gas with a wide spectrum of antimicrobial activity.

However, recent studies have shown that traditional water treatment schemes in many cases are not a barrier to the penetration of viruses, protozoa cysts and giardia into drinking water, but methods for the treatment of wastewater from helminth eggs using approved substances (chlorine, bleach, formalin , lysol, bromide metal, etc.) do not provide complete deworming of wastewater and all types of precipitation formed.

It is proved that during chlorination of wastewater, chemical compounds are formed with mutagenic and carcinogenic properties. Even a small amount of residual chlorine is toxic to the fauna of water bodies. In addition, the resulting organochlorine compounds also contaminate drinking water, since, having high resistance, they cause pollution of rivers over significant distances downstream, practically without being removed during the water treatment process. Therefore, many countries are currently intensively searching for alternative methods of disinfecting wastewater and natural waters.

The level of technology.

A known system of effective disinfection of water (Russian patent No. 2125973 dated 02.10.1999), including a system for supplying chemical reagents (chlorine, ozone, fluorine as part of a dosing unit, hydrodynamic acoustic emitters, pressure and reagent collectors, water pump.

The disadvantages of the known system are:

a) use for disinfecting water, although in smaller quantities, chemicals, such as chlorine, ozone, fluorine;

b) cavitation formed by hydrodynamic emitters is used to intensively mix the reagent with the treated water, to break up colonies of microorganisms into single bacteria, which leads to improved access of the reagent to living microorganisms;

c) the presence of toxic organochlorine compounds in treated water (3-chloromethane, 4-carbon chloride, etc.)

A known installation for cleaning and disinfecting aqueous media (Russian patent No. 2170713 from 07.20.2001), including a device for producing electroactivated water with anolyte and catholyte chambers, anolyte cavitation chamber, coagulation chamber and catholyte cavitation chamber, the cavitation chamber is combined with a photochemical reactor and contains one or more ultrasonic emitters and one or more ultraviolet emitters. The output of the anolyte chamber — a device for producing electroactivated water — is connected through the anolyte cavitation chamber to the cavitation chamber. The jet pump is connected to the catholyte chamber exit by an eliktor, a device for producing electroactivated water. The unit is equipped with a unit for receiving and supplying an ozone-containing mixture.

The disadvantages of this method are:

a) the location of the photochemical reactor in a cavitation chamber into which untreated water is supplied, although disinfection by bactericidal radiation can be carried out only when the water to be disinfected has low color and does not contain colloidal and suspended substances that absorb and scatter ultraviolet rays;

b) the use of ultrasonic vibrations for disinfecting water is accompanied by the following mandatory conditions:

- the thickness of the layer above or below the ultrasonic emitter should be no more than 10 cm;

- the exposure time of ultrasonic vibrations is 3 minutes, and the most effective frequency of ultrasonic vibrations is 722 kHz;

- the combined use of chlorine and ozone compounds can lead to both a decrease and an increase in organochlorine compounds in water;

c) high energy intensity and cost of ozonation equipment.

A known method of treating water and aqueous solutions (Russian patent No. 2240984 dated 11/27/2004), a prototype that includes adjusting the pH of the water by repeatedly decreasing the pressure of a high-pressure liquid when it is recycled to the value at which it cavitates, followed by increasing the pressure to which cavitation stops. In this case, the recirculated liquid is preheated, after which part of the high-pressure liquid is taken for filtration. From the remaining recirculation stream, a cavitating liquid with increasing pressure is taken. Next, the liquid is cooled, kept until the cavitation bubbles collapse and solid impurities precipitate, and then the stabilized liquid is returned to the low-pressure recirculation stream. To enhance the cavitation process created by a Venturi nozzle or in the center of a rounded liquid flow, it can be amplified by ultrasound or electric plasma discharge.

