METHOD OF PURIFYING NATURAL WATER AND WASTEWATER

Abstract

The invention is classified as a physicochemical method of natural and waste water treatment and can be used in the energy engineering, chemical, petrochemical, food and other industries, especially in treatment of process, domestic, precipitation, mining, oilfield, quarry water and the water of tailing pounds.

The purpose of the invention is to improve the treatment of natural and waste water, to increase the capacity of a moving bed pressure filter and also to ensure high efficiency of the cleaning of the moving bed.

The technical result is the expansion of the range of application of the moving bed pressure filter ensuring high efficiency of treatment of both low-contaminated natural water and highly contaminated waste water.

This result is obtained due to the use of additional stages of chemical treatment during water treatment (oxidizing agent, demulsifier, powder sorbent), the use of various types of a pressure flocculation reactor, grains for a single and double moving bed, which have different grain composition and density, the performance of four-stage cleaning of the moving bed, the use of a dual-flow moving bed pressure filter, as well as due to the use of the additional pressure flocculation reactor followed by the removal of severe contamination with the use of a pressurized hydrocyclone.

Claims

1. A natural and waste water treatment method including the following treatment stages: mixing of the feedwater with a coagulant, flocculation in a pressurized contact tank, mixing of the feedwater with a flocculant, filtering through the moving granular bed in a pressure clarifying filter followed by flushing of it, fine purification through the double moving granular bed and disinfection of the feedwater with sodium hypochlorite, wherein an oxidizing agent is added to the feedwater before mixing with the coagulant, the flocculation is performed during 2 and up to 30 minutes in a pressurized reactor made in the form of a vertical vessel or with upper and lower distribution devices, or with upper, lower and middle distribution devices, whereby: the feedwater with a temperature above 10° C. flows downward through the flocculation reactor, or the feedwater with a temperature below 10° C., as well as low turbid and deep color water flow upward through the flocculation reactor, or a demulsifier is additionally added to the flow of feedwater, which contains light contaminants with a density less than the density of water, after the treatment with the oxidizing agent and coagulant, and then the water flows to the middle distribution device of the vertical flocculation reactor and downward to the lower distribution device, and light contaminants are removed through the upper distribution device, the flocculant is added to the feedwater after the treatment in the flocculation reactor, which water then flows upward to a moving bed pressure, whereby: polymer grains 3-10 mm in size and grain density in the range of 0.3-0.98 g/m.sup.3 are used as grains of the moving bed and the height of the moving bed is 0.5-2.3 m, or the moving bed is double, polymer grains with a low density in the range of 0.3-0.8 g/cm.sup.3 and grain size of 1-5 mm are used as the upper bed and polymer grains with a density of 0.8-0.98 g/cm.sup.3 with a grain size of 3-20 mm are used as the lower moving bed, so the total height of the double moving bed is 1.0-2.5 m, whereby the height of the upper bed is 0.3-1.5 m, and the lower one is 0, 5-1.5 m. flushing of the pressure filter moving bed from the contaminants kept back is performed by partial emptying of the pressure filter so that the moving bed goes down and is located in the middle of the pressure filter and provides a distance between the lower boundary of the moving bed to the lower distribution device of more than 10 cm, as well as the distance between the upper the boundaries of the moving bed and the upper distribution device is also more than 10 cm, then compressed air with a pressure of 2-10 bar is supplied for 3-30 min through the lower distribution device and then the pressure filter is filled with the water by an upward or downflow, water flush is supplied downward for 2-20 minutes after the filling of the pressure filter with the water, the water flush is drained through the lower distribution device of the pressure filter.

2. The method according to claim 1, wherein, after the flocculant is added, the feedwater flows to the double-flow moving granular bed pressure filter in two directions that is upward and downward for getting filtered through the grains of the moving bed by downflow and upflow, the feedwater is drained through the middle distribution device located in the middle of the moving bed and the height of the moving bed of 1.0-3.5 m, whereby the polymer grains with a grain size in the range of 3-10 mm and a grain density in the range of 0.3-0.98 g/m.sup.3 are used as the grains of the moving bed and the flushing of the pressure filter moving bed from the contaminants kept back is performed by partial emptying of the pressure filter so that the moving bed is lowered and provides a distance between the lower boundary of the moving bed to the lower distribution device of more than 10 cm, as well as the distance between the upper the boundaries of the moving bed and the middle distribution device is also more than 10 cm, then compressed air with a pressure of 2-10 bar is supplied for 3-30 min through the lower distribution device and then the pressure filter is filled with the water by an upward or downflow, water flush is supplied downward for 2-20 minutes after the filling of the pressure filter with the water, the water flush is drained through the lower distribution device of the pressure filter.

3. The method according to claim 1, wherein before the flocculant is added, an additional sorbent, which is a powder sorbent solution, is added.

4. The method according to claim 1, wherein high-pressure or low-pressure polyethylene, polypropylene, composite materials based on polyethylene, polypropylene or their analogues are used as a material for the moving bed.

