CN216997941U - Sewage removes hard device - Google Patents

Abstract

The utility model provides a sewage hardness removal device which comprises an input pump, a first mixer, a second mixer, a third mixer, sodium hydroxide dosing equipment, PAC dosing equipment, sodium carbonate dosing equipment, PAM (polyacrylamide) pharmaceutical equipment and a water treatment tank. The device has simple structure and small occupied area, can greatly improve the sewage hardness removal efficiency, reduce the consumption cost and increase the economic benefit.

Description

Sewage removes hard device

Technical Field

The utility model relates to the technical field of water treatment, in particular to a sewage hardness removal device.

Background

The hardness index of the water body is a main control index in industrial water indexes, a large amount of high-hardness sewage which is difficult to recycle is generated in the industrial water process due to water using processes of evaporation concentration, washing, sewage discharge and the like, the hardness factor in the water body is a main hazard factor in the industrial water, the safety and stable operation of industrial water system equipment can be seriously influenced, the service life of the industrial water is shortened, and the hardness index is also a main obstacle factor for energy conservation and emission reduction in industrial production and a treatment key point and a difficult point for realizing sewage zero discharge in the industrial production.

In the prior art, because the output of high-hardness sewage in industrial production is large, various sewage softening equipment and treatment systems thereof are generally adopted, and in actual production, in order to meet the requirement of treatment of large-scale high-hardness sewage, the traditional sewage hardness removal equipment and treatment systems thereof have large construction scale and occupy a large production land.

In addition, various medicines are usually added into a sewage hardness removal system to improve sewage hardness removal efficiency, and in the prior art, the problems of low mixing degree of the medicines and sewage, lower sewage hardness removal efficiency, higher consumption cost and lower economic benefit exist.

Therefore, it is necessary to design a sewage hardness removal device which occupies a small area, is economical and practical, has high sewage hardness removal efficiency and can meet the treatment requirements of various large, medium and small chemical enterprises.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects of the prior art, the utility model provides a sewage hardness removal device, sewage is subjected to optimized addition of various medicines through three groups of mixers, precipitation can be accelerated through backflow fine sand flocculation, most of calcium and magnesium ions in water are removed, meanwhile, the content of total phosphorus, fluorine ions and other heavy metals in the sewage is reduced, and the operation of a rear system can be effectively guaranteed.

In order to achieve the above purpose, the utility model provides a sewage hardness removal device, which comprises an input pump, a first mixer, a second mixer, a third mixer, a sodium hydroxide dosing device, a PAC dosing device, a sodium carbonate dosing device, a PAM pharmaceutical device and a water treatment tank, wherein a guide cylinder and a sludge concentrator are arranged in the water treatment tank, a purified water outlet and a sludge discharge port are arranged corresponding to the water treatment tank, an outlet of the input pump and an outlet of the sodium hydroxide dosing device are connected in parallel through a pipeline and then connected with an inlet of the first mixer, an outlet of the first mixer and an outlet of the PAC dosing device are connected in parallel through a pipeline and then connected with an inlet of the second mixer, an outlet of the second mixer and an outlet of the sodium carbonate dosing device are connected in parallel through a pipeline and then connected with an inlet of the third mixer, an outlet of the third mixer is connected with an inlet at the bottom of the guide cylinder through a pipeline, be equipped with annular dosing pipe in the draft tube, be equipped with a plurality of dosing mouths on the annular dosing pipe, PAM pharmaceutical equipment's export is passed through the pipeline and is connected with annular dosing pipe, the mud discharge mouth has the sludge discharge pump through the pipe connection, the export of sludge discharge pump has whirl silt separator through the pipe connection, whirl silt separator is provided with fine sand export and sludge outlet, the fine sand export is through the dress sand device of pipe connection to water treatment tank top setting, sludge outlet passes through pipe connection to outside mud dewatering pool.

As the further improvement of above-mentioned scheme, be provided with first wall body and second wall body in the water treatment pond, first wall body and second wall body divide into flocculation district, overflow district and settling area with the water treatment pond, the draft tube is fixed to be set up in the flocculation district, flocculation district top is located to dress sand device, the flocculation district top corresponds dress sand device and sets up the fine sand and loads the mouth, the upper portion export of draft tube is higher than the setting of second wall body, purified water export and mud discharge mouth and sludge concentrator are located in the settling area.

