HU204018B - Process for chemical clarification of aqueous dispersions in multistep technology by producing and separating gradually formed floccules - Google Patents

Abstract

Aq. dispersions are clarified by flocculation. Destabilising chemical cpd(s). are added in different steps as a single or several additives. The mixt. is agitated for less than 30 secs. at more than 1/100 sec. (Camp type velocity gradient), and for more than 0.5 sec. at more than 1/200 Camp velocity gradient. Aq. soluble polymer(s) are added as flocculating agents, with agitation at less than 1/200 secs. Camp type velocity gradient. The dispersion is passed into a flocculator fitted with mechanical and/or streaming mixing elements, for a less than 20 mins. dwell time, mixing at less than 1/200 secs. (Camp velocity gradient). The flocculated dispersion is passed into a gravitational and/or mechanical separator to remove flocculated matter from the continuous phase. (-pp Dwg.No.0/0)

Description

FIELD OF THE INVENTION The present invention relates to a process for the chemical clarification of aqueous media dispersions by the production and separation of gradual floccules in a multi-step technology.

It is well known that the flocculation technique is widely used to isolate the disposed part. Floccules formed in this way allow easy separation of the liquid-solid phases, for example by sedimentation (Benedek: Phase Separation in Wastewater Treatment, WATER DOC1977).

Methods using such solutions are also gaining ground in water and wastewater treatment technologies (G. Smetburst Basic Water Treatment - Thomas Felford Ltd. London 1979). These procedures partly include the effective removal of suspended solids (R.

L. Culp-R. L. Culp: New Concepts in Water Purification - Van Nostrand Reinhold Company New York / Cincinatti / Toronto / London / Melbourne 1974; U. Triebel:

Lehr und Handbuch dér Abwassertechnik, Verlag von 20 Wilhelm Emst u. Sohn Berlin / München / Düsseldorf 1973), partly allow the separation of various dissolved pollutants such as phosphorus compounds (Benedek: Tertiary Wastewater Treatment Methods, VÍZDOK 1973). 25

The bridge between the dispersed particles plays a crucial role in the formation of floccules. Bridge bonds result in a characteristic loose, fluffy structure In the past, bridge bonds were formed mainly by the addition of hydrolyzing metal salts (aluminum sulfate, ferric chloride). In this case, the hydroxy complexes formed during the hydrolysis and having surface charge are bound together by the dispersed particles. The use of water-soluble polymers (polyelectrolytes) as a flocculating agent has gained a great impetus. These materials produce higher strength bridge bonds at higher speeds Currently, there is a wide variety of flocculating agents commercially available.

Despite the widespread use of flocculation techniques 40, the following problems often occur during implementation:

1. No flocculation occurs after the addition of the flocculant (polyelectrolyte).

2. The flocculation is incomplete, that is to say, although floccules are formed, but they contain only a portion of the dispersed material, consequently, only a partial, ineffective separation of the original dispersion can take place after liquid-solid separation. 50

3. Although flocculation occurs, the size and compactness of the flocculations produced is very different.

This makes it difficult to separate the liquid phase and the solid phase, reducing the performance of the separation device (eg settler).

4. The flocculation process is very sensitive to variation in dispersion quality, that is, to a satisfactory extent, only within a narrow range of the qualitative parameters of the dispersion. 60

5. Flocculation occurs only with a large excess of flocculating agent, which greatly increases the cost of separating the liquid and the dispersed portion. These problems occur because the flocculation technique used does not meet the technical conditions necessary to produce an effective flocculation. One group of technical conditions is of a chemical nature. These include the selection of the active ingredients (destabilizers, flocculants, excipients), the determination of their specific amounts, the order of addition and the time (response time) required for the optimal effect to be achieved. Another category of technical conditions includes hydrodynamic characteristics. These contain the properties of the flows for mixing the active ingredients and the flows for collecting and compacting the particles.

As a result of our extensive experimental and theoretical research on flocculation techniques for a wide range of dispersions, we have succeeded in developing a multi-step technology capable of providing good separation of liquid and dispersed, dispersed, in some cases, some of the dissolved components are also removed in the form of floccules.