5. The method according to claim 1, wherein the grains with a smooth surface and small inclusions, a total volume of which is not more than 10% of the volume of the grain, with the form of a sphere, hemisphere, cylinder, cubic shape, are used as the moving bed.

6. The method according to claim 1, wherein the pressure filter is equipped with upper, lower and middle peep-holes, as well as a level indicator to monitor the flushing of the moving bed.

7. The method according to claim 1, wherein a second stage flocculation reactor is installed after the pressure flocculation reactor in front of the moving bed pressure filter.

8. The method according to claim 7, wherein a pressurized hydrocyclone is installed after the second stage flocculation reactor in front of the moving bed pressure filter.

9. The method according to claim 1, wherein a flow meter is installed in the flow of the feedwater after the moving bed pressure filter.

Description

[0066] FIG. 1 shows an option of cleaning of the feedwater with the use of the pressure filter including a double-flow moving bed pressure filter (Option 1).

[0067] FIG. 2—Pressure flocculation reactor (Option 1).

[0068] FIG. 3—Pressure flocculation reactor (Option 2).

[0069] FIG. 4—Pressure flocculation reactor (Option 3).

[0070] FIG. 5—Moving bed pressure filter.

[0071] FIG. 6—Method of cleaning of the moving bed of the pressure filter.

[0072] FIG. 7—Double-flow moving bed pressure filter.

[0073] FIG. 8—Method of cleaning of the moving bed of the double-flow pressure filter.

[0074] FIG. 9—Option of treatment of the feedwater with the use of the pressure filter including double-flow moving bed pressure filter (Option 2).

[0075] FIG. 10—Option of treatment of the feedwater with the use of the filter, including double-flow moving bed pressure filter (Option 3)

[0076] FIG. 1 shows an option of treatment of the feedwater with the use of the moving bed filter. Option 1.

[0077] The feedwater under pressure 2 to 16 bar is supplied from the pump 1 through the pipe 2 to the pressure flocculation reactor 3. The coagulant solution is added beforehand from respective tank 5 to pipeline 2 under pressure from coagulant pump 4. The difference of this plant is adding of the oxidizing solution to pipe 2, which is added by means of pump 6 from respective tank 7. Adding of the oxidizing solution before adding of the coagulant enables oxidizing and destruction of complex organic contaminants in the feedwater and increase in the effectiveness of flocculation. Known mixing devices 8 are installed in the pipeline 2 for better mixing of the feedwater and chemicals in the form of an oxidizing agent and a coagulant.

[0078] Various options of the pressure flocculation reactor are showed in FIG. 2, FIG. 3 and FIG. 4.

[0079] In principle, the pressure flocculation reactor is a vessel, to which the feedwater flows after mixing with an oxidizing agent and a coagulant and in case of keeping in which, micro flocks of the contaminants are generated in the feedwater.

[0080] The volume of the pressure flocculation reactor should provide a certain time of keeping of the feedwater. The time is from 2 to 30 minutes, which depends on the temperature and contamination of the feedwater.

[0081] FIG. 2 shows a conventional (known) pressure flocculation reactor 3 (Option 1), which consists of a cylindrical vertical body 15 and, respectively, upper 16 and lower 17 spherical heads. There is an upper distribution device 18 in the upper sphere 16, which is connected to the pipeline 2 for supply of the feedwater to the pressure flocculation reactor.

[0082] There is a lower distribution device 19 in the lower sphere 17, which is connected to pipe 9 for removal of the feedwater from the pressure flocculation reactor.

[0083] The upper 18 and lower 19 distribution devices ensure a uniform downflow of the feedwater, and the internal volume of the reactor vessel ensures the duration of keeping of the feedwater in the pressure flocculation reactor, in order to form flocculated micro flocks of the contaminants in the feedwater.

[0084] At the same time, this design of the pressure flocculation reactor has several disadvantages.

[0085] Especially in case of cleaning of the feedwater at a temperature below 10° C., the flocculation process is impaired and the downflow of the feedwater with unformed micro flocks of the contaminants, which have a density greater than the density of water, pass the pressure flocculation reactor consequently resulting in loss of the efficiency of cleaning of the feedwater at the next stage of filtrating through the moving bed of the pressure filter.

[0086] Therefore, there is provided to change the flow direction of the feed water from downward to upward. The FIG. 3 shows the pressure flocculation reactor (Option 2) with the same devices as those showed in FIG. 2 with the only difference. The flow of the feedwater is supplied to the lower distribution device 19 of the pressure flocculation reactor 3 through pipe 2 and removed through upper distribution device 18 and then the water flows to the moving bed filter through pipe 9.

[0087] This solution enables increase of the flocculation effect due to previously formed micro flocks, which are suspended and will act as a catalyst for the flocculation process.

[0088] FIG. 4 shows the pressure flocculation reactor (Option 3), which is advised to use for treatment of the feedwater with light contaminants with a density lower than the density of water, especially the contaminants containing petroleum hydrocarbons and oils.

