RU2182117C2 - Flotator-settler - Google Patents

Abstract

FIELD: municipal economy, power engineering, oil and metal-working industries, mechanical engineering, motor transport, and other industries. SUBSTANCE: proposed flotator-settler designed for flotation purification of sewage water from oil products, suspended particles, and other pollutants is, essentially, complex apparatus in the form of vessel formed by two process columns one being a sewage flotation column and other one, fine water purification column both communicating through apparatus base which functions as settler. The latter is mounted on four supports and these supports are fixed in position on four respective foundation bases. Settler is, essentially, a parallelepiped-shaped reservoir divided into two sections by internal vertical partition so that water is free to flow over its bottom edge from flotation column to fine purification one. Collapsible flotation process column is vertically fixed to upper wall of left-hand section of settler coaxially with respect to opening for water overflow from flotation column to settler. Flotation column is built up of three parts: column base in the form of large-diameter pipe , flotation chamber, and head structure of column. Built inside this column is ring-shaped perforated tubular aerator. Electric flotator may be used as substitute for aerator. Sewage pipeline fitted above aerator may be brought in through flotation column top and air ejector is mounted above it. Expanded annular reservoir with tilted bottom is fixed 60-70 mm below uppermost edge of flotation column and serves to accumulate flotation mud and to discharge the latter through tilted pipeline from lowermost part of annular reservoir. Collapsible fine water purification process column is fixed in vertical position in parallel with flotation column on upper wall of settler right-hand section. Column has three parts: column base in the form of large- diameter pipe, tubular settler, and head structure of column in the form of large-diameter pipe. Purified water is conveyed from top part of fine water purification column by gravity which forms continuous laminar water flow and ensures the largest differently directed flow path for purified effluents starting from flotation chamber through settler to uppermost point of fine water purification column. In this way apparatus provides for double- stage purification of sewage water. EFFECT: reduced space and power requirement, improved quality of sewage cleaning from oil products, fats, and suspended particles. 4 cl, 4 dwg

Description

 The invention relates to a device for flotation wastewater treatment from oil products, fats, suspended particles and other pollutants and can be used in utilities, in the food, oil, metallurgical industries, energy, automotive and other industries.

 Known "Installation for flotation wastewater treatment" according to the description of the invention to a. from. USSR 1579904, class C 02 F 1/24, published in BI 27.07.07.90 (1).

This installation has some disadvantages, namely:
- drainage of the slurry is forced down with the help of scrapers and auger in the center of the tank for wastewater treatment, which complicates the design of the installation, while the auger with a casing takes away a significant part of the volume from the tank for treated wastewater;
- to drive scrapers and auger requires additional energy costs, and also reduces the reliability of the installation due to the complexity of the design of the installation.

 The aim of the invention is the creation of a design of a flotator settler rather simple, reliable, inexpensive and at the same time providing a two-stage wastewater treatment, actually combined in one apparatus. At the same time, the apparatus would occupy minimal production areas, consume a small amount of energy and ensure high quality wastewater treatment from oil products, fats and suspended particles.

 The essence of the proposed flotator settler is as follows.

 The proposed flotator is a complex apparatus in the form of a communicating vessel formed by two technological columns: a collapsible column for flotation of effluents and a collapsible column for fine purification of water, communicating with each other through the base of the apparatus - sump. The sump is installed on at least four racks, and the racks are stationary mounted respectively on four foundation bases. The sump is a tank in the form of, for example, a parallelepiped divided into two halves by an internal vertical partition, through the lower edge of which water has the ability to flow from the flotation column to the fine water column through the bottom of the sump.

 The bottom of the sump has the shape of an irregular pyramid, tapering downward and at the same time to the side, and ends with a pipeline with a valve to discharge heavy sludge; for ease of maintenance of the sump, the pipeline with the valve is moved to the side outside one of the vertical walls of the sump.

 On the left half of the sump to its upper wall, coaxially with a hole for water flow from the flotation column to the sump, a large-diameter pipe is installed vertically and motionless, which is a technological collapsible column of flotation of untreated effluents. From the inside to the wall of this column at a height equal to at least 0.3-0.5 of the height of the entire column, a tubular aerator with perforation in the form of a ring is fixedly mounted to supply compressed air to the flotation chamber. Above the aerator, at a distance from the base of the column equal to at least 0.6-0.65 of the entire height of the flotation column, a pipe has been cut into it for introducing untreated effluents into the flotation column.

