Monitoring method for preventing black and odorous river water

Abstract

The invention relates to a monitoring method for preventing black and odorous river water, which comprises the following steps of: simulating different bottom mud systems, drawing a DO-t change curve of the simulation system, and calculating the black and odorous river water on the basis of the DO-t change curve obtained in the step (2) by taking the initial Fe < 2 + > or AVS content of the bottom mud as a horizontal coordinate, taking the maximum oxygen consumption as a vertical coordinate and taking the initial Fe < 2 + > or AVS content of the bottom mud as the horizontal coordinate; and drawing a relation curve between the oxygen consumption and the bottom mud Fe < 2 + > or AVS content by taking the oxygen consumption as a vertical coordinate, obtaining a relational expression y = kx + b, the oxygen consumption y is DO initial-DOmin, calculating the bottom mud Fe < 2 + > or AVS content when the water body is black and odorous according to the corresponding oxygen consumption when the DOmin is 2mg / L, taking the bottom mud Fe < 2 + > or AVS content as a bottom mud Fe < 2 + > or AVS limit value, and setting the bottom mud Fe < 2 + > or AVS control threshold value to be less than or equal to the corresponding limit value. Monitoring according to the condition that the Fe < 2 + > or AVS content of the bottom mud does not exceed a control threshold value so as to prevent the water body from being black and odorous.

Description

Technical Field

[0001] The present invention relates to the technical field of river water pollution control and treatment, and more specifically, to a monitoring method for preventing the blackening and odorization of river water bodies. Background Art

[0002] In the "Work Guide for the Renovation of Urban Black and Odorous Water Bodies" issued in 2015, the grading standard for urban black and odorous water bodies is defined as follows: when the dissolved oxygen (DO) is between 0.2 and 2.0 mg / L, it is mildly black and odorous; when DO < 0.2 mg / L, it is severely black and odorous. Although the water body black and odorous level can be classified according to the DO concentration of the water body, even if the detected DO concentration > 2.0 mg / L after water body treatment, there may still be a secondary blackening and odorization of the water body due to the influence of other factors in the later stage. Once the detected DO concentration of the water body ≤ 2.0 mg / L, it indicates that the water body has already become black and odorous. The occurrence of the water body black and odorous phenomenon will seriously affect the balance of the water body ecosystem and the quality of the urban environment. Therefore, preventing the occurrence of water body blackening and odorization is crucial for protecting the balance of the water body ecosystem and maintaining the quality of the urban environment.

[0003] The formation cause of water body blackening and odorization is relatively complex, including various factors. Among them, the sediment is the main destination of various pollutions discharged into the river and is the main endogenous pollutant of urban water bodies. The deposited sediment is resuspended under the action of water body scouring and human influence. Subsequently, the pollutants adsorbed on the sediment particles are released back into the water body under a series of physical, chemical, and biological actions, causing secondary pollution of the water body. At the same time, a large amount of sediment is also a breeding ground for various microorganisms. Among them, actinomycetes and cyanobacteria cause the sediment to be methanated and denitrified through metabolic actions, resulting in the floating of the sediment and the blackening and odorization of the water body. However, the existing technologies mainly focus on how to identify, classify, or treat the water body after it has become black and odorous, and there are relatively few studies on how to monitor and prevent the blackening and odorization of the water body. Therefore, studying a monitoring method that can prevent the blackening and odorization of the water body is of great significance for the pollution control and treatment of river water body blackening and odorization. Summary of the Invention

