FR2565578A1 - PROCESS AND PLANT FOR TREATING WATER USING A FLAKE CLOUD BY THICKENING AND INCREASING FLOAT DIMENSIONS IN WATER CYLINDERS - Google Patents

Abstract

A.PROCESS AND INSTALLATION OF WATER TREATMENT USING A CLOUD OF FLAKES BY THICKENING AND INCREASING DIMENSIONS OF FLAKES IN WATER CYLINDERS. C. PROCESS CHARACTERIZED IN THAT THE VOLUME FOR THE CLOUD OF FLAKES IS SEPARATED INTO PARTIAL SECTIONS BY A SYSTEM OF SUBMERSIBLE VERTICAL PARTITIONS 6, THE WIDTH RANGING FROM 0.1 TO 0.4M AND THE LENGTH EQUAL TO THE WIDTH X 4 ... 20, AND INCREASING AND OVERFLOWING THE CLOUD OVER AN OVERFLOW AREA 8 FOR MUD FROM 0.05 TO 0.30M. The invention relates to a method and a plant for treating water using a cloud of flakes by thickening and increasing the dimensions of flakes in water cylinders.

Description

Method and installation for treating water with a cloud of

  flakes by thickening and increase

  dimensions of the flakes in water cylinders.

  The present invention relates to a method and a flocculation and separation plant

  flakes in the form of a cloud of flakes.

  In the apparatus for treating water with a cloud of flakes, in order to increase the yield, walls inclined in the volume of the cloud of flakes in the immersed position have been provided, dividing this volume into parts of volume. The upper inclined walls of the sections thus formed comprise baffles and the lower walls are smooth. The baffles facilitate flocculation. The flakes produced fall on the bottom wall and slide along

  this one in the direction posed to that of the flow.

  As soon as the flakes reach the lower edge of the

  wall, they are extracted by the rising flow of the liquid.

  Clarification effect is more effective by repetition

  periodic change of passage. In this montage,

  a surface charge of the clarifying elements is

  cation ranging from 15 up to 20 m.h1.

  Current known installations have the following drawbacks: the integration of the inclined walls in a rectangular tank with vertical walls increases the unused surfaces. Partial volumes are used only partly for the ascent

  since in the volume at the level of the inclined wall inferred

  there are mud deposits. The baffles are only on one side so they can not

  act on the entire volume of the suspension.

  The object of the present invention is to overcome the drawbacks of the known solutions and to this end concerns a method characterized in that the size of the flocks is thickened and increased by rotating water cylinders in a non-turbulent flow, in concave volumes between the main flow of liquid which is forced to perform a sinusoidal rise movement generated by transmitting a momentum to the main flow by undulating walls or bands provided on the walls

  planes limiting the cloud of flakes.

  According to another characteristic of the invention, the size of the flakes is thickened and increased in at least two water cylinders provided one above the other, and at most in fifteen cylinders,

  the gradient remaining constant or decreasing in the direction

  flow in the range of G = 200 up to s According to another characteristic of

  the invention, the thickening and the

  floc size by making the bond between the flakes stronger by adding an auxiliary coagulating agent and / or by changing periodically periodically, the hydro-dynamic forces in the liquid at a frequency of the order of n = 0.01 Up

0.1 Hz.

  The invention also relates to an installation for implementing this method, this installation being characterized in that the volume for the cloud of flakes is separated into partial sections by a system of submerged vertical partitions, the width ranging from 0.1 up to 0.4 m and the length being equal to the width X 4 ... 20, etoen crossing and overflowing the cloud over an overflow edge for mud

from 0.05 to 0.30 m.

  According to another characteristic of the installation, the submersible partitions are corrugated in the direction of their height, preferably

sinusoidal or polygonal.

  According to another characteristic of the installation, the submersible partitions are flat and

have deflectors.

  According to another characteristic of the installation, the length of a sinusoidal period of the immersed wall is between 2 and 6 times longer than the width of the partial section and the deviation of the sinusoidal line with respect to the axis is equal to at 1/4

  up to 1/2 of the width of the partial section.

