RU2214972C1 - Method of water treatment - Google Patents

Abstract

FIELD: treatment of sewage, domestic and industrial waste water; metallurgy; chemical, food- processing, wood-working, oil refining industries. SUBSTANCE: proposed method is used for cleaning water from contaminants, such as compounds of alkali, alkali-earth, transition, heavy and radioactive elements, petroleum products, colloidal particles, organic compounds including dyes, high-molecular agents and surfactants, as well as for thickening and reducing moisture content of sludge. Coagulant with flocculant and activating additive are introduced in water to be cleaned. Mass ratio of activating additive to coagulant ranges from 0 to 500 parts by mass. Water is also subjected to treatment with elastic oscillations at intensity ensuring realization of cavitation in water at cavitation noise level in frequency range of from 500 to 500000 Hz no below 50 dB over entire volume of reactor and acoustic macro- and micro-flows at rate no less than 1% of oscillatory velocity of surface transmitting elastic oscillations to liquid. Water is treated with all said methods simultaneously in combined mode. Solid phases are removed. EFFECT: enhanced efficiency of cleaning; reduced power and labor requirements. 13 cl, 1 dwg, 5 ex

Description

 The invention relates to methods for treating wastewater and domestic and industrial water and can be used in the chemical, metallurgical, food, wood, oil, meat, fish processing and other industries for the treatment of water from polluting components, such as compounds alkaline, alkaline earth, transition, heavy and radioactive elements, petroleum products, colloidal particles, organic compounds, including dyes, high molecular weight and surfactants and others, as well as to thicken and reduce moisture sludge from various industries.

 A known method of water purification, which uses ultrasonic treatment of water in order to create cavitation phenomena in the liquid being treated, with the help of which acid contaminants are removed from the water (JP 3221189 A, published. 09/17/98).

 The disadvantage of this method is the complexity, as well as the limitations of the scope of this method, which consists in purifying water only from hypochlorous acid.

 A known method of water purification, in which water is treated with a coagulant, ultrasound and then subjected to flotation separation (JP 58-45307 A, published. 08.10.83).

 The disadvantage of this method is the unsatisfactory degree of water purification, high consumption rates of reagents, as well as the complexity.

 A known method of water treatment, in which water together with a liquid flocculant is subjected to ultrasound treatment (US 4961860 A1, published. 09.10.90).

 The disadvantage of this method is the unsatisfactory degree of water purification, high consumption rates of reagents, as well as the complexity.

 The prototype of the invention is a method of treating wastewater by treating it with a coagulant and flocculant in the form of an aluminum-silicon reagent, followed by separation of the precipitate formed, and a gaseous and / or liquid activating additive is additionally introduced into the treated water at a mass ratio of activating additive to coagulant and flocculant equal to 0.02 -500 parts by weight (RU 2114787 A1, published. 07/10/98).

 The disadvantage of this method is the presence of an incubation period associated with the formation of active silica in the treated water, which ultimately leads to an increase in the duration of the technological cycle and the use of significant technological capacities in volume, as well as an increase in the energy consumption and laboriousness of the method.

 The invention achieves the technical result, which consists in increasing the degree of purification of water from pollution and expanding the scope of the method, including for drinking water and industrial water supply systems, while reducing the consumption of reagents, as well as reducing energy costs and the complexity of the method.

 The specified technical result is achieved as follows.

 A method of purifying water in a reactor is that a coagulant with a flocculant and an activating additive are introduced into the purified water. The mass ratio of the activating additive to the coagulant with the flocculant is 0-500 wt.h.

 The purified water is also treated with elastic vibrations with an intensity that ensures cavitation in water with a cavitation noise level in the frequency range of 500-500000 Hz not less than 50 dB over the entire volume of the reactor and acoustic macro and micro flows with a speed of at least 1% of the surface vibrational velocity, transmitting elastic vibrations in a liquid.

 In this case, the water to be treated is treated with all these methods simultaneously in a combined mode.

 The solid-phase suspensions resulting from the treatment are separated.

 In a particular case, the treatment of purified water is carried out in a continuous mode of excitation of elastic vibrations.

 Also, in a particular case, the treatment of purified water is carried out in a pulsed mode of excitation of elastic vibrations, in which the time of excitation of the oscillations is not less than 1000 oscillation periods, and the pause time is not less than 2000 oscillation periods.

