CN113522963B

CN113522963B - Device for treating polluted soil in coking field by biological composting and composting method

Info

Publication number: CN113522963B
Application number: CN202110823424.8A
Authority: CN
Inventors: 李伟; 王华伟; 孙英杰; 王亚楠; 王坤; 卞荣星; 李卫华
Original assignee: Qingdao University of Technology
Current assignee: Qingdao University of Technology
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2022-06-28
Anticipated expiration: 2041-07-21
Also published as: CN113522963A

Abstract

The application discloses a device for treating polluted soil in a coking field by biological composting and a composting method. The device comprises a tank body, a tank cover, an aeration device, a percolate collecting pipe, a percolate collecting tank, a waste gas absorbing head, a waste gas absorbing pump and a waste gas discharging port. The composting method comprises the following steps: setting a composting device, containing composting materials and continuously composting. The device and the composting method for treating the polluted soil in the coking field by using the biological compost are easy to operate, simple to operate and low in cost, and can effectively treat the soil pollution caused by the coking field.

Description

Device for treating polluted soil in coking field by biological composting and composting method

Technical Field

The invention belongs to a technical device for soil remediation treatment, and particularly relates to a device for treating contaminated soil in a coking field by biological composting and a composting method.

Technical Field

China is a large coke producing country, and the coke production capacity is in the forefront of the world for a long time. In 2018, the coke yield in China is 4.38 million tons, the ratio is increased by 0.8% compared with the last year, and the coking capacity is also increased from 6.5 million tons in 2017 to 6.9 million tons in 2018. The coke is an important solid fuel, the calorific value of the coke is 26380-31400 kJ/kg, and the coke is mainly used for smelting steel. During the coke production process, a large amount of toxic and harmful waste water, waste gas and waste residue containing polycyclic aromatic hydrocarbon, cyanide, fluoride, petroleum hydrocarbon, heavy metal and the like can be generated, and the illegal disposal of the three wastes can cause the pollution of a coking site.

In most coke plants, the pollution is mainly divided into two main categories: one is the coal dust, smoke, produced during transportation of coal and coke to the coke plant and during preparation before coking, such as loading, unloading, crushing and sieving, which floats in the atmosphere, and the larger particles settle to the nearby soil or water. The other is harmful substances to the environment generated in chemical processes such as coking process, product recovery, waste residue treatment and the like, and mainly comprises polyaromatic hydrocarbons (PAHs) such as benzo [ alpha ] pyrene, phenanthrene, naphthalene, anthracene and the like, benzene series such as benzene, toluene, ethylbenzene, xylene and the like, phenol, cyanogen, hydrosulfide and the like.

Because the coking industry has complexity, a large number of polluted sites are left, most of the sites have complex pollution conditions and multiple pollutant types, and soil and underground water are polluted to different degrees, which seriously threatens the human health of surrounding residents. In addition, in the re-development process of the polluted sites, when the protection measures are not sufficiently prepared and the safety protection is not in place, toxic and harmful chemical substances in the sites can be released again, so that construction personnel are exposed to harmful gas and toxic chemical substances, and the health of the construction personnel is threatened. Therefore, the method has important scientific significance for discussing the pollution characteristics of the soil, the underground water and the atmosphere of the coking field.

At present, the treatment mode of the polluted soil of the coking field mainly comprises three methods, namely a physical method, a chemical method and a biological method. Physical methods include steam extraction techniques, thermal desorption, supercritical extraction techniques, etc., but physical remediation techniques merely transfer or separate organic contaminants from a contaminated environment and do not remove them in a true sense. But also other areas can be contaminated if the operation is not proper. The chemical and biological methods are more in variety, and the treatment effect is much higher than that of the physical method. However, in the long term, a single chemical or biological method still suffers from problems such as high cost, large amount of chemical reagents, secondary pollution of soil caused by byproducts, change of soil physicochemical properties, and long treatment time.

Disclosure of Invention

The invention aims to provide a device and a composting method for treating coking field polluted soil by biological composting, which can solve the problem of treating the coking field polluted soil to a certain extent, effectively remove pollutants in the soil and find a way for treating other organic pollutants in the soil.

