CN106830489A - System for processing chrome-containing wastewater - Google Patents

Abstract

The invention discloses a chromium-containing wastewater treatment system, which comprises a pH adjustment pool, a filter device, a cationic resin exchange system, a water storage tank, and a first solid-liquid separation system connected in sequence; the water outlet of the cationic resin exchange system is connected to the The water storage tank is connected, the desorption liquid outlet of the cation resin exchange system is connected with the desorption liquid storage tank, and the desorption liquid storage tank is connected with the second solid-liquid separation system. The chromium-containing wastewater treatment system of the invention can effectively separate and treat Cr ⁶⁺ , and has the advantages of simple structure, high treatment efficiency and good treatment effect.

Description

Chromium-containing wastewater treatment system

technical field

The invention relates to the technical field of wastewater treatment, in particular to a chromium-containing wastewater treatment system.

Background technique

The sources of electroplating wastewater are generally: (1) plating cleaning water; (2) waste electroplating solution; (3) other wastewater, including washing the floor of the workshop, scrubbing plate washing water, condensed water from ventilation equipment, and leakage from plating tanks. Or various tank liquids and drainages of "running, popping, dripping, and leaking" caused by improper operation and management; (4) Equipment cooling water, which has not been polluted except for the temperature rise during use. The water quality and quantity of electroplating wastewater are related to the process conditions of electroplating production, production load, operation management and water use methods and other factors. The water quality of electroplating wastewater is complex and its composition is difficult to control. It contains heavy metal ions such as chromium, cadmium, nickel, copper, zinc, gold, silver, and cyanide, and some of them are highly toxic substances that are carcinogenic, teratogenic, and mutagenic.

Chromium-containing wastewater is the most common type of electroplating wastewater. The main components of chromium-containing wastewater are sulfuric acid and Cr ⁶⁺ , and also include a small amount of other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn One or more impurities such as ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ . However, the existing chromium-containing wastewater treatment system has a complex structure, low treatment efficiency, poor treatment effect, cannot efficiently separate and treat Cr ⁶⁺ , and is labor-intensive, low in automation and short in service life. Therefore, it is necessary to improve the current chromium-containing wastewater treatment system.

Contents of the invention

In view of this, a kind of chromium-containing wastewater treatment system provided by the present invention better overcomes the problems and defects in the above-mentioned prior art, can effectively separate and treat Cr ⁶⁺ , and has the advantages of simple structure, high treatment efficiency, and high treatment efficiency. The advantage of good effect.

A chromium-containing wastewater treatment system, comprising a pH adjustment tank, a filter device, a cationic resin exchange system, a water storage tank, and a first solid-liquid separation system connected in sequence;

The water outlet of the cation resin exchange system communicates with the water storage tank, the desorption liquid outlet of the cation resin exchange system communicates with a desorption liquid storage tank, and the desorption liquid storage tank communicates with a second solid-liquid separation system.

Further, a waste water storage pool is also included, and the waste water storage pool is communicated with the pH adjustment pool through a water pump.

Further, the first solid-liquid separation system includes a reduction reaction tank, a first precipitation reaction tank, a first concentration membrane device, a first sedimentation tank, a first collection tank, and a first nanofiltration-microfiltration combined device connected in sequence , the first clear water tank; the concentrated water port of the first concentration membrane device is communicated with the first sedimentation tank, and the sludge outlet of the first sedimentation tank is communicated with a first centrifuge or a filter press, and the first The clear water outlet of the concentration membrane device and the water outlet of the first sedimentation tank are both connected to the first collection tank, the water outlet of the first nanofiltration-microfiltration combined device is communicated with the first clear water tank, and the The sludge outlet of the first nanofiltration-microfiltration combined device is connected to the first sedimentation tank, and the sludge outlet of the first centrifuge or filter press is connected to the first calciner.