As a further improvement of the above scheme, a plurality of flow blocking plates are arranged in each of the first mixer, the second mixer and the third mixer, and the flow blocking plates are in staggered distribution from top to bottom.

As a further improvement of the above scheme, the water treatment pond top is provided with agitator motor, agitator motor's output is connected with the stirring rake downwards, the stirring end of stirring rake sets up in the draft tube, the paddle leaf of stirring rake upwards sets up the mixed liquid that can be used to in the stirring draft tube and provides the stirring uplift to mixed liquid.

As a further improvement of the scheme, a third wall body is arranged in the sedimentation zone, the third wall body is arranged opposite to the purified water outlet, a filling zone is arranged between the right side wall of the sedimentation zone and the third wall body, and the filling zone is formed by uniformly arranging a plurality of polypropylene inclined tubes.

As a further improvement of the scheme, the sludge discharge port is arranged in a funnel shape, four corners of the bottom of the settling area are provided with first accumulation preventing slopes, and in the overflow area, the bottom of the second wall body is provided with a second accumulation preventing slope.

As a further improvement of the scheme, an electromagnetic flowmeter is installed in front of an inlet of the first mixer, a PH meter is installed at an outlet of the second mixer, and the PH meter can control the feeding amount of the sodium hydroxide through design PID parameters of a DCS.

As a further improvement of the above scheme, a first control valve is arranged on each of the inlet pipeline and the outlet pipeline of the input pump; a first metering pump is arranged on an outlet pipeline of the sodium hydroxide dosing equipment, and a first metering valve is arranged corresponding to the first metering pump; a second metering pump is arranged on an outlet pipeline of the PAC dosing equipment, and a second metering valve is arranged corresponding to the second metering pump; a third metering pump is arranged on an outlet pipeline of the sodium carbonate dosing equipment, and a third metering valve is arranged corresponding to the third metering pump; a fourth metering pump is arranged on an outlet pipeline of the PAM pharmaceutical equipment, and a fourth metering valve is arranged corresponding to the fourth metering pump; and the inlet pipeline and the outlet pipeline of the sludge discharge pump are both provided with second control valves.

As a further improvement of the scheme, a pump room is arranged below one side of the water treatment pool, and the input pump, the first metering pump, the second metering pump, the third metering pump, the fourth metering pump and the sludge discharge pump can be arranged in the pump room.

As a further improvement of the scheme, the sodium hydroxide dosing equipment, the PAC dosing equipment, the sodium carbonate dosing equipment and the PAM pharmaceutical equipment are respectively provided with corresponding liquid level meters.

The beneficial effects provided by the utility model are as follows:

compared with the prior art, the sewage hardness removal device provided by the utility model has the advantages that sewage is introduced through the input pump, then sodium hydroxide is added through the sodium hydroxide dosing equipment and flows into the first mixer together with the sewage to be mixed, the mixed liquid flowing out of the first mixer flows into the second mixer together with the PAC added through the PAC dosing equipment to be mixed, the mixed liquid flowing out of the second mixer flows into the third mixer together with the sodium carbonate added through the sodium carbonate dosing equipment to be mixed, the mixed liquid flowing out of the third mixer enters from the inlet at the bottom of the draft tube, the stirring paddle arranged in the draft tube provides liquid lifting force, the mixed liquid entering the draft tube flows upwards, the PAM pharmacy equipment simultaneously injects PAM into the annular dosing tube, the annular dosing tube injects PAM into the draft tube through the dosing port to be mixed with the mixed liquid, and the final mixed liquid enters the overflow area from the flocculation area, reentry the settling zone from the overflow district, prevent amasss slope through the second that sets up and avoid overflow district bottom impurity deposit, the mixed liquid that gets into the settling zone is concentrated through sludge concentrator after, the lower floor of settling zone deposits impurity and gets rid of from the mud discharging port, prevent the impurity of settling zone four corners through the first of setting up and pile up, mud discharging port exhaust deposit impurity is sent into whirl silt separator, whirl silt separator discharges the fine sand from the fine sand export and adds the fine sand to the flocculation district from the fine sand filling port, whirl silt separator gets rid of mud to outside mud dehydration pond, the supernatant of settling zone flows from the purified water export after further subsiding the purification through the polypropylene pipe chute that the filling district set up, with purified water input next process.

