CN112607851A

CN112607851A - Method and reactor for synchronously removing heavy metals and nitrates from mine wastewater

Info

Publication number: CN112607851A
Application number: CN202011487507.6A
Authority: CN
Inventors: 苏俊峰; 王悦; 黄廷林; 赵廷宝; 高志宏; 白一涵; 孙毅; 杨玉珠
Original assignee: Xian University of Architecture and Technology
Current assignee: Xian University of Architecture and Technology
Priority date: 2020-12-16
Filing date: 2020-12-16
Publication date: 2021-04-06
Anticipated expiration: 2040-12-16
Also published as: CN112607851B

Abstract

The invention discloses a method and a reactor for synchronously removing heavy metals and nitrates in mine wastewater. The steps include: sludge enrichment and domestication, preparation of biological inoculants, preparation of double-layer iron-carbon fillers, biological film formation and reactor operation. The reactor includes a top-down double-layer iron-carbon packing, an air wash plate, a guide plate, a supporting layer, an outlet aeration system and a filter plate; a backwash valve is set at the bottom of the reactor, and the backwash water tank flows through the backwash flow. The flow meter is used to control the flow, and the water inlet pump is pumped with the air wash plate to realize backwashing; there are two exhaust holes on the top of the reactor; after the water is discharged from the water outlet, it enters the sedimentation tank for sedimentation and drainage. The double-layer iron-carbon filler used in the present invention removes nitrate under the action of microorganisms, and generates microbial precipitation (FeOOH, Fe ₂ O ₃ , Fe(OH) ₃ ) to achieve the effect of removing Cd ²⁺ , Pb ²⁺ and Ni ²⁺ . Adsorption removal has the characteristics of no secondary pollution, high biological activity, low cost and simple operation and management.

Description

Method and reactor for synchronously removing heavy metals and nitrates from mine wastewater

Technical Field

The invention relates to the technical field of treatment of heavy metals and nitrates in mine wastewater, and particularly relates to a method and a reactor for synchronously removing nitrates and heavy metals in mine wastewater.

Background

With the continuous development of economy in China, a large amount of heavy metal and nitrate pollutants are released into the environment by human activities such as mining, industry and agriculture, and the increasingly serious problem of mine wastewater pollution is concerned nowadays. Mine wastewater contains a large amount of toxic heavy metals such as cadmium, lead, nickel and the like, has non-biodegradability, durability and bioaccumulation, and simultaneously, sewage containing excessive nitrate and heavy metals is directly discharged, so that various chronic diseases, cancers and deterioration of soil and underground water conditions can be caused. Therefore, an economical and efficient method for removing the pollutants is urgently needed for the treatment problem of mine wastewater containing a large amount of heavy metals.

The conventional treatment methods for the two pollutants have the defects of secondary pollution, high cost, complex operation and difficult treatment of large-flow low-concentration harmful pollution.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for synchronously removing heavy metals and nitrates from mine wastewater and a reactor adopted by the method, wherein a novel double-layer iron-carbon filler is used for biofilm formation, the combination of iron ion electron gain and loss and denitrification process is realized, the nitrates are removed, and microbial precipitation (FeOOH and Fe) is used₂O₃、Fe(OH)₃) Product realization on Cd²⁺、Pb²⁺And Ni²⁺The adsorption removal of the heavy metal nitrate can synchronously solve the problem that the pollutants of the heavy metal and the nitrate in the mine wastewater exceed the standard.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a method for synchronously removing heavy metals and nitrates from mine wastewater, which comprises the following steps:

step 1, sludge enrichment and domestication:

under a closed anaerobic condition, carrying out enrichment culture on mine wastewater to be treated and FJY culture solution, and collecting precipitated sludge;

step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the obtained precipitated sludge according to the volume ratio of 2-4: 1, uniformly mixing, culturing for 3-5 days at constant temperature, removing supernatant, replacing the SJP culture solution every certain period, and performing acclimation culture for 12-14 days to form deep black bulk sludge to obtain biological agent;

step 3, preparing a double-layer iron-carbon filler:

uniformly mixing 40-55% of iron powder, 10-20% of activated carbon, 20-25% of sludge, 4-5% of manganese powder, 3-4% of magnesium powder, 5-8% of sodium silicate and water in percentage by weight, stirring to prepare spherical particles, covering the outer surfaces of the spherical particles with a mixture prepared from 30-50% of cement and 50-70% of clay in percentage by weight, drying, roasting, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler;

step 4, film forming of the double-layer iron-carbon filler biological agent:

according to the volume ratio of 1: (40-60) mixing the GMT culture solution with a biological microbial inoculum to obtain a soaking solution, soaking the double-layer iron-carbon filler in the soaking solution, performing biofilm formation for 2-4 days at normal temperature, finishing the biofilm formation after a light yellow biofilm is formed on the surface of the filler, and washing away bacteria adsorbed on the surface of the double-layer iron-carbon filler;

and 5, operating the reactor:

and (3) placing the double-layer iron-carbon filler subjected to film formation on a supporting layer of the reactor, and synchronously removing the double-layer iron-carbon filler and nitrate after the mine wastewater to be treated is subjected to film formation.

The FJY culture solution comprises the following raw materials in percentage by mass: c₆H₅Na₃O₇·6H₂0.8 to 1.2 portions of O and NaHCO₃0.8 to 1.2 parts of NaNO₃0.1 to 0.3 part of KH₂PO₄0.08 to 0.12 part of MgCl₂0.08 to 0.12 portion of CaCl₂0.04-0.06 part of FeCl₂·4H₂0.4-0.6 part of O, 1 part of trace element solution I and 1000 parts of distilled water.

The trace element solution I comprises: 0.4-0.6 g/LMgSO by mass concentration₄·7H₂O、0.9～1.1g/L EDTA、0.1～0.3g/L ZnSO₄、0.09～0.11g/L MnCl₂·4H₂O、0.4～0.6g/L FeSO₄·7H₂O、0.4～0.6g/LCuSO₄·5H₂O、0.1～0.3g/L CoCl₂·6H₂O。

The SJP culture solution comprises the following raw materials in percentage by mass: c₆H₅Na₃O₇·6H₂0.8 to 1.2 portions of O and NaHCO₃0.4 to 0.6 part of NaNO₃0.1 to 0.3 part of KH₂PO₄0.04 to 0.06 part of MgCl₂0.04 to 0.06 portion of CaCl₂0.04-0.06 part of FeCl₂·4H₂0.2-0.4 part of O, 2 parts of a trace element solution II and 1000 parts of distilled water.

The microelement solution II comprises: 0.4-0.6 g/L MgSO (MgSO) by mass concentration meter₄·7H₂O、0.8～1.2g/L EDTA、0.1～0.3g/L ZnSO₄、0.04～0.06g/L MnCl₂·4H₂O、0.08～0.12g/L FeSO₄·7H₂O、0.4～0.6g/LCuSO₄·5H₂O、0.08～0.12g/L CoCl₂·6H₂O。

The GMT culture solution comprises the following raw materials in percentage by mass: 1000 parts of sterilized mine wastewater to be treated and 2 parts of microelement III.

The microelement III is as follows: 0.1-0.3 g/L EDTA and 0.04-0.06 g/L ZnSO by mass concentration₂、0.01～0.03g/L MnCl₂·4H₂O、0.01～0.03g/L CuSO₄·5H₂An aqueous solution of O.

For the above technical solution, the present solution is further preferred:

further, in step 1, the anaerobic conditions include: the reactor was purged with nitrogen 4 times a day, 4-9L/min of nitrogen for 5 minutes each time.