Further, the second solid-liquid separation system includes a second sedimentation reaction tank, a second concentration membrane device, a second sedimentation tank, a second collection tank, a second nanofiltration-microfiltration combined device, and a second clean water pool; the concentrated water port of the second concentrated membrane device is communicated with the second sedimentation tank, and the sludge outlet of the second sedimentation tank is communicated with a second centrifuge or filter press, and the second concentrated membrane device The clear water outlet and the water outlet of the second sedimentation tank are all connected with the second collecting tank, the water outlet of the second nanofiltration-microfiltration combined device is connected with the second clear water tank, and the second nanofiltration - The sludge outlet of the combined microfiltration device is connected to the second sedimentation tank, and the sludge outlet of the second centrifuge or filter press is connected to the second calciner.

Further, the first solid-liquid separation system also includes a first dosing device and a second dosing device communicated with the reduction reaction tank, the first dosing device is used for dosing to the reduction reaction tank acidic substance, the second dosing device is used to add reducing agent to the reduction reaction tank; the reduction reaction tank is provided with a first pH monitoring device and a potential controller, and the first pH monitoring device is connected with the The first dosing device is connected, and the potential controller is connected with the second dosing device.

Further, the first solid-liquid separation system also includes a third dosing device communicated with the first precipitation reaction tank, and the third dosing device is used to add alkaline substances to the precipitation reaction tank; The first precipitation reaction tank is provided with a second pH monitoring device, and the second pH monitoring device is connected with the third dosing device.

Further, the second solid-liquid separation system also includes a fourth dosing device communicated with the second precipitation reaction tank, the fourth dosing device is used to add alkaline to the second precipitation reaction tank Substance; the second precipitation reaction tank is provided with a third pH monitoring device, and the third pH monitoring device is connected with the fourth dosing device.

Further, the first sedimentation tank is communicated with the first centrifuge or filter press through the first sludge storage tank; the water outlet of the first centrifuge or filter press is connected with the first concentration membrane device connected.

Further, the second sedimentation tank is communicated with the second centrifuge or filter press through the second sludge storage tank; the water outlet of the second centrifuge or filter press is connected with the second concentration membrane device connected.

Further, the cation resin exchange system includes several cation resin exchangers.

Compared with the prior art, the beneficial effects of the chromium-containing wastewater treatment system of the present invention are:

(1), the chromium-containing wastewater treatment system of the present invention effectively separates Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ² by using a cationic resin exchange system ⁺ , Cr ³⁺ , Ca ²⁺ and one or more impurities are separated, and then the waste water containing Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ are separated by the solid-liquid separation system. , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and other one or more impurities are subjected to solid-liquid separation treatment, with high treatment efficiency and good treatment effect.

(2), further, the solid-liquid separation system of the present invention generates precipitation by causing the metal ions in the wastewater to react with alkaline substances such as sodium hydroxide in the precipitation reaction tank, and then concentrate through the concentration membrane device to make the precipitated particles Concentration and aggregation thicken and increase, accelerate precipitation, and then carry out solid-liquid separation in the sedimentation tank, and the clean water collected in the collection tank can be more thoroughly removed after double filtration of microfiltration and nanofiltration by setting up a nanofiltration-microfiltration combination device A small amount of fine suspended solids in the filter, the sediment obtained by filtration is discharged into the sedimentation tank in batches for further treatment, and the sediment in the sedimentation tank is dehydrated by a centrifuge or a filter press, and the obtained solid waste does not contain PAC and PAM and other organic impurities, the water content is also low, and then calcined in a calciner, the metal oxides and other compounds obtained can not only be recycled, but also achieve zero pollutant discharge, effectively reducing the cost and load of sludge treatment, and solving the problem of It eliminates the problem of resource waste, and greatly reduces the production cost of enterprises, which has great social and economic benefits.

(3), further, the solid-liquid separation system of the present invention monitors the pH value in the reaction tank in real time by setting a pH monitoring device to the precipitation reaction tank, and controls the automatic dosing of the dosing device according to the corresponding pH value, so that the degree of automation of the system is improved. High, safe and stable operation, simple operation, convenient management and better processing effect.

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is the first structural representation of the chromium-containing wastewater treatment system of the present invention;

Fig. 2 is the second structural representation of the first solid-liquid separation system of the present invention;

Fig. 3 is a schematic diagram of the third structure of the second solid-liquid separation system of the present invention.