Drawings

FIG. 1 is a schematic view of the structure of the present invention;

fig. 2 is a schematic structural view of a water treatment tank in the present invention.

As shown in the figures 1 and 2, 1-input pump, 2-first mixer, 3-second mixer, 4-third mixer, 5-sodium hydroxide dosing equipment, 6-PAC dosing equipment, 7-sodium carbonate dosing equipment, 8-PAM pharmaceutical equipment, 9-water treatment tank, 901-purified water outlet, 902-sludge discharge port, 903-sand charging device, 904-first wall, 905-second wall, 906-flocculation zone, 907-overflow zone, 908-precipitation zone, 909-third wall, 10-draft tube, 11-sludge concentrator, 12-sludge discharge pump, 13-cyclone sludge-sand separator, 14-spoiler, 15-stirring motor, 1501-stirring paddle, 16-filling zone, 17-first anti-accumulation slope, 18-a second accumulation prevention slope, 19-an electromagnetic flow meter, 20-a PH meter, 21-a first metering pump, 22-a second metering pump, 23-a third metering pump and 24-a fourth metering pump.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in figure 1, the sewage hardness removal device provided by the utility model comprises an input pump 1, a first mixer 2, a second mixer 3, a third mixer 4, sodium hydroxide dosing equipment 5, PAC dosing equipment 6, sodium carbonate dosing equipment 7, PAM pharmaceutical equipment 8 and a water treatment pool 9.

The input pump 1 is a frequency conversion horizontal centrifugal pump, the inlet pipeline and the outlet pipeline of the input pump 1 are respectively provided with a first control valve, the input pump 1 can introduce sewage, the outlet of the input pump 1 and the outlet of the sodium hydroxide dosing device 5 are connected in parallel through a pipeline and then connected with the inlet of the first mixer 2, the sodium hydroxide dosing device 5 can add sodium hydroxide with the concentration of 45% into the first mixer 2 to be mixed with the sewage, carbonate generated by reaction of hydroxyl and alkalinity in water is utilized to remove calcium hardness, and hydroxyl is utilized to directly remove magnesium hardness.

The outlet of the first mixer 2 is connected with the outlet of the PAC dosing device 6 in parallel through a pipeline and then is connected with the inlet of the second mixer 3, and the PAC dosing device 6 adds the PAC solution into the second mixer 3 to be mixed with the solution, so that the colloid in the PAC solution is destabilized.

The outlet of the second mixer 3 is connected with the outlet of the sodium carbonate dosing device 7 in parallel through a pipeline and then is connected with the inlet of the third mixer 4, the sodium carbonate dosing device 7 adds sodium carbonate into the third mixer 4 to be mixed with the solution in the third mixer, and calcium with high solubility in sewage is enabled to generate calcium carbonate which is difficult to dissolve, so that the calcium carbonate is convenient to precipitate.

Be equipped with draft tube 10 and sludge concentrator 11 in the water treatment pond 9, the bottom access connection of pipeline and draft tube 10 is passed through in the export of third blender 4, is equipped with annular dosing pipe 101 in the draft tube 10, is equipped with a plurality of dosing mouths on the annular dosing pipe 101, PAM pharmaceutical equipment 8's export is passed through the pipeline and is connected with annular dosing pipe 101, and draft tube 10 lower part opening bore is greater than upper portion opening bore.

All be provided with multilayer spoiler 14 in first blender 2, second blender 3, the third blender 4, multilayer spoiler 14 is crisscross distribution from top to bottom, installs electromagnetic flowmeter 19 before the import of first blender 2, and PH appearance 20 is installed in the exit of second blender 3, and PH appearance 20 accessible DCS system design PID parameter control sodium hydroxide volume of advancing.

A first wall 904 and a second wall 905 are arranged in the water treatment pool 9, and the water treatment pool 9 is divided into a flocculation area 906, an overflow area 907 and a settling area 908 by the first wall 904 and the second wall 905.