 A somewhat 60-70 mm lower end of the flotation column’s upper edge still has a widened annular tank with an inclined bottom for collecting slurry, its continuous collection and discharge through the pipeline. An ejector for suctioning atmospheric air is also mounted in the raw sewage input line, which, even before entering the flotation column, is mixed with drains and helps to intensify the flotation process of oil products and fats.

 In the process of flotation of wastewater, sludge under the influence of air bubbles in the flotation chamber rises up and flows into a widened annular container for collecting flotation sludge and is discharged along an inclined bottom and pipe, and the water purified from oil products, fats and suspended particles is lowered by a laminar flow to the bottom of the flotation column, and then into the lower part of the settler of heavy sludges and suspended particles, and then along the bottom edge of the vertical partition of the settler through its bottom flows into the column of fine water purification. In this case, heavy sludge and suspended particles settle to the bottom of the sump.

In parallel with the flotation column, on the upper wall of the right half of the sump, coaxially with an opening for the flow of water from the sump into a collapsible column for fine purification of water, a large diameter pipe is installed vertically and motionlessly. The height of this pipe is equal to at least 0.1-0.3 the height of the entire column, and to the upper part of this pipe to the flange is a tubular sump, which is a package of many small diameter tubes fixed together and motionless by two flanges; the tubes are installed with an inclination to the vertical at approximately an angle of 30 ^o .

 A large diameter pipe is fixedly attached to the upper flange of the tubular sump, which is a continuation of the process column for fine water purification and its crown. In the tubular sump, even the smallest and lightest suspended particles, hitting the walls of numerous tubes, lose their speed and inertia and slide (settle) down the walls of these tubes into the sludge sump.

 Purified water flows out of the fine water column from its upper part through a discharge pipe, and this creates a continuous movement of water in a laminar flow, starting from the flotation chamber, through the sump and to the highest point of the fine water column.

 Thus, the wastewater treatment process occurs in a laminar flow along the largest and at the same time multidirectional trajectory of water movement in two columns: first from top to bottom from the flotation column to the sump, then from the sump to the top through the entire fine column, while in both columns there is intense deposition of heavy and lighter suspended particles, almost double cleaning with minimal energy consumption.

 The flotation column and the fine water column have the same height, and the flow rate of the purified water in the upper part of the fine water column is set approximately 30-50 mm below the level of the upper cut of the flotation column.

 Thus, the proposed flotator settler works with minimal energy only to supply untreated wastewater to the flotator and compressed air through the ejector to the aerator.

 As a close analogue of the proposed flotator-settler, you can take "Installation for flotation wastewater treatment" according to.with. USSR 1579904 (1).

 The list of figures in the drawings.

 In FIG. 1 shows schematically the construction of the proposed flotator-sump in the context; an option in which air through the ejector is additionally supplied with drains.

 In FIG. 2 shows the proposed flotator-settler in the context, the option of supplying wastewater through the top of the flotation column through a vertical pipe and at the same time air through an ejector located in the uppermost part of the supply pipe.

 In FIG. 3 shows the proposed flotator-settler in the context, the installation of electroflotator in the flotation column.

 In Fig.4 shows the proposed flotator-settler, a side view in A of Fig. 1, which shows the bottom of the sludge sump with piping and gate valve that has been removed to the side for ease of maintenance.

 The proposed "Flotator-settler" Potok-1 "consists of the following units, assemblies and parts.

 On four foundation bases 1, for example, and four racks 2, the base of the flotator settler is installed, which is a settler 3 for sludge and suspended particles (Fig. 1).

 In the lower part, the sump has the shape of an irregular pyramid, and the upper part has the shape of, for example, a rectangular parallelepiped. The sump 3 inside is divided in the middle, approximately, into two equal parts by a steel vertical partition 4, welded with an airtight seam, and so that in the lowermost part of the sump 3 in the bottom, having the shape of an irregular pyramid and tapering down, an opening for water flow is formed from the left half of the sump to the right half.

 The sump 3 in the upper part has an upper horizontal wall (ceiling), on the left half coaxially with the hole for the flow of water from the flotation column to the sump 3, a large diameter pipe 5 is vertically and motionless, which is the lower part of the effluent flotation column.

 A flotation chamber 7 is installed on the pipe 5 by means of a flange connection 6 in the form of a large diameter pipe mounted vertically. In the lower part of the flotation chamber 7 at a height of at least 0.3 of the total height of the flotation column (which is equal to the sum of the heights of the pipe 5 and flotation chamber 7), a stationary tube with a perforation in the pipe walls in the form of a ring, an aerator 8 is installed on the inside of the flotation chamber 7 supply of compressed air to the flotation column 7 through the pipeline 9; through this pipeline 9, various solutions, coagulants or flocculants can be fed into the flotation column.

