CN111302561A

CN111302561A - Biological filtration system and PRB system for treating underground water polluted by iron and manganese

Info

Publication number: CN111302561A
Application number: CN201911142390.5A
Authority: CN
Inventors: 李静; 魏晓慧; 付乃鑫; 沈洋
Original assignee: Shandong Xianquan Environmental Protection Engineering Consulting Co ltd
Current assignee: Shandong Xianquan Environmental Protection Engineering Consulting Co ltd
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2020-06-19

Abstract

The invention discloses a biological filtration system and a PRB system for treating underground water polluted by iron and manganese, comprising: the device comprises a first buffer unit, an iron processing unit, a second buffer unit, a manganese processing unit and a third buffer unit; the iron treatment unit and the manganese treatment unit are sequentially filled with filling media made of different materials from top to bottom, and the materials of the filling media are different according to different pollutant types and concentrations. The system has the advantages of thorough treatment, no need of adding any nutrient substances and strains, wide temperature range of treatment and the like.

Description

Biological filtration system and PRB system for treating underground water polluted by iron and manganese

Technical Field

The invention relates to the technical field of polluted underground water remediation, in particular to a biological filtration system and a PRB system for treating iron and manganese-containing polluted underground water.

Background

Iron and manganese are representative metal elements, are widely distributed in the natural world and are main constituent elements of the earth crust, and underground water can have complex chemical reaction with the earth crust when flowing through the strata, so that the underground water contains iron and manganese, which are formed by the native geological environment, and therefore, iron and manganese pollution in the underground water is generally called as native pollution. Because the underground water contains organic matters and carbon dioxide gas, the degradation of the organic matters in the underground water consumes oxygen in the water or soil layer to reduce the oxidation-reduction potential of the medium, and the decomposition generates free carbon dioxide to enhance the humus of the water body. Meanwhile, the carbon dioxide is dissolved to enable the water body to be weakly acidic, so that the stability of substances such as iron, manganese and the like in the specific medium environment is weakened, the solubility is increased, the iron and the manganese are continuously migrated from the aquifer, and the content of the iron and the manganese in the underground water body is increased. Since groundwater is usually acidic and contains no or very low levels of dissolved oxygen, iron and manganese are present substantially in the form of dissolved iron (II) and manganese (II). A small amount of iron and manganese in water has no adverse effect on human health, but the excessive intake of the iron and the manganese can cause chronic toxicity to human bodies, and the iron and the manganese in the water can leave yellow spots on sanitary equipment and appliances after being oxidized, so that people can dislike the iron and the manganese. Excessive water containing iron and manganese can generate red water and black water, and the water passing section of the water conveying pipeline can be seriously reduced during large-scale deposition, so that the water conveying capacity is greatly reduced. The industrial production is very sensitive to iron and manganese, and the iron and manganese in the water can directly cause the reduction of the product quality. In industrial circulating water, iron and manganese deposits can adhere to the walls of heat exchangers and pipelines, affect heat transfer, sometimes cause iron bacteria to breed, accelerate metal corrosion, and cause pipeline blockage.

The research on the biological removal of the iron and manganese on the same layer shows that under the condition of medium and low concentration iron content, iron (II) and manganese (II) can be successfully removed at the same time, but when the iron concentration is too high, because iron (II) is easier to be oxidized compared with manganese (II), a large amount of iron mud is generated during treatment to block a filter tank, so that frequent back washing at the initial stage of biological filter layer culture is caused, and the maturation of the filter layer is greatly disturbed. In order to shorten the maturation period of the filter layer, it is generally necessary to remove iron (II) from the groundwater and then remove manganese (II). For manganese ion removal, biofiltration promotes microbial mediated manganese (II) oxidation, converting soluble manganese (II) to insoluble manganese (III/IV) oxide precipitates that are easily filtered by the filter media in a biofiltration system. However, the activity of the microorganisms is temperature dependent. Low temperatures severely impede the activity of neutrophilic manganese (II) oxidizing bacteria, resulting in long start-up times. For example, at 8 ℃, the oxidizing activity of neutrophilic manganese (II) oxidizing bacteria is inhibited to 50% -80% of its oxidizing activity at room temperature. However, neutrophilic manganese (II) oxidizing bacteria are ubiquitous in natural and engineered environments such as deep sea, rivers, lake sediments, fjords, and waterways. Improving the low temperature adaptability of neutrophilic manganese (II) oxidizing bacteria is critical for the occurrence of manganese (II) oxidation and the production of biological manganese oxides. However, a neutral manganese (II) oxidizing bacterium capable of rapidly producing a manganese oxide at a low temperature has not been widely reported in the field studies of the past. Furthermore, the initiation, adaptation and acceleration of mn (ii) removal under cryogenic conditions has not been extensively described in biofiltration studies conducted in the field.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a biofiltration system and a PRB system for treating underground water polluted by iron and manganese, which have the advantages of thorough treatment, no need of adding any nutrient substance and strain, wide temperature range of treatment and the like.