The main features of our flocculation technology are:

1. working with several (at least two) active substances,

2. uses several technological steps until complete flocculation occurs: blending of preparative agents, blending of flocculant polymer, flocculation.

3. successive technological steps gradually bring the dispersion system closer to the fullest flocculation state,

4. pays equal attention to the combination of chemical and hydrodynamic effects and optimal conditions at each technological step.

The present invention relates to a process for the chemical clarification of aqueous media dispersions by the production and separation of stepwise flocculants in a multi-step process comprising the step of adding one or more destabilizing agents to the aqueous dispersion in one or more increments of one or more excipients and 100 sec characterized by greater than ⁴ at Camp's sebességgradienssel agitation intensity, then characterized by time greater than 0.5 minutes of residence and greater than 20 sec ⁴ at Camp's sebességgradienssel stirring mixed into useful flocculating the dispersion of one or more water-soluble polymer 200 with a Camp rate gradient of less than ⁴ sec, then the dispersion is stirred in a flocculator operated by mechanical and / or flow stirrers for 20 minutes. more residence time of 200 sec and less than ⁴ characterized Camp's sebességgradienssel mixing and the flocculated dispersion of gravity and / or mechanical system, őnmagá2

HU 204018 Β, in which the floccular cavities are separated from the medium.

The active ingredients we use fall into three groups.

The first group is destabilizing agents. Their function is to change the surface layer of the particles of the dispersion to make them adherent to one another, thereby initiating coagulation in the dispersion. In other words, the zeta potential of the particles is shifted towards zero. Such destabilizing agents include: polyvalent ions, hydrolyzing metal salts, low molecular weight water soluble polymers. Since dispersions in practical dispersions generally have a negatively charged surface (zeta potential less than -10 mV), destabilizing agents have a positive charge. Of the simple metal ions, divalent calcium and magnesium ions are used primarily. Preferably, the metal salt of hydrolysis is aluminum sulfate, aluminum chloride, polyaluminium salts, ferrous sulfate, ferric chloride, mixtures thereof or mixtures thereof. Of the low molecular weight water-soluble polymers, cationic polymers are used primarily for this purpose. Examples are ROHAFLOC KF 945 (ROHM), PRAESTOL 85K (STOCKHAUSEN), PURIFLOC C31 (ROHM).

The second group of active ingredients is called excipients by a summary name. Their role is to facilitate the introduction into the flocculent of the various components of the dispersion, the removal of which from the medium of dispersion is one of the tasks of the flocculation technology in the particular case. Such excipients include, for example, minerals with a high specific surface area, particularly reactive on their surface, or derivatives thereof made more reactive by activation (various clay minerals, zeolites, and the like), which help to collect difficult to destabilize particles of the dispersions into floccules. Namely, said excipients bind the particles to be removed by surface adhesion and then react chemically with water-soluble polymers to form a bridge bond. Further, solid particulate sorbents or solid reaction product chemicals are used as an excipient to remove some of the dissolved components in the dispersion medium from the dispersion by collecting them in floccules. Such excipients include, for example, powdered activated carbon or potassium permanganate solution (the solid reaction product of which is manganese dioxide) used to remove organic impurities in the raw water to be purified for drinking water purification.

The first and second classes of active ingredients are called preparative active ingredients. Their addition to the dispersion always precedes the addition of the water-soluble polymers used as the flocculant.

The third group of active ingredients are bridge-linking flocculants (flocculants). Various water-soluble polymers (polyelectrolytes) are used as flocculating agents. These include non-ionic and anionic water-soluble polymers of various acrylate and vinyl bases, various degrees of hydrolysis and molecular weight, and mixtures thereof. Also used are cationic character quaternary ammonium polyelectrolytes, cationic chain polymers, and mixtures thereof.

The flocculation technology of the present invention performs the separation of the materials of the dispersion in several steps. These technological steps are as follows:

admixture of preparation agent (s), admixture of flocculant, flocculation, solid-liquid separation.