In order to achieve the aim, the invention provides a device for treating the polluted soil of a coking field by biological composting, which comprises a tank body, a tank cover, an aeration device, a percolate collecting pipe, a percolate collecting tank, a waste gas absorbing head, a waste gas absorbing pump and a waste gas discharging port, wherein the tank cover is arranged on the tank body; the tank body is of a cylindrical tank structure, and a material storage area for containing compost materials is formed in the tank body; the tank cover is detachably and hermetically arranged on the tank body; the top of the tank cover is provided with a medicine feeding port; the aeration device is arranged in the tank body and positioned at the bottom of the material storage area of the tank body, and the aeration device is used for introducing air and uniformly distributing the air into the compost materials; the input port of the percolate collecting pipe is arranged at the bottom of the tank body and is communicated with the material storage area; the percolate collecting pool is arranged opposite to the output port of the percolate collecting pipe and is used for collecting percolate guided by the percolate collecting pipe; the waste gas absorption head is arranged on the tank cover and corresponds to the material storage area; the waste gas absorption pump is arranged on the tank cover, and the air suction end of the waste gas absorption pump is communicated with the waste gas absorption head; the exhaust gas discharge port is communicated with the exhaust end of the exhaust gas absorption pump.

Further, the device for biologically composting the polluted soil in the coking field further comprises a temperature and humidity detector which is arranged on one side of the tank cover facing the material storage area.

Further, the device for treating the polluted soil of the coking field by the biological compost also comprises a waste gas purifier which is arranged between the waste gas absorption pump and the waste gas discharge port.

Further, the exhaust gas purifier and the percolate collecting tank are both positioned at the bottom of the tank body.

Furthermore, the device for treating the polluted soil of the coking field by using the biological compost also comprises a percolate suction port, a percolate recirculation pump, a percolate recirculation pipe and a percolate spraying head; the percolate suction port is arranged in the percolate collecting pool; the leachate recirculation pump is communicated with the leachate absorption port; the percolate return pipe is communicated to the percolate recirculation pump and extends to the tank cover; the percolate spray head is arranged on the lower surface of the tank cover and is communicated with the percolate return pipe.

Further, the aeration device comprises a plurality of aeration holes, and the aeration holes are arranged on the aeration device at intervals.

Further, the structure of the tank cover detachably and hermetically arranged on the tank body comprises a fixing bolt, a movable buckle and a hinge; the fixing bolt is arranged on the top edge of the outer side surface of the tank body; the movable buckle is arranged on the tank cover and corresponds to the fixing bolt; the hinge is connected to the tank body and the tank cover respectively, and a connecting line of the hinge and the fixing bolt is located on a symmetrical axis of the tank body.

Further, the compost materials comprise polluted soil of a coking site, a surfactant, animal wastes and a microbial inoculum; the adding amount of the control microbial inoculum is 10-20% of the polluted soil of the coking field; the adding amount of the surfactant in the compost material is 500-1000 mg/Kg; the animal waste regulates C: n = 15: 1; the water content of the compost material is 25-35%.

Further, the microbial inoculum comprises strains belonging to one or more of the genera Methylobacterium, Burkholderia, Rhodococcus, Chryseobacterium and Microbacterium.

The invention also provides a composting method, which comprises the following steps:

a composting device is arranged, and the device for treating the polluted soil of the coking field by biological composting is arranged;

a compost material containing step of containing compost materials in the device for biologically composting the polluted soil of the coking field; the compost materials comprise coking field polluted soil, a surfactant, animal wastes and a microbial inoculum; the adding amount of the control microbial inoculum is 10-20% of the soil polluted by the coking field; the adding amount of the surfactant in the compost material is 500-1000 mg/Kg; the animal waste regulates C: n = 15: 1; the water content of the compost material is 25-35%; the bacterial agent comprises bacterial strains belonging to one or more of the genus Methylobacterium, the genus Burkholderia, the genus Rhodococcus, the genus Chryseobacterium and the genus Microbacterium; and

A continuous composting step, namely performing intermittent aeration on the pile body by utilizing an aeration device, wherein the continuous aeration is performed for 10-30 minutes per hour; monitoring the temperature and moisture content change in the stack body in real time through a temperature and humidity detector, starting a percolate recharging pump when the moisture content of the stack body is lower than 25%, spraying percolate on the surface of the stack body through a sprayer until the moisture content of the stack body is higher than 35%, and stopping spraying; waste gas generated in the composting process is purified by a waste gas treatment device and then is discharged through a waste gas discharge port; and finishing compost degradation of the polluted soil after continuously operating for 15-20 days at the temperature of 30 ℃.