Explanation of reference numbers:

1-chromium-containing wastewater treatment system; 100-wastewater storage tank; 200-pump; 300-pH adjustment tank; 400-filter device; 500-cation resin exchanger; ; 701-reduction reaction tank; 7011-the first dosing device; 7012-the second dosing device; 7013-the first pH monitoring device; 7014-potential controller; 702-the first precipitation reaction tank; 7022-the second pH monitoring device; 703-the first concentration membrane device; 704-the first sedimentation tank; 705-the first collection tank; 706-the first nanofiltration-microfiltration combined device; 707-the first clear water pool; 708-the first sludge storage tank; 709-the first centrifuge or filter press; 710-the first calciner; 800-desorption liquid storage tank; 900-the second solid-liquid separation system; 901-the second sedimentation Reaction tank; 9011-the fourth dosing device; 9012-the third pH monitoring device; 902-the second concentration membrane device; 903-the second sedimentation tank; 904-the second collection tank; 905-the second nanofiltration-microfiltration Combined device; 906-the second clear water tank; 907-the second sludge storage tank; 908-the second centrifuge or filter press; 909-the second calciner.

detailed description

In order to facilitate the understanding of the present invention, the chromium-containing wastewater treatment system will be described more fully below with reference to the relevant drawings. The preferred embodiment of the chromium-containing wastewater treatment system is given in the accompanying drawings. However, the chromium-containing wastewater treatment system can be implemented in many different forms and is not limited to the examples described herein. Rather, the purpose of providing these examples is to make the disclosure of the chromium-containing wastewater treatment system more thorough and comprehensive.

In describing the present invention, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientations or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and It is not to indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, or operate in a particular orientation, and thus should not be construed as limiting the invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the present invention, unless otherwise stipulated and limited, it should be noted that the terms "installation", "connection" and "communication" should be understood in a broad sense, for example, they can be mechanical communication or electrical communication,

It may also be internal communication between two elements, either directly or indirectly through an intermediary. Those skilled in the art can understand the specific meanings of the above terms according to specific situations.

Referring to FIG. 1 , the present invention provides a chromium-containing wastewater treatment system 1 , including a pH adjustment tank 300 , a filter device 400 , a cationic resin exchange system, a water storage tank 600 , and a first solid-liquid separation system 700 connected in sequence.

The water outlet of the cationic resin exchange system is communicated with the water storage tank 600, the desorption liquid outlet of the cationic resin exchange system is communicated with a desorption liquid storage tank 800, and the desorption liquid storage tank 800 is communicated with a second solid-liquid separation system 900.

It should be understood that the filter device 400 is used to filter impurities such as solid particles in the chromium-containing wastewater, so as to avoid affecting the adsorption performance of the cation exchange resin in the subsequent cation resin exchange system. The filter device 400 can be exemplified as a quartz sand filter, an activated carbon filter, a ceramic filter, a multimedia filter, or a fiber filter.

It should be noted that the cation resin exchange system includes a regeneration device (not shown). In the cation resin exchange system of the present invention, the cation exchange resin is filled in the cation resin exchanger 500 to adsorb metal ions other than Cr ⁶⁺ such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and one or more impurities, so that Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ^{3 +} , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and one or more impurities are separated. Wastewater containing Cr ⁶⁺ is discharged into the storage tank 600 through the water outlet; while other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ are adsorbed , Ca ²⁺ and other one or more impurity cation exchange resin enters the regeneration device through the desorption and regeneration process to regenerate the resin, and the obtained cation exchange resin containing other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and other one or more impurities are discharged into the desorption liquid storage tank 800 through the desorption liquid outlet.

It can be understood that the first solid-liquid separation system 700 is used for solid-liquid separation of the waste water containing Cr ⁶⁺ discharged into the storage tank 600; the second solid-liquid separation system 900 is used for desorption Liquid storage tank 800 containing other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and other impurities The desorbed liquid is subjected to solid-liquid separation.

Preferably, the chromium-containing wastewater treatment system 1 of the present invention further includes a wastewater storage tank 100 , and the wastewater storage tank 100 communicates with the pH adjustment tank 300 through a pump 200 .