Further, in the step 2, the SJP culture solution is replaced every 3 days in the following order:

1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Replacing SJP culture medium with liquid culture solution A consisting of 2mg/L pH 7.0 mixed solution; then 1 volume of SJP culture medium and 2 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium A consisting of 4mg/L mixed solution with pH 6.5; then 1 volume of SJP culture medium and 3 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium C composed of 6mg/L pH 4.5 mixed solution; then the Cd is added²⁺、Pb²⁺、Ni²⁺The liquid medium C was replaced with a mixed solution of 10mg/L pH 5.0.

Further, in the step 3, during the preparation of the double-layer iron-carbon filler, water is added and stirred to prepare spherical particles with the particle size of 1-3cm, then the spherical particles are dried at the temperature of 100-.

Correspondingly, the invention provides a reactor adopted by the method, which comprises a reactor body, wherein the reactor body sequentially comprises a double-layer iron-carbon filler, a gas washing plate, a flow guide plate, a supporting layer, an outlet aeration system and a filter plate from top to bottom; the air washing plate and the outlet aeration system are connected through an aeration pipe by a blower; the bottom of the reactor is communicated with a back washing pump and a back washing water tank through a back washing valve, and the top of the reactor is communicated with a tap water pipe through a water inlet pump to be matched with a gas washing plate for back washing; the back washing top is provided with an exhaust hole; the side wall of the bottom is communicated with a sedimentation tank.

Furthermore, cobbles with the grain diameter of 2.0-4.0cm are adopted in the bearing layer, and the laying thickness is 0.25-0.40 m; the laying thickness of the double-layer iron-carbon filler is 1.1-1.5 m.

The operation method of the reactor comprises the following steps:

1) opening a water inlet valve, enabling mine water to be treated to enter the device through the water inlet by a water inlet pump, enabling the mine water to flow through the double-layer iron-carbon filler, removing nitrates and organic matters in the water to be treated, and discharging generated gas into the atmosphere through a gas outlet;

2) the water flow enters the supporting layer through the guide plate, and then is aerated intermittently in the outlet aeration system, and the dissolved oxygen concentration in the aeration stage is controlled, so that the excessive Fe²⁺Further oxidation is carried out, so that the problem that the quality of effluent water exceeds the standard is avoided;

3) the treated effluent flows into a sedimentation tank through a water outlet;

4) and (3) backwashing the reactor every 3-10 days after the reactor operates for a certain time, realizing gas washing through a gas washing plate, opening a backwashing valve to realize water washing, completing gas-water backwashing by matching the gas washing plate and the backwashing valve, closing the backwashing valve after the backwashing is completed, and restarting the system.

Further, the inverted trapezoidal grooves are formed in the guide plate in the step 2), the flow velocity of mine wastewater is reduced, and the retention time of the wastewater in the double-layer iron-carbon filler area is prolonged.

Further, in the steps 1) and 2), the outlet aeration system is connected with an air blower through an aeration pipe to realize aeration.

Further, in the step 4), the quantity of backwashing water is 11-14L/s.m²The time is 2-5 min.

Further, in the step 6), intermittent aeration is carried out for 2 hours every day, the concentration of dissolved oxygen in an aeration stage is 2-4 mg/L, and the mine wastewater can be further purified on the bearing layer.

The invention has the beneficial effects that:

based on the combination of iron ion electron gain and loss and the denitrification process, the invention adopts double-layer iron-carbon filler, and Fe under the action of microorganisms²⁺Oxidation to Fe³⁺The electrons lost in the process are transferred to nitrate nitrogen to remove nitrate and form microbial precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Realize the Cd pairing²⁺、Pb²⁺And Ni²⁺The adsorption and removal of the heavy metal ion pollutants and the nitrate can achieve the synchronous and efficient effect of the heavy metal ion pollutants and the nitrate, and a novel and harmless water treatment technology is provided.

The advantages are that:

1. the invention can realize the synchronous removal of heavy metals and nitrates in mine wastewater, the sludge after enrichment and domestication is prepared into the biological microbial inoculum, and the prepared biological microbial inoculum is utilized to carry out biological film formation on the novel double-layer iron-carbon filler, so that the Fe continuously released outwards after the electrochemical reaction of the internal iron-carbon²⁺Under the action of microorganisms, Fe²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺). The method does not need an external bacteria source, has the advantages of no secondary pollution, high biological activity, strong adaptability, simple operation, low cost and good treatment effect, and can synchronously remove various heavy metal ions and nitrate pollutants in the mine wastewater in one reactor.

2. Compared with the traditional double-layer iron-carbon filler with insufficient strength, iron corrosion, easy loss and easy caking, the double-layer iron-carbon filler prepared by the invention has the characteristics of simple preparation, strong stability, high activity, long service cycle and the like, is more suitable for treating heavy metals and nitrates in mine wastewater, and can effectively remove C0D and chromaticity in the wastewater. The inner layer of the novel double-layer iron-carbon filler film is an iron-carbon spherical particle which continuously provides Fe outwards under the action of electrochemical reaction²⁺(ii) a The outer layer is wrapped with a thin layer of a mixture of cement and clay to increaseThe roughness of the surface of the filler is more beneficial to film formation; under the dual function of inside and outside, novel double-deck iron carbon filler changes and forms strong stable form biomembrane behind the biological agent biofilm culturing.

3. The outlet aeration system adopted by the invention can effectively solve the problem that the quality of the effluent water exceeds the standard, and under the action of the outlet aeration system, excessive Fe in the wastewater of the bearing layer area²⁺Further oxidation is realized, and the effluent quality is ensured; a guide plate is arranged below the gas washing plate, so that the flow speed of the mine wastewater to be treated is reduced, and the reaction is fully carried out.

Drawings

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

FIG. 2(a) is a schematic diagram showing the nitrate removal effects of examples 1, 2 and 3;

FIG. 2(b) shows examples 1, 2 and 3Cd²⁺A schematic diagram of the removal effect;

FIG. 2(c) shows Pb in examples 1, 2 and 3²⁺A schematic diagram of the removal effect;

FIG. 2(d) shows Ni in examples 1, 2 and 3²⁺A schematic diagram of the removal effect;

FIG. 3(a) is a schematic diagram showing the nitrate removal effects of examples 4, 5 and 6;

FIG. 3(b) shows examples 4, 5 and 6Cd²⁺A schematic diagram of the removal effect;

FIG. 3(c) shows Pb in examples 4, 5 and 6²⁺A schematic diagram of the removal effect;

FIG. 3(d) shows Ni in examples 4, 5 and 6²⁺And (5) a schematic diagram of the removal effect.

Reference numbers in the figures: 1-double-layer iron-carbon filler, 2-air washing plate, 3-air vent, 4-guide plate, 5-supporting layer, 6-outlet aeration system, 7-filter plate, 8-blower, 9-aeration pipe, 10-flowmeter, 11-1-water inlet pump, 11-2-backwashing pump, 12-backwashing valve, 13-1-first gate valve, 13-2-second gate valve, 13-3-backwashing water inlet valve, 13-4-backwashing water outlet valve, 14-sedimentation tank and 15-backwashing water tank.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

As shown in fig. 1, the reactor adopted for the method for synchronously removing heavy metals and nitrates from mine wastewater according to the embodiment of the present invention comprises a reactor body, wherein the reactor body sequentially comprises a double-layer iron-carbon filler 1, a gas washing plate 2, a guide plate 4, a support layer 5, an outlet aeration system 6 and a filter plate 7 from top to bottom; the air washing plate 2 and the outlet aeration system 6 are connected with an aeration pipe 9 through a blower 8; the top of the reactor is communicated with a tap water pipe through a water inlet pump 11-1, a first gate valve 13-1 and a flowmeter 10 and is matched with a gas washing plate 2 for back washing; the back washing top is provided with an exhaust 3; the bottom of the reactor is communicated with a backwashing pump 11-2 and a backwashing water tank 15 through a backwashing valve 12, the backwashing water tank 15 is communicated with the backwashing pump 11-2, a flowmeter 10 and a backwashing water inlet valve 13-3 through a circulation pipe, and the other circulation pipe is communicated with the flowmeter 10 and a backwashing water outlet valve 13-4 to the backwashing valve 12 at the bottom of the reactor; the side wall of the bottom of the reactor is communicated with a sedimentation tank 14 through a second gate valve 13-2.