[0089] This device differs from the device showed in FIG. 2 and FIG. 3 by the fact that the feedwater is supplied to the pressure flocculation reactor 3 through additional middle distribution device 20 through pipeline 2 after mixing with chemicals, that is an oxidizing agent and a coagulant.

[0090] Device 20 makes it possible to separate light contaminants such as petroleum hydrocarbons and oils with a density less than the density of water from the feedwater, which contaminants will tend to go up from distribution device 20 due to these densities.

[0091] As far as the light contaminants are accumulated in the upper part of the body of pressure flocculation reactor 3, they are removed through upper distribution device 18 which is connected to outer pipeline 21 and in case of regular opening of valve 22.

[0092] The feedwater flows after passing of middle distribution device coiner 20 downward to lower distribution device 19 and then is removed through outer pipeline 9 to the next treatment stage that is the moving bed pressure filter.

[0093] After the feedwater passes pressure flocculation reactor 3 (FIG. 1), it flows through pipeline 9 to moving bed pressure filter 14.

[0094] Flocculant solution 11 is added before to pipeline 9 through mixing device 8 by means of pump 10 from flocculant solution tank 11.

[0095] In case of severe contamination of the feedwater with mineral oil or other organic substances, there is provided adding of the aqueous solution of powdered activated carbon or other sorbent to pipeline 9 through mixing device 8 by means of pump 12 from sorbent solution tank 13, which is provided before adding of the flocculant solution.

[0096] FIG. 5 shows pressure filter 14 with moving bed 29 consisting of vertical cylindrical body 23 and, respectively, the upper 24 and lower 25 spherical heads. There is lower distribution device 26 in lower sphere 25, which device is connected to pipeline 9 for the supply of the feedwater after passing of the pressure flocculation reactor 3 (FIG. 1).

[0097] There is upper distribution device 27 in upper sphere 24, which device is connected to feedwater drainage pipe 28. There is moving bed 29 inside pressure filter 14.

[0098] There are respective valves for supply of the feedwater 30, discharge and partial drainage of water flush 31 and supply of compressed air 32 on pipeline 9.

[0099] There are respective valves for the removal of feedwater 33 and supply of water flush 34 on pipeline 28. There is an exhaust air-vent device that is valve 35 on the upper sphere 24.

[0100] In case of operation of pressure filter 14 with moving bed 29, the feedwater is supplied through open valve 30 to lower distribution device 26, which provides the uniform upflow of the feedwater along the section of pressure filter 14. Next, the feedwater, which has been treated with various chemicals that is oxidizing agent, coagulant, flocculant and a solution of powdered sorbent (FIG. 1), filtered through moving bed 29, on the surface of the grains of which the contaminants will be kept back in the form of micro flocks formed before in pressure flocculation reactor 3 (FIG. 1).

[0101] The feedwater is removed out of moving bed 29, through upper distribution device 27 and through pipeline 28 with open valve 33.

[0102] As far as moving bed 29 is contaminated, there is a resistance to the process of filtering of the feedwater, which results in decrease of capacity of pressure filter 14. There is provided to perform control of the operability of pressure filter 14 by means of flow meter 36 located on outlet pipeline 28 after valve 33. This location of flow meter 36 is provided to extend its run life. Do not install flow meter 39 on outlet pipeline 9, as the latter will fail because of its contamination with micro flocks of the feedwater.

[0103] There is provided additionally to switch off pressure filter 14 for cleaning of moving bed 29 according to a signal of the pressure sensor especially according to pressure drop between inlet 9 and outlet 28 pipelines.

[0104] FIG. 6 represents a method of cleaning of the moving bed, which is performed within four steps according to the invention.

[0105] Partial emptying of pressure filter 14 with moving bed 29 is performed at the first stage (FIG. 6a). If valves 31 and 35 are opened, moving bed 29 goes down due to water discharge out of pressure filter 14.

[0106] The partial emptying of filter 14 is completed, if the lower bed 29 is at a distance of 10 cm or more from the lower distribution device 26 and the top moving bed is at a distance of 10 cm or more from upper distribution device 27. Valve 31 is closed after that.

[0107] To control the stage of the partial discharge of the water out of pressure filter 14, peep-holes 37 are used, the lower one of which shows bottom moving bed 29 and the upper peep-hole shows the top moving bed 29, in case of the partial discharge. The middle peep-hole shows bottom moving bed 29 during filtering of feedwater (FIG. 5) and during flushing of moving bed 29 with water flush (FIG. 6d).

[0108] In case of automation of the process, there is provided to install level parameter 38, which will provide information on completion of the partial emptying of pressure filter 14 with moving bed 29.

[0109] Compressed air under pressure 2-10 bar is supplied with open valve 32 to lower distribution device 26 at the second stage (FIG. 6b), after which the upflow of the compressed air destroys “cementation” (clogging) of moving bed 29 and provides random motion of its grains in the water layer resulting in friction of grains and consequently providing intensive removal of the contaminants stuck to the surface of the grains of moving bed 29. The compressed air is vented to the atmosphere through open valve 35.