 A conduit 10 for supplying dirty drains is mounted in the flotation chamber 7 at a height of at least 0.6-0.65 of the total height of the flotation column, and an ejector 11, in turn, is mounted in the pipe 10 for suctioning atmospheric air into the dirty draining line. The pipe 5 has a height equal to about 0.1-0.2 of the total height of the entire flotation column.

On the upper part of the flotation chamber 7, a broadened annular container 12 is welded with an inclined bottom for collecting sludge, while the level of the upper cut of the flotation chamber (pipe) 7 is 60-70 mm higher than the base level of the broadened ring container 12. To the lower inclined part of the tank 12 at a certain angle (15-20 ^o ) to the horizontal surface, a pipe 13 is welded to drain the slurry.

 When flotation of slightly contaminated wastewater, their supply can be carried out according to the variant shown in Fig. 2, namely, the wastewater can be brought in vertically mounted at the very top of the flotation chamber 7, pipe 14 and pipe 15, welded at an angle to pipe 14. Moreover, in the upper part pipeline 14 installed an ejector for suction of atmospheric air.

 The proposed design of the flotator settler provides for the possibility of installing the electroflotator 16 on the pipe 5 (Fig. 3), while dirty drains are fed above the level of the electroflotator, and accordingly, the flotation chamber 7 is mounted above the electroflotator.

 A large-diameter pipe 17 is fixedly fixed to the upper wall of the right half of the settling tank 3 coaxially with an opening in it for the flow of water from the flotation column through the settling tank 3 into the fine water treatment column, approximately 0.1-0.3 high in height of the entire fine cleaning column. A tubular sump 18 is fixedly attached to the upper part of the pipe 17 to its flange 6, and a large diameter pipe 19 is fixedly attached to the upper flange of the sump 18, equal to the diameter of the pipe 17 and being the upper part and the crown of the entire fine water treatment column, formed respectively by the pipe 17, tubular sump 18 and pipe 19.

 A pipe 20 is horizontally welded to the upper part of the pipe 19 to remove purified water from the fine water treatment column. Moreover, the water level in the discharge pipe 20 is set 30-50 mm below the level of the upper cut of the flotation column (flotation chamber 7).

 The proposed flotator sedimentation tank can provide for the cleaning of very dirty effluents, for example, with a content of oil products and fats from 100 to 1000 mg / l. To do this, there is a saturator 21 (figure 1), through which a solution of aluminum sulfate with air is fed into the aerator 8.

 A pipe 22 with a valve 23 (Figs. 1 and 4) is cut into the lowest part of the bottom of the sump 3 for periodic discharge of heavy sludge that accumulates during wastewater treatment.

 The proposed "Flotator-settler" Potok-1 "works as follows.

 Before being put into operation, clean water is poured into both columns and the flotator sump to the level of drained purified water through line 20 in the fine column. Then untreated wastewater is fed into flotation chamber 7 through line 10 (Fig. 1) and at the same time compressed air is supplied from the compressor through line 9 and aerator 8. In this embodiment, oil and fat concentrations from 15 to 100 mg / l are used.

 At low concentrations of wastewater pollution with oil products and fats, for example up to 15 mg / l, it is possible to simultaneously supply air directly from the atmosphere through the ejector 11 to the pipeline 10 supplying untreated effluents, and not to supply compressed air to the aerator 8. You can also clean up according to the scheme shown in figure 2, i.e. untreated wastewater feed through pipelines 15 and 14 with ejection of atmospheric air. And this ensures high-quality flotation wastewater treatment.

 At high concentrations of contaminants in the effluents with oil products and fats, for example from 100 to 1000 mg / l, an electroflotator is installed, and an aerator 8 is fed, for example, a solution of aluminum sulfate with air passed through a saturator 21, which is included in the flotation system of wastewater at high concentrations pollutants in drains.

 In the flotation chamber 7, air bubbles, continuously coming from the aerator 8, penetrate the whole mass of untreated effluents, while the light fractions of pollutants - oil products, fats and light suspended particles - rise up, foaming, collect in a tank 12 to collect flotation sludge and gradually gravity discharge pipeline 13. Heavy suspended particles in the flotation chamber 7 fall down under their own weight, and are also captured by the laminar flow of water also down, as the excess water in the connecting two columns begins to pour I’m from the fine water purification column through pipeline 20, since the water level in this pipeline is 30–50 mm lower than the upper cut, flotation column 7. This creates a directed laminar flow from flotation column 7 through the lowest part of the settler (baffle 4 ) through the sump 3 to the uppermost part of the column of fine water purification.

