SE500144C2 - Apparatus for purifying water by flocking - Google Patents

Abstract

Apparatus for purification of waste water or untreated (raw) water by a floculation method, comprising a container (1) having an inlet (2) for untreated water and an outlet (3) for floculated water, and having means (4) for stirring the water during its passage through the floculation container, and in which the floculation contaitner (1) contains partition walls (8, 9) forming concentric floculation chambers (10-12), and in which each partition wall (8, 9) and the wall (6) into the outlet (3) has passageway openings (13-15) for bringing the flow of water to pass successively inwards or outwards through the several floculations chambers (10-12) from the inlet (2) to the outlet (3), and in which a flexible or resilient deflection wall (16) is arranged in each floculation chamber adjacent the flow openings (13-15) thereof for directing the flow of water into the succeeding floculation chamber (11, 12) and for allowing a stirring means (19) to pass said deflection wall (16) in the floculation chamber (10-12).

Description

all the boundary walls in the flocculation chambers are cylindrical, and the water is led in particular through the flocculation chambers from the outermost to the innermost of the concentrically arranged flocculation chambers.

In this device, the volume between the cylinder surfaces corresponds to the chambers of a conventional flocculator. By arranging an end wall in each individual cylinder chamber and a flow opening in the inner wall, which at the same time forms an outer wall in the cylinder chamber located immediately inside, a continuous, long flocculation chamber is formed in this way by the multiple, concentric cylinder chambers. One of the advantages of a long, continuous flocculation chamber is that it enables a so-called "pug flow", which in turn allows a control of a continuously decreasing agitation, whereby each particle assembly can be given the agitation required for the fastest possible and best flock formation and / or for uniform agitation along the entire "waterway". Stirring can take place spontaneously at the passage of water through the concentric cylinder chambers or by means of a specially arranged stirrer.

In the simplest design of the flocculation device, the water is led into the outermost cylinder chamber and taken out through the center cylinder. The water's own kinetic energy must provide the required agitation turbulence. In an alternative embodiment, the flocculation chamber can be designed as a uniform spiral.

However, these two simple embodiments are flow sensitive and often require regular manual cleaning, especially with large flow variations.

To obtain a more flow-independent and self-cleaning flocculator, mechanical agitation or agitation with air is required. The kinetic energy supplied in this way must, in order for the system to become flow-independent, be supplied so that the agitation dominates over the agitation which the water flow itself provides.

It is also possible, in contrast to what is mentioned above, to introduce the water into the center cylinder and take out the flocculated water in the outermost cylinder chamber.

It is also possible to design the water intake in such a way that any chemicals, such as flocculation chemicals such as lime, aluminum sulphate, iron chloride, etc. are added to the inlet part, so that an effective mixing of the chemicals can be done at this place if needed.

In an alternative design of the device, two different water flows can be led into the flocculator in different places. The flows can, for example, have different additions and / or individually be more or less difficult to flock. The different l i (fl Al) (c) ... fx l "-.

Jm. the flows meet in one of the intermediate chambers for joint flocculation and joint departure through the outlet.

STIRING The stirring required for efficient flocculation can take place in three different ways, namely through the water flow's own kinetic energy, through air stirring or through mechanical stirring.

When stirred with the aid of the water's own movement, the necessary turbulence is created at the contact surface between the liquid and the flocculator walls and in the entire mass of water through the curvature of the chamber and the chambers, respectively. with completely bare walls, flocking becomes very flow-dependent. The system can be made more insensitive to the flow by placing turbulence-creating obstacles such as screens or the like on, for example, the walls of the chamber.

In the case of air agitation, the aeration is adjusted point by point or along the entire length of the chamber bottom with decreasing intensity in the direction of flow. Turbulence-increasing screens can also be used here.

However, mechanical agitation is recommended. This enables the creation of a flow-independent and self-cleaning flocculator, which is very important in practical operation. In the device described below, the mechanical stirrer is designed in such a way that a single, continuous stirring unit can be used for stirring in all sub-chambers.