[0004] In view of the above defects or improvement requirements of the existing technology, the present invention provides a monitoring method for preventing the blackening and odorization of river water bodies. The purpose is to simulate different sediment culture systems by adding different masses of FeSO4 or NaS, and it is found that based on the DO-t change curve of the culture system, it is possible to plot the relationship curve between the oxygen consumption and the sediment Fe 2+ or AVS content with the initial sediment Fe 2+ or AVS content as the abscissa and the maximum oxygen consumption as the ordinate, and obtain the relational formula as y = kx + b, where the oxygen consumption y is DO 初 -DO min ; according to the oxygen consumption y corresponding to DO min being 2 mg / L, calculate the sediment Fe 2+or the AVS content limit, according to the sediment Fe 2+ or the AVS content does not exceed the corresponding limit for monitoring to prevent the water body from becoming black and odorous, thereby solving the technical problem that the prior art lacks a monitoring method for preventing the water body from becoming black and odorous.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided a monitoring method for preventing the blackening and odoring of river water bodies, which includes the following steps:

[0006] (1) Simulate different sediment systems: Collect the sediment in the target river area, add different masses of FeSO4 or NaS after removing impurities, and mix them evenly to make the initial Fe of the sediment in the culture system 2+ or the AVS content range cover the Fe of the sediment in the urban area river 2+ or the AVS content;

[0007] (2) Draw the change curve of DO-t in the simulation system: Simulate the flow state of the water body in the sampling river for cultivation, measure the DO concentration of the overlying water in each culture system during the cultivation period, and draw the DO-t change curve of the corresponding culture system;

[0008] (3) Calculate the sediment Fe 2+ or the AVS content limit

[0009] Based on the DO-t change curve obtained in step (2), with the initial Fe of the sediment 2+ or the AVS content as the abscissa and the maximum oxygen consumption as the ordinate, draw the relationship curve between the oxygen consumption and the sediment Fe 2+ or the AVS content, and obtain the relational expression y = kx + b, where the oxygen consumption y is DO 初 -DO min , x is the sediment Fe 2+ or the AVS content; Calculate the sediment Fe 初 -2) to calculate the sediment Fe 2+ or the AVS content limit;

[0010] Set the control threshold of the sediment Fe 2+ or AVS to ≤ the corresponding limit, and monitor according to the sediment Fe 2+ or the AVS content does not exceed the control threshold to prevent the water body from becoming black and odorous.

[0011] Preferably, for the monitoring method, static cultivation is used for rivers with relatively static water bodies. If the DO in the DO-t change curve corresponding to the culture system with FeSO4 added min > 2mg / L, with the AVS content of the sediment as the monitoring index, monitor according to the AVS content not exceeding the control threshold.

[0012] Preferably, for the relatively static rivers in Dongguan City in the monitoring method, static cultivation is adopted, and the AVS limit value of the river sediment is calculated according to the relational formula between the oxygen consumption and the AVS content of the sediment: y = 0.3184x + 0.0417.

[0013] Preferably, in the monitoring method, the AVS content limit value of the sediment is calculated according to the oxygen consumption y of (DO 初 -2), and the monitoring is carried out according to the control threshold of sediment AVS ≤ the limit value of sediment AVS.

[0014] Preferably, in the monitoring method, the control thresholds of sediment AVS corresponding to Class I, Class II, and Class III river water bodies are 17 g / kg, 12 g / kg, and 9 g / kg respectively.

[0015] Preferably, for the rivers with flowing water in the monitoring method, stirring cultivation is adopted to simulate the water flow velocity. If the DO in the DO-t change curve corresponding to the cultivation system without the addition of NaS min <2 mg / L, the content of sediment Fe 2+ is used as the monitoring index, and the monitoring is carried out according to the content of Fe 2+ not exceeding the control threshold.

[0016] Preferably, for the rivers with flowing water in Dongguan City in the monitoring method, stirring cultivation is adopted to simulate the resuspension of sediment. According to the relational formula between the oxygen consumption and the content of sediment Fe 2+ : y = 0.0961x + 2.3948, the limit value of sediment Fe 2+ in this river is calculated.

[0017] Preferably, in the monitoring method, the content limit value of sediment Fe is calculated according to the oxygen consumption y of (DO 初 -2), and the monitoring is carried out according to the control threshold of sediment Fe 2+ ≤ the limit value of sediment Fe 2+ : the control threshold of sediment Fe 2+ ≤ the limit value of sediment Fe for monitoring.