[0110] The compressed is supplied within 3 to 30 minutes, after which valve 32 is closed.

[0111] Pressure filter 14 with a moving bed 29 is filled with water at the third stage (FIG. 6c), wherefore valve 30 for supply of the feedwater is opened. In case of the filling of pressure filter 14, moving bed 29 goes up and displaces the air from upper sphere 24, which is removed to the atmosphere through valve 35. If pressure filter 14 is completely filled, moving bed 29 occupies upper sphere 24 and the part of cylindrical body 23 of pressure filter 14. Then, valves 30 and 35 are closed.

[0112] The water flush is supplied at the fourth stage (FIG. 6d), which is supplied under pressure through open valve 34, pipeline 28 and upper distribution device 27. Then, the downflow of the water flush flushes the contaminants, which come unstuck from the surface of the grains of moving bed 29 and which are removed under their own weight and under the flow of the water flush from pressure filter 14 through the lower distribution device 26, through pipeline 9 with open valve 31. This operation lasts for 2-20 minute, after which valves 34 and 31 are closed.

[0113] When the above stages of the treatment of moving bed 29 are passed, pressure filter 14 with moving bed 29 is put into operation or is on standby.

[0114] To intensify the water treatment process, especially, to increase the capacity of the moving bed filter, there is provided a new device that is a double-flow moving granular bed pressure filter, which is showed in FIG. 7.

[0115] Actually, this filter 39 is similar to pressure filter 14 with moving bed 29 (FIG. 5) and consists of vertical cylindrical body 23 and, consequently, upper 24 and lower 25 spherical heads. There is lower distribution device 26 in lower sphere 25, which device is connected to lower pipeline 9 for supply of the feedwater, which passed pressure flocculation reactor 3 (FIG. 1).

[0116] There is upper distribution device 27 in upper sphere 24, which device is connected to upper pipeline 9 for supply of the feedwater, which passed pressure flocculation reactor 3 (FIG. 1)

[0117] There is moving bed 29 inside the body of double-flow pressure filter 39.

[0118] There are respective valves for supply of the feedwater 30, discharge of the water flush and partial drainage 31 and compressed air supply 32 on the lower pipeline 9.

[0119] There are relevant valves for supply of the feedwater 30a and supply of the water flush 34 on the upper pipeline 9. There is an air-vent device that is valve 35 on upper sphere 24.

[0120] The treated water is removed from middle distribution device 40, which is located in the middle of moving bed 29. Middle distribution device 40 is connected to pipeline 28 and treated water drain valve 33. There is also flow meter 36 after valve 33 on pipeline 28.

[0121] In case of operation of double-flow pressure filter 39 with moving bed 29, the feedwater is supplied through upper and lower pipelines 9 with open valves 30 and 30a to upper 27 and lower 26 distribution devices.

[0122] Then the feedwater, which is treated before with various chemicals that is an oxidizing agent, coagulant, flocculant and a powder sorbent solution (FIG. 1), is filtered by upflow and downflow through moving bed 29, on the surface of which the grains will be kept back in the form of micro flocks generated before, in pressure flocculation reactor 3 (FIG. 1).

[0123] The treated water is removed out of moving bed 29 through middle distribution device 40 and through pipeline 28 with open valve 33.

[0124] As far as moving bed 29 is contaminated, there is a resistance to the process of filtering of the feedwater, which results in decrease of capacity of double-flow pressure filter 39 with moving bed 29. There is provided to perform control of the operability of pressure filter 39 by means of flow meter 36 located on outlet pipeline 28 after valve 33. This location of flow meter 36 is provided to extend its run life. Do not install flow meter 39 on outlet upper and lower pipelines 9, as the latter will fail because of its contamination with micro flocks of the feedwater.

[0125] There is provided additionally to switch off double-flow pressure filter 14 for cleaning of moving bed 29 according to a signal of the pressure sensor especially according to pressure drop between inlet 9 and outlet 28 pipelines.

[0126] FIG. 8 represents a method of cleaning of the moving bed of the double-flow pressure filter, which is performed within four steps according to the invention.

[0127] Partial emptying of double-flow pressure filter 39 with moving bed 29 is performed at the first stage (FIG. 8a) due to opening of valves 31 and 35 and moving bed 29 goes down due to water discharge.

[0128] The partial emptying of the filter is completed, if the lower bed 29 is at a distance of 10 cm or more from the lower distribution device 26, as well as when the top moving bed 29 is at a distance of 10 cm or more from middle distribution device 40 that is in the middle between of distribution devices 26 and 40. Valve 31 is closed after that.

[0129] To control the stage of the partial discharge of the water peep-holes 37 are used, the lower one of which shows bottom moving bed 29 and the upper peep-hole shows the top moving bed 29, in case of the partial discharge. The middle peep-hole shows bottom moving bed 29 during filtering of feedwater (FIG. 7) and during flushing of moving bed 29 with water flush (FIG. 8d).