According to a first aspect of the present invention, there is provided a biofiltration system for treating groundwater contaminated with iron and manganese, comprising: the device comprises a first buffer unit, an iron processing unit, a second buffer unit, a manganese processing unit and a third buffer unit; the iron treatment unit and the manganese treatment unit are sequentially filled with filling media made of different materials from top to bottom, and the materials of the filling media are different according to different pollutant types and concentrations.

Optionally, the iron treatment unit includes: the system comprises an iron filter aeration drop facility, an iron filter overflow pipe, an iron filter effective area, an iron filter anthracite loading area, an iron filter fine sand loading area, an iron filter coarse sand loading area, an iron filter gravel loading area, an iron filter long-handle filter head, an iron filter water distribution area and an iron backwashing water tank;

the iron filter aeration drop facility is used for supplementing oxygen to underground water to be treated and ensuring that microorganisms in the water smoothly carry out aerobic digestion;

the iron filter overflow pipe is arranged above the effective area of the iron filter and is used for discharging excessive underground water in the system operation process;

the iron filter anthracite loading area, the iron filter fine sand loading area, the iron filter coarse sand loading area and the iron filter gravel loading area are sequentially filled into the iron filter from top to bottom to serve as main biological filtration places;

the long-handle filter head of the iron filter is arranged at the bottom of a gravel filling area of the iron filter, is connected with a water distribution area of the iron filter, and is used for filtering redundant impurities and simultaneously ensuring that treated underground water is uniformly distributed in the water distribution area of the iron filter;

the iron filter backflushing water tank is used for providing sludge and backflushing water required by reaction.

Optionally, the manganese treatment unit includes: the device comprises a manganese filter aeration drop facility, a manganese filter overflow pipe, a manganese filter effective area, a manganese filter anthracite loading area, a manganese filter fine sand loading area, a manganese filter coarse sand loading area, a manganese filter gravel loading area, a manganese filter long-handle filter head, a manganese filter water distribution area and a manganese backwashing water tank;

the manganese filter aeration drop facility is used for supplementing oxygen to underground water to be treated and ensuring that microorganisms in the water smoothly carry out aerobic digestion;

the overflow pipe of the manganese filter is arranged above the effective area of the manganese filter and is used for discharging excessive underground water in the system operation process;

the manganese filter anthracite loading area, the manganese filter fine sand loading area, the manganese filter coarse sand loading area and the manganese filter gravel loading area are sequentially filled into the manganese filter from top to bottom to serve as main biological filtration places;

the manganese filter long-handle filter head is arranged at the bottom of a gravel filling area of the manganese filter, is connected with a water distribution area of the manganese filter, and is used for filtering redundant impurities and ensuring that treated underground water is uniformly distributed in the water distribution area of the manganese filter;

the manganese filter backflushing water tank is used for providing sludge and backflushing water required by reaction.

Optionally, the height of the iron/manganese filter aeration drop facility can be adjusted appropriately according to the requirements of microbial reaction.

Optionally, sludge ports in the iron/manganese treatment unit are uniformly distributed on the filter and used for adjusting the sludge amount used for biological filtration.

Optionally, the system further comprises an auxiliary system, wherein the auxiliary system comprises: the system comprises an underground water buffer pool, an underground water online monitoring system, an iron filter online monitoring system and a manganese filter online monitoring system;

the underground water buffer tank is positioned at the foremost end of the biological filtering system and is used for providing underground water serving as a raw material required by reaction;

the underground water online monitoring system is used for online monitoring physical parameters, iron (II) content and manganese (II) content of the raw material underground water;

the iron filter online monitoring system is used for online monitoring the physical property parameters, the iron (II) content and the manganese (II) content of the underground water treated by the iron filter;

the manganese filter online monitoring system is used for online monitoring physical parameters, iron (II) content and manganese (II) content of underground water after treatment is completed.