  According to another characteristic of the installation, the deflectors are located at the partial section alternately on opposite sides at angles of 45 to 70 with respect to the horizontal plane and project between 1/6 to 1/3 of the width

  of the partial section and the distances between deflections

  are equal to the width of the partial section

multiplied by 0.5 up to 3.

  The flocculation and flake separation process according to the invention overcomes the disadvantages

  known solutions. According to the invention, the characteristic

  The general problem lies in the fact that the flocks are thickened and their size increased by rotating them in cylinders of water following a non-turbulent flow in the concave volumes between the main flow of the liquid so as to create force a

  sinusoidal rise motion generated by the trans-

  a number of movements of the main flow, by a corrugation of the shape of the walls or stops provided on the smooth walls, limiting the cloud of flakes. The thickening and the increase of the size of the flakes is done in at least two water cylinders provided one above the other, and there are at most 15 such cylinders, the gradient being kept constant or in decrease in the direction of flow between C = 200 up to 20 sr. thickening

  and the increase in the size of the flakes is

  surrounded by stronger bonds between the flakes by addition of an auxiliary coagulation agent and / or by

  periodic repetition of the change of hydro-

  dynamics in the liquid at frequencies of the order

from n = 0.01 to 0.1 Hz.

  In the installation according to the invention, the volume of the cloud of the flakes is separated by a system of submerged vertical walls providing a view of the partial sections whose width is between 0.1 to 0.4 m and the length is equal to the width multiplied by 4 - 20 so as to intersect and to overhang the overflow edge of mud between 0.05 m and 0.30 m. The submerged walls have a wavy shape in the direction of their height; this corrugation is preferably sinusoidal or polygonal with a sharp edge. The submerged walls can also be smooth and include deflectors. At the length of a sinusoidal period the submersible wall is between 2 and 6 times longer than the width of the partial section and the deviation of the sinusoidal line with respect to the axis is included

  between 1/4 to 1/2 of the width of the partial section.

  The baffles may be located in partial sections alternately on the opposite sides following

  an angle between 45 and 70 from the horizontal plane

  zontal and protrude 1/6 to 1/3 of the width of the partial section; the distance between the baffles is equal to the width of the partial sections

  multiplied by a coefficient between 0.5 and 3.

  The process and the installation according to the

  In particular, the invention provides the following advantages: the volume of the fluff cloud is separated by the vertical walls so that it can be easily integrated into tanks or containers with rectangular or circular sections. The shape of the surfaces

  walls being sinusoidally or poly-corrugated

  gonale with sharp edge, or alternatively with baffles on smooth walls, creates a sinusoidal path for flow. This generates water cylidnres

  on both sides of the concave parts of the walls. -

  The length of a sinusoidal period or distance between the baffles is either the same or greater in the direction of flow, which is advantageous in the case of brittle flakes since the gradient is decreasing. The dimensions of the different

  partial sections are chosen in such a way that

  not be turbulent, that is, the Reynold number must be less than Re vx R 600, where v is the average forward speed R is the hydraulic radius, p is the cynematic viscosity A part of the flakes escapes from the rotating flow and rises to pass into the next water cylinder, in which the process is repeated. Small pulses generated in general by a floating mixing element, float alternately at the entrance to the space of the

  cloud of flakes and facilitate the accumulation of flakes.

  The submerged walls project over the overflow edge into the thickening space and separate into smaller sections. This way with the pulsations of the sludge level controls the overflow of the sludge, which minimizes the

  quantity of flakes entrained with the treated water.

  Examples of the process and the installation

  Flocculation and flake cloud separation will be described hereinafter, with the aid of the accompanying drawings, in which:

  - the figure shows a mode of

  known from a clarification plant, of rectangular shape, in which. is integrated a device according to the invention;

  - Figure lb shows the same installation

  clarification in longitudinal section;

  - Figure lc shows the same clarification

cross sectional cation;

  - Figure 2a shows a way of

  known in a circular form of clarification installation in which is integrated a device according to the invention; FIG. 2b is a longitudinal section of the installation of FIG. 2a; FIG. 3 is a vertical section of an integrated sinusoidal corrugation assembly; Figure 4 is a vertical section of a corrugated assembly of polygonal shape; - Figure 5 is a vertical section

  a low mounting, integrated and with deflectors.