The active ingredients are added in separate technological steps, but in any order and in one or more portions. This also means that the administration of different types of preparative agents can be combined. Among the possible combinations, the following dosage sequences are highlighted:

- first adding the destabilizing agent and then the excipient,

- first adding the excipient and then the destabilizing agent,

- adding a portion of the excipient first, followed by the destabilizing agent, and finally the remainder of the excipient, wherein the excipient added in the last step is the same as or different from that added in the first step.

However, it is also possible to use only a destabilizing agent or an excipient as a preparative agent.

Three cases of mixing of the active ingredients are distinguished:

Case 1: mixing of hydrolyzing metal salts,

Case 2: admixture of other preparative active substances (destabilizing agents and excipients) without a subsequent stay,

Case 3: Addition of other preparative agents (destabilizing agents and excipients) with retention.

For each admixture, it should be taken into account that, for technical and partly economic reasons, less active ingredient is added to the dispersion than the amount of substance which could be chemically reacted or physically sorbed with the components in the dispersion. Therefore, the active ingredients must be dispersed rapidly enough throughout the dispersion to reach all sites before being depleted or rendered ineffective by chemical reaction or physical sorption. In fact, the current flocculation techniques often have the mistake of overdosing at the site of drug delivery, and not at all delivering the remainder of the dispersion.

In determining the mixing characteristics of the hydrolyzing metal salts (Case 1), the mechanisms of action should be taken as a starting point. The hydrolyzing metal salts exert their destabilizing effect by hydrolysis to form positively charged multi-core hydroxy complexes and these intermediate reaction products are capable of

EN 204018 Β to reduce the negative surface charge of particles in the dispersion or to shift their zeta potential to zero. These effective hydroxy complexes are short-lived (up to 10-15 sec), eventually transforming into inactive metal hydroxides by continuing hydrolysis. Therefore, the hydrolyzing metal salts must be mixed so rapidly that the effective hydroxocomplexes reach the full volume of the dispersion. However, following the rapid agitation of the hydrolyzing metal salts, a residence time is required until the next technological step occurs to aggregate the destabilized particles to form foci more suitable for the bridge-linked flocculation than the destabilized individual particles. Stirring at a much lower intensity during the residence time is sufficient.

Of the other preparative active substances (destabilizing substances and excipients) which do not require a residual residence time (case 2), only the general aspects of the active substance mixing need be considered. It is thus a rapid distribution of the active ingredient, the technical solution of which is not limited by the magnitude of the shear force that is applied. In case 3 (incorporation of other preparative active substances with a post-residence time), this also provides for a residence time longer than the time of rapid distribution before the next step in the technological process.

When mixing the polymer solution used as a flocculating agent, it should be noted, first of all, that the bridge-linked flocculation starts as soon as the polymer solution is contacted with the particles capable of binding (destabilized, excipient-bound). , making it harder for them to do more than a certain amount of shear. In fact, using high shear mixing to disperse the polymer would break the bridge bonds, which are the essence of flocculant formation.

In the flocculation technology of the present invention, the numerical limits for the technical requirements for the incorporation of each active ingredient are as follows:

Indication of the active substance to be mixed mixing time sec residential time minute Camp Gradient, G Mixing space sec ' ¹ Lounge sec ⁴ hydrolyzing <20 > 0.5 > 100 > 20 metal salts 5-15 1-10 200-1600 300-700 20-800 Other preparatory work <30 > 200 - active ingredients without a subsequent stay 5-30 200-1600 Other preparatory work <30 > 1 > 200 > 20 active ingredients with retention 5-30 1-60 300-1600 20-800 flocculants <20 <20 <200 <200 polymer solutions used 1-10 2-10 10-150 40-150 40-120

In aqueous dispersions - in some cases, flocculants can be easily formed by simply mixing a solution of high-efficiency flocculating agents containing water-soluble polymers. However, in order to compact the particles of the dispersion into nearly 100% large, uniform, easily separable flocculants, there is in each case a separate technological step: flocculation in a flocculator. In the technology we have developed, flocculation directly follows the mixing of the polymer solution, the polymer mixer and the flocculator being directly connected to one another. During flocculation, the proper flow conditions of the polymer chains on their surface must be ensured by establishing proper flow conditions. The particles of dispersions occurring in technical practice do not exhibit significant Brownian motion. Therefore, the displacement of the particles relative to one another requires a velocity distribution in the fluid surrounding the particles which allows the flow not only to seize the particle but also to force it to move due to the forces applied. For such a flow, a turbulent flow having a mean, turbulent velocity gradient of Camp over a defined value range should be used. The effect of flow on the particles in the suspension naturally implies that the desired value of the mean turbulent velocity gradient should be realized not only for the flocculator as a whole but also for its smallest volume. According to our experiments a