DESCRIPTION OF THE INVENTION The invention will now be described in more detail in connection with the accompanying drawing, in which Figure 1 shows a cross section through a device according to the invention, and Figure 2 shows a side view of the device according to Figure 1, partly in cut-up condition.

The device shown consists of a substantially cylindrical container 1 with inlet 2 for waste water or other raw water and outlet 3 for flocculated water and with a stirring means 4 for the water.

The container 1 is substantially cylindrical and can have any desired dimensions and ratios between diameter and height. The container is closed in the bottom 5, and the bottom 5 seals against the outlet 3, which is designed as a tube 6 with an open bottom arranged concentrically inside the container 1. In the case of working with "reverse" flow direction, ie where the water flow goes from the center and outwards, the outlet pipe 6 must of course be designed with (51 a bottom.

Between the outer wall 7 of the container 1 and the outlet pipe 6, a number, in the case shown two, inner partitions 8, 9 of cylindrical shape are mounted concentrically inside the main container 1, which form a first, a second and a third cylindrical inner chamber 10, 11, 12 inside the main container 1. The number of partitions and concentric chambers can be varied according to needs and special circumstances. Likewise, the volume of the inner chambers 10-12 can be varied with each other, for example so that all the chambers have substantially the same volume, or so that the volume gradually increases from the outermost chamber 10 to the innermost chamber 12. In this latter case the important for some cases is achieved the advantage that the flow rate of the flowing water gradually decreases during the passage from inlet 2 to outlet 3. It is also possible, for other special conditions, to design the chambers for the inverse ratio, ie that the flow rate increases gradually.

It should be pointed out that it is also possible to arrange the flow through the flocculator with "reverse" flow, ie that the water enters at the center cylinder 6 and departs from the outermost flocculation chamber 10, the center cylinder 6, as mentioned above, being designed with a sealing bottom. The inlet 2 consists in the case shown of a pipe, which is preferably fixedly mounted in the jacket surface of the container 1. There may be several inlets, or the inlet may be divided as a cascade inlet at the jacket of the master cylinder 1.

The water can also be introduced into the first cylinder chamber through a bottom passage, or from above, which later does not require a special inlet.

All partitions 8, 9 and the wall of the inner cylinder 6 are formed with through-flow holes 13, 14, 15, for example axially running flow holes, for admitting water from the nearest outer cylinder chamber. The openings can extend over the entire wall height or only parts thereof, whereby so-called short-circuit currents are counteracted. For this purpose, one can, for example, arrange a first opening placed low and a subsequent opening placed high and vice versa. If there are openings at the bottom between all the chambers or compartments and into the center cylinder 6, sediment will be discharged faster from the flocculator. If there are openings both at the bottom and at the surface, at least at the center cylinder 6, or in the event of a "reverse" flow at the outermost sub-chamber 10, then easily and hard-sedimentable particles can be separated for disposal in different basins.

In order to prevent a backflow in the cylinder chambers arranged in several turns outside / inside each other, and to effect a deflection of the water flow from a cylinder chamber to the nearest inner cylinder chamber, a flexible separator wall 16 is arranged close behind the respective flow opening 13-15. in the flow direction. For reasons which will appear in the following, the separator walls 16 must be designed so that they can be bent off under mechanical action to let stir agitator rods, for example by folding, turning, sliding to the side or rotating. At the same time, the separator walls must have such rigidity against deflection that they force a flow of water from a flocking chamber into the flocking chamber located immediately inside (or outside) through the flow opening 13-15.

In a simplified embodiment of the invention, it is also possible to design the flocculator without separator walls, whereby the water has the possibility of circulating several turns in the same chamber before it seeks its way into the next chamber.

