CN111077920A - Automatic control system for dissolved oxygen and pH in overlying water of lake sediments - Google Patents
Automatic control system for dissolved oxygen and pH in overlying water of lake sediments Download PDFInfo
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- CN111077920A CN111077920A CN201911292286.4A CN201911292286A CN111077920A CN 111077920 A CN111077920 A CN 111077920A CN 201911292286 A CN201911292286 A CN 201911292286A CN 111077920 A CN111077920 A CN 111077920A
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- dissolved oxygen
- supply pipeline
- control device
- standard value
- detection probe
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 62
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 239000001301 oxygen Substances 0.000 title claims abstract description 52
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 52
- 239000013049 sediment Substances 0.000 title claims abstract description 17
- 238000001514 detection method Methods 0.000 claims abstract description 48
- 239000007789 gas Substances 0.000 claims abstract description 32
- 239000000523 sample Substances 0.000 claims abstract description 29
- 239000007788 liquid Substances 0.000 claims abstract description 28
- 239000002253 acid Substances 0.000 claims abstract description 8
- 239000003513 alkali Substances 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims description 17
- 239000002184 metal Substances 0.000 claims description 17
- 238000007789 sealing Methods 0.000 claims description 17
- 230000002572 peristaltic effect Effects 0.000 claims description 9
- 239000002585 base Substances 0.000 claims description 4
- 239000001307 helium Substances 0.000 claims description 4
- 229910052734 helium Inorganic materials 0.000 claims description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 3
- 241000195493 Cryptophyta Species 0.000 abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 235000015097 nutrients Nutrition 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 241000192710 Microcystis aeruginosa Species 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000012851 eutrophication Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000029553 photosynthesis Effects 0.000 description 2
- 238000010672 photosynthesis Methods 0.000 description 2
- 230000029058 respiratory gaseous exchange Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000027288 circadian rhythm Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D21/00—Control of chemical or physico-chemical variables, e.g. pH value
- G05D21/02—Control of chemical or physico-chemical variables, e.g. pH value characterised by the use of electric means
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Apparatus Associated With Microorganisms And Enzymes (AREA)
Abstract
The invention relates to a system for automatically controlling dissolved oxygen and pH of water coated on lake sediments, which comprises a PLC control device and at least one group of culture units; the set of culture units comprises: the device comprises a culture column, a pH detection probe, a dissolved oxygen detection probe, an air supply pipeline, a liquid supply pipeline and an electromagnetic valve; the pH detection probe and the dissolved oxygen detection probe are introduced into an upper water layer of the culture column, detection signals are fed back to the PLC control device, and the PLC control device controls the electromagnetic valve to introduce corresponding gas or acid and alkali into the upper water layer through the air supply pipeline or the liquid supply pipeline according to measured values, so that the automatic control of dissolved oxygen and pH is realized. The automatic control system for dissolved oxygen and pH of the overlying water of the lake sediment can accurately control the dissolved oxygen and pH level of the overlying water, has the fluctuation range within 0.5, can control the culture temperature of a sediment-water system through a temperature control device, and has important significance for researching the endogenous release mechanism of the sediment and the influence of the endogenous release mechanism on the growth of algae.
Description
Technical Field
The invention belongs to the technical field of environmental monitoring, and particularly relates to an automatic control system for dissolving oxygen and pH in water on lake sediments.
Background
Lake eutrophication is one of the main problems faced by the current water environment in China. The excessive input of nutrient salts such as nitrogen, phosphorus and the like can cause algae in the Water body to rapidly grow and breed, so that the clear and verdure Water becomes turbid and has different colors, even the Water bloom phenomenon (Water bloom) occurs, the Water ecology is damaged, and the Water supply safety of a drinking Water source is influenced. After the exogenous pollution enters the lake, a large part of the exogenous pollution is deposited in the sediments in the lake, and the accumulated nutrient salts can be released again under proper conditions to supply the algae to grow so as to form endogenous pollution. The research on the endogenous release conditions of lakes and the influence of the endogenous release conditions on the growth of algae is an important content of the current lake eutrophication treatment. The main factors influencing the endogenous release of nutrient salts in lake sediments are the temperature, dissolved oxygen and pH of the water body. Because of factors such as photosynthesis and respiration of algae, synthesis and degradation of organic matters in water and the like, dissolved oxygen and pH of water often fluctuate, the eutrophic lake water is difficult to quantitatively study the environmental conditions of endogenous release of lake sediments.