[0130] In case of automation of the process, there is provided to install level parameter 38, which will provide information on completion of the partial emptying of double-flow pressure filter 39 with moving bed 40.

[0131] Compressed air under pressure 2-10 bar is supplied with open valve 32 to lower distribution device 26 at the second stage (FIG. 8b), after which the upflow of the compressed air destroys “cementation” (clogging) of moving bed 29 and provides random motion of its grains in the water layer resulting in friction of grains and consequently providing intensive removal of the contaminants stuck to the surface of the grains of moving bed 29. The compressed air is vented to the atmosphere through open valve 35.

[0132] The compressed is supplied within 3 to 30 minutes, after which valve 32 is closed.

[0133] The double-flow pressure filter 39 with moving bed 29 is filled with water at the third stage (FIG. 8d), for which valve 30 is opened for supply of the feedwater through lower pipe 9 and lower distribution device 26. In case of supply of the feedwater by upflow, moving bed 29 goes up and displaces air from the upper part of the vertical cylindrical body 23 and from upper sphere 24, which is removed to the atmosphere through valve 35.

[0134] When double-flow pressure filter 39 is completely filled with water, moving bed 29 occupies upper sphere 24 and the upper part of cylindrical body 23 and then valves 30 and 35 are closed.

[0135] Moving bed 29 is cleaned at the fourth stage (FIG. 8d) with the water flush, which is supplied under pressure through open valve 34, and then through upper distribution device 27. Then, the downflow of the water flush flushes the contaminants, which come unstuck from the surface of the grains of moving bed 29 and which are removed under their own weight and under the flow of the water flush through the lower distribution device 26, through pipeline 9 and through open valve 31. This operation lasts for 2-20 minute, after which valves 34 and 31 are closed. When the above stages of the treatment of moving bed 29 are passed, double-flow pressure filter 39 with moving bed 29 is put into operation or is on standby.

[0136] The FIG. 9 shows an option for treatment of the feedwater with the use of the pressure filter including the double-flow moving bed pressure filter. Option 2.

[0137] This option differs from Option 1 (FIG. 1) by the fact that second stage pressure flocculation reactor 41 is installed after pressure flocculation reactor 3 in front of pressure filter 14 or before double-flow moving bed pressure filter 39.

[0138] This solution ensures highly effective generation of micro flocks of the contaminants in the feedwater and also ensures reduction of consumption of the chemicals for the treatment of the feedwater, which will result in lower operating costs.

[0139] The second-stage pressure flocculation reactor can be represented with regard to design in three modifications showed in FIGS. 2, 3, 4.

[0140] The difference of the second stage pressure flocculation reactor is lesser time of keeping of the feedwater in this second stage reactor, which is 1-10 minutes depending on the degree of contamination of the feedwater and its temperature.

[0141] After the feedwater passes second stage pressure flocculation reactor 41, it flows to moving bed pressure filter 14 or to double-flow pressure filter 39. The modifications of the pressure filter including double-flow moving bed pressure filter and methods of cleaning of the moving bed are showed above in FIG. 5, FIG. 6, FIG. 7, FIG. 8.

[0142] FIG. 10 shows an option for treatment of the feedwater with the use of the pressure filter including the double-flow moving bed pressure filter. Option 3.

[0143] This option differs from Option 2 showed in FIG. 9 by the fact that pressure hydrocyclone 42 of known designs is installed after the second stage pressure flocculation reactor 41 in front of pressure filter 14 or in front of double-flow moving bed pressure filter 39. This solution enables removal of the most severe contamination in the feedwater including coagulating heavy impurities through the lower conical device of pressure hydrocyclone 42, consequently resulting in decrease of the amount of the contaminants penetrating pressure filter or double-flow moving bed pressure filter 39, which results in extension of time between cleanings of the moving bed.

[0144] The number of pressure flocculation reactors, pressure hydrocyclones and moving bed pressure filters for various modifications of the water treatment plants showed in FIG. 1, FIG. 9 and FIG. 10 is selected depending on the capacity of the plant, the dimensions and volume of the equipment, the amount of the equipment, which is operated, flushed or on standby.

[0145] This invention is explained by the following examples.

EXAMPLE 1

[0146] In case of treatment of the water of the reservoir to produce drinking water in the amount of 80 m.sup.3/h, the following successive stages of the water treatment at the treatment plant are used: [0147] adding of the coagulant solution (aluminum sulfate) to the pressure pipe of the feedwater; [0148] supply of the flocculated water to the vertical pressure flocculation reactor (PFR) with a diameter of 2.0 meters and height of 3.0 meters in the downflow and the time of keeping of water in it for 7 minutes; [0149] adding of the flocculant solution (Seurvey) to the pipeline after the PFR; [0150] supply of the feedwater treated with chemicals in the upflow to the moving bed pressure filter (MBPF) with a diameter of 2.6 meters. In this case, there are two MBPF filters, one of which is in operation, and the second one is under the conditions of cleaning of the moving bed or is on standby; [0151] disinfection of the treated water by adding of the sodium hypochlorite to it, and then supply of the treated water for domestic needs as drinking water.