EN 204018 Β Flocculants that can be formed with water soluble polymeric flocculants require a flow rate of less than G-200 sec ⁴ and greater than G-20 sec ⁴ with a Camp gradient. Optimal G values are between 40 and 120 sec ' ¹ . The residence time depends on the composition of the dispersion to be purified and the active ingredients employed, but is in any case between 1 minute and 20 minutes. In our experiments, we achieved the best results between 2 minutes and 10 minutes.

Flocculators suitable for flocculation include both flocculators with movable agitators and flocculators in which fluid agitation is effected by means of flow openings or flow breakers. When designing flocculators, it should be taken into account that the Camp's average turbulent velocity gradient values for flow characterization must be valid for both the total volume of the flocculator and the smallest volume fraction.

1-4. Figures 1-4 show Figures 1-4. in accordance with the specific embodiments described in the Examples. 1-4. 1-4. Examples are described in Examples.

Example 1

The filters of the dual-layer (sand, activated carbon) closed filter system for the preparation of utility drinking water are cleaned (regenerated) at regular intervals (72 hours). During the regeneration, the flow rate of water from the filters is 150 m ³ / h and its solid impurity content is 180 g / m ³ . The rinse water thus obtained is purified by flocculation technology. Purification is carried out according to the flowchart 1.

The active substances used are: destabilizing agent: aqueous solution of aluminum sulphate at 20 kg / m ³ , excipient: aqueous suspension of bentonite at 60 kg by weight, 10 kg / m ^{3 in} activated state, flocculating agent under the trade name SEPARAN AP30 (DOW), aqueous solution of partially hydrolysed polyacrylamide at a concentration of 0,5 kg / m ³ .

In the first step, the suspended particles in the filter-rinse water are destabilized. Therefore, aluminum sulphate solution is first mixed in the filter rinse water. A two-part chemical mixer is used for this purpose. In the first part of the agitator (mixing space) the water is held for 10 seconds. Here, the agitation intensity is characterized by an average turbulent velocity gradient of G-420 sec ' ¹ Camp, produced by a mechanical rotary agitator. The net power input to the agitator shaft is 70 W. The aluminum sulphate solution (flow rate 1.25 dm ³ / min) is supplied via pipeline to the agitator space.

In the mixing chamber, aluminum sulphate is evenly distributed in the water and reaches a concentration of 10 g / m ³ . The water then enters the mixer sump where it stays for 2 minutes. The slow mixing in this space is provided by the kinetic energy of the incoming water. At a flow rate of 0.46 m / sec, the mixing intensity in the living space is characterized by a G-30 sec ' ¹ Camp gradient. Solid particles suspended in water are destabilized during and as a result of hydrolysis of aluminum sulfate in the holding space.

In the second technological step, the smallest (colloidal) particles are bonded to a large surface area reactive excipient. Therefore, a bentonite suspension (specific added amount of 10 g / m ³ dry matter) was mixed with the filter-rinse water in the same manner as described for aluminum sulfate blending in a two-part active blender.

The first two technologies are used to initiate flocculation in a dispersion prepared for flocculation by adding a polymer solution. A 2.0 dm ³ / min polymer solution delivered with a metering pump is first introduced into the diluent. Here, the polymer concentration is reduced to 0.025 g / dm ³ by mixing with 38 dm ³ / min of dilution water (clarified water). The diluted polymer solution is mixed with the filter-rinse water in a non-moving (flow) polymer mixer. With a residence time of 2 seconds, the polymer blender develops a G-63 sec average turbulent velocity gradient.

The concentration of flocculant polymer in the water leaving the polymer mixer is 0.4 g / m ³ .