The disadvantages of this method are:

a) the selection of hot water for domestic needs or to feed the swimming pool is done before the cavitator, which means that the water is simply heated and passed through the filter without cavitation disinfection;

b) the filtered impurities are washed off by a hot stream and sent by a pump through a heat exchanger and cavitator to a precipitating stabilizer, where they accumulate in the lower part of the precipitating agent and then are periodically removed along line VII;

c) the need to preheat the source fluid to 90 ° C, which is associated with high energy consumption;

d) the use of a Venturi nozzle or a swirling flow as a cavitator with the formation of a low pressure zone in the center requires multiple passes of fluid through the cavitator due to the inability to lower the pressure in the entire flowing fluid flow;

e) the use of ultrasound or an electric plasma discharge as an additional means of exposure to a microorganism, which sharply increases the specific energy consumption for disinfection of 1 m ^{3 of} liquid, requires complex hardware design and compliance with unprecedented safety measures.

Disclosure of the invention.

The technical problem to which the invention is directed is to create a line for the disinfection of wastewater and natural waters with increased efficiency for the destruction of viruses, protozoa cysts, giardia and helminth eggs by hydrodynamic cavitation without the use of other sources and methods of influencing pathogenic microflora.

The task is achieved by the fact that in the claimed line of disinfection of wastewater and natural waters, the well-known properties of hydrodynamic cavitation and the creation of conditions for the formation of cavitation bubbles and their subsequent "collapse" are used.

The invention solves the problem of expanding the functionality of the method of cavitation disinfection of wastewater and natural waters by stepwise increasing the pH of the treated water from 7 to 9.5 or more to ensure the death of pathogenic microflora by 99.99%.

Achieving this task is ensured by the creation of a technological line for the disinfection of natural and waste waters, including:

a) the division of the zone of cavitation treatment of water into three zones:

- zones of reduced pressure;

- areas of high pressure;

- discharge zones.

b) the creation of cavitation bubbles in the treated water, providing: mechanical, thermal, electrical and chemical effects on bacteria.

New in the claimed production line for the disinfection of natural and waste waters is that cavitation bubbles in a liquid are created by lowering the pressure below the pressure of saturated vapors at a given temperature.

It is known that cavitation is the phenomenon of vaporization and air release due to a decrease in pressure in the liquid. The reason for its occurrence is the boiling of a liquid at normal temperature and low pressure. The appearance of cavitation is facilitated by air dissolved in water, which is released when pressure decreases (I. Pirsol. Cavitation p. 9).

In the life of a cavitation bubble, two phases are distinguished - expansion and collapse, which together form a complete thermodynamic cycle.

In the pressure zone, the hydrostatic pressure decreases to such an extent that the forces acting on the liquid molecules become greater than the forces of molecular bonds. As a result of a sharp change in hydrostatic equilibrium, the liquid, as it were, bursts, creating numerous tiny bubbles. Cavitation occurs the earlier, the more the fluid is “contaminated” with solid particles or other foreign bodies (such as bacteria), the higher its temperature or the more gases dissolved in it. Cavitational "boiling" of the liquid is due to the fact that a thin layer of air is adsorbed on the surfaces of these particles, the particles of which, when they enter the zone of reduced pressure, serve as foci that contribute to the occurrence of cavitation.

Bacterial flora located in the treated fluid also serves as centers for the formation of cavitation bubbles. When liquid enters the zone of reduced pressure, the liquid boils, and in bacteria located in the center or near the formed cavitation bubble, the cell membrane completely or partially breaks down under the influence of the pressure difference inside them and the surrounding space.