[0152] The moving bed is contaminated during the operation of the MBPF, therefore, it was cleaned once a day due to the preliminary supply of the upflow of the compressed air, and then the downflow of the water flush for 15 minutes at a flow rate of 150 m.sup.3/h.

[0153] The capacity of the water treatment plant decreased from 80 m.sup.3/h to 30 m.sup.3/h in a month of operation of the plant. The moving bed was inspected and it has been found that 30% of its volume were “cemented” (clogging). The repeated cleanings of the moving bed did not provide an increase of the plant capacity.

[0154] It was proposed to clean the moving bed within four stages, namely, partial emptying of the moving bed, then supply of the upflow of the compressed air, filling of the pressure filter with water and then flushing with water in the downflow (FIG. 6.) As a result of passing of these stages the moving bed was completely cleaned and the plant provided rated capacity of 80 m.sup.3/h.

[0155] There were also problems in meeting standard target parameters of SanPiN “Drinking Water” in winter and during summer flowering of the reservoir, which are showed in Table 1.

TABLE-US-00001 TABLE 1 Summer period “Flowering” SanPiN Winter season of the reservoir requirement Parameter Treated Treated “Drinking name Feedwater water Feedwater water water” Turbidity, 10-20 1.5-2.2 15-35 1.5-3.0 1.5 mg/dm.sup.3 Iron, mg/dm.sup.3 0.6-0.8 0.28-0.41 0.8-1.2 0.3-0.5 0.3 Color grade 50-60 18-28 110-180 20-30 20 Permanganate  8-11 4.8-6.2 12-18 6-8 5.0 index, mgO/dm.sup.3 Water 3-5 3-5 18-20 18-20 — temperature, ° C.

[0156] To improve the flocculation process, the downflow in the PFR was changed to upflow, which made it possible to improve the flocculation process at the low temperature of the feedwater (3-5° C.) due to the micro flocks generated before, which are suspended in the PFR and are a catalyst for their enlargement.

[0157] Added to this is the fact that an oxidizing agent (sodium hypochlorite) was added to the feedwater before adding of the coagulant in the summer period, which ensured the oxidation of organic iron complexes during flowering of the reservoir and improved the flocculation process.

[0158] The quality of the feedwater and the treated water after taking of these measures is showed in Table 2.

TABLE-US-00002 TABLE 2 Summer period SanPiN Winter season “Flowering” requirement Parameter Treated Treated “Drinking name Feedwater water Feedwater water water” Turbidity, 10-20 Less 15-35 Less 1.5 mg/dm.sup.3 than 1.5 than 1.5 Iron, mg/dm.sup.3 0.6-0.8 0.1-0.2 0.8-1.2 0.1-0.15 0.3 Color grade 50-60 10-20 110-180 8-15 20 Permanganate  8-11 3.8-4.8 12-18 3.0-4.2  5.0 index, mgO/dm.sup.3 Water 3-5 3-5 18-20 18-20  — temperature, ° C.

EXAMPLE 2

[0159] In case of treatment of industrial waste water containing 20-50 mg/dm.sup.3 of petroleum hydrocarbons and a capacity of 200 m.sup.3/h, the following successive stages of water treatment are used to supply the feedwater to circulating water cycles of the oil refinery: [0160] adding of the coagulant solution (polyoxychloride aluminum) to the pressure pipeline and waste water pipeline; [0161] supply of the flocculated water in the downflow to vertical pressure flocculation reactors (PFR) in the amount of 2 pcs., with a diameter of 3.0 meters and height of 3.0 meters each, the time of keeping of the water in them is 13 minutes; [0162] adding of the flocculant solution (Seurvey) to the pipeline after PFR; [0163] supply of treated waste water in the upflow to moving bed pressure filters (MBPF) in the amount of 3 pcs., with a diameter of 3.0 meters and height of 3 meters each. In this case, two MBPFs are under the conditions of cleaning and the third MBPF is under the conditions of cleaning of the moving bed or on standby. [0164] disinfection of the treated water by adding of the sodium hypochlorite to it and then the treated water is supplied to feed the circulating water cycles.

[0165] The problem of low quality of the treated water because of remaining petroleum hydrocarbons was faced during the operation of the MBPF.

[0166] The quality of the waste water and treated water, as well as the requirements for make-up water of circulating water cycles are given in Table 3.

TABLE-US-00003 TABLE 3 Standards for make-up water Waste in circulating Parameter name water Treated water water cycles Content of suspended 20-30 Less than 5 Less than 5 solids, mg/dm.sup.3 Content of petroleum 20-50  8-15 Less than 5 hydrocarbons, mg/dm.sup.3 Water temperature, ° C. 18-25 18-25 No more than 30

[0167] To improve the removal of petroleum hydrocarbons in the process of the waste water treatment, an additional middle distribution device was provided in the PFR, which is located in the middle of the PFR. Also, after the coagulant was added, a demulsifier based on surfactants was added before passing of the PFR.