Opening a backwashing water inlet gate valve 13-3, monitoring the water inlet flow by using a flow meter 10, and pumping water by a backwashing water tank 15 by a backwashing pump 11-2 to start backwashing; simultaneously, the backwashing is carried out by matching with the gas washing plate 2, and the backwashing water outlet valve 13-4 is opened to be monitored by using the flow meter 10, so that the backwashing water outlet enters the backwashing water tank 15; the top of the reactor is communicated with a tap water pipe by opening a first gate valve 13-1 and matching a water inlet pump 11-1 with a flow meter 10 so as to realize water inlet.

The method for synchronously removing the heavy metal and the nitrate in the mine wastewater comprises the following steps:

step 1, sludge enrichment and domestication:

step 2, preparing a biological agent:

step 3, preparing a double-layer iron-carbon filler:

step 4, film forming of the double-layer iron-carbon filler biological agent:

and 5, operating the reactor:

The reaction process of the double-layer iron-carbon filler for biofilm formation is as follows:

double layer iron-carbon filled anode (Fe): Fe-2e^-→Fe²⁺；

Double layer iron carbon filled cathode (C) 2H⁺+2e^-→2[H]→H₂；

Fe²⁺+NO₃ ^-+2H⁺→Fe³⁺+H₂O+N₂；

Fe³⁺+3H₂O→Fe(OH)₃+3H⁺；

And under the action of microorganisms, Fe²⁺Iron oxide (FeOOH, Fe) formed by autoxidation₂O₃) Adsorption of heavy metals.

The effects of the present invention will be further described below by way of specific examples.

Example 1:

the mine wastewater to be treated in the embodiment is from wastewater in a certain mining area of Shaanxi province, and nitrate and heavy metal (Cd) are supplemented artificially²⁺、Pb²⁺、Ni²⁺) According to the technical scheme of the invention, the water body is deeply treated, which comprises the following steps:

step 1, sludge enrichment and domestication:

uniformly mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 3:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, introducing 7L/min nitrogen into a reactor for 4 times every day, wherein each time is 5 minutes, in the enrichment culture process, 7 days is a culture period, replacing half of supernatant fluid with the FJY culture solution, adopting a shaking table with the rotating speed of 140r/min, and after 3 weeks of enrichment, when the nitrate removal rate is more than 70%, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O 1.0g，NaHCO₃ 1.0g，NaNO₃ 0.2g，KH₂PO₄ 0.1g，MgCl₂ 0.1g，CaCl₂ 0.05g，FeCl₂·4H₂0.5g of O, 1mL of trace element solution I, 1000mL of distilled water, and the pH value of the solution is 7.0.

The trace element solution I comprises: measured by mass concentration, 0.5g/L MgSO₄·7H₂O、1.0g/L EDTA、0.2g/L ZnSO₄、0.1g/L MnCl₂·4H₂O、0.5g/L FeSO₄·7H₂O、0.5g/LCuSO₄·5H₂O、0.2g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 3:1, culturing for 3 days at 25 ℃, pouring out supernatant, and replacing liquid culture solution every 3 days to remove heavy metal (Cd) through acclimatization²⁺、Pb² ⁺、Ni²⁺) The capacity of (2) is domesticated and cultured for 12 days, and the replacement sequence is as follows: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Replacing SJP culture medium with liquid culture solution A consisting of 2mg/L pH 7.0 mixed solution; then 1 volume of SJP culture medium and 2 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium A consisting of 4mg/L mixed solution with pH 6.5; then 1 volume of SJP culture medium and 3 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium C composed of 6mg/L pH 4.5 mixed solution; then the Cd is added²⁺、Pb²⁺、Ni²⁺The liquid medium C was replaced with a mixed solution of 10mg/L pH 5.0. When the bottom of the reactor forms deep black bulk sludge and the nitrate removal rate is over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O 1.0g，NaHCO₃ 0.5g，NaNO₃ 0.2g，KH₂PO₄0.05g，MgCl₂ 0.05g，CaCl₂ 0.05g，FeCl₂·4H₂0.3g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

Wherein, the microelement solution II comprises: measured by mass concentration, 0.5g/L MgSO₄·7H₂O、1g/L EDTA、0.2g/L ZnSO₄、0.05g/L MnCl₂·4H₂O、0.1g/L FeSO₄·7H₂O、0.5g/LCuSO₄·5H₂O、0.1g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 42 percent of iron powder, 20 percent of active carbon, 22 percent of sludge, 5 percent of manganese powder, 3 percent of magnesium powder and 8 percent of sodium silicate according to weight percentage, stirring to prepare spherical particles with the particle size of 2.5cm, covering a thin layer on the outer surface by using a mixture consisting of 30 percent of cement and 70 percent of clay according to weight percentage, drying at 100 ℃ for 35min, roasting at 600 ℃ in a roasting furnace filled with inert gases such as nitrogen and the like for 60min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

Step 4, performing biological agent biofilm formation on the double-layer iron-carbon filler:

the film forming filler is prepared by processing a double-layer iron-carbon filler according to a volume ratio of 1: 50 of GMT culture solution and biological agent, 2L of mixed solution is added into each kilogram of double-layer iron-carbon filler in a closed reactor, the membrane is formed at 25 ℃ for 2 days, after a light yellow biological membrane is formed on the surface of the filler, the membrane is shown to be finished, and bacteria adsorbed on the surface of the double-layer iron-carbon filler are washed away by continuous tap water.

The GMT culture solution comprises: 1000ml of sterilized mine wastewater to be treated; 2ml of trace element III;

the microelement III is as follows: by mass concentration, 0.3g/L EDTA, 0.04g/L ZnSO₂、0.02g/L MnCl₂·4H₂O、0.03g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

adopting a reactor for synchronously removing heavy metal and nitrate in mine wastewater, preparing a biological microbial inoculum by utilizing enriched and domesticated sludge to form a novel double-layer iron-carbon filler biofilm, forming a strong stable biological film on the rough surface of the filler, and providing Fe outwards after the electrochemical reaction of the inner iron-carbon²⁺，Fe²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater² ⁺、Pb²⁺、Ni²⁺)。

In this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 35mm, and the laying thickness is 0.3 m; the packing layer adopts iron-carbon particles with the particle size of 25mm and the laying thickness of 1.2 m.

A water inlet pump 11-1 pumps water, and water flow sequentially passes through a double-layer iron-carbon filler 1, a gas washing plate 2, a guide plate 4, a support layer 5, an outlet aeration system 6 and a filter plate 7 from top to bottom; the air washing plate 2 and the outlet aeration system 6 are sequentially connected through an air blower 8 and an aeration pipe 9; a back washing valve 12 is arranged at the bottom of the reactor, the flow rate of the back washing water tank is controlled by a back washing flow meter 10, and a back washing pump 11-2 pumps water to match with the gas washing plate 2 for back washing; the top of the reactor is provided with two exhaust holes 3; the water outlet enters a sedimentation tank 14 for sedimentation and drainage after yielding water.