Preferably, as shown in Figure 2, in the embodiment of the present invention, the first solid-liquid separation system 700 includes a reduction reaction tank 701, a first precipitation reaction tank 702, a first concentration membrane device 703, a first precipitation pool 704, the first collection pool 705, the first nanofiltration-microfiltration combined device 706, and the first clear water pool 707; the concentrated water port of the first concentrated membrane device 703 communicates with the first sedimentation tank 704, The sludge outlet of a sedimentation tank 704 is connected with a first centrifuge or a filter press 709, and the clear water port of the first concentration membrane device 703 and the water outlet of the first sedimentation tank 704 are connected to the first collection tank 705 The water outlet of the first nanofiltration-microfiltration combined device 706 is connected with the first clear water tank 707, and the sludge outlet of the first nanofiltration-microfiltration combined device 706 is connected with the first sedimentation tank 704, and the sludge outlet of the first centrifuge or filter press 709 is connected with the first calciner 710.

In the reduction reaction pool 701, Cr ⁶⁺ in the waste water is reduced to Cr ³⁺ by adding a reducing agent, such as sodium sulfite, sodium metabisulfite or sodium bisulfite. As an illustration, when the reducing agent is sodium sulfite, the specific reduction reaction formula is: 4Cr ⁶⁺ +3S ₂ O ₅ ^2- +9H ₂ O=4Cr ³⁺ +6SO ₄ ^2- +18H ⁺ . The amount of reducing agent used is slightly greater than the theoretical amount of reaction, which is convenient for sufficient reaction to occur.

Preferably, the first solid-liquid separation system 700 further includes a first dosing device 7011 and a second dosing device 7012 communicated with the reduction reaction tank 701, and the first dosing device 7011 is used to supply the Acidic substances are added to the reduction reaction tank 701, and the second dosing device 7012 is used to add a reducing agent to the reduction reaction tank 701; the reduction reaction tank 701 is provided with a first pH monitoring device 7013 and a potential controller 7014 , the first pH monitoring device 7013 is connected to the first dosing device 7011 , and the potential controller 7014 is connected to the second dosing device 7012 .

It should be noted that, in order to ensure that the reduction reaction in the reduction reaction pool 701 achieves the best effect, that is, completely reduce Cr ⁶⁺ in the wastewater to Cr ³⁺ , the pH value in the reaction pool must reach 2.5-3.0. Therefore, in the embodiment of the present invention, the first pH monitoring device 7013 is used to monitor the pH value of the wastewater in the reduction reaction tank 701 in real time. When the monitored pH value is greater than 3.0, the first pH monitoring device 7013 automatically controls The first dosing device 7011 adds acidic substances to the reduction reaction tank 701; when the monitored pH value is lower than 2.5, the first pH monitoring device 7013 automatically controls the first dosing device 7011 to reduce the reaction tank 701 Addition of acidic substances is stopped in the pool 701. The acidic substance can be exemplified by sulfuric acid or hydrochloric acid.

It should be noted that, in order to ensure that the reduction reaction in the reduction reaction pool 701 achieves the best effect, that is, completely reduce Cr ⁶⁺ in the wastewater to Cr ³⁺ , the potential in the reaction pool must be controlled at 220-270mV. Therefore, in the embodiment of the present invention, the potential controller 7014 (ORP meter) is used to monitor the potential of the wastewater in the reduction reaction tank 701 in real time. When the monitored potential is higher than 270mV, the potential controller 7014 (ORP meter) ) automatically controls the second dosing device 7012 to add reducing agent to the reduction reaction tank 701; when the monitored pH value is lower than 220mV, the potential controller 7014 (ORP meter) automatically controls the second dosing The device 7012 stops adding the reducing agent to the reduction reaction tank 701.

In the above-mentioned first precipitation reaction tank 702, the pH value of the Cr3 ⁺ -containing wastewater obtained after reduction in the reduction reaction tank 701 is adjusted to a certain range, and the alkaline substance is used to react with Cr3 ⁺ to generate Cr(OH) _{3Precipitation} , To remove Cr ³⁺ in wastewater. The alkaline substance is preferably sodium hydroxide, and of course the alkaline substance may also include lime or a mixture of lime and sodium hydroxide. The specific reaction formula is: Cr ³⁺ +3OH ^- =Cr(OH) ₃ ↓.