After mixing the active ingredients, the filter-rinse water is introduced into a 25m ³ flocculator (10 minutes residence time). Rotating motors in the flocculator create a G-95 sec ' ¹ turbulent velocity gradient. The energy dissipation in the water is then 225 W. The flocculator develops well-settled, well-settled floccules, which contain more than 98% of the solid (floating) impurity in the filter-flush water.

The flocculated suspension was passed from the clarifier to a sloped plate settler. Solid impurities, concentrated in large floccules, are separated from the pure water at a surface load of 7 m / h. The suspended water content of the purified water was 3.5 mg / dm ³ .

The flowchart of the described procedure is shown in Figure 1:

11. aluminum sulfate solution tank; concentration in kg / m ³

12. metering pump; dosing solution 1.25 dm ³ / min

13. two-part chemical mixer for aluminum sulfate; specific 10 g / m ³

21) bentonite slurry tank; concentration of 10 kg / m ³

22. dosing pump; metered suspension

2.5 dm ³ / min

23. two-part chemical mixer bentonite; specific g / m ³

31) polymer solution container; concentration of 0.5 kg / m ³

32. metering pump; dosing solution 2 dm ³ / min

33. polymer solution dilution

34. polymer solution mixer; specific 0.4 g / m ³

4. Flocculator

5. settler

HU 204018 Β

Surfing backwash water; flow rate 150 m ³ / h, floating 180 g / m ³

Dilution water B 38 dm ³ / min

C clarified water; floating 3.5 g / m ³

D sludge.

Example 2

In a water mill installed on a surface water base, chemical water is used to purify the water for industrial water. The purified water is directly fed into the grid. The surface water flow rate is 180 m ³ / h.

The active compounds used are the following: destabilizing agent: 45 kg / m ³ aqueous solution of ferric chloride in flocculant A commercially available hydrolyzed polyacrylamide solution of 0 $ kg / m ^{3 under the} trade name ROHAFLOC SF380 (ROHM).

The first step is to destabilize the floating particles in the raw water. Therefore, iron (HT) chloride solution (stirring time 12 sec) is first mixed with the surface water. After mixing the iron (ED chloride solution) the hydrolysis and the formation of the active nuclei are delayed for 2 minutes before the next technological step (polymer mixing). To mix and hold the iron (IH) chloride solution, a one-part chemical mixer is used. Using a rotary mixer, 6 m ^{3 of} usable volume of water flow and residence time, with a mixing ratio of 2: 1 height / diameter and a propeller mixer, the 12 sec. mixing time requires 480 rpm. which creates a G-730 sec ' ¹ Camp gradient in the mixer. The chemical mixer is piped through a 0.53 dm ³ / min solution of ferric chloride (8 g / m) in the water to be purged. ³ concentrations.

Flocculation is initiated by the addition of a polymer solution in the dispersion destabilized with ferric chloride. The 2.4 dm ³ / min polymer solution supplied with the dosing pump is first introduced into the diluent. Here, the polymer concentration is reduced to 0.025 g / dm ³ by mixing 45.6 dmV / min of dilution water (clarified water). The diluted polymer solution is mixed with the surface water in a (flow) polymer mixer with no moving parts. The ^two surface water passing through the polimerbekeverőn 2 second residence time, wherein due to the injection of the polymer solution hígtott G-63 ^sec-1 Camp's average velocity turbulent formed.

The flocculation that started when the polymer solution was mixed in the surface water is complete in the flocculator. With a useful volume of 20 m ³ , a flocculator with mechanical stirrer has a residence time of 6.7 minutes and a G-75 sec ' ¹ Camp gradient. In flocculated surface water, solid-liquid separation 5 is performed in a directed flow settler with a surface load of 6 m / h.

The flowchart of the described procedure is shown in Figure 2:

11. iron (HI) chloride container; concentration 45 kg / m ³

12. metering pump; added solution 0.53 dmTperc θ

13. one-part chemical mixer for ferric chloride; specific gravity 8 g / m ³

21) polymer solution container; concentration of 0.5 kg / m ³

22. dosing pump; solution added 2.4 dm ³ / min 5 23 dilution of polymer solution 20 times

24) polymer solution mixer; specific gravity 0.4 g / m ³ ·

3. Flocculator

4. settler

Surface water; flow rate 180 m ³ / h) dilution water B

C clarified water

D sludge.