[0168] As a result, after the waste water is treated with a coagulant and demulsifier, it flows to the middle distribution device of the PFR, after passing of which petroleum hydrocarbons go up to the upper part of the PFR and are removed from the PFR through the upper distribution device (FIG. 4), and the main flow with low content of petroleum hydrocarbons (8-15 mg/dm.sup.3) goes downward out of the PFR through the lower distribution device.

[0169] The flocculant is added to the treated waste water after passing of the PFR, which then flows to the MBPF.

[0170] As a result of this resolution, the waste water treatment was provided at the MBPF and the content of petroleum hydrocarbons in the treated water was less than 5 mg/dm.sup.3.

EXAMPLE 3

[0171] In case of treatment of mining waste water with a high content of suspended solids (500-1500 mg/dm.sup.3), which mainly consist of coal dust, the following stages are used to treat this waste water with a capacity of 1000 m.sup.3/h to meet the standards of surface impoundment: [0172] adding of the coagulant solution (polyoxychloride aluminum) to the waste water pressure pipeline; [0173] supply of the flocculated water in the downflow to vertical pressure flocculation reactors (PFR) in the amount of 5 pcs., with a diameter of 3.4 meters and height of 4.5 meters each, the time of keeping of the water in them is 12 minutes; [0174] adding of the flocculant solution (Seurvey) to the pressure pipeline after the PFR; [0175] supply of the treated waste water in the upflow to the moving bed pressure filters (MBPF) in the amount of 8 pcs., with a diameter of 3.4 meters and height of 3.0 meters each. In this case, seven MBPF filters are under the conditions of cleaning and the eighth MBPF is under the conditions of cleaning of the moving bed or is on standby. Polymer grains with grain composition of 5-8 mm and a density of 0.9 g/cm.sup.3 are used as a moving bed the height of the moving bed is 2.0 meters; [0176] disinfection of the treated water by adding of the sodium hypochlorite to it followed by surface impoundment (river).

[0177] The high quality of the treated water was assured in accordance with all standard parameters during the operation of this plant for treatment of the mining water.

[0178] The only problem is a short cycle of the water treatment (filter cycle) at each MBPF between the cleanings of the moving bed (less than two hours), and the amount of the waste water flush was up to 30% of the plant capacity.

[0179] The quality of the mining waste water, treated water and the requirements for the discharge of the treated water are given in Table 4.

TABLE-US-00004 TABLE 4 Treated water Mining standards waste Treated before surface Parameter name water water impoundment Content of suspended  500-1500 less than 3.0  3.0 solids, mg/dm.sup.3 Aluminum, mg/dm.sup.3 0.1-0.3 less than 0.04 0.04 Total biological oxygen 5-8 less than 3.0  3.0 demand, mgO.sub.2/dm.sup.3 Content of petroleum  0.1-0.25 less than 0.05 0.05 hydrocarbons, mg/dm.sup.3 Phosphates, mg/dm.sup.3 0.1-0.2 less than 0.1  0.1 Manganese, mg/dm.sup.3 0.1-0.4 less than 0.1  0.1 Iron, mg/dm.sup.3 0.7-1.6 less than 0.1  0.1

[0180] To solve the above problem, two vertical second stage pressure flocculation reactors (second stage PFR) with a diameter of 3.4 meters and height of 4.5 meters each were installed, to which the water treated with the flocculant is supplied after passing of the PFR, in order to enlarge the flocculated flocks of suspended substances.

[0181] After the water passes the second stage PFR, it is supplied to two newly installed pressure hydrocyclones with a diameter of 0.8 meters each, through the lower conical device of which flocculated contaminants (suspended solids) are removed.

[0182] Partially clarified water with a residual content of suspended solids of 10-30 mg/dm.sup.3 flows upward after passing of the hydrocyclones to the existing MBPF (8 pcs), after passing of which the treated water complies with the surface impoundment requirement. In this case, the time of water treatment (filter cycle) for each MBPF between the cleanings of the moving bed increased from 1.5-2 hours to 23-28 hours, and the amount of waste water flush decreased from 30% to 2-3% of the plant capacity ensuring high effective operation of the mining waste water treatment plant.

EXAMPLE 4

[0183] To increase the contaminant capacity of the moving bed (the amount of water contaminants kept back by a certain volume of the moving bed), as well as to improve the treatment, comparative laboratory tests of a single bed and a double bed were performed.

[0184] The following successive stages of the treatment of the feedwater at the laboratory-scale plant were used for the tests: [0185] adding of the coagulant to the pressure pipeline of the feedwater; [0186] supply of the flocculated water in the downflow to the vertical pressure flocculation reactor (PFR) with a diameter of 0.2 meters and height of 2.0 meters, the time of keeping of water in the PFR is 13 minutes; [0187] a flocculant is added to the feedwater after passing of the PFR, and then it flows to the moving bed pressure filter (MBPF) with a diameter of 0.2 meters and height of 2.5 meters; [0188] the feedwater is removed from the MBPF through the upper distribution device.