Disclosure of Invention
The invention aims to provide an automatic control system for dissolving oxygen and pH in overlying water of lake sediments.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
an automatic control system for dissolving oxygen and pH in water on lake sediments comprises a PLC control device and at least one group of culture units; the set of culture units comprises: the device comprises a culture column, a pH detection probe, a dissolved oxygen detection probe, an air supply pipeline, a liquid supply pipeline and an electromagnetic valve;
the pH detection probe and the dissolved oxygen detection probe are introduced into an upper water layer of the culture column, detection signals are fed back to the PLC control device, and the PLC control device controls the electromagnetic valve to introduce corresponding gas or acid-base into the upper water layer through the air supply pipeline or the liquid supply pipeline according to measured values.
As a further improvement of the invention, the top of the culture column is closed by a cover; the sealing cover is provided with a plurality of through holes, and the pH detection probe, the dissolved oxygen detection probe, the air supply soft pipeline and the liquid supply pipeline respectively penetrate through the through holes to be introduced with the overlying water. Furthermore, two annular grooves are formed in the side face of the sealing cover, and a silica gel ring is arranged on each annular groove. The sealing cover can be tightly combined with the column body by the elasticity of the silica gel ring for sealing.
As a further improvement of the invention, the system also comprises a stirrer, one end of the stirrer is connected with the PLC control device, and the other end of the stirrer is introduced into the overlying water. And stirring the overlying water by using a stirrer to uniformly mix the water in the culture column.
As a further improvement of the invention, the air supply pipeline and the liquid supply pipeline are composed of a hose and a metal pipe connected at the head of the hose, and the metal pipe passes through the through hole to be introduced with the overlying water. Further, the joint of the metal pipe and the sealing cover is sealed; preferably with a rubber band seal.
As a further improvement of the invention, the air supply pipeline is connected with an air bottle through an air pump; the control end of the air pump is connected with the electromagnetic pump; and a gas flowmeter is arranged on the gas supply pipeline and is connected with the PLC control device.
As a further improvement of the invention, the liquid supply pipeline is connected with the acid cylinder/alkali cylinder through a peristaltic pump; the control end of the peristaltic pump is connected with the electromagnetic pump. Peristaltic pumps can control liquid flow rate and volume.
As a further improvement of the invention, the system also comprises a temperature control device for controlling the temperature of the culture column; preferably, the temperature control device is a water bath. Furthermore, the water bath is sealed by a metal cover, and the metal cover is provided with at least one through hole matched with the outer diameter of the culture column for accommodating the culture column.
As a further improvement of the invention, the culture tube further comprises an exhaust tube which passes through the through hole and is in gas communication with the inside of the culture tube.
As a further improvement of the invention, the device also comprises a drainage device; the drainage device comprises a drainage pipe, a pressure valve and a water storage device, wherein the drainage pipe is connected with the culture column, and liquid enters the drainage pipe to flush the pressure valve and enter the water storage device after exceeding the liquid level so as to control the liquid level of the overlying water within a certain range.
As a further improvement of the invention, the sealing cover is provided with a columnar groove, the inner surface of the columnar groove is provided with threads, and the sealing cover can be taken down in combination with a screw rod.
In the method of the present invention, the control flow of the PLC control device is:
(1) opening the gas valve to fill the gas supply pipeline with gas; setting a pH standard value, a dissolved oxygen standard value, a pH standard value deviation, a dissolved oxygen standard value deviation and a probe sampling interval;
(2) receiving detection signals sent by a pH detection probe and a dissolved oxygen detection probe, and comparing the detection signals with standard values respectively;
(3) when the absolute value of the difference between the dissolved oxygen detection value and the standard value is greater than the deviation of the standard value, the corresponding electromagnetic pump is opened, and helium or oxygen is introduced until the absolute value of the difference between the detection value and the standard value is less than the deviation of the standard value; and when the absolute value of the difference between the pH detection value and the standard value is greater than the deviation of the standard value, opening the corresponding electromagnetic pump, and introducing acid or alkali until the absolute value of the difference between the detection value and the standard value is less than the deviation of the standard value.
Further, the method also comprises the following steps: when the electromagnetic pump is started, the stirrer is started.