Optionally, the iron treatment unit and/or the manganese treatment unit are/is inoculated by selectively using sludge in the buffer unit 2 and/or the buffer unit 3.

Based on the specific implementation mode, the invention provides a permeable reactive wall PRB system for in-situ biological treatment of iron and manganese-containing polluted underground water, which is characterized in that: the system comprises an auxiliary system, a reaction system and a monitoring system; the auxiliary system is connected with the reaction system and is used for guaranteeing the smooth flow of underground water; the reaction system comprises an iron treatment unit and a manganese treatment unit, and is used for sequentially treating iron (II) and manganese (II) in the underground water; and the monitoring system penetrates through the auxiliary system and the reaction system to monitor the process of the PRB system in real time.

Optionally, the reaction system comprises an air injection pipe, a back-flushing injection pipe, a gas-liquid mixing zone after iron reaction, an iron-permeable reaction wall and a manganese-permeable reaction wall;

the air injection pipe is connected with the gas-liquid mixing area/the gas-liquid mixing area after the iron reaction, so that oxygen is supplemented to the polluted underground water to be treated, and the aerobic digestion of microorganisms in the water is ensured to be smoothly carried out;

the iron-permeable reactive barrier/manganese-permeable reactive barrier is filled with medium types, and the number of layers is determined according to the type and concentration adjustment of pollutants;

the orifice of the back flushing injection pipe is arranged at the bottom of the iron-permeable reactive barrier/manganese-permeable reactive barrier to prevent scaling in the operation of the system.

Optionally, the auxiliary system comprises an underground water distribution area, an underground water buffer area, an underground water distribution area after iron reaction, an underground water distribution area after manganese reaction and an underground water redistribution area;

the underground water buffer area is arranged at the foremost end of the PRB system and is used for buffering polluted underground water which is pre-entered into the system;

the underground water distribution area after the underground water distribution area/iron reaction uniformly distributes polluted underground water to the gas-liquid mixing area/the gas-liquid mixing area after the iron reaction, so that the air injection amount is effectively controlled;

after the underground water distribution area after the iron reaction is arranged in the gas-liquid mixing area after the iron reaction, ensuring that the underground water after the iron reaction is uniformly distributed to the manganese-permeable reactive barrier;

and the underground water distribution area after the manganese reaction is connected with the underground water redistribution area, is arranged at the tail end of the PRB system, receives and distributes clean underground water in the manganese-permeable reaction wall, and simultaneously ensures the safe and effective operation of the whole system.

The invention has the following technical effects: the invention discloses a biological filtration technology for treating underground water polluted by iron and manganese, which removes iron (II) and manganese (II) in the polluted underground water by means of indigenous microorganism action, selectively uses backwashing and backwashing sludge inoculation means to oxidize the iron (II) and the manganese (II) in the polluted underground water Into Insoluble Iron (III) and manganese (III/IV) to form precipitate and discharge.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 is a process flow diagram of a biofiltration system for treating iron and manganese containing contaminated groundwater according to the present invention.

FIG. 2 is a filtration system for ectopic biological treatment of groundwater polluted by iron and manganese.

FIG. 3 is a permeable reactive barrier PRB system for in situ biological treatment of iron and manganese containing contaminated groundwater according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that although the terms first, second, third, etc. may be used to describe … … in embodiments of the present invention, these … … should not be limited to these terms. These terms are used only to distinguish … …. For example, the first … … can also be referred to as the second … … and similarly the second … … can also be referred to as the first … … without departing from the scope of embodiments of the present invention.

The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.

According to a first aspect of the present invention, as shown in fig. 1, according to an embodiment of the present invention, there is provided a biofiltration system for treating groundwater contaminated with iron and manganese, as shown in fig. 1, the biofiltration system comprising: the device comprises a first buffer unit 1, an iron filtering system, a second buffer unit 2, a manganese filtering system and a third buffer unit 3; the iron treatment unit and the manganese treatment unit are sequentially filled with filling media made of different materials from top to bottom, and the materials of the filling media are different according to different pollutant types and concentrations.

As shown in fig. 2, the iron filtering system may include: an iron filter extraction pump 1.2, an iron filter water inlet valve 1.3, an iron filter water inlet check valve 1.4, an iron filter aeration water drop facility 1.6, an iron filter overflow pipe 1.7, an iron filter effective area 1.8, an iron filter detection point 1.9, an iron filter sludge port 1.10, an iron filter anthracite loading area 1.11, an iron filter fine sand loading area 1.12, an iron filter coarse sand loading area 1.13, an iron filter gravel loading area 1.14, an iron filter long handle filter head 1.15, an iron filter water distribution area 1.16, an iron filter water outlet valve 1.17, an iron filter backwashing water outlet valve 1.19, an iron filter backwashing water tank 1.20, an iron filter extraction pump 1.21, an iron filter backwashing water inlet valve 1.22 and an iron filter backwashing check valve 1.23.