Draft tube 10 is fixed to be set up in flocculation district 906, 9 tops in water treatment pond are provided with agitator motor 15, agitator motor 15 locates flocculation district 906 top, agitator motor 15's output downwardly connected with stirring rake 1501, the stirring end of stirring rake 1501 sets up in draft tube 10, the paddle of stirring rake 1501 upwards sets up the mixed liquid that can be used to in the stirring draft tube 10 and provides the stirring uplift to mixed liquid, the mouth is loaded to the fine sand and locates flocculation district 906 top, the upper portion export of draft tube 10 is higher than the setting of second wall body 905, make the mixed liquid possess sufficient uplift and get into settling zone 908 in the flocculation district 906.

An overflow area 907 is arranged between the first wall 904 and the second wall 908, the mixed liquid in the flocculation area 906 can enter the sedimentation area 908 only when being higher than the second wall 905, so that the sufficient mixing reaction time of sewage and medicines is guaranteed, in addition, in order to avoid impurity accumulation at the corners of the overflow area 907, a second accumulation preventing slope 18 is arranged at the bottom of the second wall 905, and the second accumulation preventing slope 18 can adopt a concave curved surface design.

A purified water outlet 901 and a sludge discharge opening 902 are arranged corresponding to the water treatment tank 9, the purified water outlet 901, the sludge discharge opening 902 and the sludge concentrator 11 are arranged in the sedimentation zone 908, the purified water outlet 901 is arranged at the upper part of the right side wall of the sedimentation zone 908, and the sludge discharge opening 902 is arranged at the bottom of the sedimentation zone 908.

In order to avoid impurity accumulation at the corners of the deposition region 908, the first accumulation preventing slopes 17 are disposed at four corners of the bottom of the deposition region 908, and the first accumulation preventing slopes 17 may be designed with concave curved surfaces.

Mud discharging port 902 is the infundibulate setting, mud discharging port 902 has mud discharging pump 12 through the pipe connection, mud discharging pump 12 is the centrifugal pump, the export of mud discharging pump 12 has whirl silt separator 13 through the pipe connection, whirl silt separator 13 is provided with fine sand export and mud export, fine sand export sets up the dress sand device 903 of flocculation area 906 top installation through pipe connection to water treatment pond 9 top, dress sand device 903 can be regularly with fine sand from the fine sand of lower part setting load mouthful add flocculation area 906 in, accelerate the settling velocity, mud export is through pipe connection to outside mud dewatering pool.

The upper part in the settling zone 908 is also provided with a third wall 909, the third wall 909 is arranged opposite to the purified water outlet 901, a filling zone 16 is arranged between the upper part of the right side wall of the settling zone 908 and the third wall 909, the purified water outlet 901 is positioned above the filling zone 16, the filling zone 16 is formed by uniformly arranging a plurality of polypropylene inclined pipes, the height of the filling zone can be set to be two meters, the filling zone is fixed by stainless steel wires, and the distance from the bottom funnel-shaped sludge discharge hole 902 is at least 2 meters.

PAM pharmaceutical equipment 8 is including three medical kits of group, and every medical kit all is furnished with stirring, liquid level switch, solenoid valve, switch board, can dispense medicine in the whole journey is automatic.

Be equipped with first measuring pump 21 on sodium hydroxide charge equipment 5's the outlet pipeline, be equipped with first metering valve corresponding first measuring pump 21, PAC is equipped with second measuring pump 22 on charge equipment 6's the outlet pipeline, be equipped with the second metering valve corresponding second measuring pump 22, be equipped with third metering pump 23 on sodium carbonate charge equipment 7's the outlet pipeline, be equipped with the third metering valve corresponding third metering pump 23, be equipped with fourth measuring pump 24 on PAM pharmaceutical equipment 8's the outlet pipeline, it is provided with the fourth metering valve to correspond fourth measuring pump 24, it all designs for the frequency conversion to add the medicine metering pump, add the dose according to frequency adjustment, make the system reach balanced economic operation.

The inlet pipeline and the outlet pipeline of the sludge discharge pump 12 are provided with second control valves, the lower part of one side of the water treatment pool 9 is provided with a pump room, and the input pump 1, the first metering pump 21, the second metering pump 22, the third metering pump 23, the fourth metering pump 24 and the sludge discharge pump 12 can be arranged in the pump room for convenient centralized management.