Further, in the step (1), different dissolved oxygen standard values and pH standard values are set at different time intervals. The dissolved oxygen and pH at different time periods are controlled to simulate the circadian rhythm of high dissolved oxygen and pH due to photosynthesis in the daytime and low dissolved oxygen due to respiration in the evening.
Furthermore, the PLC control device controls a gas flowmeter according to the difference range of the detection value and the standard value, the peristaltic pump adjusts the flow rate of gas and acid-base entering the overlying water, and when the difference between the detection value and the standard value is too large, the flow rate is increased so as to quickly recover the dissolved oxygen and pH level.
The automatic control system for dissolved oxygen and pH of the overlying water of the lake sediment can accurately control the dissolved oxygen and pH level of the overlying water, has the fluctuation range within 0.5, can control the culture temperature of a sediment-water system through a temperature control device, and has important significance for researching the endogenous release mechanism of the sediment and the influence of the endogenous release mechanism on the growth of algae.
Drawings
Fig. 1 is a schematic structural diagram of a system device according to embodiment 1 of the present invention.
FIG. 2 is a schematic view showing the structure of the joint between the flexible tube and the culture column.
Fig. 3 is a schematic view of the configuration of the annular groove and the cylindrical groove of the closure.
Fig. 4 is a schematic structural diagram of a system device according to embodiment 2 of the present invention.
Fig. 5 is a schematic top view of the water bath.
Fig. 6 is a schematic structural diagram of a system device according to embodiment 3 of the present invention.
Fig. 7 is a schematic diagram of a software flow control front panel.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings and the detailed implementation mode.
Example 1
The system for automatically controlling the oxygen dissolution and the pH value of the overlying water of the lake sediments as shown in figures 1-3 comprises a PLC control device 3 and at least one group of culture units;
the set of culture units comprises:
the culture column consists of a column body 1 and a sealing cover 2; the sediment, the overlying water and the gas are sequentially arranged in the column body from bottom to top; the upper end of the column body 1 is sealed by a sealing cover 2, a plurality of through holes are formed in the sealing cover 2, and the pH detection probe 5, the dissolved oxygen detection probe 6, the first air supply pipeline 7, the second air supply pipeline 8, the first liquid supply pipeline 9 and the second liquid supply pipeline 10 respectively penetrate through the through holes to be introduced with the overlying water. The exhaust pipe 16 is in gas communication with the inside of the culture tube through the through hole. Each tube is connected to the culture column 1 through an independent through hole.
The first air supply pipeline 7 and the second air supply pipeline 8 are respectively connected with an oxygen steel cylinder 72 and a helium steel cylinder 82 through air inlets of a first air pump 71 and a second air pump 81; the control ends of the first air pump 71 and the second air pump 81 are connected with the first electromagnetic pump 11; the first liquid supply pipeline 9 and the second liquid supply pipeline 10 are respectively connected with an acid cylinder 92 (hydrochloric acid inside) and an alkali cylinder 102 (sodium hydroxide inside) through liquid inlets of a first peristaltic pump 91 and a second peristaltic pump 101; the control ends connected with the first liquid pump 91 and the second liquid pump 101 are connected with the second electromagnetic pump 12; the first air supply pipeline 7 and the second air supply pipeline 8 are provided with gas flow meters 73 and 83, and the pH detection probe 5, the dissolved oxygen detection probe 6, the first electromagnetic pump 11, the second electromagnetic pump 12 and the flow meters 73 and 83 are respectively connected to the PLC control device 3.
The first air supply pipeline 7, the second air supply pipeline 8, the first liquid supply pipeline 9 and the second liquid supply pipeline 10 are composed of a hose and a metal pipe 14 connected with a pipe head, and the metal pipe 14 penetrates through the through hole to be filled with the upper cover water. The joint of the metal tube 14 and the sealing cover 2 is sealed; in this embodiment, a rubber band 15 is used for sealing. The metal pipe 14 is a rigid pipe and is easy to connect a sealing cover or take out, and the metal pipe is made of a stainless steel pipe and is resistant to acid and alkali corrosion.
The system of this embodiment still includes agitator 13, and PLC controlling means is connected to agitator one end, and the other end passes through the perforating hole and lets in overlying water.