[0018] Preferably, in the monitoring method, the control thresholds of sediment Fe corresponding to Class I, Class II, and Class III river water bodies are 32 g / kg, 16 g / kg, and 6 g / kg respectively. 2+

[0019] Preferably, in the monitoring method, the content of sediment Fe 2+ or AVS is the content of surface sediment Fe 2+ or AVS.

[0020] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0021] ​The present invention fully considers the impact of sediment on the blackening and odor of water bodies. By using this method, it is possible to monitor rivers with relatively static water bodies and rivers with flowing water bodies respectively. The collected sediment is mixed with different masses of FeSO4 or NaS, and the initial Fe in the sediment of the culture system is 2+ or the AVS content range covers the Fe in the sediment of the urban rivers 2+ or AVS content. The flow state of the water body in the sampling river is simulated for cultivation, and the corresponding DO-t change curve within the cultivation time t is plotted. A relationship curve between the maximum oxygen consumption and the Fe in the sediment is established 2+ or the relationship curve between the AVS content. Based on the curve expression, the corresponding Fe in the sediment when the water body becomes black and odorous is deduced 2+ or the AVS content limit value. Monitoring is carried out according to the Fe in the sediment 2+ or the AVS content not exceeding the corresponding limit value to prevent the water body from becoming black and odorous, which is beneficial to the pollution prevention and control and timely treatment of river water body blackening and odor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Oxygen sag curve;

[0023] Figure 2 Fe 2+ Content and absorbance standard curve;

[0024] Figure 3 FeSO4 addition amount in each culture system and Fe in the surface sediment 2+ Content;

[0025] Figure 4 DO-t change under static culture state with different amounts of FeSO4 added;

[0026] Figure 5 AVS content in the surface sediment of each culture system;

[0027] Figure 6 DO-t change with different amounts of Na2S added;

[0028] Figure 7 Relationship between AVS content and oxygen consumption in the surface sediment of each culture system;

[0029] Figure 8 DO-t change under stirring culture state with different amounts of FeSO4 added;

[0030] Figure 9 Fe in the surface sediment under stirring culture 2+ Relationship between content and oxygen consumption;

[0031] Figure 10 DO-t change under stirring culture state with different amounts of Na2S added. DETAILED DESCRIPTION OF THE INVENTION

[0032] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on the specific implementation manners, structures, features and their effects of the present invention as follows.

[0033] Terms:

[0034] Acid-volatile sulfide (AVS) is an important pollutant in sediment, mainly produced by anaerobic decomposition of organic matter. AVS usually exists in the form of hydrogen sulfide and can be converted into sulfate or sulfate ions through oxidation. The content of AVS is one of the important indicators for evaluating the degree of water pollution, especially in black and odorous waters and polluted sediments.

[0035] Overlying water, sediment and interstitial water constitute the three main interfaces in the water environment. Among them, overlying water refers to the water body covering the sediment surface, usually located at a certain distance (such as 0 - 10 cm) above the sediment; sediment refers to the substances suspended or deposited at the bottom of the water body, including organic and inorganic particles; interstitial water refers to the water existing in the pores of the sediment, also known as pore water or void water. Interstitial water is the medium for the transition of sediment to overlying water and can carry soluble substances in the sediment into the overlying water.

[0036] Dissolved oxygen (DO) refers to the content of molecular oxygen dissolved in water, usually expressed in milligrams of oxygen per liter of water (mg / L), and is a parameter for measuring the oxygen content in water.

[0037] Oxygen uptake rate (OUR) refers to the rate of oxygen consumption in the system per unit time and can be calculated by measuring the change in dissolved oxygen concentration. For example, the closed intermittent aeration method is a commonly used measurement method. By recording the change in dissolved oxygen concentration over time, a DO-t curve is plotted to calculate the oxygen uptake rate (OUR).