 In sedimentation tank 3, heavy suspended particles under their own weight settle to the bottom, and part of lighter suspended particles together with a laminar flow of water, continuing their movement through pipe 17 and especially through tubular settler 18, hitting the walls of numerous tubes, lose their inertia and speed and along the walls of these tubes slide down into the sump 3.

 Purified water, moving first down in flotation column 7, and then flowing through the bottom of sump 3 to a fine water treatment column, changes the direction of movement in the opposite direction - up, and as a result, suspension of suspended particles from the water occurs twice, and thus due to movement purified water along the largest trajectory achieved a high degree of wastewater treatment.

 Purified water is discharged from the uppermost part of the fine water treatment column through pipeline 20.

 Heavy sludge and suspended particles during flotation of untreated wastes accumulate in the lower narrowed part of the sump 3 and are periodically discharged to the dump through the pipe 22 and valve 23.

 An experimental sample of the proposed flotator-settler for wastewater treatment was made and tested at one of the industrial enterprises of Omsk; provides high-quality wastewater treatment from oil products, fats and suspended particles, helps to reduce COD and guarantees water quality indicators corresponding to the maximum permissible concentrations of these pollutants in treated wastewater.

The proposed flotator settler has the following advantages compared to the analogue:
- reduced the production area occupied by the flotator by increasing the height of the flotator;
- reduced flotation area in the flotation chamber and at the same time intensified the flotation process;
- the flotation area and the collection surface of the sludge are reduced to the optimum value, which makes it possible to more densely and intensively saturate the effluents with air and remove the sludge without using scrapers and auger, and by gravity.

 The performance of the proposed device ranged from 5 to 100 cubic meters of water per hour. For the effective and optimal operation of the proposed flotator-settler, depending on the volume of water being cleaned and the degree of its pollution, a hydraulic calculation of the parameters of each specific flotator is performed.

Literature
1. "Installation for flotation wastewater treatment", a description of the invention to and.with. USSR 1579904, class C 02 F 1/24, published in BI 27.07.07.90.

Claims (4)

 1. Flotator-sump containing a flotation tank with a supply of purified water, a collection of sludge with a discharge pipe, an aerator, a sludge settler, pipes for removing purified water and sludge, characterized in that it contains a complex apparatus in the form of a communicating vessel formed of at least one on four foundation bases and, respectively, on four racks and being the basis of the entire apparatus, a sedimentation tank for heavy suspended particles and sludge, made in the form of a parallelepiped, divided into two halves morning vertical partition providing water flow from one half to the other through the bottom having the shape of irregular pyramid tapered downwards and ending with a valve outlet pipe for the slurry; A collapsible flotation column installed vertically and motionlessly on the left half of the sump is coaxial with an opening in the upper wall of the sump for the flow of water into the sump from the flotation column with it installed motionlessly on the inner wall of the column at a distance from its base equal to at least 0.3 of the entire height columns, tubular with perforation by an annular aerator, with a cut-in at a distance from the base of the column equal to at least 0.6-0.65 of the height of the entire column, a pipeline for supplying untreated effluents, with installed motionless at the upper cut of the flotation column with an expanded annular tank with an inclined bottom and with a discharge pipe for flotation sludge; A collapsible column for fine water purification installed vertically and motionlessly on the right half of the sump is coaxial with an opening in the upper wall of the sump for the flow of water from the sump into this column, consisting of a lower pipe of large diameter, fixedly connected along the upper flange to the tubular sump, and along the upper a flange of a tubular sump with an upper pipe of large diameter, in the upper part of which a pipe is cut in, from which purified water flows by self-discharge, while the water level in the discharge pipe It becomes 30-50 mm below the upper edge of the flotation column.  2. A flotator-settler according to claim 1, characterized in that it comprises a sewage supply pipe installed vertically in the upper part of the flotation column, in the uppermost part of which a atmospheric air ejector is installed above the sewage supply level.  3. Flotator-settler according to claim 1, characterized in that it contains an electroflotator installed in the flotation chamber below the level of the supply of the sewage pipeline.  4. Flotator-settler according to claim 1, characterized in that it contains a saturator, designed for additional enrichment of waste air.

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