Preferably, the first solid-liquid separation system 700 also includes a third dosing device 7021 communicated with the first sedimentation reaction tank 702, and the third dosing device 7021 is used to add Alkaline substances: the first precipitation reaction tank 702 is provided with a second pH monitoring device 7022, and the second pH monitoring device 7022 is connected to the third dosing device 7021.

It should be noted that, in order to ensure the best effect of the reaction in the first precipitation reaction tank 702, that is, the complete reaction of alkaline substances and Cr ³⁺ , the pH value in the reaction tank should be controlled between 10 and 11.5. Therefore, in the embodiment of the present invention, the second pH monitoring device 7022 is used to monitor the pH value of the wastewater in the first precipitation reaction tank 702 in real time. When the monitored pH value is less than 10, the second pH monitoring device 7022 Automatically control the third dosing device 7021 to add alkaline substances to the first precipitation reaction tank 702; when the monitored pH value is greater than, the third pH monitoring device 9012 automatically controls the fourth dosing device 9011 The addition of alkaline substances to the first precipitation reaction tank 702 is stopped.

Preferably, as shown in Figure 3, in the embodiment of the present invention, the second solid-liquid separation system 900 includes a second precipitation reaction tank 901, a second concentration membrane device 902, a second sedimentation tank 903, a second Collection tank 904, the second nanofiltration-microfiltration combination device 905, the second clear water tank 906; the concentrated water port of the second concentrated membrane device 902 is communicated with the second sedimentation tank 903, and the second sedimentation tank 903 The sludge outlet is connected with a second centrifuge or a filter press 908, and the clear water outlet of the second concentration membrane device 902 and the water outlet of the second sedimentation tank 903 are both connected with the second collection tank 904, and the first The water outlet of the second nanofiltration-microfiltration combination device 905 is communicated with the second clear water tank 906, and the sludge outlet of the second nanofiltration-microfiltration combination device 905 is communicated with the second sedimentation tank 903, and the The sludge outlet of the second centrifuge or filter press 908 is connected with a second calciner 909 .

In the above ^{- mentioned} first ^{precipitation reaction tank 702 , one kind} or The pH value of wastewater with various impurities is adjusted to a certain range, while using alkaline substances and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ^{3 +} , Ca ²⁺ and other one or more reactions to form metal hydroxide precipitation to remove other metal ions in wastewater such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ^{2 +} , Cr ³⁺ , Ca ²⁺ and one or more impurities. The alkaline substance is preferably sodium hydroxide, and of course the alkaline substance may also include lime or a mixture of lime and sodium hydroxide. The specific reaction formula can be listed as follows:

Cu ²⁺ +2OH ^- ＝Cu(OH) ₂ ↓;

Ni ²⁺ +2OH ⁻ =Ni(OH) ₂ ↓.

Preferably, the second solid-liquid separation system 900 further includes a fourth dosing device 9011 communicated with the second precipitation reaction tank 901, and the fourth dosing device 9011 is used to supply 901 dosing alkaline substances; the second precipitation reaction tank 901 is provided with a third pH monitoring device 9012, and the third pH monitoring device 9012 is connected to the fourth dosing device 9011.

The working principle of the third pH monitoring device 9012 is the same as that of the above-mentioned second pH monitoring device 7022, that is, it is used to monitor the pH value in the second precipitation reaction tank 901 in real time, and control the fourth dosing device 9011 according to the corresponding pH value Start or stop dosing alkaline substances.

Both the first concentrated membrane device 703 and the second concentrated membrane device 902 can be exemplified as high-pressure reverse osmosis coiled membranes, high-pressure reverse osmosis disc membranes, vibrating membranes, or forward osmosis membranes. Both the first concentration membrane device 703 and the second concentration membrane device 902 can also be exemplified as nanofiltration membranes, ultrafiltration membranes, microfiltration membranes or general filter elements. In the concentration membrane device, through membrane separation, the hydroxide precipitated particles are further concentrated, aggregated, thickened and enlarged.

Preferably, the first sedimentation tank 704 communicates with the first centrifuge or filter press 709 through the first sludge storage tank 708; A concentrated membrane device 703 communicates.