[0038] Reaeration rate refers to the rate at which the water body obtains dissolved oxygen supplementation from the atmosphere through contact with the air. When the oxygen uptake rate is greater than the reaeration rate, the dissolved oxygen in the water body gradually decreases, leading to an anoxic or even anaerobic environment; while when the reaeration rate is greater than the oxygen uptake rate, the dissolved oxygen gradually recovers, restoring the self-purification ability of the water body.

[0039] The oxidation-reduction potential (ORP) of the surface sediment refers to the relative equilibrium state of the oxidation and reduction processes in the surface sediment, usually expressed in millivolts (mV). The ORP value reflects the dynamic balance between oxidants and reductants in the sediment and is an important indicator for measuring the oxidation-reduction environment of the sediment.

[0040] The oxygen sag curve refers to a curve with a concave shape in the river section polluted by aerobic organic matter, where the dissolved oxygen concentration is distributed along the river course. As shown in Figure 1 , in the curve, a is the cumulative oxygen consumption vertical curve of organic matter decomposition, b is the cumulative reoxygenation vertical curve of water body, c is the oxygen sag curve, and the lowest point C p is the maximum hypoxia point, called the oxygen sag point. When the river water is polluted by organic matter, microorganisms decompose the organic matter through biological oxidation, resulting in a significant decrease in the dissolved oxygen concentration; subsequently, due to atmospheric reoxygenation and photosynthesis of aquatic plants, the dissolved oxygen gradually recovers, forming a concave curve shape. Among them, in the descending stage of the curve: the oxygen consumption rate is greater than the reoxygenation rate, and the dissolved oxygen concentration gradually decreases; at the critical point (the lowest point): the oxygen consumption rate is equal to the reoxygenation rate, and the dissolved oxygen concentration reaches the lowest value (called the oxygen sag point); in the ascending stage of the curve: the oxygen consumption rate is less than the reoxygenation rate, and the dissolved oxygen concentration gradually recovers.

[0041] In the present invention, different mass gradients of FeSO4 and NaS are added to the sediment respectively to simulate the situation of different Fe 2+ , AVS contents in the sediment. By measuring the Fe 2+ , AVS contents in the sediment after adding different gradients of FeSO4 and NaS, the Fe 2+ , AVS content ranges in the sediment after addition cover the Fe 2+ , AVS content ranges in the river sediment in this area to determine the appropriate addition gradients of FeSO4 and NaS.

[0042] Different methods are adopted for simulation according to the flow state of the river water body. Among them, for the relatively static river water body, static culture is used to simulate the relatively static river, and the change of DO concentration in the overlying water of each culture system is measured during the static culture; for the flowing river, stirring culture is used to simulate the flowing river; and the DO concentration in the overlying water of each culture system is measured during the static or stirring culture, and the DO-t change curves corresponding to different culture systems are plotted during the measurement.

[0043] Based on the DO-t change curves corresponding to different culture systems, with the initial Fe 2+ or AVS content in the sediment as the abscissa and the maximum oxygen consumption as the ordinate, the relationship curves between the oxygen consumption and the Fe 2+ , or AVS content in the sediment are plotted. Among them, the expression between the oxygen consumption and the AVS content in the sediment satisfies the relationship formula y1 = k1x1 + b1, where x1 is the AVS content in the sediment, with the unit of g / kg, and the oxygen consumption y1 is DO 初 -DO min , with the unit of mg / L; the relationship between the oxygen consumption and the Fe 2+ content in the sediment satisfies the relationship formula y2 = k2x2 + b2, where x2 is the Fe content in the sediment2+ Content, unit: g / kg, oxygen consumption y2 is DO 初 -DO min , unit: mg / L.

[0044] According to the oxygen consumption of (DO 初 -2), the corresponding Fe is calculated by the extrapolation method 2+ and AVS content limits. The control threshold of Fe 2+ or AVS in the river sediment can be set to ≤ its corresponding limit value, and the water body can be monitored according to the determined control threshold to prevent the water body from turning black and stinking. The occurrence of black and stinking of the water body can be prevented by monitoring the content of Fe 2+ and AVS in the sediment. If the content of Fe 2+ and AVS in the sediment exceeds its control threshold, treatment measures shall be taken to make the content of Fe 2+ and AVS in the sediment lower than the control threshold, such as excavating the sediment exceeding the control threshold to prevent the water body from turning black and stinking.