The reactor was run as follows:

1) putting the double-layer iron-carbon filler subjected to film formation on a supporting layer of a reactor, starting a water inlet pump 11-1, opening a water inlet valve 13-1, allowing mine water to be treated to enter the device through the water inlet by the water inlet pump, allowing the mine water to flow through the double-layer iron-carbon filler 1, and allowing Fe to react under the action of microorganisms²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺) The gas generated by the reaction is exhausted into the atmosphere through two exhaust holes 3;

2) the water flow enters the supporting layer 5 through the guide plate 4, and the guide plate 4 is provided with an inverted trapezoidal groove so as to reduce the flow velocity of the waste water and increase the retention time of the mine waste water to be treated in the double-layer iron-carbon filler area; an outlet aeration system 6 is arranged below the supporting layer, and adopts intermittent aeration for 2 hours every day, the dissolved oxygen concentration in the aeration stage is 2mg/L, so that the excessive Fe is generated²⁺Further oxidation is carried out, so that the problem that the iron content of the water exceeds the standard is avoided;

3) the treated effluent flows into a sedimentation tank 14 through a water outlet, and is precipitated and discharged;

4) the reactor is backwashed after running for 1-2 days, a backwash valve 12 is opened, and the quantity of the backwash water is adjusted to be 11L/s.m²The neutralization time is 5min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is backwashed after 6 days of operation, gas washing is realized through the gas washing plate 2, and the quantity of the backwashed water is controlled to be 11L/s.m.²And the time is 3min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

The mine waste water to be treated is manually added into the mouldIn the water inlet pipe of the device, the sewage volume is ensured to be not less than 3/4 of the volume of the equipment. After each operation period, sampling by using a special syringe, operating at room temperature, sampling, analyzing and testing nitrate and Cd²⁺、Pb²⁺、Ni²⁺And (4) indexes.

As can be seen from fig. 2(a), the nitrate removal rate gradually increases with the steady operation of the apparatus, and finally remains at about 96% after 6 hours of operation.

As can be seen from FIGS. 2(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 79.00%, 61.62% and 59.87%, and after the equipment runs stably, Cd²⁺、Pb²⁺、Ni²⁺The removal rate is basically maintained at 88.00%, 73.02% and 79.12%, and the whole process shows that the heavy metal ions (Cd) are removed well synchronously²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

Example 2:

step 1, sludge enrichment and domestication:

uniformly mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 4:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, introducing 5L/min nitrogen for 4 times every day into a reactor, introducing 5 minutes every time, changing half of supernatant into the FJY culture solution in 7 days as a culture period in the enrichment culture process, adopting a shaking table with the rotating speed of 130r/min, enriching for 2 weeks, and when the nitrate removal rate is more than 70%, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O 0.8g，NaHCO₃1.2g，NaNO₃ 0.2g，KH₂PO₄ 0.12g，MgCl₂ 0.09g，CaCl₂ 0.04g，FeCl₂·4H₂O0.6g, 1mL of trace element solution I, 1000mL of distilled water, and pH 7.0.

The trace element solution I comprises: measured by mass concentration, 0.4g/L MgSO₄·7H₂O、1.1g/L EDTA、0.2g/L ZnSO₄、0.09g/L MnCl₂·4H₂O、0.4g/L FeSO₄·7H₂O、0.6g/LCuSO₄·5H₂O、0.2g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 2:1, culturing for 5 days at 25 ℃, pouring out supernatant, replacing the liquid culture solution every 3 days, performing acclimation culture for 12 days, and replacing the liquid culture solution in the following sequence: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Replacing SJP culture medium with liquid culture solution A consisting of 2mg/L pH 7.0 mixed solution; then 1 volume of SJP culture medium and 2 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium A consisting of 4mg/L mixed solution with pH 6.5; then 1 volume of SJP culture medium and 3 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium C composed of 6mg/L pH 4.5 mixed solution; then the Cd is added²⁺、Pb²⁺、Ni²⁺The liquid medium C was replaced with a mixed solution of 10mg/L pH 5.0. When the bottom of the reactor forms deep black bulk sludge and the nitrate removal rate is over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O1.1g，NaHCO₃ 0.6g，NaNO₃0.1g，KH₂PO₄0.04g，MgCl₂0.06g，CaCl₂0.06g，FeCl₂·4H₂0.2g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

Wherein the microelement solution II comprises: measured by mass concentration, 0.4g/L MgSO₄·7H₂O、0.8g/L EDTA、0.3g/L ZnSO₄、0.06g/L MnCl₂·4H₂O、0.1g/L FeSO₄·7H₂O、0.6g/LCuSO₄·5H₂O、0.11g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 43% of iron powder, 18% of activated carbon, 25% of sludge, 4% of manganese powder, 4% of magnesium powder and 6% of sodium silicate according to weight percentage, stirring to prepare spherical particles with the particle size of 3cm, covering a thin layer on the outer surface of the spherical particles by using a mixture consisting of 60% of cement and 40% of clay according to weight percentage, drying at 120 ℃ for 45min, roasting at 550 ℃ in a roasting furnace filled with inert gases such as nitrogen and the like for 70min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

the film forming filler is prepared by processing a double-layer iron-carbon filler according to a volume ratio of 1: 60 of GMT culture solution and a mixed solution of a biological agent are soaked, 2L of the mixed solution is added into each kilogram of double-layer iron-carbon filler in a closed reactor, the membrane is formed for 3 days at 25 ℃, after a light yellow biological membrane is formed on the surface of the filler, the membrane is shown to be finished, and bacteria adsorbed on the surface of the double-layer iron-carbon filler are washed away by continuous tap water.

the microelement III is as follows: according to mass concentration, 0.2g/L EDTA and 0.06g/L ZnSO₂、0.01g/L MnCl₂·4H₂O、0.01g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

in this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 40mm, and the laying thickness is 0.4 m; the packing layer adopts iron-carbon particles with the particle size of 20mm and the laying thickness of 1.3 m.

The reactor was run as follows:

1) coating the film with double layers of iron and carbonFilling material is put on a supporting layer of the reactor, a water inlet pump 13-1 is started, a water inlet valve is opened, so that mine water to be treated enters the device through the water inlet by the water inlet pump, flows through the double-layer iron-carbon filling material 1, and Fe is generated under the action of microorganisms²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺) The gas generated by the reaction is exhausted into the atmosphere through two exhaust holes 3;

2) the water flow enters the supporting layer 5 through the guide plate 4, and the guide plate 4 is provided with an inverted trapezoidal groove so as to reduce the flow velocity of the waste water and increase the retention time of the mine waste water to be treated in the double-layer iron-carbon filler area; an outlet aeration system 6 is arranged below the supporting layer, and adopts intermittent aeration for 2 hours every day, the dissolved oxygen concentration in the aeration stage is 4mg/L, so that the excessive Fe is generated²⁺Further oxidation is carried out, so that the problem that the iron content of the water exceeds the standard is avoided;

4) after the reactor runs for 1-2 d, back flushing is carried out, a back flushing valve is opened, 12, and the back flushing water quantity is adjusted to be 13L/s.m²The neutralization time is 4min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is backwashed after 8 days of operation, gas washing is realized through the gas washing plate 2, and the quantity of the backwashed water is controlled to be 13L/s.m.²And the time is 5min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

The mine wastewater to be treated is manually added into a water inlet pipe of the simulation device, so that the volume of the wastewater is not less than 3/4 of the volume of the equipment. After each operation period, sampling by using a special syringe, operating at room temperature, sampling, analyzing and testing nitrate and Cd²⁺、Pb²⁺、Ni²⁺And (4) indexes.

As can be seen from fig. 2(a), the nitrate removal rate gradually increased with the stable operation of the apparatus, and finally remained at about 96.35% after 7 hours of operation.