As mentioned earlier, it is important that a stirring is effected by the water in the flocking chambers 10-12, and for this purpose a stirrer 4 is used, which in the case shown is driven by a motor 17, on the rotating shaft of which one or more transverse arms 18 are mounted, where the arms or each arm carries a stirrer rod 19 with stirrer paddle blades 20 for each individual flocking chamber. The paddle blades may be fixedly mounted on the stirrer rods or may be free-hanging. The paddle blades can also be designed so that at the same time as the stirring of the water they cause a co-scraping of sediment along the chamber bottom for discharge from the flocculator. The stirrer with the stirrer rods 19 is arranged concentrically with the flocculation chambers, so that the stirrer rods can be rotated back and forth and / or around a vertical axis in the flocculation chambers 10-12.

The stirrer rods 19 are able to pass the separator walls 16 by bending them elastically or resiliently as the rods 19 pass, after which they pivot or bend back and close to the flocculation chamber so that the water passes into the next, inner chamber 11 and 12, respectively, through the openings 13, 14.

In the above-mentioned simplified embodiment of the invention, the separator walls can be formed fixed but with a vertical gap through which the stirrer rods 19 can pass. The narrow vertical strips on each side of the vertical gap contribute to an increased turbulence in the water flow and to a deflection of the water in, or out, to the next flocculation core.

Conveniently, the stirrer can be designed speed-controlled, so that the stirring intensity is kept constant with increasing and decreasing water flow, respectively.

To increase the turbulence in the flocking chambers, these may be formed with turbulence raising means, for example wings 21, which are attached to the cylinder chamber walls as indicated by the chamber 12 in Figure 2. The wings 21 may be arranged to accelerate a vertical agitation in the water, and they can, for example, be angled in relation to the horizontal plane to enhance the stirring effect.

Suitably the shaft of the agitator motor 17 is designed so long that it extends to a place below the lower edge of the outlet pipe 6, and it can there be provided with, for example, an asymmetrically designed cone 22 with the tip upwards. The cone fulfills two functions: it must prevent erosion in the underlying sludge cover, it must also disperse the water in the separation basin, so that short-circuit currents are eliminated.

The centrally located motor 17 and the drive shaft can also be used for two additional functions when the flocculator is installed in, for example, smaller sewage systems, namely partly to drive a bottom scraper winch, partly to drive the spreading arms in an overlying biobed. The requirement for a lower rotational speed for the latter two functions can be met by increasing the number of support arms and stirrer rods in the flocculator to maintain sufficient agitation in it.

The specified design of the flocculator can thus in an excellent way result in savings of drive units on small plants and enable a very compact plant. In connection with the inlet, or outside the flocculator, there may be per se known means for adding and mixing in flocculants or other chemicals. It is also possible to design the flocculator with a square, oval or other regular polygonal cross-sectional shape and, if necessary, to design the stirrer backstage-controlled for the corresponding square or polygonal movement. In some cases, it can be both functional and labor-saving to be able to achieve an "automatic cleaning" of the flocculator. One such case is when directly precipitating poorly sludged water, or when using the flocculator to trap and flock completely untreated wastewater. For this purpose, the device in the bottom can be formed with one or possibly more radially placed narrow cleaning gaps 23, which are covered by an upwardly spring-loaded bottom cover. The cleaning column 23 is opened at the same time as the stirrer 4 is rotated. The latter can be valuable, especially in small plants, which can thereby be operated without a special sludge or coarse separation device.

The cleaning can be done by manually opening the cleaning door. for example, a few times a week, but it can also be automated by a timer. It is also possible to arrange a central rising hatch by designing the stirrer rods 19 so that during the rotation of the stirrer they continuously scrape in sediment towards the center of the flocculator, where it exits through an openable bottom hatch intended for this purpose. The opening can also be the opening 15.