The sodium hydroxide dosing equipment 5, the PAC dosing equipment 6, the sodium carbonate dosing equipment 7 and the PAM pharmaceutical equipment 8 are respectively provided with corresponding liquid level meters, and the height of the liquid level of the liquid medicine can be monitored at any time.

The utility model provides a working principle of a sewage hardness removal device, which is characterized in that sewage is introduced through an input pump 1, then sodium hydroxide is added through a sodium hydroxide dosing device 5 and flows into a first mixer 2 together with the sewage to be mixed, a mixed solution flowing out of the first mixer 2 flows into a second mixer 3 together with a PAC added through a PAC dosing device 6 to be mixed, a mixed solution flowing out of the second mixer 3 flows into a third mixer 4 together with sodium carbonate added through a sodium carbonate dosing device 7 to be mixed, a mixed solution flowing out of the third mixer 4 enters from an inlet at the bottom of a guide cylinder 10, a stirring paddle 1501 arranged in the guide cylinder 10 provides a liquid lifting force, the mixed solution entering the guide cylinder 10 flows upwards, a PAM pharmaceutical device 8 injects PAM into an annular dosing pipe 101, the annular dosing pipe 101 injects PAM into the guide cylinder 10 through a dosing port to be mixed with the mixed solution, so that alum floc is generated and is removed in the separation stage. The mixed liquor enters an overflow area 907 from a flocculation area 906, then enters a settling area 908 from the overflow area 907, impurity deposition at the bottom of the overflow area 907 is avoided through a second accumulation prevention slope 18, the mixed liquor entering the settling area 908 is concentrated 11 through a sludge concentrator, the lower-layer precipitated impurities of the settling area 908 are discharged from a sludge discharge port 902, impurity accumulation at four corners of the settling area 908 is avoided through a first accumulation prevention slope 17, the precipitated impurities discharged from the sludge discharge port 902 are sent to a cyclone silt separator 13, the cyclone silt separator 13 discharges fine silt from a fine silt outlet and sends the fine silt to a silt loading device 903, the cyclone silt separator 13 discharges the silt to an external sludge dewatering tank for dewatering treatment, supernatant of the settling area 908 is further settled and purified through a polypropylene inclined pipe arranged in a filling area 16 and then flows out from a purified water outlet, and purified water is input to the next process.

This device simple structure, area is little, add through the optimization of three blender of group to each medicine, effectively improve medicine and sewage mixedness, through the fine sand flocculation of backward flow, accelerate the sediment, get rid of most calcium in the aquatic, magnesium ion, reduce total phosphorus in the sewage simultaneously, the content of fluorinion and other heavy metals, can effectively ensure the operation of back system, make sewage remove hard efficiency and obtain improving, the consumption cost is reduced, increase economic benefits, can satisfy the processing requirement of various big, middle and small chemical enterprises simultaneously.

While there have been shown and described what are at present considered to be the basic principles and essential features of the utility model and advantages thereof, it will be apparent to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (10)

1. The utility model provides a sewage removes hard device which characterized in that: comprises an input pump (1), a first mixer (2), a second mixer (3), a third mixer (4), sodium hydroxide dosing equipment (5), PAC dosing equipment (6), sodium carbonate dosing equipment (7), PAM pharmaceutical equipment (8) and a water treatment pool (9), wherein a draft tube (10) and a sludge concentrator (11) are arranged in the water treatment pool (9), a purified water outlet (901) and a sludge discharge port (902) are arranged corresponding to the water treatment pool (9), the outlet of the input pump (1) and the outlet of the sodium hydroxide dosing equipment (5) are connected in parallel through a pipeline and then are connected with the inlet of the first mixer (2), the outlet of the first mixer (2) and the outlet of the PAC dosing equipment (6) are connected in parallel through a pipeline and then are connected with the inlet of the second mixer (3), the outlet of the second mixer (3) and the outlet of the sodium carbonate dosing equipment (7) are connected in parallel through a pipeline and then are connected with the inlet of the third mixer (4), the export of third blender (4) passes through the bottom access connection of pipeline and draft tube (10), be equipped with annular dosing pipe (101) in draft tube (10), be equipped with a plurality of dosing mouths on annular dosing pipe (101), the export of PAM pharmaceutical equipment (8) is passed through the pipeline and is connected with annular dosing pipe (101), mud discharging mouth (902) have mud pump (12) through the pipe connection, the export of mud pump (12) has whirl silt separator (13) through the tube coupling, whirl silt separator (13) are provided with silt outlet and sludge outlet, silt outlet is through pipe connection to dress sand device (903) that water treatment pond (9) top set up, sludge outlet is through pipe connection to outside mud dehydration pond.