Example 3

Utility sewage contaminated with industrial effluents was treated in a continuous, semi-sized plant. The main characteristics of the treated wastewater were:

water flow: 1 m ³ / h

Solid (floating) impurity I: 250-350 g / m ³ Chemical oxygen demand: 400-500 g / m ³ Total phosphorus content: 25-35 g / m ³ .

Purification is carried out according to the flowchart 3.

The active ingredients used are: a destabilizing agent. aluminum sulfate 33 kg / m ³ of an aqueous solution of a concentration of excipient: 60% bentonite colors content assets condition of 10 kg / m ³ of an aqueous solution of flocculant concentration: ERCOPOL-20H of known commercial polyacrylamide-based water-soluble polymer can be 0.25 kg / m Aqueous solution of ³ concentrations.

The aluminum sulfate solution is first mixed in the waste water. The useful volume of the one-part chemical mixer is 30 dm ³ . The waste water stays there for 1.8 minutes. For mixing, use a high speed disc mixer. A mixing time of up to 12 seconds can be achieved with at least 456 rpm. With the 1440 rpm we use, the mixing time is about 4 seconds. The aluminum sulfate solution (flow rate 30 cm ³ / min) supplied with the metering pump is piped into the chemical mixer. The specific dosage is 60 g / m ³ . The mechanical power dissipated in the mixer was 13.7 W, which resulted in a G-630 sec ⁴ Camp gradient in the mixing chamber.

The wastewater then flows into the bentonite mixer. The bentonite mixer has the same design as the aluminum sulfate mixer: a 30 dm ³ single volume mixing bowl with a rotary speed of 1440 rpm. Accordingly, the residence time is 1.8 minutes and the Camp velocity gradient is G-630 sec ' ¹ . The bentonite suspension supplied by the metering pump reached a concentration of 50 g / m ³ in the effluent after mixing.

The flocculant is then mixed with the waste water.

The polymer solution, delivered from a storage tank by a dosing pump, is first diluted 10-fold with clear water and then at a concentration of 0.025 kg / m ³ .

HU 204018 Β is mixed with the wastewater in the polymer mixer. A (flow) mixer containing no moving component is used to mix the polymer solution.

From the polymer blender, the waste water is discharged into a 67 dm ³ , 3-blender flocculator with a volume of 4 minutes. The flocculator develops an average turbulent velocity gradient of G-82 sec ' ¹ Camp resulting in a power dissipated in the fluid of 0.45 W.

In this flocculator, very large flocculae are formed in the effluent, which is suitable for flocculation with the active compounds. The formation of floccules can also be monitored by direct observation, but we have made a device which can directly measure the properties of the floccules formed in the flocculator. The wastewater flows from the flocculator to a continuous settler. The settler has a horizontal cross-sectional area of 0.13 m ² for sedimentation, with the flocculated suspension passing through a vertical flow. The clear water leaves the settler top with an overflow. The sludge that accumulates on the bottom of the settler is occasionally drained and analyzed (dry matter content, on average, 2 to 5%). Occasionally, the clarified effluent from the settler is sampled and some water quality components are analyzed on site and others in the laboratory. The following data are used to illustrate the effectiveness of a pilot-scale experiment:

Quality of purified water:

Chemical oxygen demand (dichromate) 40-80 g / m ³ suspended solids 40-60 g / m ³ total PO4 3-9 g / m ³ .

The settling surface load is 8 m / h.

The flowchart of the described procedure is shown in Figure 3:

11. aluminum sulfate container; concentration of 33 kg / m ³

12. metering pump; solution added 30 cm ³ / min

13. one-part chemical mixer for aluminum sulfate; specific 60 g / m ³

21) bentonite slurry tank; concentration in kg / m ³

22. dosing pump; added suspension 83 cm ³ / min

23. one-part chemical mixer bentonite; specific g / m ³

31) polymer solution container; concentration of 0.25 kg / m ³

32. metering pump; solution added 33 cm ³ / min

33. polymer solution dilution 10-fold

34. polymer solution mixer; specific 0.5 g / m ³

4. Flocculator

5. settler

Utility wastewater; flow rate 1 m ³ / h B dilution water C clarified water D sludge.