As shown in fig. 2, the manganese filtration system may include: a manganese filter water inlet valve 1.18, a manganese filter water inlet check valve 1.24, a manganese filter aeration water drop facility 1.26, a manganese filter overflow pipe 1.27, a manganese filter effective area 1.28, a manganese filter detection point 1.29, a manganese filter sludge port 1.30, a manganese filter anthracite filling area 1.31, a manganese filter fine sand filling area 1.32, a manganese filter coarse sand filling area 1.33, a manganese filter gravel filling area 1.34, a manganese filter long handle filter head 1.35, a manganese filter water distribution area 1.36, a manganese filter water outlet valve 1.37, a manganese filter backwashing water outlet valve 1.39, a manganese filter backwashing water tank 1.40, a manganese filter backwashing extraction pump 1.41, a manganese filter water inlet valve 1.42, a manganese filter backwashing check valve 1.43 and a water outlet valve 1.44.

Optionally, the system further comprises an auxiliary system, wherein the auxiliary system comprises: 1.1 parts of a groundwater buffer pool, 1.5 parts of a groundwater on-line monitoring system, 1.25 parts of an iron filter on-line monitoring system and 1.38 parts of a manganese filter on-line monitoring system.

The biological filtration system for treating the groundwater polluted by iron and manganese shown in figure 1 mainly comprises the following processes:

after the polluted underground water is buffered by the buffer unit 1, the air quantity determined according to the flow rate of the underground water, the concentration of pollutants in the water and the like is injected, the oxygen content in the water is adjusted, the air enters the iron treatment unit to remove iron (II) in the polluted underground water, then the air enters the buffer unit 2, the air enters the manganese treatment unit to remove manganese (II) in the underground water after the oxygen content is adjusted again, and the air is discharged through the buffer unit 3 after the underground water is treated.

The biological filtration system for treating the underground water polluted by iron and manganese is used for removing iron (II) and manganese (II) in the water by means of the action of indigenous microorganisms in the polluted underground water;

according to different types and concentrations of pollutants, filling media made of different materials are sequentially filled in the iron treatment unit and the manganese treatment unit from top to bottom, so that the complete effect of indigenous microorganisms on the pollutants is ensured; in one embodiment, the iron pollution filling material is anthracite, fine sand and coarse sand, the high filling material is mainly anthracite, fine sand and coarse sand, and mainly comprises a anthracite layer, a fine sand layer and a coarse sand layer from top to bottom, the thicknesses of the layers are different under different concentrations, the higher the concentration is, the thicker the layers are, for example, when the pollutant concentration ranges from 0.5 to 500mg/L, the anthracite thickness is generally 20 to 30cm, the fine sand thickness is generally 30 to 40cm, and the coarse sand thickness is generally 10 to 20 cm; for example, when the concentration of the pollutants is 500-1000mg/L, the thickness of the anthracite is generally 30-40cm, the thickness of the fine sand is generally 40-60cm, and the thickness of the coarse sand is generally 20-30 cm.

Selectively back washing the iron treatment unit and the manganese treatment unit in order to prevent the hardening of the interiors of the iron treatment unit and the manganese treatment unit, wherein the back washing times and the flow rate are determined according to the actual conditions; for example, 3-5 backflushing times.

In order to ensure the treatment effect of the whole technology, the sludge in the buffer unit 2/the buffer unit 3 is selectively used for inoculating the iron treatment unit/the manganese treatment unit.

The embodiments of the biofiltration technology for treating iron-manganese contaminated groundwater provided by the present invention will be described in further detail with reference to the following specific embodiments and the accompanying drawings, but the following description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent modification, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

A filtration system for ex situ biological treatment of iron and manganese containing contaminated groundwater as described in figure 2 comprising: auxiliary system, iron filtration system, manganese filtration system, automatic control system.