Compared with the prior art, the device and the composting method for treating the polluted soil in the coking field by using the biological compost are easy to operate, simple to operate and low in cost, and can effectively treat the soil pollution caused by the coking field.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for biologically composting contaminated soil of a coking site according to the invention;

FIG. 2 is a floor plan of a bottom aeration device of the composting apparatus of the invention;

FIG. 3 is a flow diagram of the composting process of the invention.

Identification in the legend: the device comprises a fixing bolt 1, a movable buckle 2, a tank cover 3, a waste gas absorption pump 4, a waste gas conveying pipe 5, a waste gas absorption head 6, a leachate spraying head 7, a hinge 8, a temperature and humidity detector 9, a leachate backflow pipe 10, a material storage area 11, an aeration hole 12, a leachate backflow pump 13, a waste gas purifier 14, a waste gas discharge port 15, a leachate absorption opening 16, a leachate collecting pipe 17, a dosing opening 18, a tank body 19, an aeration device 20, a leachate guiding pipe 21 and a leachate collecting tank 22.

Detailed Description

The invention is described in more detail below with reference to an embodiment and with reference to the drawings.

As shown in fig. 1 and 2, the structure of the device for biologically composting contaminated soil of a coking site according to the present invention comprises: the device comprises a tank cover 3, a percolate spraying head 7, a temperature and humidity detector 9, a material storage area 11, a waste gas purifier 14, a percolate collecting pipe 17, a tank body 19 and an aeration device 20. The tank body 19 of the composting device is of a cylindrical tank structure, and the bottom surface made of acid-resistant steel plates is surrounded by a cylindrical structure with the diameter of 5m and the height of 7.5 m; the composting device is provided with a portable temperature and humidity detector 9 so as to monitor the temperature and the moisture content change in the compost body in real time; the composting device is provided with an aeration device 20, aeration amount and aeration time in the composting process are adjusted through external control, and the bottom of the composting device is provided with an aeration port 12 so as to uniformly distribute introduced air into composting materials; the bottom of the composting device is provided with evenly distributed percolate collecting pipes 17 which flow into a percolate collecting tank 22 through a percolate guide pipe 21 at the lower part; the leachate collecting pool is made of acid and alkali resistant plastic and used for storing leachate generated in the composting process; the composting device is also provided with a percolate recovery device consisting of a percolate suction port 16, a percolate recirculation pump 13, a percolate return pipe 10 and a percolate spray head 7, so that percolate generated at the initial stage of composting and collected in a percolate collecting pool 22 flows into the percolate return pipe 10 under the action of the percolate recirculation pump 13 and is sprayed to the surface of a heap body through the percolate spray head 7 to adjust the water content of the heap body; the composting device is also provided with a waste gas absorption pump 4 which absorbs waste gas generated in the composting process through a waste gas absorption head 6, and the waste gas is sent into a waste gas purifier 14 through a waste gas conveying pipe 5 for purification and then is discharged through a waste gas discharge port 15.

Specifically, a cavity for containing compost materials is formed in the tank body 19 and serves as a material storage area 11; the tank cover 3 is detachably arranged on the tank body 19 in a sealing manner; the top of the tank cover 3 is provided with a medicine feeding port 18; the aeration device 20 is arranged in the tank body 19 and is positioned at the bottom of the material storage area 11 of the tank body 19, and the aeration device 20 is used for introducing air and uniformly distributing the air into the compost materials; the input port of the percolate collecting pipe 17 is arranged at the bottom of the tank body 19 and is communicated with the material storage area 11; the percolate collecting tank 22 is arranged opposite to the output port of the percolate collecting pipe 17 and is used for collecting percolate guided by the percolate collecting pipe 17; the waste gas absorbing head 6 is arranged on the tank cover 3 and corresponds to the material storage area 11; the waste gas absorption pump 4 is arranged on the tank cover 3, and the air suction end of the waste gas absorption pump is communicated with the waste gas absorption head 6; the exhaust gas discharge port 15 communicates with the exhaust end of the exhaust gas absorbing pump 4. The temperature and humidity detector 9 is arranged on one side of the tank cover 3 facing the material storage area 11. The exhaust gas cleaner 14 is provided between the exhaust gas absorption pump 4 and the exhaust gas discharge port 15. The exhaust gas cleaner 14 and the leachate collection tank 22 are both located at the bottom of the tank body, so that the space can be reasonably utilized.