Example 4

It is well known that well-functioning chemical clarification can not only remove suspended solids from surface waters, but can also significantly reduce the amount of microorganisms remaining in the water, since most of these are incorporated into floccules. It is therefore advisable to operate chemical water exploration permanently (throughout the year) in a drinking water plant installed on a surface water base. It is also known that the suspended solids content of shallow-water lakes varies over a wide range: it rises above 100 g / m ^{3 in} windy conditions, drops below 20 g / m ^{3 in} quiet weather and barely reaches 1-2 g / m ³ in winter . However, in order to be truly effective, and thus significantly reduce the number of microorganisms, suspended solids in excess of 30 g / m ³ are required. Therefore, it is expedient to maintain the floating matter content of the raw water above this limit by adding artificial floating material. Fine-ground zeolite powder is excellent for artificial floating material, which, even with its high sorption capacity, enhances the efficiency of chemical clarification. A flow diagram of such an experimental plant clarifier, which can be implemented by the method we have developed, is shown in Figure 4.

The active substances used are: destabilizing agent: 45 kg / m ³ aqueous solution of iron (HI) chloride, flocculating agent: partially hydrolyzed polyacrylamide commercially available as PRAESTOL 2935IR (STOCKHAUSEN) at 0.5 kg / m ³ , excipients: 1. aqueous suspension of ground zeolite at a concentration of 35 kg / m ³ ,

2. aqueous solution of potassium permanganate at 3.5 kg / m ³ .

Potassium permanganate solution is first added to the raw water at a flow rate of 36 m ³ / h to reduce the chemical oxygen demand. For mixing, a two-part rotary agitator mixer is used, with a mixing time of 30 seconds and a residence time of 10 minutes. From these data, taking into account the flow of water, the useful volume of the mixing chamber is 0.3 m ³ and the residual space is 6 m ³ . Rotating the mixer with a net power of 30 W produces a Camp gradient of G = 316 sec ' ¹ . The potassium permanganate solution is supplied by a metering pump at a flow rate of 350 cm ³ / min via pipeline to the mixing chamber where the potassium permanganate concentration is 2 g / m ³ . Water flows from the mixing chamber at a velocity of 1 m / sec into the quiescent space, whereby G-29 sec ' ¹ becomes the Camp's average turbulent velocity gradient.

A zeolite suspension is then added to the water as required in an amount of artificial floating material such that the combined concentration of natural and artificial floating material is greater than 30 g / m ³ . A one part chemical mixer was used to mix the suspension with a mixing time of 30 sec and a G-600 sec ' ¹ gradient. This requires a mixing tank of 0.3 m ³ capacity and a paddle mixer with a net capacity of 108 W.

The water exiting the zeolite mixer then flows to a two-part chemical mixer in which iron (HI) chloride solution is added to destabilize the dispersed particles. G-600 sec ¹ Camp Gradient ho7 in mixing space with 10 sec mixing time

HU 204018,, with a G-30 sec velocity gradient within a 2-minute stay in the fitness area. With these data, the usable volume of the mixing chamber is 0.1 m ³ , the net power for driving the rotary mixer therein is 36 W, the useful volume of the standing space is 1.2 m ³ , 5 the flow rate of the water is 0.42 m / sec. The ferric chloride solution is transported via a dosing pump via a pipeline to the mixing chamber. For a specific addition of ¹⁰ g / m ^3, iron (H) chloride solution (133 cm ³ / min) should be added to the mixing tank.