 Also, in a particular case, the treatment of purified water is carried out in a flowing system at a hydrodynamic flow rate not exceeding the vibrational velocity of the surface, transmitting elastic vibrations to the liquid.

 In a particular case, a liquid-phase aluminosilicon reagent is used as a coagulant with a flocculant.

 Also in the particular case, solid-phase reagents are used as a coagulant, which are added in a concentration of from 0.01 mg / l to 10 g / l.

 Also in the particular case, gaseous reagents, for example, air or oxygen or ozone, are used as an activating additive.

 In the particular case, liquid reagents, for example, cationic polyelectrolytes or solutions of inorganic salts or surfactants or high molecular weight compounds or mixtures thereof, are used as activating additives.

 Also in the particular case, as an activating additive, liquid and gaseous reagents are simultaneously used.

 Also, in the particular case, at least one hydrodynamic emitter operating in the frequency range of 500-10000 Hz is used as a source of elastic vibrations.

 Also, in the particular case, at least one electro-acoustic transducer of piezoceramic or magnetostrictive types, operating in the frequency range of 10000-500000 Hz, is used as a source of elastic vibrations.

 In a particular case, hydrodynamic emitters operating in the frequency range of 500-10000 Hz and electro-acoustic transducers of piezoceramic or magnetostrictive types operating in the frequency range of 10,000-100,000 Hz are used as sources of elastic vibrations.

 Also, in a particular case, piezoelectric or magnetostrictive type electroacoustic transducers operating in the frequency range of 10,000-100,000 Hz and piezoceramic type electroacoustic transducers operating in the frequency range of 100,000-500,000 Hz are used as sources of elastic vibrations.

 The effect of elastic vibrations on the processes of flotation water purification leads to a sharp decrease in the time of formation of nuclei of the solid phase of a coagulant with a highly developed active surface. The combination of adsorption and flocculation processes with the participation of highly dispersed particles of the coagulant determines a high degree of water purification from pollution of various origins.

 The simultaneous use in the combined mode of elastic vibrations in a wide frequency range with flotation methods of water treatment leads to an increase in the degree of removal of contaminants and a wider scope of application of this technology, while reducing the consumption of reagent, including for drinking water and industrial water supply systems. This ensures the accelerated deposition of the formed precipitate and faster removal of contaminants.

 The invention is illustrated by the drawing, which schematically shows a device with which can be implemented the method of water purification according to the invention.

 A water purification device comprises a reactor 1, a hydrodynamic emitter 2, a nozzle 4 for introducing a coagulant, a flocculant and an activating additive into the reactor 1, a unit 5 for introducing purified water into the reactor vessel 1, made in the form of a rotatable "comb".

 The device also contains a tray 6 for removing purified water, a tray 7 for removing foam, an ultrasound system 8, consisting of an electro-acoustic transducer of piezoceramic or magnetostrictive types and a rod-type waveguide emitter.

 For additional ultrasonic intensification of the cleaning process, the device is equipped with a circuit 9, consisting of an additional hydrodynamic emitter 3 and a pump 10 (installed optionally).

 The method of water purification is as follows.

 The purified water is fed through a hydrodynamic emitter 2, which creates elastic vibrations in the frequency range 500-10000 Hz and implements a cavitation field in water, and then through a rotated "comb" 5 into the reactor 1. The hydrodynamic emitter 2 is equipped with a nozzle 4, which allows ejection of a liquid-phase coagulant with flocculant and activating additives in a passing stream of water.

 As a coagulant with a flocculant, one reagent that performs both of these functions simultaneously, and two reagents, each of which performs the functions of the flocculant and coagulant separately, can be used. Moreover, in the case of using two separate reagents as a coagulant and flocculant, the mass ratio of the activating additive is selected from the range of 0-500 wt.h. in relation to the total amount of these reagents.

 Due to the rotation of the "comb" 5 there is a more uniform distribution of the flow of water and rising bubbles of the introduced gaseous activating additive throughout the reactor volume.

 To accelerate wastewater treatment processes (hydrolysis of a liquid-phase coagulant, formation and growth of coagulant particles, etc.), an ultrasonic system 8 is immersed in the reactor. Ultrasonic oscillations in the frequency range of 10000-500000 Hz are transmitted from the waveguide surface and propagate in the treated water throughout the reactor 1 .