The auxiliary system, the iron filtering system and the manganese filtering system are all connected with the automatic control system, and the automatic control system is used for controlling the operation of the auxiliary system, the iron filtering system and the manganese filtering system;

the iron filtering system is connected with the manganese filtering system and is used for sequentially treating iron (II) and manganese (II) in the underground water;

the auxiliary system penetrates through the iron filtering system and the manganese filtering system and is used for providing needed iron and manganese containing polluted underground water and carrying out process monitoring on the whole system.

Optionally, the iron/manganese filtration system comprises: the iron/manganese filter aeration water drop facility is 1.6/1.26 and is used for supplementing oxygen to underground water to be treated and ensuring that microorganisms in the water smoothly carry out aerobic digestion; an overflow pipe 1.7/1.27 of the iron/manganese filter is arranged above an effective area 1.8/1.28 of the iron/manganese filter and is used for discharging excessive underground water in the system operation process; 1.11/1.31 of an iron/manganese filter anthracite filling area, 1.12/1.32 of an iron/manganese filter fine sand filling area, 1.13/1.33 of an iron/manganese filter coarse sand filling area and 1.14/1.34 of an iron/manganese filter gravel filling area are sequentially filled into the iron/manganese filter from top to bottom to serve as a main biological filtration place; the long-handle filter head 1.15/1.35 of the iron/manganese filter is arranged at the bottom of a gravel filling area 1.14/1.34 of the iron/manganese filter and is connected with a water distribution area 1.16/1.36 of the iron/manganese filter, and is used for filtering redundant impurities and ensuring that treated underground water is uniformly distributed in the water distribution area 1.16/1.36 of the iron/manganese filter.

Optionally, the sludge port of the iron/manganese filter is 1.10/1.30, and is uniformly distributed on the filter for regulating the sludge amount used for biological filtration.

The underground water buffer tank 1.1 is positioned at the foremost end of the whole system and provides the underground water which is the raw material required by the reaction.

The iron/manganese filter backwashing water tank is 1.20/1.40, and sludge and backwashing water required by reaction are provided.

Optionally, the automatic control system includes an operation control system and a display control system. The automatic control system unifies the switch, the valve and the extraction pump in the whole system, and all operations except the assembly, disassembly and moving of the system are carried out on a control panel; the parameters of each machine and instrument and the monitoring point data are displayed by a control panel of the automatic control system.

The invention utilizes the backwashing sludge to respectively carry out inoculation and domestication on the iron and manganese filters, and utilizes the microbial action of the filter layer which is completed by the inoculation and domestication in the filter to effectively treat iron (II) and manganese (II) in the underground water.

The specific implementation mode of the filtering system suitable for ectopic biological treatment of underground water polluted by iron and manganese is as follows:

and (3) completing the assembly and debugging of the whole system, and when enough water exists in the underground water buffer tank 1.1, utilizing an automatic control system to sequentially open an iron filter extraction pump 1.2, an iron filter water inlet valve 1.3, an iron filter water inlet check valve and an underground water online monitoring system 1.5, and adjusting the flow rate of the underground water to the required requirement. When the groundwater level reaches the top of the effective area of the iron filter, opening an outlet valve 1.17 of the iron filter, an inlet valve 1.18 of the manganese filter, a water inlet check valve 1.24 of the manganese filter and an online monitoring system 1.25 of the iron filter in sequence, adjusting the flow rate of inlet water, when the water levels of the iron and manganese reactors reach the top of the effective area, opening an outlet valve 1.37 of the manganese filter, an online monitoring system 1.38 of the manganese filter and a reverse flushing outlet valve 1.39 of the manganese filter, and then adjusting the flow rate of inlet water and outlet water, so that the water levels of the iron and manganese filters reach the tops of the effective areas 1.8 and 1.28.