As can be seen from FIGS. 2(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 79.35%, 62.70% and 59.77%, and after the equipment runs stably, Cd²⁺、Pb²⁺、Ni²⁺The removal rate is basically maintained at 88.97%, 73.00% and 79.00%, and the whole body shows better synchronous removal of heavy metal ions (Cd)²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

Example 3:

step 1, sludge enrichment and domestication:

uniformly mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 2:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, introducing 8L/min nitrogen for 4 times every day, introducing 5 minutes every time, changing half of supernatant into the FJY culture solution in 7 days as a culture period in the enrichment culture process, adopting a shaking table with the rotating speed of 120r/min, enriching for 3 weeks, and when the nitrate removal rate is more than 70%, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O1.2g，NaHCO₃ 0.8g，NaNO₃ 0.1g，KH₂PO₄ 0.09g，MgCl₂ 0.1g，CaCl₂ 0.06g，FeCl₂·4H₂0.4g of oxygen, 1mL of trace element solution I and 1000mL of distilled water, wherein the pH value is 7.0.

The trace element solution I comprises: measured by mass concentration, 0.6g/L MgSO₄·7H₂O、0.9g/L EDTA、0.3g/L ZnSO₄、0.11g/L MnCl₂·4H₂O、0.6g/L FeSO₄·7H₂O、0.4g/LCuSO₄·5H₂O、0.3g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 4:1, culturing for 4 days at 25 ℃, pouring out supernatant, and replacing liquid culture solution every 3 days for acclimatization to remove heavy metal (Cd)²⁺、Pb² ⁺、Ni²⁺) The capacity of (2) is domesticated and cultured for 12 days, and the replacement sequence is as follows: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Replacing SJP culture medium with liquid culture solution A consisting of 2mg/L pH 7.0 mixed solution; then 1 volume of SJP culture medium and 2 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium A consisting of 4mg/L mixed solution with pH 6.5; then 1 volume of SJP culture medium and 3 volumes of Cd-containing medium were added²⁺、Pb²⁺、Ni²⁺Replacing liquid culture medium B with liquid culture medium C composed of 6mg/L pH 4.5 mixed solution; then the Cd is added²⁺、Pb²⁺、Ni²⁺The liquid medium C was replaced with a mixed solution of 10mg/L pH 5.0. When the bottom of the reactor forms deep black bulk sludge and the nitrate removal rate is over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O1.2g，NaHCO₃0.4g，NaNO₃0.3g，KH₂PO₄ 0.06g，MgCl₂ 0.04g，CaCl₂0.04g，FeCl₂·4H₂0.4g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

The microelement solution II comprises: measured by mass concentration, 0.6g/L MgSO₄·7H₂O、1.2g/L EDTA、0.1g/L ZnSO₄、0.04g/L MnCl₂·4H₂O、0.12g/L FeSO₄·7H₂O、0.4g/LCuSO₄·5H₂O、0.08g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 50 wt% of iron powder, 12 wt% of activated carbon, 23 wt% of sludge, 5 wt% of manganese powder, 3 wt% of magnesium powder and 7 wt% of sodium silicate, stirring to prepare spherical particles with the particle size of 2.5cm, covering a thin layer on the outer surface of the spherical particles by using a mixture consisting of 50 wt% of cement and 30 wt% of clay, drying at 110 ℃ for 50min, roasting at 500 ℃ in a roasting furnace filled with inert gases such as nitrogen and the like for 80min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

the film forming filler is prepared by processing a double-layer iron-carbon filler according to a volume ratio of 1: 45 of GMT culture solution and a biological agent, 2L of mixed solution is added into each kilogram of double-layer iron-carbon filler in a closed reactor, the membrane is formed for 4 days at 25 ℃, after a light yellow biological membrane is formed on the surface of the filler, the membrane is shown to be finished, and bacteria adsorbed on the surface of the double-layer iron-carbon filler are washed away by continuous tap water.

the microelement III is as follows: according to mass concentration, 0.1g/L EDTA, 0.05g/L ZnSO₂、0.03g/L MnCl₂·4H₂O、0.02g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

in this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 25mm, and the paving thickness is 0.25 m; the filler layer adopts iron-carbon particles with the particle size of 30mm and the laying thickness of 1.1 m.

The reactor was run as follows:

1) putting the double-layer iron-carbon filler subjected to film formation on a supporting layer of a reactor, starting a water inlet pump 13-1, opening a water inlet valve, enabling mine water to be treated to enter the device through the water inlet by the water inlet pump, enabling the mine water to flow through the double-layer iron-carbon filler 1, and allowing Fe to react under the action of microorganisms²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrateMicrobial precipitate (FeOOH, Fe) formed₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺) The gas generated by the reaction is exhausted into the atmosphere through two exhaust holes (3);

2) the water flow enters the supporting layer 5 through the guide plate 4, and the guide plate 4 is provided with an inverted trapezoidal groove so as to reduce the flow velocity of the waste water and increase the retention time of the mine waste water to be treated in the double-layer iron-carbon filler area; an outlet aeration system 6 is arranged below the supporting layer, and adopts intermittent aeration for 2 hours every day, the dissolved oxygen concentration in the aeration stage is 3mg/L, so that the excessive Fe is generated²⁺Further oxidation is carried out, so that the problem that the iron content of the water exceeds the standard is avoided;

3) the treated effluent flows into a sedimentation tank (14) through a water outlet, and is precipitated and discharged;

4) the reactor is backwashed after running for 1-2 days, a backwash valve 12 is opened, and the quantity of the backwash water is adjusted to be 14L/s.m²The neutralization time is 5min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is backwashed after 7 days of operation, gas washing is realized through the gas washing plate 2, and the quantity of the backwashed water is controlled to be 14L/s.m.²And the time is 5min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

As can be seen from fig. 2(a), the nitrate removal rate gradually increases with the stable operation of the equipment, and finally remains at about 97.35% after 6 hours of operation;

as can be seen from FIGS. 2(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 79.35%, 62.75% and 58.90%, and after the equipment runs stably, Cd²⁺、Pb²⁺、Ni²⁺The removal rate is basically maintained at 88.78%, 72.93% and 78.10%, and the whole process shows that the heavy metal ions (Cd) are removed well synchronously²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

Example 4:

step 1, sludge enrichment and domestication:

uniformly mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 4:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, introducing nitrogen gas into a reactor for 4 times and 6L/min every day, wherein each time is 5 minutes, in the enrichment culture process, 7 days is a culture period, replacing half of supernatant fluid with the FJY culture solution, adopting a shaking table with the rotating speed of 140r/min, enriching for 2 weeks, and when the nitrate removal rate is more than 70%, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O 0.8g，NaHCO₃ 1.2g，NaNO₃ 0.2g，KH₂PO₄0.09g，MgCl₂ 0.09g，CaCl₂ 0.06，FeCl₂·4H₂0.5 of O, 1mL of trace element solution I and 1000mL of distilled water, wherein the pH value is 7.0.