Preferably, the second sedimentation tank 903 communicates with the second centrifuge or filter press 908 through the second sludge storage tank 907; the water outlet of the second centrifuge or filter press 908 is connected to the first The two concentration membrane devices 902 are in communication.

It should be understood that the above sludge storage tank is used to store the sludge discharged from the sludge outlet of the sedimentation tank, and after accumulating to a certain amount, it is transported to a centrifuge or filter press for dehydration and separation, so as to avoid the intermittent supply of sludge from the sedimentation tank. The sludge is fed to the centrifuge or filter press, which affects the service life of the centrifuge or filter press.

The solid-liquid separation system of the embodiment of the present invention recycles the waste water obtained after dehydration and separation by a centrifuge or a filter press to the concentration membrane device, so as to realize the secondary recovery, treatment and utilization of the waste water, and reduce discharge pollution.

Preferably, the cation resin exchange system comprises several cation resin exchangers 500 . According to the actual amount of chromium-containing wastewater to be treated, it can be set as 2 or 3 cationic resin exchangers 500 in parallel or in series, so that Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , One or more impurities such as Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ are completely separated. Preferably, in the embodiment of the present invention, the cation resin exchange system includes two cation resin exchangers 500 connected in series.

The technological process of chromium-containing wastewater treatment system 1 of the present invention is:

As shown in Figure 1, the chromium-containing wastewater in the wastewater storage tank 100 is pumped into the pH adjustment tank 300 through the pump 200, the pH is adjusted to 3.0-7.0, and filtered through the filter device 400 to remove solid particles in the chromium-containing wastewater and other impurities, the filtrate passes through two cationic resin exchangers 500 in series for ion exchange, and Cr ⁶⁺ and other metal ions in the wastewater such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ^{2 +} , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and one or more impurities are separated. Wastewater containing Cr ⁶⁺ is discharged into the storage tank 600 through the water outlet, and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , and Cr ³⁺ are adsorbed. , Ca ²⁺ and other one or more impurity cation exchange resin undergoes desorption and regeneration process to regenerate the resin, and the obtained cation exchange resin containing other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ² The desorption liquid containing one or more impurities such as ⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ is discharged into the desorption liquid storage tank 800 through the desorption liquid outlet.

As shown in Figure 2, the waste water containing Cr ⁶⁺ in the water storage tank 600 passes through the reduction reaction tank 701 in the first solid-liquid separation system 700, and after the Cr ⁶⁺ in the waste water is reduced to Cr ³⁺ , it passes through the first solid-liquid separation system 700. Precipitation reaction tank 702 reacts to generate Cr(OH) ₃ precipitation, and then concentrates through the first concentration membrane device 703, so that the Ni(OH) ₂ precipitation particles are concentrated, aggregated, thickened and enlarged; then enter the first precipitation tank 704 for solid-liquid separation , the supernatant that obtains is discharged in the first collection tank 705 by the water outlet of the first sedimentation tank 704; When the amount of sludge in the sludge storage tank 708 reaches a certain amount, the sludge pump (not shown in the figure) is pumped to the first centrifuge or filter press 709 for dehydration and separation, and the obtained waste water is recycled to the first concentration membrane device Continue the secondary treatment in 703, and the obtained solid waste residue is automatically transported to the first calcination furnace 710 for direct high-temperature calcination or intermittent calcination after being placed to obtain chromium oxide with high purity. It is also possible to further reduce the chromium oxide to elemental chromium by feeding hydrogen and nitrogen into the first calciner 710, and finally recycle the chromium or chromium oxide. The supernatant collected in the first collection tank 705 is further removed through the first nanofiltration-microfiltration combination device 706 to further remove trace fine suspended solids in the supernatant collected in the first collection tank 705, and the precipitate obtained by filtering The waste is discharged into the first sedimentation tank 704 in batches to continue secondary treatment, and the filtered water is discharged into the first clear water tank 707 for recycling.