2. The hardness-removing device for sewage water according to claim 1, wherein: the water treatment device is characterized in that a first wall body (904) and a second wall body (905) are arranged in the water treatment pool (9), the first wall body (904) and the second wall body (905) divide the water treatment pool (9) into a flocculation area (906), an overflow area (907) and a settling area (908), the guide cylinder (10) is fixedly arranged in the flocculation area (906), the sand loading device (903) is arranged at the top of the flocculation area (906), a fine sand loading opening is formed in the top of the flocculation area (906) corresponding to the sand loading device (903), an upper outlet of the guide cylinder (10) is higher than the second wall body (905) in arrangement, and a purified water outlet (901), a sludge discharge opening (902) and a sludge concentrator (11) are arranged in the settling area (908).

3. The hardness-removing device for sewage water according to claim 1, wherein: multilayer spoilers (14) are arranged in the first mixer (2), the second mixer (3) and the third mixer (4), and the spoilers (14) are distributed in a staggered mode from top to bottom.

4. The hardness-removing device for sewage water according to claim 1, wherein: the water treatment pond (9) top is provided with agitator motor (15), the output of agitator motor (15) is connected with stirring rake (1501) downwards, the stirring end of stirring rake (1501) sets up in draft tube (10), the paddle leaf of stirring rake (1501) upwards sets up the mixed liquid that can be used to in stirring draft tube (10) and provides the stirring uplift to mixed liquid.

5. The hardness-removing device for sewage water according to claim 2, wherein: a third wall body (909) is arranged in the settling zone (908), the third wall body (909) is opposite to the purified water outlet (901), a filling zone (16) is arranged between the right side wall of the settling zone (908) and the third wall body (909), and the filling zone (16) is formed by uniformly arranging a plurality of polypropylene inclined pipes.

6. The hardness-removing device for sewage water according to claim 2, wherein: the mud discharging port (902) is arranged in a funnel shape, four corners of the bottom of the settling zone (908) are provided with first anti-accumulation slopes (17), and in the overflow zone (907), the bottom of the second wall body (905) is provided with a second anti-accumulation slope (18).

7. The hardness-removing device for sewage water according to claim 1, wherein: install electromagnetic flowmeter (19) before first blender (2) import, PH appearance (20) are installed in the exit of second blender (3), PH appearance (20) accessible DCS system design PID parameter control sodium hydroxide dosage.

8. The hardness-removing device for sewage water according to claim 1, wherein: the inlet pipeline and the outlet pipeline of the input pump (1) are respectively provided with a first control valve;

a first metering pump (21) is arranged on an outlet pipeline of the sodium hydroxide dosing equipment (5), and a first metering valve is arranged corresponding to the first metering pump (21);

a second metering pump (22) is arranged on an outlet pipeline of the PAC dosing equipment (6), and a second metering valve is arranged corresponding to the second metering pump (22);

a third metering pump (23) is arranged on an outlet pipeline of the sodium carbonate dosing equipment (7), and a third metering valve is arranged corresponding to the third metering pump (23);

a fourth metering pump (24) is arranged on an outlet pipeline of the PAM pharmaceutical equipment (8), and a fourth metering valve is arranged corresponding to the fourth metering pump (24);

and the inlet pipeline and the outlet pipeline of the sludge pump (12) are both provided with a second control valve.

9. The hardness-removing device for sewage water according to claim 1, wherein: the sewage treatment device is characterized in that a pump room is arranged below one side of the water treatment pool (9), and the input pump (1), the first metering pump (21), the second metering pump (22), the third metering pump (23), the fourth metering pump (24) and the sludge discharge pump (12) can be arranged in the pump room.

10. The hardness-removing device for sewage water according to claim 1, wherein: and the sodium hydroxide dosing equipment (5), the PAC dosing equipment (6), the sodium carbonate dosing equipment (7) and the PAM pharmaceutical equipment (8) are respectively provided with corresponding liquid level meters.

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