The trace element solution I comprises: measured by mass concentration, 0.6g/L MgSO₄·7H₂O、1.1g/L EDTA、0.2g/L ZnSO₄、0.09g/L MnCl₂·4H₂O、0.4g/L FeSO₄·7H₂O、0.4g/L CuSO₄·5H₂O、0.3g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding the mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 2:1, and 3Culturing at 0 deg.C for 4 days, pouring out supernatant, and changing liquid culture solution every 3 days for acclimatization to remove heavy metal (Cd)²⁺、Pb² ⁺、Ni²⁺) The capacity of (2) is domesticated and cultured for 12 days, and the replacement sequence is as follows: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Liquid culture medium consisting of 2mg/L mixed solution with pH 7.0, 1 volume of SJP culture solution, and 2 volumes of Cd-containing culture solution²⁺、Pb²⁺、Ni² ⁺Liquid culture medium consisting of 4mg/L mixed solution with pH of 6.5, 1 volume of SJP culture solution, and 3 volumes of mixed solution containing Cd²⁺、Pb²⁺、Ni²⁺Liquid culture medium comprising 6mg/L mixed solution of pH 4.5 and Cd²⁺、Pb²⁺、Ni²⁺The pH of the mixed solution was 5.0 at 10 mg/L. When the bottom of the reactor forms deep black bulk sludge and the nitrate removal rate is over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O1.1g，NaHCO₃ 0.6g，NaNO₃0.1g，KH₂PO₄0.04g，MgCl₂ 0.06g，CaCl₂ 0.06g，FeCl₂·4H₂0.2g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

The microelement solution II comprises: measured by mass concentration, 0.6g/L MgSO₄·7H₂O、0.8g/L EDTA、0.3g/L ZnSO₄、0.06g/L MnCl₂·4H₂O、0.1g/L FeSO₄·7H₂O、0.6g/LCuSO₄·5H₂O、0.11g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 40 wt% of iron powder, 20 wt% of activated carbon, 25 wt% of sludge, 4 wt% of manganese powder, 4 wt% of magnesium powder and 7 wt% of sodium silicate, stirring to prepare spherical particles with the particle size of 2cm, covering a thin layer on the outer surface of the spherical particles by using a mixture consisting of 50 wt% of cement and 50 wt% of clay, drying at 110 ℃ for 50min, roasting at 550 ℃ in a roasting furnace filled with inert gases such as nitrogen for 60min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

the microelement III is as follows: according to mass concentration, 0.1g/L EDTA, 0.05g/L ZnSO₂、0.01g/L MnCl₂·4H₂O、0.02g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

in this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 35mm, and the laying thickness is 0.25 m; the filler layer adopts iron-carbon particles with the particle size of 20mm and the laying thickness of 1.2 m.

The reactor was run as follows:

1) putting the double-layer iron-carbon filler subjected to film formation on a supporting layer of a reactor, starting a water inlet pump 13-1, opening a water inlet valve 13-1, enabling mine water to be treated to enter the device through the water inlet by the water inlet pump and flow through the double-layer iron-carbon filler 1, and under the action of microorganisms, Fe²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺) The gas generated by the reaction is exhausted into the atmosphere through two exhaust holes 3;

2) the water flow enters the supporting layer 5 through the guide plate 4, and the guide plate 4 is provided with an inverted trapezoidal groove to reduce the flow speed of the waste water and increase the waste water to be treatedTreating the retention time of the mine wastewater in the double-layer iron-carbon filler area; an outlet aeration system 6 is arranged below the supporting layer, and adopts intermittent aeration for 2 hours every day, the dissolved oxygen concentration in the aeration stage is 4mg/L, so that the excessive Fe is generated²⁺Further oxidation is carried out, so that the problem that the iron content of the water exceeds the standard is avoided;

4) the reactor is backwashed after running for 1-2 days, a backwash valve 12 is opened, and the quantity of the backwash water is adjusted to be 13L/s.m²The neutralization time is 4min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is backwashed after 8 days of operation, the gas washing is realized by the gas washing plate (2), and the quantity of the backwashed water is controlled to be 13L/s.m.²And the time is 3min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

As can be seen from fig. 3(a), the nitrate removal rate gradually increases with the stable operation of the apparatus, and finally remains around 94.89% after 7 hours of operation;

as can be seen from FIGS. 3(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 78.22%, 60.86% and 71.35%, and after the equipment runs stably, Cd²⁺、Pb²⁺、Ni²⁺The removal rate is basically maintained at 89.77%, 67.82% and 80.02%, and the whole body shows better synchronous removal of heavy metal ions (Cd)²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

Example 5:

the mine wastewater to be treated in the embodiment is from wastewater in a certain mining area of Shaanxi province, and nitrate and heavy gold are artificially supplementedGenus (Cd)²⁺、Pb²⁺、Ni²⁺) According to the technical scheme of the invention, the water body is deeply treated, which comprises the following steps:

step 1, sludge enrichment and domestication:

uniformly mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 3:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, introducing 8L/min nitrogen for 4 times every day, introducing 5 minutes every time, changing half of supernatant into the FJY culture solution in 7 days as a culture period in the enrichment culture process, adopting a shaking table with the rotating speed of 150r/min, and enriching for 3 weeks, wherein Cd is obtained when the nitrate removal rate is more than 70 percent²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O 1.0g，NaHCO₃ 1.0g，NaNO₃ 0.2g，KH₂PO₄ 0.1g，MgCl₂ 0.1g，CaCl₂ 0.05，FeCl₂·4H₂O0.6, 1mL of the trace element solution i, 1000mL of distilled water, and pH 7.0.

The trace element solution I comprises: measured by mass concentration, 0.5g/L MgSO₄·7H₂O、0.9g/L EDTA、0.3g/L ZnSO₄、0.11g/L MnCl₂·4H₂O、0.6g/L FeSO₄·7H₂O、0.6g/L CuSO₄·5H₂O、0.3g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 4:1, culturing at 30 ℃ for 3 days, pouring out supernatant, and replacing the liquid culture solution every 3 days to remove heavy metal (Cd)²⁺、Pb² ⁺、Ni²⁺) The capacity of (2) is domesticated and cultured for 12 days, and the replacement sequence is as follows: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Liquid medium consisting of 2mg/L mixed solution of pH 7.0, 1 volume of SJP medium, and 2 volumes of SJP mediumContaining Cd²⁺、Pb²⁺、Ni² ⁺Liquid culture medium consisting of 4mg/L mixed solution with pH of 6.5, 1 volume of SJP culture solution, and 3 volumes of mixed solution containing Cd²⁺、Pb²⁺、Ni²⁺Liquid culture medium comprising 6mg/L mixed solution of pH 4.5 and Cd²⁺、Pb²⁺、Ni²⁺The pH of the mixed solution was 5.0 at 10 mg/L. When the bottom of the reactor forms deep black bulk sludge and the nitrate removal rate is over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O 1.2g，NaHCO₃ 0.5g，NaNO₃ 0.3g，KH₂PO₄0.06g，MgCl₂ 0.04g，CaCl₂ 0.04g，FeCl₂·4H₂0.4g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

The microelement solution II comprises: measured by mass concentration, 0.5g/L MgSO₄·7H₂O、1.2g/L EDTA、0.1g/L ZnSO₄、0.05g/L MnCl₂·4H₂O、0.12g/L FeSO₄·7H₂O、0.4g/LCuSO₄·5H₂O、0.08g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 43% of iron powder, 20% of activated carbon, 20% of sludge, 5% of manganese powder, 3% of magnesium powder and 7% of sodium silicate according to weight percentage, stirring to prepare spherical particles with the particle size of 2cm, covering a thin layer on the outer surface of the spherical particles by using a mixture consisting of 30% of cement and 70% of clay according to weight percentage, drying at 120 ℃ for 35min, roasting at 600 ℃ in a roasting furnace filled with inert gases such as nitrogen and the like for 70min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

the microelement III is as follows: by mass concentration, 0.3g/L EDTA, 0.04) g/L ZnSO₂、0.03g/L MnCl₂·4H₂O、0.03g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

in this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 30mm, and the laying thickness is 0.3 m; the packing layer adopts iron-carbon particles with the particle size of 25mm and the laying thickness of 1.3 m.