The second phase of the life of the acknowledgment bubble - collapse (condensation), occurs in the zone of high pressure, where it moves together with the processed fluid. The condensation process of the cavitation bubble occurs almost instantly. Particles of fluid surrounding the bubble move to its center with great speed. As a result, the kinetic energy of the contained particles causes local hydraulic micropumps at the moment of bubble closure, accompanied by a local increase in pressure to 10 ⁴ kg / cm ² and a local temperature increase to 1000-1500 ° C. Under conditions of flow of hydrodynamic cavitation at high speeds of the working bodies inside cavitators of 28-33 m / s, most of the cavitation bubbles are deformed and have an elliptical or conical shape. When such bubbles collapse, high-energy cumulative streams appear that destroy everything that comes in their way. The collapse of a separate cavitation bubble does not give the expected effect, but there are many cavitation bubbles and “grab” them many thousands per second, therefore, together they can have a significant destructive or other effect without high-temperature heating of the treated fluid.

Thus, in addition to the mechanical effect, cavitation has a bacterial flora and microsterilization effect under ultrahigh-temperature conditions in the region where the cavitation bubble disappears.

The walls of the cavitation bubble and liquid droplets inside it are charged with unlike electricity. When the bubbles are compressed, their sizes sharply decrease and the charges are located on the surfaces of the bubbles of very small sizes. As a result of a sharp decrease in the surface of cavitation bubbles, the voltage of static electricity increases sharply. Between the walls of cavitation bubbles and droplets inside them, electric discharges resembling microscopic lightning slip through. These high-voltage electric discharges also have the detrimental effect of non-bacteria, which turned out to be the source of the appearance of these bubbles.

High temperatures and pressures arising at the points of disappearance of cavitation bubbles, as well as micromagnets of static electricity, contribute to the decomposition of water through the reactions:

Н ₂ О↔Н ⁺ + (ОН) ^-

2H ₂ OH (OH) ⁺ + H ₂

hydroxyl groups (OH) ⁺ and (OH) ^- , emitted on the shells of cavitation bubbles, upon condensation of the latter form hydrogen peroxide by reactions

(OH) ⁺ + (OH) ^- → H ₂ O ₂

2 (OH) ^- → H ₂ O ₂ + 2e ^-

The occurrence of cavitation on the surfaces of bacteria surrounded by adsorbed air is accompanied by the formation of free radicals OH ^- , HO ₂ , N, as well as the final products of their recombination H ₂ O ₂ , HNO ₂ , HNO ₃ .

The formation of hydrogen peroxide of free radicals and acids also has a detrimental effect on the bacterial flora of the treated fluid.

The course of all the above chemical reactions allows, by gradually increasing the pH, to bring its value at the last stage of disinfection to 9.5 without using any chemical reagents and preheating, to provide softening of the treated liquid, its disinfection by 99.99%, partial desalination and preparation of water for fine filtration.

Example 1

The effectiveness of disinfecting natural water from an open reservoir and Salmonella bacteria colonized in it for 1, 2, 3, 4, 5 passes through the rotary cavitator has been verified.

The effectiveness of the cavitation method was evaluated by the ratio of living and dead bacteria in the field of view of the Biolam microscope

- After the first pass, 61% of bacteria, mainly saprophyte, died;

- After the second pass - 85% of various bacteria, including salmonella;

- After the third pass - 91%;

- After the fourth pass - 98%;

- After the fifth pass - 100%;

The drawing shows a diagram of a technological line for cavitation disinfection of waste and natural waters, which consists of the following main nodes:

1, 2, 3, 4, 5 - tanks for receiving the source and treated water (I, II, III, IV and V stages of treatment)

6, 7, 8, 9, 10 - rotary cavitators (I, II, III, IV, V stages of processing)

11, 12, 13, 14, 15 — suction nozzles of cavitators (6, 7, 8, 9, 10), respectively.

16, 17, 18, 19, 20 - pressure pipes of cavitators (6, 7, 8, 9, 10).

21 - pipeline for draining sludge from 4 and 5 tanks into the sewer.

22 - pipeline supplying water to the clarification line.

A production line for implementing the method of cavitation disinfection of wastewater and natural waters will develop as follows.

