RU2116264C1 - Method for sewage treatment - Google Patents

Abstract

FIELD: methods of sewage treatment in agriculture, food industry, etc. SUBSTANCE: method includes ionization of sewage in the circulating circuit where sewage waters are exposed to ultrasonic effect, and further on, they are mixed with sorbent based on zeolite and/or ash of burnt peat, and/or shales, and/or dust - waste of cement production. Produced liquid fraction is homogenized, its ph is varied to at least 3 and sorbent is added and pH of liquid phase is increased up to at least 10, mixed with coagulant and/or flocculant and settled with correction of pH to normal value. Then liquid is saturated with air and exposed to ultrasonic effect under conditions of cavitation and ultraviolet radiation in continuous or pulse mode, with pulse frequency of 1-10 Hz and power density of at least 20 kW/sq.m. It makes it possible to efficiently precipitate substances dissolved in sewage and to separate the precipitated sediment from treated liquid. EFFECT: higher efficiency. 3 dwg, 13 tbl

Description

 The invention relates to methods for the treatment of effluents in agricultural production, food industry.

 Known methods of wastewater treatment, including exposure to them by physical factors with subsequent regulation of the pH of the liquid part [3,4]. The physical effect in these cases can be in the form of exposure to radiation, ultrasound, etc., however, these methods are ineffective, since with heavily polluted effluents the degree of release of solid particles and dissolved material from the liquid is small.

 Also known is a method of treating domestic wastewater, including mechanical treatment of water with subsequent exposure to the liquid by a physical factor - ultraviolet and filtration [2]. This sequence of operations allows for finer cleaning, however, its degree in most cases is insufficient.

 Closest to the proposed is a method of wastewater treatment, including ozonation of wastewater with subsequent coagulation and flotation, sedimentation and separation of the liquid from the solid sediment [1]. However, in this case, the quality of cleaning is not enough.

 The objective of the invention is to increase the efficiency of the method, i.e. better cleaning.

This problem is solved by the fact that ozonation is carried out in a circulation circuit, and also in this circuit the effluents are sonicated and the effluents are further mixed with a sorbent based on zealite and / or ash from burning peat and / or shale, and / or dust, which is waste in the production of cement, after which the resulting liquid fraction is homogenized with a change in its pH to at least 3, then a sorbent is fed with an increase in the pH of the liquid fraction to at least 10, mixed with a coagulant and / or flocculant, after which it is settled with correction pH to the normal value, more liquid saturated with air and sonicated under cavitation conditions and further exposure to ultraviolet radiation in a pulsed mode with a pulse frequency of 1-10 Hz and a power density per pulse of at least 20 kW / m ^2.

 In FIG. 1-3 shows the stages of the method. The method is implemented as follows.

At the first stage (Fig. 1), the effluents enter a circulation circuit consisting of a jet pump 1, at the input of which there is an ejector 2 for air intake and ozone injection, and a cavitation chamber 3, the role of which can be played by the output diffuser of pump 1 or a separate magnetostrictive ultrasonic emitter, as well as the reaction chamber 4. Water with air bubbles entering it due to ejection is then pumped 1 to the cavitation chamber 3, where it is exposed to an ultrasonic (ultrasound) field with a frequency of 25-35 kHz and a power of 0.05-1 W / cm ² . Under the influence of the ultrasound field, partial destruction of macromolecules and agglomerates occurs, ozone is produced (at least 0.1 mg / l), air bubbles disperse, and volumetric degassing occurs. The wastewater entering chamber 4 is mixed with a sorbent, which can be used as a sorbent [6] and then fed back to pump 1. This makes it possible to efficiently mix the sorbent with wastewater and, after passing through their circuit many times, increase the efficiency of the sorbent. The latter is a sorbent based on zealite and / or ash from the combustion of peat and / or shale, and / or dust, which is a waste from cement production, and these components are sintered at high (more than 1000 ^o С) temperatures, i.e. those waste, the price of which is hundreds of times lower than the known used sorbents. During high temperature treatment, radical or ionic type active centers form on the surface of the sorbents, i.e. sorbents-catalysts with high selectivity.

 In the table. Figure 1-3 shows the particle size of the sorbent, the content of macrocomponents and trace elements, respectively, and in table 4 - the content of clarified water when diluted in it sorbent in a ratio of 1:10.

 In the second purification step (Fig. 2), the wastewater is collected in a sewage pumping station, where it is homogenized with a change in pH to a value of at least 3, then transferred to a reaction chamber 6, where the pH is changed to at least 10 with a simultaneous supply of sorbent, after which the drains served in sedimentation tanks 7, where a coagulant and / or flocculant is fed with simultaneous correction of pH of the effluents to a normal state (6-7). In sedimentation tank 7, the solid phase is rapidly separated from the clarified liquid effluents and deposited at the bottom. In this case, the clarified part is discharged, and the dry residue can be processed further. In certain cases, the sorbent can be modified by the addition of oxidizing agents (such as manganese oxide). The cleaning results at this stage are given in table. 5-11.

At the third stage (Fig. 3), liquid from the sump 7 enters the circuit, including a jet pump 8 with an ejector 9 and a cavitation chamber 10 (the chamber 10 can be made on a separate ultrasonic emitter), a photochemical reactor 11, and a filter 12. The liquid from the sump 7 enters the pump 8, where air is sucked from the ejector 9, ozone is formed in the cavitation chamber 10 in the liquid under the action of ultrasound, and when the reactor 11 passes, hydrogen peroxide and many active radicals also occur, which very effectively affects the microflora and allows to oxidize and bind the inclusions and compounds remaining in the liquid part. Ultraviolet radiation acts on a liquid in a continuous or pulsed mode with a pulse frequency of 1-10 Hz and a power density of at least 20 kW / m ² was obtained experimentally. In the table. 12 and 13 show the results of the implementation of wastewater treatment in the third stage of treatment.

 The proposed method allows a high degree of efficiency to carry out the treatment of wastewater of various industries with very low energy and reagent costs.

Claims (1)

A method of wastewater treatment, including ozonation of wastewater followed by coagulation and flotation, sedimentation and separation of the liquid from the solid sediment, characterized in that the ozonation is carried out in a circulation circuit, ultrasound also interacts with the wastewater in this circuit, and the wastewater is further mixed with a sorbent based on zealite , and / or ash from burning peat and / or shale, and / or dust, which is a waste from cement production, after which the resulting liquid fraction is homogenized with a change in its pH to at least 3, sorben is fed t and increase the pH of the liquid fraction to at least 10, mix with a coagulant and / or flocculant, after which it is defended with a correction of the pH value to a normal value, then the liquid is saturated with air and sonicated in cavitation mode and then exposed to ultraviolet radiation in continuous or pulsed mode with a pulse frequency of 1-10 Hz and a power density of at least 20 kW / m ² .

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