And (3) fixing the flow rate of inlet and outlet water, opening a backwash water outlet valve 1.19 of the iron filter when the water level of the iron filter is close to the height of an overflow pipe 7 of the iron filter, lowering the water level in the iron filter to the top of an effective area 1.7 of the iron filter, and then fixing the flow rate of outlet water of the iron filter. Observing the water levels in the iron filter and the manganese filter, when the water level of one of the iron filter and the manganese filter is overhigh, closing an iron filter extraction pump 1.2, an iron filter water inlet valve 1.3, an iron filter water inlet check valve 1.4, a manganese filter water inlet valve 1.18, an iron filter backwashing water outlet valve 1.19, a manganese filter water inlet check valve 1.24 and a manganese filter backwashing water outlet valve 1.39 in sequence, opening an iron filter backwashing extraction pump 1.21, an iron filter backwashing water inlet valve 1.22, an iron filter backwashing check valve 1.23, a manganese filter backwashing extraction pump 1.41, a manganese filter backwashing water inlet valve 1.42 and a manganese filter backwashing check valve 1.43 in sequence, washing the iron filter with the water of an iron filter water tank 1.20 according to the required flow rate, and backwashing the manganese filter with the manganese filter backwashing water of a manganese filter water tank 1.40. After the agglomerated sludge in the filter is redistributed uniformly, the manganese filter backwashing check valve 1.43, the manganese filter backwashing water inlet valve 1.42, the manganese filter backwashing extraction pump 1.41, the iron filter backwashing check valve 1.23, the iron filter backwashing water inlet valve 1.22 and the iron filter backwashing extraction pump 1.21 are closed. And opening an iron filter extraction pump 1.2, an iron filter water inlet valve 1.3, an iron filter water inlet check valve 1.4, a manganese filter water inlet valve 1.18 and an iron filter back flushing check valve 1.23 in sequence, fixing the water inlet flow rate, adjusting the water outlet flow rate, controlling the water level to an effective area, repeating the previous process when the water level rises to the height of 1.7/1.27 of the overflow pipe, and carrying out back flushing on the filter again.

And observing and analyzing data of the underground water online monitoring system 1.5, the iron filter online monitoring system 1.25 and the manganese filter online monitoring system 1.38, when the data of the iron filter online monitoring system 1.25 and the manganese filter online monitoring system 1.38 are continuously stable and do not reach the required concentration, evenly distributing sludge at the bottoms of the iron filter backwashing water tank 1.20 and the manganese filter backwashing water tank 1.40 to the filters through a sludge port 1.10 of the iron filter and a sludge port 1.30 of the manganese filter for inoculation, repeating the backwashing process, and then adjusting the flow rate of an outlet to finish the acclimatization process. And the concentration of iron (II) and manganese (II) is monitored by an underground water online monitoring system 1.5, an iron filter online monitoring system 1.25 and a manganese filter online monitoring system 1.38 at any time, after the data are stabilized again, if the concentration of iron (II) is up to the standard as shown by 1.25 data and the concentration of iron (II) and manganese (II) are up to the standard as shown by 1.38 data, the backwashing sludge inoculation is stopped, otherwise, the inoculation acclimatization process is carried out on a specific filter according to the concentration index until the monitoring data are up to the standard, the inoculation is stopped, and the whole filtering system enters a stabilization treatment stage.

And monitoring data of an underground water online monitoring system 1.5, an iron filter online monitoring system 1.25 and a manganese filter online monitoring system 1.38 at any time, and performing a secondary inoculation-backwashing-domestication process when the data do not meet the standard requirements so as to achieve a secondary stabilization treatment stage.

According to a second aspect of the present invention, as shown in fig. 3, the present invention provides a permeable reactive wall PRB system for in situ biological treatment of iron and manganese-containing polluted groundwater, which is characterized in that: the system comprises an auxiliary system, a reaction system and a monitoring system; the auxiliary system is connected with the reaction system and is used for guaranteeing the smooth flow of underground water; the reaction system comprises an iron treatment unit and a manganese treatment unit, and is used for sequentially treating iron (II) and manganese (II) in the underground water; and the monitoring system penetrates through the auxiliary system and the reaction system to monitor the process of the PRB system in real time.

Permeable Reactive Barrier (PRB) technology is a pollution treatment technology for intercepting, blocking and remedying pollution plumes in situ. Consisting essentially of a water-permeable reactive media, typically placed downstream of the contaminant plume. When the pollutant plume passes through the reaction wall under the action of hydraulic gradient, the pollutants in water and the active reaction medium generate precipitation, adsorption, oxidation-reduction, biodegradation reactions and the like, so that the pollutants in water are converted into an environmentally acceptable form. The repair mechanism of PRB is divided into biological and non-biological, which mainly includes adsorption, precipitation, oxidation reduction and biodegradation, so PRB can be divided into adsorption reaction wall, precipitation reaction wall, oxidation reduction reaction wall and biodegradation reaction wall according to the reaction property. The biodegradation reaction wall is widely applied to the aspect of in-situ groundwater treatment due to the advantages of no need of external power, no floor space, no need of storage, transportation, cleaning, low operation and maintenance cost and the like.