  In the various figures, the reference 1 designates the entry of contaminated water containing agents

  coagulation, in the clarification facility.

  Reference 2 denotes the flocculation volume; reference 3 designates the mixing elements; 4 denotes perforated pipes in Figure 1 or intervals in Figure 2 between the flocculation and clarification volumes; reference 5 is a partial section of a cloud of flakes; 6 denotes a submerged wall; the reference 7 designates the deflectors; 8 denotes a sludge overflow edge;

  9 denotes a treated water channel; the reference

  reference 10 designates the outlet of the treated water; the reference

  11 denotes the thickening volume of the sludge;

  reference 12 designates the evacuation pipe.

  Water with coagulation agents, basic, arrives in the flocculation volume 2 by the pipe 1. The flotation advantageously acts on the mixing elements 3 in suspension. This suspension flows in the perforated pipe or in the interval 4 and is distributed by submerged partitions 6 in different sections of flake clouds 5. In the concave volumes of the immersed partitions, corrugated, and between the deflectors 7 on has rotating cylinders of water, in which the flakes thicken and increase in size. This process is repeated in different water cylinders placed one above the other. The treated water flows through the channels 9 in the discharge line 10. The mud of the flake clouds or the level thereof

  above the overflow edge 8 whose volume of thickening

  11 and is evacuated periodically through

of the pipe 12.

  In the devices described in FIGS. 1a, a surface charge of 15 m.sup.-1 can be obtained with a ferric coagulating agent and an auxiliary coagulant is added up to 20 mh.sup.-1. The device described can also be applied to separate the particles. formed during

  softening of water and bioflocculation.

List of references -

  1 - Clarifier inlet 2 - flocculation space 3 - mixing elements 4 - perforated pipe or intervals - partial cut of the cloud of flakes 6 - submersible partition 7 - baffle 8 - overflow edge 9 - treated water discharge channel - exhaust pipe 11 - sludge thickening volume 12 - sludge discharge pipe

Claims (4)

CLAIMS) A process for flocculating and separating flakes according to a cloud of flakes, wherein the flocs are thickened and increased by rotating water cylinders in a non-turbulent flow in concave volumes between the flakes. main flow of liquid which is forced to perform a sinusoidal rise movement generated by transmitting an amount of motion to the main flow by undulating walls or strips provided on the planar walls limiting the cloud of flakes.   2) Process according to claim 1,   characterized by thickening and increasing the size   flakes in at least two water cylinders   one above the other, and at the most in fifteen   the gradient remaining constant or decreasing in the direction of flow in the range from G = 200 to -1 s 1 3) Process according to any one of   Claims 1 and 2, characterized in that   thickening and increasing the size of the flakes by making the bond between the flakes stronger by adding an auxiliary coagulation agent and / or by changing periodically periodically, the hydro-dynamic forces in the liquid to a frequency of   the order of n = 0.01 to 0, 1 Hz.   4) Installation for implementation   process according to any one of claims 1 to 3,   characterized in that the volume for the cloud of flakes is separated into partial sections by a system of partitions   submerged vertical sections (6), the width   than 0.4 m and the length being equal to the width X 4 ... 20, and crisscrossing and overflowing the cloud over an overflow edge (8) for the mud from 0.05 up to at 0.30 m.    Installation according to claim 4, characterized in that the submersible partitions (6)   are waved in the direction of their height, preferably   sinusoidally or polygonally.   6 0) Installation according to claim 4, characterized in that the submersible partitions (6) are   planes and comprise deflectors (7).   7) Installation according to claim 5, characterized in that the length of a sinusoidal period of the submerged wall (6) is between 2 to 6 times longer than the width of the partial section and the deflection of the sinusoidal line relative to at the axis is equal to 114   Up to 1/2 of the width of the partial section (5).   8) Installation according to claim 4, characterized in that the baffles (7) are located at the partial section (5) alternately on opposite sides at angles of 45 to 70 relative to the horizontal plane and protrude between 1 / 6 Up to 1/3 of the width of the partial seciton and the distances between the deflectors (7) are equal to the width of the section   partial multiplied by 0.5 up to 3.