 It was experimentally established that under the above parameters and excitation conditions, the intensity of elastic vibrations excited by a hydrodynamic emitter 3 and an ultrasonic system 8 ensures cavitation in water with a cavitation noise level in the frequency range of 500-500000 Hz not less than 50 dB over the entire volume of the reactor and acoustic macro - and microflows with a speed of at least 1% of the vibrational velocity of the surface, transmitting elastic vibrations in the liquid.

 Air bubbles rise to the surface of the water and carry along the products of hydrolysis of the liquid-phase coagulant, which adsorb various water pollution. Thus on the surface of the water a layer of foamy product is formed, which is removed from the reactor 1 using the tray 7 to remove foam. The purified water flows by gravity into the tray 6 to drain the purified water.

 If the costs of the water to be treated are large and the quality of the treatment is insufficiently additionally apply the circuit 9 of the ultrasonic intensification of the water treatment process. In this case, the purified water, in which the coagulant and flocculant is already present, is additionally passed through the hydrodynamic emitter 3 using the pump 10. Thus, the effective time of a single volume of water in an intense ultrasonic field is increased.

 In addition, through an additional hydrodynamic emitter 3, it is possible to carry out additional ejection of a gaseous activating additive (air, oxygen, ozone), which also speeds up the process and increases the depth of wastewater treatment from pollution.

Specific examples of the implementation of the method
Example 1
The wastewater of the paint and varnish production of a furniture company, having the following composition, mg / l: suspended solids 1360, iron 48, polyurethane varnish 1410, is continuously processed by elastic vibrations created in the liquid by the emitter of an electro-acoustic transducer, with a frequency of 25000 Hz with an intensity that ensures implementation in water cavitation with a cavitation noise level in the frequency range of 10000-500000 Hz at a distance of 100 mm from the radiating surface of at least 50 dB, with the introduction of aluminum-silicon reagent in the amount of 0.08 l / m ³ and activating additives (air) in a ratio of 100 wt. including by bubbling. In this case, the speed of the resulting macro and micro flows is 10% of the vibrational velocity of the surface, transmitting elastic vibrations in the liquid.

The experiments were carried out on standard technological equipment using an ultrasonic setup consisting of a 1 kW ultrasonic generator, a magnetostrictive transducer of a magnetostrictive type, and a waveguide-emitting system with a rod type radiator with a radiating surface of 25 cm ³ .

 The precipitate formed is separated through a film-cloth filter. Purified water has a composition, mg / l: the amount of suspended solids is less than 30, iron (III) is less than 0.5, polyurethane varnish is less than 0.8.

Example 2
The proposed method is carried out analogously to example 1, but the turbid technological effluents of the refinery containing suspended solids and petroleum products in the amount of (mg / l) 180 and 340, respectively, are processed while simultaneously introducing an activating additive in the system - air with a mass ratio to aluminum-silicon reagent equal to 500. The speed of the resulting macro and micro flows is 15% of the vibrational velocity of the surface, transmitting elastic vibrations in the liquid.

 An easily removable foam product is formed.

 The content of suspended solids and oil products after processing is (mg / l) 2 and 0.4, respectively. The organoleptic characteristics of purified water improve: there is no opalescence and smell.

Example 3
The proposed method is carried out analogously to example 1, but the process water of bottle washing production is treated sequentially with an aluminum-silicon reagent and activating additives — a high molecular weight cationic polyelectrolyte with a ratio of the polyelectrolyte to the aluminum-silicon reagent equal to 0.02 and air with a mass ratio of the latter to the aluminum-silicon reagent equal to 12.

 After processing, the content (mg / l) of suspended solids decreased from 68 to 0.2, hardness salts from 85 to 0.8, and sodium ions from 200 to 80, respectively, which corresponds to sanitary and hygienic standards for household and drinking water. Without the introduction of activating additives, the efficiency of water treatment is lower by 50%.

Example 4
The proposed method was carried out analogously to example 1, but the treatment with elastic vibrations was carried out in a pulsed excitation mode, in which the excitation time was 40,000 oscillation periods, and the pause time was 80,000 oscillation periods.