The assistance system may include: 2.2 parts of an underground water distribution area, 2.4 parts of an underground water buffer area, 2.5 parts of an underground water distribution area after iron reaction, 2.10 parts of an underground water distribution area after iron reaction, 2.6 parts of an underground water distribution area after manganese reaction and 2.9 parts of an underground water redistribution area.

The reaction system may include: an air injection pipe 2.12, a gas-liquid mixing area 2.13, an iron-permeable reactive barrier 2.14, a gas-liquid mixing area after iron reaction 2.11, a manganese-permeable reactive barrier 2.7 and a back flushing injection pipe 2.15.

The monitoring system may include: 2.1 of an underground water monitoring well and 2.8 of an underground water monitoring point; the groundwater flow direction is 2.3.

A permeable reactive wall PRB system for in situ biological treatment of iron and manganese containing contaminated groundwater as illustrated in fig. 3, comprising: auxiliary system, reaction system, monitoring system.

The auxiliary system is connected with the reaction system and is used for sequentially treating iron (II) and manganese (II) in the polluted underground water and ensuring the smooth flow of the underground water;

the monitoring system runs through the auxiliary system and the reaction system and monitors the whole system in real time.

Optionally, the reaction system comprises: the air injection pipe 2.12 is connected with the gas-liquid mixing area 2.11 after the gas-liquid mixing area 2.13/iron reacts, so as to supplement oxygen to the polluted underground water to be treated and ensure that microorganisms in the water smoothly carry out aerobic digestion; the iron-permeable reactive barrier 2.14/manganese-permeable reactive barrier 2.7 are different in filling medium, the types and the layers of the filling medium in the permeable reactive barrier are adjusted and designed according to the types and the concentrations of pollutants, the growth of microorganisms in a water body is promoted, and a main place is provided for microbial reaction; the orifice of the back flushing injection pipe 2.15 is arranged at the bottom of the iron-permeable reactive barrier 2.14/manganese-permeable reactive barrier 2.7 to prevent the scaling in the system operation.

The assistance system includes: the underground water buffer zone 2.4 is arranged at the foremost end of the whole system and is used for buffering the polluted underground water which is pre-entered into the system; the underground water distribution area 2.5 uniformly distributes the polluted underground water into the gas-liquid mixing area 2.13 after the iron reaction in the underground water distribution area 2.2, so that the control of air injection amount is facilitated; after the underground water distribution area 2.10 after the iron reaction is arranged in the gas-liquid mixing area 2.11 after the iron reaction, the underground water is ensured to be uniformly distributed to the manganese-permeable reactive barrier 2.7 after the iron reaction; the underground water distribution area 2.6 after the manganese reaction is connected with the underground water redistribution area 2.9 and is arranged at the tail end of the whole system, so that the clean underground water in the demanganization-permeable reactive barrier 2.7 is received and distributed, and the safe and effective operation of the whole system is ensured.

The permeable reactive barrier PRB system for in-situ biological treatment of underground water polluted by iron and manganese comprises the following specific implementation modes:

the method comprises the steps that the polluted underground water containing iron and manganese enters an underground water buffer zone 2.4 along an underground water flow direction 2.3 to be buffered, then enters a gas-liquid mixing zone 2.13 through an underground water distribution zone 2.2, the amount of air entering the gas-liquid mixing zone 2.13 from an air injection pipe 2.12 is controlled, the oxygen content in the gas-liquid mixing zone 2.13 is enhanced and maintained, then the polluted underground water enters an iron-permeable reaction wall 2.14, iron (II) is removed in combination with the action of indigenous microorganisms, the treated polluted underground water enters a gas-liquid mixing zone 2.11 after iron reaction from an underground water distribution zone 2.5 after iron reaction, the air injection pipe 2.12 further adjusts and stabilizes the oxygen content, then enters an underground water redistribution zone 2.9 after iron reaction from the gas-liquid mixing zone 2.11 to be distributed to a manganese-permeable reaction wall 2.7, manganese (II) in the polluted underground water is removed in combination with the action of different kinds of indigenous microorganisms, the treated underground water enters an underground water distribution zone 2.6 after manganese reaction to be redistributed to be distributed to the underground water zone 2.9 And (4) dispensing.