As shown in Figure 3, the desorption liquid containing other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ² The desorption liquid of one or more impurities such as ⁺ is separated from the solid and liquid through the second solid-liquid separation system 900, and first passes through the second precipitation reaction tank 901 to generate metal hydroxide precipitation, and then is concentrated through the second concentration membrane device 902, The metal hydroxide precipitated particles are concentrated, aggregated, thickened and enlarged; then enter the second sedimentation tank 903 for solid-liquid separation, and the obtained supernatant is discharged into the second collection tank 904 through the outlet of the second sedimentation tank 903; Sediment is discharged in the second sludge storage tank 907 by the sludge outlet of the second settling tank 903, treats that the sludge amount in the second sludge storage tank 907 reaches a certain amount, through the sludge pump (not shown in the figure) ) to the second centrifuge or filter press 908 for dehydration and separation, the waste water obtained is recycled to the second concentration membrane device 902 to continue secondary treatment, and the solid waste residue obtained is automatically transported to the second calciner 909 for direct high-temperature calcination or Calcination is performed intermittently after standing to obtain a mixture of metal oxides and compounds, and finally the mixture of metal oxides and compounds is recycled. The supernatant collected in the second collection tank 904 is further removed through the second nanofiltration-microfiltration combination device 905 to further remove traces of fine suspended solids in the supernatant collected in the second collection tank 904, and the precipitate obtained by filtering The waste is discharged into the second sedimentation tank 903 in batches to continue secondary treatment, and the filtered water is discharged into the second clear water tank 906 for recycling.

In summary, the beneficial effects of the chromium-containing wastewater treatment system of the present invention are:

(1), the chromium-containing wastewater treatment system of the present invention effectively separates Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ³⁺ , Zn ²⁺ , Fe ² by using a cationic resin exchange system ⁺ , Cr ³⁺ , Ca ²⁺ and one or more impurities are separated, and then the waste water containing Cr ⁶⁺ and other metal ions such as Cu ²⁺ , Ni ²⁺ , Co ²⁺ are separated by the solid-liquid separation system. , Fe ³⁺ , Zn ²⁺ , Fe ²⁺ , Cr ³⁺ , Ca ²⁺ and other one or more impurities are subjected to solid-liquid separation treatment, with high treatment efficiency and good treatment effect.

(2), further, the solid-liquid separation system of the present invention generates precipitation by causing the metal ions in the wastewater to react with alkaline substances such as sodium hydroxide in the precipitation reaction tank, and then concentrate through the concentration membrane device to make the precipitated particles Concentration and aggregation thicken and increase, accelerate precipitation, and then carry out solid-liquid separation in the sedimentation tank, and the clean water collected in the collection tank can be more thoroughly removed after double filtration of microfiltration and nanofiltration by setting up a nanofiltration-microfiltration combination device A small amount of fine suspended solids in the filter, the sediment obtained by filtration is discharged into the sedimentation tank in batches for further treatment, and the sediment in the sedimentation tank is dehydrated by a centrifuge or a filter press, and the obtained solid waste does not contain PAC and PAM and other organic impurities, the water content is also low, and then calcined in a calciner, the metal oxides and other compounds obtained can not only be recycled, but also achieve zero pollutant discharge, effectively reducing the cost and load of sludge treatment, and solving the problem of It eliminates the problem of resource waste, and greatly reduces the production cost of enterprises, which has great social and economic benefits.

(3), further, the solid-liquid separation system of the present invention monitors the pH value in the reaction tank in real time by setting a pH monitoring device to the precipitation reaction tank, and controls the automatic dosing of the dosing device according to the corresponding pH value, so that the degree of automation of the system is improved. High, safe and stable operation, simple operation, convenient management and better processing effect.

Although terminologies representing structures are often used above, such as "first precipitation reaction tank", "first concentration membrane device", "first pH monitoring device", etc., the possibility of using other terms is not excluded. These terms are used only for the purpose of describing and explaining the essence of the present invention more conveniently; interpreting them as any kind of additional limitation is against the spirit of the present invention.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. Should be covered within the protection scope of the present invention.

Claims (10)

1. a kind of system for processing chrome-containing wastewater, it is characterised in that：Including the pH regulating reservoirs, filter, the cation that are sequentially communicated Resins exchange system, tank, the first solid-liquid separation system；

The delivery port of the cation resin exchange system is connected with the tank, the solution of the cation resin exchange system Imbibition outlet has stripping liquid reservoir, and the stripping liquid reservoir is communicated with the second solid-liquid separation system.