The reactor was run as follows:

1) putting the double-layer iron-carbon filler subjected to film formation on a supporting layer of a reactor, starting a water inlet pump 13-1, opening a water inlet valve 13-1, enabling mine water to be treated to enter the device through the water inlet by the water inlet pump and flow through the double-layer iron-carbon filler 1, and under the action of microorganisms, Fe²⁺The electrons lost as electron donors are transferred to nitrate nitrogen to remove nitrate, and simultaneously the generated microorganism precipitates (FeOOH, Fe)₂O₃、Fe(OH)₃) Adsorption removal of heavy metal ions (Cd) in wastewater²⁺、Pb²⁺、Ni²⁺) The gas generated by the reaction is exhausted into the atmosphere through two exhaust holes (3);

4) the reactor is backwashed after running for 1-2 days, a backwash valve 12 is opened, and the quantity of the backwash water is adjusted to be 11L/s.m²The neutralization time is 5min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is backwashed after 7 days of operation, gas washing is realized through the gas washing plate 2, and the quantity of the backwashed water is controlled to be 11L/s.m.²And the time is 5min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

As can be seen from fig. 3(a), the nitrate removal rate gradually increases with the stable operation of the apparatus, and finally remains around 94.92% after 7 hours of operation;

as can be seen from FIGS. 3(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not less than 79.00%, 59.26% and 70.85%, and Cd is obtained after the equipment runs stably²⁺、Pb²⁺、Ni²⁺The removal rate is basically maintained at 89.54%, 68.62% and 80.12%, and the whole body shows better synchronous removal of heavy metal ions (Cd)²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

Example 6:

step 1, sludge enrichment and domestication:

mixing 10L of mine wastewater to be treated with FJY culture solution according to the volume ratio of 2:1, placing the mixture in a constant-temperature incubator (25-30 ℃) for enrichment culture, and carrying out enrichment culture every dayIntroducing 7L/min nitrogen into the reactor for 4 times, each time for 5 minutes, in the enrichment culture process, taking 7 days as a culture period, replacing half of the supernatant as FJY culture solution, adopting a shaking table with the rotating speed of 130r/min, and after enriching for 3 weeks, when the nitrate removal rate is more than 70%, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the enrichment culture is finished, and the precipitated sludge is collected.

The formula of the FJY culture solution is as follows: c₆H₅Na₃O₇·6H₂O1.2g，NaHCO₃ 0.8g，NaNO₃ 0.1g，KH₂PO₄ 0.12g，MgCl₂ 0.1g，CaCl₂ 0.04，FeCl₂·4H₂O0.4, 1mL of the trace element solution i, 1000mL of distilled water, and pH 7.0.

The trace element solution I comprises: measured by mass concentration, 0.4g/L MgSO₄·7H₂O、1.0g/L EDTA、0.2g/L ZnSO₄、0.1g/L MnCl₂·4H₂O、0.5g/L FeSO₄·7H₂O、0.5g/L CuSO₄·5H₂O、0.2g/L CoCl₂·6H₂O。

Step 2, preparing a biological agent:

adding mine wastewater to be treated and SJP culture solution into the precipitated sludge obtained in the step 1 according to the volume ratio of 3:1, culturing at 30 ℃ for 5 days, pouring out supernatant, and replacing the liquid culture solution every 3 days to remove heavy metal (Cd)²⁺、Pb² ⁺、Ni²⁺) The capacity of (2) is domesticated and cultured for 12 days, and the replacement sequence is as follows: 1 volume of SJP culture medium and 1 volume of Cd-containing medium²⁺、Pb²⁺、Ni²⁺Liquid culture medium consisting of 2mg/L mixed solution with pH 7.0, 1 volume of SJP culture solution, and 2 volumes of Cd-containing culture solution²⁺、Pb²⁺、Ni² ⁺Liquid culture medium consisting of 4mg/L mixed solution with pH of 6.5, 1 volume of SJP culture solution, and 3 volumes of mixed solution containing Cd²⁺、Pb²⁺、Ni²⁺Liquid culture medium comprising 6mg/L mixed solution of pH 4.5 and Cd²⁺、Pb²⁺、Ni²⁺The pH of the mixed solution was 5.0 at 10 mg/L. When the bottom of the reactor is formed deepBlack bulk sludge with nitrate removal rate of over 70 percent, Cd²⁺、Pb²⁺、Ni²⁺When the removal rate is over 60 percent, the biological agent is obtained.

The SJP culture solution comprises the following components: c₆H₅Na₃O₇·6H₂O 1.0g，NaHCO₃ 0.4g，NaNO₃ 0.2g，KH₂PO₄0.05g，MgCl₂ 0.05g，CaCl₂ 0.05g，FeCl₂·4H₂0.3g of O, 2mL of a trace element solution II, 1000mL of distilled water, and a pH value of 7.0.

The microelement solution II comprises: measured by mass concentration, 0.4g/L MgSO₄·7H₂O、1g/L EDTA、0.2g/L ZnSO₄、0.04g/L MnCl₂·4H₂O、0.1g/L FeSO₄·7H₂O、0.5g/LCuSO₄·5H₂O、0.1g/L CoCl₂·6H₂O。

Step 3, preparing a double-layer iron-carbon filler:

adding water into 50 wt% of iron powder, 12 wt% of activated carbon, 23 wt% of sludge, 5 wt% of manganese powder, 3 wt% of magnesium powder and 7 wt% of sodium silicate, stirring to prepare spherical particles with the particle size of 2cm, covering a thin layer on the outer surface of the spherical particles by using a mixture consisting of 60 wt% of cement and 40 wt% of clay, drying at 100 ℃ for 45min, roasting at 500 ℃ in a roasting furnace filled with inert gases such as nitrogen and the like for 80min, and naturally cooling to room temperature to obtain the double-layer iron-carbon filler.

the film forming filler is prepared by processing a double-layer iron-carbon filler according to a volume ratio of 1: 50 of GMT culture solution and biological agent, 2L of mixed solution is added into each kilogram of double-layer iron-carbon filler in a closed reactor, the membrane is formed for 4 days at 25 ℃, after a light yellow biological membrane is formed on the surface of the filler, the membrane is shown to be finished, and bacteria adsorbed on the surface of the double-layer iron-carbon filler are washed away by continuous tap water.

the microelement III is as follows: measured by mass concentration, 0.2g/LEDTA、0.06g/L ZnSO₂、0.02g/L MnCl₂·4H₂O、0.01g/L CuSO₄·5H₂An aqueous solution of O.

And 5, operating the reactor:

in this example, the reactor is cylindrical, made of concrete, with a diameter of 0.4m and a total reactor height of 2.5 m; the supporting layer adopts cobblestones with the grain diameter of 40mm, and the laying thickness is 0.4 m; the filler layer adopts iron-carbon particles with the particle size of 30mm and the laying thickness of 1.1 m.

The reactor was run as follows:

4) the reactor is backwashed after running for 1-2 days, a backwash valve 12 is opened, and the quantity of the backwash water is adjusted to be 14L/s.m²The neutralization time is 5min, the hydraulic retention time is 4h, the backwashing valve 12 is closed after the backwashing is finished, and the system is restarted. The reactor is back-flushed after 6 days, the gas-washing is realized by the gas-washing plate 2, and the back-flushing valve 12 is opened to control the back-flushing water quantity to be 14L/sm²And the time is 5min, the air-water backwashing is completed by matching with the air washing plate 2, the backwashing valve 12 is closed after the backwashing is completed, and the system is restarted.

As can be seen from fig. 3(a), the nitrate removal rate gradually increases with the stable operation of the apparatus, and finally remains around 94.79% after 7 hours of operation;

as can be seen from FIGS. 3(b), (c) and (d), the present invention is directed to Cd in mine wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 79.26%, 57.51% and 70.24%, and after the equipment runs stably, Cd²⁺、Pb²⁺、Ni²⁺The removal rate is basically kept at 89.97%, 67.80% and 79.85%, and the whole body shows better synchronous removal of heavy metal ions (Cd)²⁺、Pb²⁺、Ni²⁺) And the capacity of nitrate.