 The textile process water containing polyvinyl alcohol was treated with aluminum-silicon reagent using sodium carbonate as an activating agent with a mass ratio of the latter to aluminum-silicon reagent equal to 50. The content (mg / l) of suspended solids and polyvinyl alcohol in the water amounted to 1300 and 1115 before treatment , and after processing 3,5 and 12 respectively.

Example 5
The proposed method is carried out analogously to example 1.

Stocks of a pig farm with a composition, mg / l: suspended substances 2980, sulfur-containing compounds 18.6, iron 37.8, ammonium nitrogen 281, sodium phosphates 146, oil products 55.2, oils 440, ether-extractable substances 827, pH 8.5 are treated with aluminum-silicon reagent after the introduction of an activating additive, a cationic surfactant (alkyl, C ₁₀ -C ₁₈ -trimethylammonium chloride) into the stock. The ratio of activating additive to aluminosilicon reagent in stock is 0.02.

 An analysis of the water composition after treatment showed the presence of contaminants in water in the amount, mg / l: suspended solids 1.5, sulfides 0.1, iron 0.3, ammonium nitrogen 0.9, phosphates 0.1, oil 0.5, oils 3.1, ether-extractable substances 2. Without the introduction of an activating additive, the degree of purification of water, for example, from petroleum products is reduced by 2 times.

Claims (13)

 1. The method of purification of water in the reactor, which consists in the fact that a coagulant with a flocculant and an activating additive are introduced into the purified water at a mass ratio of the activating additive to the coagulant with the flocculant equal to 0-500 wt. hours, additionally purified water is treated with elastic vibrations with an intensity that ensures the implementation of cavitation in water with a cavitation noise level in the frequency range of 500-500000 Hz not less than 50 dB over the entire volume of the reactor and acoustic macro and micro flows with a speed of at least 1% of the vibrational the surface velocity transmitting elastic vibrations in the liquid, while the purified water is treated with all these methods simultaneously in the combined mode and the solid-phase suspensions formed are separated.  2. The method according to p. 1, which consists in the fact that the treatment of purified water is carried out in a continuous mode of excitation of elastic vibrations.  3. The method according to p. 1, which consists in the fact that the treatment of purified water is carried out in a pulsed mode of excitation of elastic vibrations, in which the time of excitation of the oscillations is not less than 1000 periods of oscillation, and the pause time of not less than 2000 periods of oscillation.  4. The method according to p. 1, which consists in the fact that the treatment of purified water is carried out in a flowing system at a hydrodynamic flow rate not exceeding the vibrational velocity of the surface, transmitting elastic vibrations to the liquid.  5. The method according to p. 1, which consists in the fact that as a coagulant with a flocculant use a liquid-phase alumina-silicon reagent.  6. The method according to p. 1, which consists in the use of solid-phase reagents as a coagulant, which are added in a concentration of from 0.01 mg / l to 10 g / l.  7. The method according to p. 1, which consists in the fact that as an activating additive use gaseous reagents, such as air, or oxygen, or ozone.  8. The method of claim 1, wherein liquid activating agents, for example cationic polyelectrolytes, or solutions of inorganic salts, or surfactants, or high molecular weight compounds, or mixtures thereof, are used as activating additives.  9. The method according to p. 1, which consists in the fact that as an activating additive at the same time use liquid and gaseous reagents.  10. The method according to p. 1, which consists in the fact that at least one hydrodynamic emitter operating in the frequency range 500-10000 Hz is used as a source of elastic vibrations.  11. The method according to p. 1, which consists in the fact that at least one electro-acoustic transducer of piezoceramic or magnetostrictive types operating in the frequency range of 10000-500000 Hz is used as a source of elastic vibrations.  12. The method according to p. 1, which consists in the fact that hydrodynamic emitters operating in the frequency range of 500-10000 Hz and electro-acoustic transducers of piezoceramic or magnetostrictive types operating in the frequency range of 10,000-100,000 Hz are used as sources of elastic vibrations.  13. The method according to p. 1, which consists in the fact that the sources of elastic vibrations using electro-acoustic transducers of piezoceramic or magnetostrictive types, operating in the frequency range of 10000-100000 Hz and electro-acoustic transducers of piezoceramic type, operating in the frequency range of 100000-500000 Hz.