The whole reaction process is monitored in real time through a groundwater monitoring point 2.8 of a groundwater monitoring well 2.1, and the necessity of utilizing local sludge inoculation and air purging means is evaluated according to a monitoring result. If the monitoring value of the contents of iron (II) and manganese (II) after the sludge in the polluted underground water is too small and treated by the iron-permeable reactive barrier 2.14/manganese-permeable reactive barrier 2.7 is far larger than the required standard value, selecting sludge at the bottom of the gas-liquid mixing area 2.11/underground water redistribution area 2.9 and placing the sludge in the iron-permeable reactive barrier 2.14/manganese-permeable reactive barrier 2.7 for inoculation and domestication, and ensuring the effective use of the whole system; if the water level at the top of the iron-permeable reactive barrier 2.14/manganese-permeable reactive barrier 2.7 is changed significantly due to scaling during the operation of the system, the air of the required flow rate is injected by the back-flushing injection pipe 2.15 until the water level is restored, and the part of the air used is counted in the total amount of the air injected by the air injection pipe.

The invention discloses a biological filtration technology for treating underground water polluted by iron and manganese, which removes iron (II) and manganese (II) in the polluted underground water by means of indigenous microorganism action, selectively uses backwashing and backwashing sludge inoculation means to oxidize the iron (II) and the manganese (II) in the polluted underground water Into Insoluble Iron (III) and manganese (III/IV) to form precipitate and discharge.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A biofiltration system for treating groundwater contaminated with iron and manganese, comprising: the device comprises a first buffer unit, an iron processing unit, a second buffer unit, a manganese processing unit and a third buffer unit; the iron treatment unit and the manganese treatment unit are sequentially filled with filling media made of different materials from top to bottom, and the materials of the filling media are different according to different pollutant types and concentrations.

2. The biofiltration system as claimed in claim 1, wherein: the iron treatment unit includes: the system comprises an iron filter aeration drop facility, an iron filter overflow pipe, an iron filter effective area, an iron filter anthracite loading area, an iron filter fine sand loading area, an iron filter coarse sand loading area, an iron filter gravel loading area, an iron filter long-handle filter head, an iron filter water distribution area and an iron backwashing water tank;

3. The biofiltration system as claimed in claim 2, wherein: the manganese treatment unit includes: the device comprises a manganese filter aeration drop facility, a manganese filter overflow pipe, a manganese filter effective area, a manganese filter anthracite loading area, a manganese filter fine sand loading area, a manganese filter coarse sand loading area, a manganese filter gravel loading area, a manganese filter long-handle filter head, a manganese filter water distribution area and a manganese backwashing water tank;

4. A biofiltration system according to claim 2 or 3, characterized in that: the height of the iron/manganese filter aeration drop facility can be properly adjusted according to the requirements of microbial reaction.

5. The biofiltration system according to claim 4, wherein: sludge ports in the iron/manganese treatment unit are uniformly distributed on the filter and used for adjusting the sludge amount used for biological filtration.

6. The biofiltration system as claimed in claim 1, wherein: further comprising an assistance system, the assistance system comprising: the system comprises an underground water buffer pool, an underground water online monitoring system, an iron filter online monitoring system and a manganese filter online monitoring system;

7. The biofiltration system as claimed in claim 1, wherein: optionally using sludge in the buffer unit 2 and/or the buffer unit 3 to inoculate the iron treatment unit and/or the manganese treatment unit.

8. A permeable reactive barrier system for in-situ biological treatment of underground water polluted by iron and manganese is characterized in that: the system comprises an auxiliary system, a reaction system and a monitoring system; the auxiliary system is connected with the reaction system and is used for guaranteeing the smooth flow of underground water; the reaction system comprises an iron treatment unit and a manganese treatment unit, and is used for sequentially treating iron (II) and manganese (II) in the underground water; the monitoring system penetrates through the auxiliary system and the reaction system and monitors the process of the permeable reactive barrier system in real time.

9. The permeable reactive wall system of claim 8, wherein: the reaction system comprises an air injection pipe, a back flushing injection pipe, a gas-liquid mixing area, an iron-reacted gas-liquid mixing area, an iron-permeable reaction wall and a manganese-permeable reaction wall;

10. The permeable reactive wall system of claim 8, wherein: the auxiliary system comprises an underground water distribution area, an underground water buffer area, an underground water distribution area after iron reaction, an underground water distribution area after manganese reaction and an underground water redistribution area;

the underground water buffer area is arranged at the foremost end of the permeable reactive wall system and is used for buffering the polluted underground water which enters the system in advance;

and the underground water distributing area after the manganese reaction is connected with the underground water redistributing area, is arranged at the tail end of the permeable reactive wall system, receives and distributes clean underground water in the manganese-permeable reactive wall, and simultaneously ensures the safe and effective operation of the whole system.