2. system for processing chrome-containing wastewater according to claim 1, it is characterised in that：Also include effluent storage pond, it is described useless Water storage pool is connected by suction pump with the pH regulating reservoirs.

3. system for processing chrome-containing wastewater according to claim 1, it is characterised in that：First solid-liquid separation system includes Reduction reaction pond, the first precipitation reaction pond, the first concentration film device, the first sedimentation basin, the first collecting pit, first being sequentially communicated Nanofiltration-micro-filtration combination unit, the first clear water reserviors；The concentrated water spout of the first concentration film device is connected with first sedimentation basin, The sludge outlet of first sedimentation basin is communicated with the first centrifuge or filter press, the clean water outlet of the first concentration film device and The delivery port of first sedimentation basin is connected with first collecting pit, the water outlet of first nanofiltration-micro-filtration combination unit Mouth is connected with first clear water reserviors, and the sludge outlet of first nanofiltration-micro-filtration combination unit connects with first sedimentation basin Logical, the sludge outlet of first centrifuge or filter press is communicated with the first calcining furnace.

4. system for processing chrome-containing wastewater according to claim 1, it is characterised in that：Second solid-liquid separation system includes The second precipitation reaction pond, the second concentration film device, the second sedimentation basin, the second collecting pit, the second nanofiltration-micro-filtration group being sequentially communicated Attach together put, the second clear water reserviors；The concentrated water spout of the second concentration film device is connected with second sedimentation basin, second precipitation The sludge outlet in pond is communicated with the second centrifuge or filter press, the clean water outlet of the second concentration film device and second precipitation The delivery port in pond is connected with second collecting pit, the delivery port and described second of second nanofiltration-micro-filtration combination unit Clear water reserviors are connected, and the sludge outlet of second nanofiltration-micro-filtration combination unit is connected with second sedimentation basin, described second from The sludge outlet of scheming or filter press is communicated with the second calcining furnace.

5. system for processing chrome-containing wastewater according to claim 3, it is characterised in that：First solid-liquid separation system is also wrapped The first chemicals dosing plant and the second chemicals dosing plant connected with the reduction reaction pond are included, first chemicals dosing plant is used for described Reduction reaction pond adds acidic materials, and second chemicals dosing plant is used to add reducing agent to the reduction reaction pond；It is described to go back Former reaction tank is provided with a pH monitoring devices and control of Electric potentials instrument, and a pH monitoring devices connect with first chemicals dosing plant Connect, the control of Electric potentials instrument is connected with second chemicals dosing plant.

6. system for processing chrome-containing wastewater according to claim 3, it is characterised in that：First solid-liquid separation system is also wrapped The 3rd chemicals dosing plant connected with the first precipitation reaction pond is included, the 3rd chemicals dosing plant is used for the precipitation reaction pond Add alkaline matter；The first precipitation reaction pond is provided with the 2nd pH monitoring devices, the 2nd pH monitoring devices and described Three chemicals dosing plants are connected.

7. system for processing chrome-containing wastewater according to claim 4, it is characterised in that：Second solid-liquid separation system is also wrapped The 4th chemicals dosing plant connected with the second precipitation reaction pond is included, the 4th chemicals dosing plant is used for anti-to the described second precipitation Ying Chi adds alkaline matter；The second precipitation reaction pond is provided with the 3rd pH monitoring devices, the 3rd pH monitoring devices and institute State the connection of the 4th chemicals dosing plant.

8. system for processing chrome-containing wastewater according to claim 3, it is characterised in that：First sedimentation basin is dirty by first Mud reservoir is connected with first centrifuge or filter press；The delivery port of first centrifuge or filter press is dense with described first Contracting film device is connected.

9. system for processing chrome-containing wastewater according to claim 4, it is characterised in that：Second sedimentation basin is dirty by second Mud reservoir is connected with second centrifuge or filter press；The delivery port of second centrifuge or filter press is dense with described second Contracting film device is connected.

10. system for processing chrome-containing wastewater according to claim 1, it is characterised in that：The cation resin exchange system Including some cation resin exchange devices.