[0189] The flow rate through the laboratory-scale plant was kept within the range of 300-400 l/h.

[0190] Two series of tests were performed. Polymer grains with grain composition of 3-5 mm and density of 0.9 g/cm.sup.3 were used as a moving bed in the first series of the tests. The height of the moving bed was 1.8 meters.

[0191] A double moving bed was used in the second series of tests, the top bed consisted of polymer grains with a size of 2-3 mm and density of 0.7 g/cm.sup.3, and the bottom bed consisted of polymer grains with a size of 5-7 mm and density of 0.9 g/cm.sup.3. The total height of the double bed made also 1.8 meters, of which 0.9 meters were the top bed and 0.9 meters were the bottom bed.

[0192] The quality of the feedwater and treated water, as well as the amount of the treated water between cleanings of the moving bed (filter cycle) according to the series of the performed tests is given in Table 5.

[0193] Five filter cycles were completed in each test series for unbiased assessment of similar conditions for adding of the chemicals (coagulant, flocculant). The MBPF was switched off for cleaning at a pressure drop of more than 1 bar that is upstream/downstream pressure difference.

TABLE-US-00005 TABLE 5 Treated water Treated water of the first of the second Parameter name Feedwater test series test series Suspended substances, 20-25  1-2 less than 1.0  mg/dm.sup.3 Iron, mg/dm.sup.3 0.7-0.8   0.1-0.15 less than 0.1  Color grade 110-120  17-20 11-14 Permanganate index, 8.2-9.1  3.7-4.2 2.9-3.3 mgO/dm.sup.3 Phosphates, mg/dm.sup.3 0.4-0.45 0.05-0.1  less than 0.05 Petroleum hydrocarbons, 0.2-0.23 0.09-0.11 0.05-0.07 mg/dm.sup.3 Amount of feedwater —  13-1.9 13.2-13.8 per filter cycle, m.sup.3

[0194] The results of Table 5 allow of the conclusion that the double moving bed provides more effective treatment of the feedwater and also makes it possible to increase the amount of the treated water almost twofold compared to the single moving bed.

[0195] It can be explained by the fact that the bottom bed of the double bed provides high contaminant capacity due to large grains (5-7 mm), and the top bed assures high quality of the treated water due to small grains (2-3 mm) The grain size is 3-5 mm in the top bed.

EXAMPLE 5

[0196] To intensify filtration through the moving bed pressure filter, that is, to increase its capacity at the laboratory plant showed in Example 4, two series of laboratory tests were also performed.

[0197] The first series of the tests were performed in the same way as the first series of tests in Example 4.

[0198] The difference of the second series of the tests was that an MBPF with a diameter of 0.2 meters was used, but its height was increased to 3.5 meters instead of 2.5 meters. An additional middle distribution device was installed at a height of 0.9 meters from the upper distribution device in the MBPF. Polymer grains with a size of 3-5 mm and density of 0.9 g/cm.sup.3 were used as a moving bed in the first and second series of the tests and the height of the moving bed was 1.8 meters.

[0199] Five filter cycles were completed in each series of the tests for unbiased assessment. The MBPF was switched off to clean the moving bed at pressure difference more than 1.0 bar that is upstream/downstream pressure difference.

[0200] The results of two series of the laboratory tests are given in Table 6 that is the quality of the feedwater and treated water, the filter cycles between cleanings of the moving bed of the MBPF, as well as the nominal and maximal capacity of the MBPF.

TABLE-US-00006 TABLE 6 Treated water Treated water of the first of the second Parameter name Feedwater test series test series Suspended substances, 20-25  1-2 1-2 mg/dm.sup.3 Iron, mg/dm.sup.3 0.7-0.8   0.1-0.15  0.1-0.15 Color grade 110-120  17-20 17-20 Permanganate index, 8.2-9.1  3.7-4.2 3.7-4.2 mgO/dm.sup.3 Phosphates, mg/dm.sup.3 0.4-0.45 0.05-0.1  0.05-0.1  Petroleum hydrocarbons, 0.2-0.23 0.09-0.11 0.09-0.11 mg/dm.sup.3 Amount of the treated — 7.3-7.9 14.1-15.3 water, m.sup.3 Nominal capacity, 1/h — 350  700 Maximal capacity, 1/h — 500 1000 Amount of water flush, 1 — 140-160 140-160 Percentage of water flush — 1.9-2.0 0.5-1   of the amount of treated water, %

[0201] The comparative results of the laboratory tests allow of the following conclusions on the advantage of the double-flow MBPF over the single-flow MBPF: [0202] the quality of the treated water is the same; [0203] the capacity doubled; [0204] the amount of the treated water (filter cycle) increased by a factor of two; [0205] the amount of the water flush during the cleaning of the moving bed is the same, but in terms of the amount of the treated water decreased by a factor of two.