As can be seen from the above examples, the invention can treat Cd in wastewater²⁺、Pb²⁺、Ni²⁺The removal rate is not lower than 78.22%, 57.51% and 58.90%, and the synchronous removal capacity is high.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. a method for synchronously removing heavy metal and nitrate in mine waste water, is characterized in that, comprises the steps:

Step 1, sludge enrichment and domestication:

Under closed anaerobic conditions, the mine wastewater to be treated and the FJY culture solution were taken for enrichment culture, and the sedimented sludge was collected;

Step 2, preparation of biological inoculum:

To the obtained sedimented sludge, add the mine waste water to be treated and the SJP culture solution according to the volume ratio of 2 to 4:1 and mix well. After culturing at a constant temperature for 3-5 days, remove the supernatant, and then replace the SJP culture solution every certain period. , acclimatized and cultivated for 12-14 days to form dark black scattered sludge to obtain biological bacteria agent;

Step 3, preparation of double-layer iron-carbon filler:

By weight, 40-55% iron powder, 10-20% activated carbon, 20-25% sludge, 4-5% manganese powder, 3-4% magnesium powder, 5-8% sodium silicate and water are mixed uniformly, Stir to make spherical particles, then cover the outer surface of spherical particles with a mixture of 30-50% cement and 50-70% clay by weight, dry, roast, and naturally cool to room temperature to obtain double-layer iron-carbon fillers ;

Step 4, double-layer iron-carbon filler biological bacterial agent hanging film:

According to the volume ratio of 1: (40-60), the GMT culture solution and the biological agent are mixed to obtain a soaking solution, and the double-layer iron-carbon filler is soaked in the soaking solution, and the film is hung at room temperature for 2-4 days. After the yellow biofilm, the film hanging ends, and the bacteria adsorbed on the surface of the double-layer iron-carbon filler are washed away;

Step 5, the reactor runs:

The double-layer iron-carbon filler after film hanging is placed on the support layer of the reactor. After the double-layer iron-carbon filler is filmed, the mine wastewater to be treated is removed simultaneously with nitrate.

2 . The method according to claim 1 , wherein the FJY culture solution comprises raw materials in the following mass ratios: 0.8-1.2 parts of C ₆ H ₅ Na ₃ O ₇ ·6H ₂ O and 0.8-1.2 parts of NaHCO ₃ . , NaNO ₃ 0.1～0.3 part, KH ₂ PO ₄ 0.08～0.12 part, MgCl ₂ 0.08～0.12 part, CaCl ₂ 0.04～0.06 part, FeCl ₂ ·4H ₂ O 0.4～0.6 part, trace element solution I 1 part, distilled water 1000 share;

The trace element solution I includes: in terms of mass concentration, 0.4-0.6g/LMgSO ₄ ·7H ₂ O, 0.9-1.1g/LEDTA, 0.1-0.3g/L ZnSO ₄ , 0.09-0.11g/L MnCl ₂ · 4H ₂ O, 0.4-0.6 g/L FeSO ₄ ·7H ₂ O, 0.4-0.6 g/LCuSO ₄ ·5H ₂ O, 0.1-0.3 g/L CoCl ₂ ·6H ₂ O.

3 . The method according to claim 1 , wherein the SJP culture solution comprises raw materials in the following mass ratios: 0.8-1.2 parts of C ₆ H ₅ Na ₃ O ₇ ·6H ₂ O and 0.4-0.6 parts of NaHCO ₃ . , NaNO ₃ 0.1～0.3 part, KH ₂ PO ₄ 0.04～0.06 part, MgCl ₂ 0.04～0.06 part, CaCl ₂ 0.04～0.06 part, FeCl ₂ ·4H ₂ O 0.2～0.4 part, trace element solution II 2 part, distilled water 1000 share;

The trace element solution II includes: in terms of mass concentration, 0.4-0.6g/L MgSO ₄ ·7H ₂ O, 0.8-1.2g/LEDTA, 0.1-0.3g/L ZnSO ₄ , 0.04-0.06g/L MnCl ₂ · 4H ₂ O, 0.08 to 0.12 g/L FeSO ₄ · 7H ₂ O, 0.4 to 0.6 g/LCuSO ₄ · 5H ₂ O, 0.08 to 0.12 g/L CoCl ₂ ·6H ₂ O.

4 . The method according to claim 1 , wherein the GMT culture solution comprises raw materials in the following mass ratios: 1000 parts of sterilized mine wastewater to be treated and 2 parts of trace element III; 5 .

The trace element III is: in terms of mass concentration, 0.1-0.3g/L EDTA, 0.04-0.06g/L ZnSO ₂ , 0.01-0.03g/L MnCl ₂ ·4H ₂ O, 0.01-0.03g/L CuSO ₄ • Aqueous solution of _5H2O .

5 . The method according to claim 1 , wherein the anaerobic conditions in step 1 include: feeding nitrogen into the reactor 4 times a day, feeding 4-9 L/min nitrogen, 5 min each time. 6 .

6. method according to claim 1, is characterized in that, in described step 2, replaces SJP culture liquid every 3 days, and replacement order is:

Replace the SJP medium with liquid medium A consisting of 1 volume of SJP culture medium and 1 volume of mixed solution containing Cd ²⁺ , Pb ²⁺ , Ni ²⁺ 2 mg/L pH=7.0; then add 1 volume of SJP culture medium with 2 volumes of liquid medium B consisting of a mixed solution of pH=6.5 containing Cd ²⁺ , Pb ²⁺ , and Ni ²⁺ 4 mg/L were used to replace liquid medium A; then 1 volume of SJP medium and 3 volumes of Cd ²⁺ , Pb ²⁺ , ^Ni ²⁺ ^6mg /L pH=4.5 mixed solution composed of liquid medium C to replace liquid medium B ^; Replace liquid medium C with the mixed solution.

7. The method according to claim 1, wherein in the step 3, in the preparation of the double-layer iron-carbon filler, adding water and stirring to prepare spherical particles with a particle size of 1-3 cm, and then drying at 100-120 ° C 30-50min, then roasting at 500-600℃ for 60-80min in a roasting furnace, and naturally cooled to room temperature to obtain double-layer iron-carbon filler.

8. A reactor based on the method of any one of claims 1-7, characterized in that,

Including a reactor body, the reactor body is, from top to bottom, a double-layer iron-carbon packing (1), an air wash plate (2), a guide plate (4), a supporting layer (5), and an outlet aeration system (6) ) and the filter plate (7); the air wash plate (2) and the outlet aeration system (6) are connected with the aeration pipe (9) through the blower (8); A flushing pump (11-2) and a backwashing water tank (15), the top of the reactor is connected to a tap water pipe through an inlet water pump (11-1) to cooperate with an air washing plate (2) for backwashing; the top of the backwashing is provided with an exhaust hole (3) ); the bottom side wall communicates with the sedimentation tank (14).

9. The reactor according to claim 8, characterized in that, the supporting layer (5) adopts cobblestones with a particle size of 2.0-4.0cm, and the laying thickness is 0.25-0.40m; the double-layer iron-carbon filler is laid The thickness is 1.1-1.5m.

10. The reactor operating method according to claim 9, characterized in that, comprising:

1) Open the water inlet valve (13), the mine water to be treated enters the device through the inlet pump through the water inlet, and flows through the double-layer iron-carbon packing (1) to remove nitrate and organic matter in the water to be treated, and the generated gas passes through the exhaust hole (3) discharge into the atmosphere;

2) The water flow enters the supporting layer (5) through the deflector (4), and then is intermittently aerated in the outlet aeration system (6) to control the dissolved oxygen concentration in the aeration stage;

3) The treated effluent flows into the sedimentation tank (14) through the water outlet;

4) The reactor is backwashed every 3 to 10 days, and the air wash is realized by the air wash plate (2), and the backwash valve (12) is opened to realize the water wash. Flush valve (12) and restart the system.