Reference numerals 1 container 2 inlet 3 'outlet 4 stirrer 5 bottom (on 1) 6 outlet pipes 7 outer wall (on 1) 8 partition wall 9 partition wall 10 inner chamber 1 1 inner chamber 12 in down chamber 13 flow holes (i 8) 14 flow holes (i 9) 15 flow holes (in 6) 16 separator wall 1 7 motor 18 arm 1 9 stirrer rod 20 paddle blades 21 wing 22 cone 23 cleaning gap

Claims (9)

PATENT REQUIREMENTS Device for purification of waste water or other raw water, or of emulsions or mixtures of water and oil or oil-like products by a flocculation process, consisting of a container (1) with inlet (2) for untreated water and outlet (3) for flocculated water , and wherein the flocculation container (1) houses a plurality of partitions (8, 9) arranged concentrically in the flocculation container (1), which form a plurality of concentric flocculation chambers (10-12), which are substantially closed at the bottom, characterized by that - each partition wall (8, 9) and the wall (6) of the outlet (3) have flow holes or slots (13-15), which extend over the entire wall height, - and which are arranged so that the water flow can pass successively inwards or outwards through the multiple flocculation chambers (10-12) from the inlet (2) to the outlet (3), - and in that the flocculation chambers (10-12) have one or more means (16) for forcibly directing the water flow from a flocculation chamber (10) , by respe flow holes or slots (13-15) to the nearest flocking chamber (11) and to the outlet (3), respectively, and to forcibly prevent flow in the opposite direction to the intended flow direction. Device according to claim 1, characterized in that the means for forcibly directing the water flow from one flocculation chamber to the next flocculation chamber (10-12) consists of a separator path (16) which is arranged substantially across the flocculation chamber close behind the nearest flocculation chamber. flow holes or slots (13-15). seen in the direction of water flow. Device according to claim 2, which is provided with means (4) for stirring the water during its passage in the flocculation container, and wherein the stirrer (4) is driven by a motor (17) to provide a reciprocating and / or movement in the respective flocculation chamber (10-12), and in that the stirrer comprises one or more stirrer rods (19) for each flocculation chamber (10-12), and where each stirrer rod (19) can be provided with e.g. paddle blades (20) for amplifying the stirring effect and / or fastening wings (21) along the stirrer rods to increase the turbulence in the water flow, characterized in that the separator wall (16) is arranged to be passed by the stirrer rods or to be temporarily opened mechanically. 10 Device according to claim 3, characterized in that the separator walls (16) are flexible or resilient so that they are opened under certain mechanical action, for example by a passing agitator (19), after which they close automatically. Device according to claim 3, characterized in that each flocculation chamber (10-12) has a only partially closing separator wall, which forms a narrow, vertical gap, through which stirrer rods (19) can pass, and which leaves a narrow edge next to at least one of the walls, which edge contributes to increasing the turbulence in the water flow and to directing the (or out) the water to the next flocking chamber (10-12). Device according to claim 5, wherein the stirring rods (19) are provided with paddle blades (20), characterized in that one or more of the paddle blades (20) are angled towards the horizontal plane to provide a vertical mixing in the water stream and / or are designed to provide a co-scraping of sludge along the bottom of the flocculation chamber (10-12) (through 23). Device according to claims 5 and 6, characterized in that the axis of the agitator motor (17) extends to a place below the outlet (6) of the flocculator, and in that it carries at this point an asymmetrical cone (22) facing upwards to prevent erosion in the underlying sludge cover and to disperse the water in the underlying sedimentation basin. Device according to one of the preceding claims, characterized in that the flocculation container (1) and all concentrically arranged flocculation chambers (10-12) are cylindrical with a circular, square, oval or regular polygonal cross-section, and in that the flow of water through the concentrically the flocculation chambers (10-12) are arranged to take place from an inlet (2) arranged in the outermost flocculation chamber (10) and successively through the following flocculation chambers (11, 12) to a centrally arranged outlet pipe (6), from which the flocculated water is released down into a sedimentation basin or Hknande. Device according to one of the preceding claims, characterized in that it is designed with two or more inlets opening into different flocculation chambers, wherein the different water streams can be of different types and / or have different mixtures of chemicals, and where the respective streams radiate together. in the second or one of the following flocking chambers (11, 12).