In a percolate recovery device consisting of a percolate suction port 16, a percolate recirculation pump 13, a percolate recirculation pipe 10 and a percolate spraying head 7, the percolate suction port 16 is arranged in a percolate collecting tank 22; the leachate recirculation pump 13 is communicated with the leachate suction port 16; the percolate return pipe 10 is communicated to the percolate return pump 13 and extends to the tank cover 3; the percolate spray head 7 is arranged on the lower surface of the tank cover 3 and is communicated with the percolate return pipe 10.

As shown in fig. 2, the aeration device 20 includes a plurality of aeration holes 12, and the aeration holes 12 are arranged at intervals on the aeration device 20.

The composting device provided by the invention is sealed to ensure the tightness. The structure of the tank cover 3 which is detachably and hermetically arranged on the tank body 19 comprises a fixed bolt 1, a movable buckle 2 and a hinge 8; the fixing bolt 1 is arranged on the top edge of the outer side surface of the tank body 19; the movable buckle 2 is arranged on the tank cover 3 and corresponds to the fixing bolt 1; the hinge 8 is respectively connected to the tank body 19 and the tank cover 3, and a connecting line of the hinge 8 and the fixing bolt 1 is located on a symmetrical axis of the tank body 19.

The compost materials comprise polluted soil of a coking site, a surfactant, animal wastes and a microbial inoculum; the adding amount of the control microbial inoculum is 10-20% of the polluted soil of the coking field; the adding amount of the surfactant in the compost material is 500-1000 mg/Kg; the animal waste regulates C: n = 15: 1; the water content of the compost material is 25-35%.

The microbial inoculum related by the invention is screened from soil in a certain coking field by using polycyclic aromatic hydrocarbon as a unique carbon source and utilizing an enrichment culture technology. As a result of 16sDNA sequencing of the strains, the test strains were found to belong to the following 5 strains Methyl [1] bacterium (Methylobacillus), Burkholderia (Burkholderia), Rhodococcus (Rhodococcus), Chryseobacterium (Chryseobacterium), Microbacterium (Microbacterium).

As shown in FIG. 3, the present invention also provides a composting method comprising the following steps S1-S3:

s1, setting a composting device, namely setting the device for biologically composting the polluted soil of the coking field;

s2, containing compost materials, namely containing the compost materials in the device for treating the polluted soil of the coking field by using the biological compost; the compost materials comprise coking field polluted soil, a surfactant, animal wastes and a microbial inoculum; the adding amount of the control microbial inoculum is 10-20% of the soil polluted by the coking field; the adding amount of the surfactant in the compost material is 500-1000 mg/Kg; the animal waste regulates C: n = 15: 1; the water content of the compost material is 25-35%; the bacterial agent comprises bacterial strains belonging to one or more of the genus Methylobacterium, the genus Burkholderia, the genus Rhodococcus, the genus Chryseobacterium and the genus Microbacterium; and

S3, continuously composting, namely, intermittently aerating the compost by utilizing an aeration device, and continuously aerating for 10-30 minutes per hour; monitoring the temperature and moisture content change in the stack body in real time through a temperature and humidity detector, starting a percolate recharging pump when the moisture content of the stack body is lower than 25%, spraying percolate on the surface of the stack body through a sprayer until the moisture content of the stack body is higher than 35%, and stopping spraying; waste gas generated in the composting process is purified by a waste gas treatment device and then is discharged through a waste gas discharge port; and finishing compost degradation of the polluted soil after continuously operating for 15-20 days at the temperature of 30 ℃.

When the device for treating the polluted soil in the coking field by using the biological compost is used, the strains screened out by experiments are mixed with the soil which is subjected to controllable pre-oxidation treatment, and the adding amount of the microbial inoculum is controlled to be 10% of the soil; 755mg/Kg of surfactant rhamnolipid; c is adjusted by adding other animal wastes (pig manure and chicken manure): n = 15: 1; controlling the water content to be 32.5%; the compost materials are uniformly mixed through a bag turning machine and are placed in a material storage area of a composting device. The aeration device is used for carrying out intermittent aeration on the stack body, and the aeration is continuously carried out for 10 minutes per hour. Through temperature moisture detector real-time supervision heap body in temperature and moisture content change, when the heap body moisture content is less than 35%, start filtration liquid recirculation pump 13, spray filtration liquid on the heap body surface through the shower nozzle, until the heap body moisture content is higher than 35%, stop spraying: waste gas generated in the composting process is absorbed by a waste gas treatment device and is purified and discharged through a bottom exhaust port. After continuous operation for 21 days at 30 ℃, polycyclic aromatic hydrocarbon in the polluted soil in the composting device is degraded under the action of aerobic microorganisms in the compost.