As shown in figure 3, two annular grooves 21 are arranged on the side surface of the sealing cover 2, a silica gel ring is arranged on the annular grooves 21, and the sealing cover 2 can be tightly combined with the column body of the culture column 1 and sealed by the elasticity of the silica gel ring. In order to facilitate the removal of the closure 2, a cylindrical recess 20 is also provided in the closure 2.
The control flow of the PLC control device is realized based on LabVIEW, and software control is realized by communicating with a LabVIEW control program in an upper computer through an OPC communication protocol.
The control flow of the PLC control device in this embodiment is as follows:
(1) opening the gas valves to fill the first gas supply hose 7 and the second gas supply hose 8 with gas; setting a pH standard value, a dissolved oxygen standard value, a pH standard value deviation, a dissolved oxygen standard value deviation and a probe sampling interval;
in this example, the pH standard value and the dissolved oxygen standard value were set at different time intervals, and the pH standard value and the dissolved oxygen standard value were set for 2 to 12 hours as one cycle, and were arbitrarily adjusted at intervals of 2 hours.
(2) Receiving detection signals sent by a pH detection probe 5 and a dissolved oxygen detection probe 6, and comparing the detection signals with standard values respectively;
(3) when the absolute value of the difference between the dissolved oxygen detection value and the standard value is greater than the deviation of the standard value, the corresponding first electromagnetic pump 11 is started, and helium or oxygen is introduced until the absolute value of the difference between the detection value and the standard value is less than the deviation of the standard value; and when the absolute value of the difference between the pH detection value and the standard value is greater than the deviation of the standard value, the corresponding second electromagnetic pump 12 is opened, and acid or alkali is introduced until the absolute value of the difference between the pH detection value and the standard value is less than the deviation of the standard value. When the first electromagnetic pump 11 or the second electromagnetic pump 12 is started, the agitator 13 is started.
The PLC control device controls the gas flowmeter according to the difference range of the detection value and the standard value, the peristaltic pump adjusts the flow rate of gas and acid-base entering the overlying water, and when the difference between the detection value and the standard value is too large, the flow rate is increased so as to quickly recover the dissolved oxygen and pH level.
In this embodiment, a data storage interval is set based on software, and the data is stored in the local database in the EXCEL format for subsequent research.
The system for automatically controlling dissolved oxygen and pH of the overlying water in the lake sediment can accurately control the dissolved oxygen and pH level of the overlying water, and the fluctuation range is within 0.5.
Example 2
As shown in FIGS. 4 to 5, this example is different from example 1 only in that it further comprises a temperature control device 4 for controlling the culture temperature of the sediment-water system in the culture column; the temperature control device described in this embodiment is a water bath, and the liquid level of the water bath is flush with the liquid level of the overlying water in the culture column.
The water bath is sealed by a metal cover 41, and the metal cover 41 is provided with at least one through hole 42 matched with the outer diameter of the culture column for accommodating the culture column. FIG. 5 shows a case where the system comprises 12 culture units, and 12 through-holes 42 are uniformly distributed in an array form to accommodate 12 culture columns.
Example 3
As shown in fig. 6, the present embodiment is different from embodiment 1 only in that it further includes a drainage device including a drainage pipe 17, a pressure valve 18, and a water storage tank 19. The drain pipe 17 can be connected with the drain pipe 17 by leading in the upper water through the sealing cover 2 or opening a drain hole on the column body of the culture column 1, the pressure valve 18 is an overflow valve, and after the liquid level exceeds a certain height, the pressure valve 18 is opened to discharge the redundant water and maintain the upper water covering amount in the culture system.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911292286.4A CN111077920A (en) | 2019-12-16 | 2019-12-16 | Automatic control system for dissolved oxygen and pH in overlying water of lake sediments |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911292286.4A CN111077920A (en) | 2019-12-16 | 2019-12-16 | Automatic control system for dissolved oxygen and pH in overlying water of lake sediments |
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| CN111077920A true CN111077920A (en) | 2020-04-28 |
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| CN201911292286.4A Pending CN111077920A (en) | 2019-12-16 | 2019-12-16 | Automatic control system for dissolved oxygen and pH in overlying water of lake sediments |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111735934A (en) * | 2020-07-23 | 2020-10-02 | 天津大学 | Methods for the effects of temperature and disturbance degree on nitrogen and phosphorus fluxes in lake sediments |
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2019
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