The source of natural or waste water enters the tank 1 (the first stage of disinfection - I), from which it is sent through the suction pipe 11 to the hydrodynamic cavitator 6. The hydrodynamic cavitator is made with a displaced rotor, in the high pressure zone of which the vacuum necessary for the formation of bubbles is maintained, and in the zone of increased pressure formed by jamming of a part of the liquid between adjacent blades and the cavitator body — increased pressure providing “collapse” of cavitation bubbles and the fluid supply through the pressure pipe 16 into the tank 2 (II stage).

The entire cycle of formation and "collapse" of cavitation bubbles is carried out for 1 revolution of the rotor of a hydrodynamic cavitator.

From the tank 2 through the suction pipe 12, the fluid is directed to the zone of reduced pressure of the cavitator 7, and from the zone of high pressure through the pressure pipe 17 to the tank 3 (III stage).

Inside the cavitator 7, the same processes occur as the cavitator 6. From the tank 3 through the suction pipe 13, the liquid is directed to the reduced pressure zone of the cavitator 8, from which it flows through the pressure pipe 18 into the tank 4 (IV - stages). The water entering tank 4 already has a pH of 8.5, so it provides primary sediment of insoluble salts and organic sediments. On the suction pipe 14, located at a height of 0.5-0.7 m from the bottom of the tank 4, the fluid is sent to the cavitator 9 in the zone of low pressure, and then from the zone of high pressure through the pressure pipe 19 to the tank 5 (V stage). From the tank 5 through the suction pipe 15, located similarly to the pipe 14, the liquid enters the zone of reduced pressure of the cavitator 10, and then from the zone of increased pressure of the cavitator through the pressure pipe 20 either to the tank for additional processing, or through the pipe 22 to the clarification line. Precipitation of insoluble salts, mechanical and organic impurities through the pipeline 21 is periodically routed through the sludge drain line to the sewer.

The equipment of the technological line for disinfecting wastewater and natural waters is simple in design and can be manufactured at any machine-building enterprise.

Information sources

1. Patent of Russia No. 2125973 dated 02.10.1999.

2. Russian Patent No. 2240984 dated November 27, 2004.

3. Patent of Russia No. 2214969 dated October 27, 2003.

4. L.A. Kulsky, P.P. Strokach, V.A. Slipchenko, E.I. Saychak. Water purification by electrocoagulation. - Kiev: Busvilnik, 1978, pp. 5-12, 18-23, 44-48, 79-82.

5. V.A. Klyachko, I.E. Apeltsin. Natural water treatment. - Moscow: Stroyizdat, 1971, pp. 288-293, 321-332.

6. I. Pirsol. Cavitation. - M .: Mir 1975, pp. 9-14, 69-72.

7.T.M.Bashta. Engineering hydraulics. - Moscow: Engineering, 1971, pp. 44-49.

8. Physics 9/1989, L. G. Druzhinin, G. P. Markov, V. I. Stapko. “Sounding Light” and “Glowing Sound”, Moscow: Knowledge - 1989, pp. 17-24, 54-62.

9. I.G. Kharbenko. Beyond the Hearing. - Moscow: Mechanical Engineering, - 1981, pp. 86-92.

Claims (1)

A technological line for cavitation disinfection of wastewater and natural waters, including five stages, each of which contains a tank and a hydrodynamic cavitator, characterized in that each hydrodynamic cavitator is made in the form of a rotary cavitator with a suction nozzle and a pressure nozzle, the capacity of the first stage is connected to the suction nozzle of the cavitator the pressure port of which is connected to the capacity of the second stage; the cavitator of the second stage is connected by nozzles to the tanks of the second and third stage; the cavitator of the third stage is connected by nozzles to the tanks of the third and fourth stage; the cavitator of the fourth stage is connected by nozzles to the tanks of the fourth and fifth stages, the cavitator of the fifth stage by nozzles is connected to the capacity of the fifth stage and the clarification line, and the lower parts of the capacities of the fourth and fifth stages are connected by pipelines to the drain line of sewage into the sewers.