Compared with the prior art, the device and the composting method for biologically composting the polluted soil in the coking site are easy to operate, simple to operate and low in cost, and can effectively treat the soil pollution caused by the coking site.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

The device and the composting method for biologically composting contaminated soil of a coking site provided by the embodiments of the application are introduced in detail, and the principles and the embodiments of the application are explained by applying specific embodiments in the text, and the description of the embodiments is only used for helping to understand the technical scheme and the core idea of the application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. The utility model provides a device of contaminated soil in bio-compost processing coking yard which characterized in that includes:

The tank body is of a cylindrical tank structure, and a material storage area for containing compost materials is formed in the tank body; the compost materials comprise polluted soil of a coking site, a surfactant, animal wastes and a microbial inoculum; the adding amount of the control microbial inoculum is 10-20% of the polluted soil of the coking field; the adding amount of the surfactant in the compost material is 500-1000 mg/Kg; the animal waste regulates C: n = 15: 1; the water content of the compost material is 25-35%; the bacterial agent comprises bacterial strains belonging to one or more of the genus Methylobacterium, the genus Burkholderia, the genus Rhodococcus, the genus Chryseobacterium and the genus Microbacterium;

the cover is detachably and hermetically arranged on the tank body; the top of the tank cover is provided with a drug feeding port;

the aeration device is arranged in the tank body and positioned at the bottom of the material storage area of the tank body, and the aeration device is used for introducing air and uniformly distributing the air into the compost materials;

the input port of the percolate collecting pipe is arranged at the bottom of the tank body and is communicated with the material storage area;

the percolate collecting pool is arranged opposite to the output port of the percolate collecting pipe and is used for collecting percolate guided by the percolate collecting pipe;

The waste gas absorption head is arranged on the tank cover and corresponds to the material storage area;

the waste gas absorption pump is arranged on the tank cover, and the air suction end of the waste gas absorption pump is communicated with the waste gas absorption head;

the exhaust gas discharge port is communicated with the exhaust end of the exhaust gas absorption pump;

the temperature and humidity detector is arranged on one side of the tank cover facing the material storage area; and

and the waste gas purifier is arranged between the waste gas absorption pump and the waste gas discharge port.

2. A device for bio-composting contaminated soil from a coking site as claimed in claim 1, wherein the waste gas cleaner and the percolate collection tank are both located at the bottom of the tank.

3. An apparatus for bio-composting contaminated soil from a coking yard as claimed in claim 1, further comprising:

the percolate suction port is arranged in the percolate collecting pool;

the leachate recirculation pump is communicated with the leachate absorption port;

the leachate return pipe is communicated to the leachate recirculation pump and extends to the tank cover; and

and the percolate spraying head is arranged on the lower surface of the tank cover and communicated with the percolate return pipe.

4. An apparatus as claimed in claim 1, wherein the aeration means includes a plurality of aeration holes, and the aeration holes are arranged at intervals on the aeration means.

5. An apparatus for bio-composting contaminated soil from a coking site as claimed in claim 1, wherein the structure of the lid removably and sealingly attached to the tank body comprises:

the fixing bolt is arranged on the top edge of the outer side face of the tank body;

the movable buckle is arranged on the tank cover and corresponds to the fixing bolt; and

the hinge is connected to the tank body and the tank cover respectively, and a connecting line of the hinge and the fixing bolt is located on a symmetrical axis of the tank body.

6. A method of composting, comprising the steps of:

a composting device setting step of setting a device for biologically composting contaminated soil of a coking site according to claim 3;

A continuous composting step, namely performing intermittent aeration on the pile body by utilizing an aeration device, wherein the continuous aeration is performed for 10-30 minutes per hour; monitoring the temperature and moisture content change in the stack body in real time through a temperature and humidity detector, starting a percolate recharging pump when the moisture content of the stack body is lower than 25%, spraying percolate on the surface of the stack body through a sprayer until the moisture content of the stack body is higher than 35%, and stopping spraying; waste gas generated in the composting process is purified by a waste gas treatment device and then is discharged through a waste gas discharge port; and (3) continuously operating for 15-20 days at 30 ℃ to finish the compost degradation of the polluted soil.