The des tabilizált dispersion without going component (flow) then moving over Here polimerbekeverőre 2 sec ^-1 are as 0.025 g / ^dm3 concentration of the diluted polymer solution was mixed with a flowrate Ί2 dm ³ / minute, with which the water 15 to be cleaned polimeikoncentráció 0.3 g / m ³ . Prior to mixing, the polymer solution supplied with the dosing pump must be diluted 20 times with tap water. In the polymer blender, an average turbulent velocity gradient of G = 55 sec ⁴ Camp occurs as a result of the injection of the diluted polymer solution. From the polymer blender, the surface water is fed to the flocculator. Here, flocculation is complete with a flow of slow-rotating agitators characterized by a G-80 sec ¹ Camp gradient over a residence time of 5 minutes. The useful volume of the flocculator is 3 m ³ and the power dissipated in the liquid 25 is 20 W. The fluid containing the flocculants is then placed in a settler with a surface load of 5 m / h where the solid-liquid separation takes place.

The flowchart of the described procedure is shown in Figure 4: 30

11. potassium permanganate solution tank; concentration 3.5 kg / m ³

12. metering pump; administered a solution of 350 cm ³ / min

13. two-part chemical mixer for potassium peimanganate; specific 2 g / m ³ 35

21) zeolite suspension tank; concentration 35 kg / m ³

22. dosing pump; up to 510 cm ³ / min

23. one part chemical mixer for zeolite

31. ferric chloride solution tank; concentration 45 kg / m ³ 40

32. metering pump; was added 133 cm ³ / min

33. two-part chemical mixer for ferric (H) chloride; specific 10 g / m ³

41. polymer solution container; concentration of 03 kg / m ³

42. metering pump; solution added 360 cm ³ / min 45

43. polymer solution dilution 20-fold

44. a polymer blender; specific 0.3 g / m ³

5. Flocculator

6. settler

Surface water; flow rate 36 m ³ / m 50

Diluting water B; flow rate 7 dm ³ / min C clarified water

Claims (10)

PATENT CLAIMS A process for the chemical clarification of aqueous peat dispersions by the production and separation of stepwise flocculants in a multi-step process, characterized in that one or more destabilizing agents and / or one or more adjuvants are added to the aqueous dispersion in separate technological steps. addition time of 100 sec and values greater than ⁴ Camp's sebességgradienssel agitation intensity, then characterized by a greater time 0.5 min residence and greater than 20 sec ⁴ Camp's sebességgradienssel stirring mixed into the dispersion can be used as a flocculant in one or more water-soluble polymer stirred for 200 sec to a smaller operating at ⁴ Camp's sebességgradienssel stirring, then the dispersion is a mechanical and / or flow mixing elements residing within 20 minutes flocculator si time 200 sec and less than ⁴ characterized Camp's sebességgradienssel stirring and gravity of the flocculated dispersion and / or into a mechanical system of a known type of separator in which the flocculate was separated from the media. Process according to claim 1, characterized in that the destabilizing agent is 1-100 g / m ^{3 of} hydrolyzing metal salt, 0.1-10 g / m ^{3 of} low molecular weight polymer or 10-500 g / m ^{3 of} 3. A process according to claim 1, wherein the excipient is a solution of a chemical which gives a solid reaction product with the solvent to be removed, or a suspension of a finely divided solid which binds the surface of the solvent to be removed or the dispersed particle. 4. The process of claim 3 wherein the solid reactant is a potassium permanganate solution. 5. A process according to claim 3 wherein the finely divided solid is a high specific surface active mineral or an activated derivative thereof or a solid particulate sorbent. 6. A process according to claim 5 wherein the finely divided solid is clay, zeolite or activated carbon. 7. The method of claim 1, wherein the destabilizing agent is mixed at a stirring intensity of 5 to 30 seconds and a speed gradient of ^{4 to 16} seconds at ⁴ Camp. The process of claim 2, wherein the hydrolyzing metal salts are mixed at a stirring intensity of 5 to 15 sec and a gradient of 300 to 700 sec at a ⁴ Camp rate gradient. The process of claim 1, wherein the mixing of the water soluble polymer is carried out at a mixing intensity characterized by a mixing time of 1 to 10 seconds and a ⁴ Camp rate gradient of 10 to 150 seconds. 10. The method of claim 1, wherein the dispersion is agitated in the flocculator with a stirring intensity of 2 to 10 minutes and a ⁴ Camp gradient of 40 to 120 seconds.