[0045] Based on this, the present invention provides a monitoring method for preventing black and stinking of river water bodies, which includes the following steps:

[0046] (1) Simulate different sediment systems

[0047] Determine the addition amounts of FeSO4 and NaS: Collect sediment samples in the target river area according to the designed sampling points. After pre-treating the sediment samples, divide them into multiple groups with equal mass, and add 0, m1, m2, m3...m i of FeSO4 or NaS respectively. After mixing evenly, take the surface sediment to measure the Fe 2+ content or AVS content of the sediment, and determine the appropriate addition gradient of FeSO4 or NaS based on the measured Fe 2+ content or AVS content range of the sediment covering the actual content range of the urban river sediment.

[0048] (2) Plot the change curve of DO-t in the simulated system

[0049] Simulate in different ways according to the flow state of the sampled river water body. For the river with relatively static water body, static culture is used to simulate the river with relatively static water body, and for the river with flowing water body, stirring culture is used to simulate the river with flowing water body; and measure the DO concentration of the overlying water in each culture system during static or stirring culture, and plot the DO-t change curves corresponding to the culture systems with different amounts of FeSO4 and NaS added during the culture time t.

[0050] (3) Calculate the limit value of the Fe 2+ content or AVS content of the sediment

[0051] Establish the relationship between oxygen consumption and Fe in the sediment2+ Relationship between the content or AVS content: Based on the obtained DO-t change curves corresponding to different culture systems, with the initial Fe in the sediment 2+ or AVS content as the abscissa and the maximum oxygen consumption as the ordinate, draw the relationship curve between the oxygen consumption and the sediment Fe 2+ or AVS content;

[0052] Among them, the expression between the oxygen consumption and the sediment AVS content satisfies the relationship y1 = k1x1 + b1, where x1 is the sediment AVS content and y1 is the DO 初 -DO min corresponding oxygen consumption; the relationship between the oxygen consumption and the sediment Fe 2+ content satisfies the relationship y2 = k2x2 + b2, where x2 is the sediment Fe 2+ content and y2 is the DO 初 -DO min corresponding oxygen consumption.

[0053] According to the maximum oxygen consumption corresponding to DO min of 2 mg / L, the corresponding Fe in the sediment when the water body becomes black and odorous is calculated by the extrapolation method 2+ or AVS content, and use it as the limit value of the sediment Fe 2+ or AVS content. The control threshold of the sediment Fe in this river 2+ or AVS content can be set to ≤ its corresponding limit value. Monitor according to the sediment Fe 2+ or AVS content not exceeding the control threshold to prevent the water body from becoming black and odorous.

[0054] Low DO is a typical feature of black and odorous water bodies: The "Work Guide for the Renovation of Urban Black and Odorous Water Bodies" issued in 2015 stipulates the grading standard for urban black and odorous water bodies as mild black and odorous when the dissolved oxygen is between 0.2 and 2.0 mg / L, and severe black and odorous when the dissolved oxygen < 0.2 mg / L. Although the water body black and odorous level can be classified according to the content of dissolved oxygen in the water body, even if the detected DO concentration > 2.0 mg / L after the water body treatment, there will still be a secondary black and odor of the water body caused by the influence of the sediment in the later stage. Once the detected DO concentration of the water body ≤ 2.0 mg / L, it means that the water body has become black and odorous. Moreover, the change of the dissolved oxygen content in the water body has no obvious rule to follow. This is mainly because the factors affecting the dissolved oxygen in the water body are various, including physical (such as temperature, altitude terrain, water flow velocity, etc.), chemical (such as organic matter and pollutants, chemical composition of the water body, etc.) and biological factors (such as biological activities). These factors act together to determine the dynamic balance of dissolved oxygen in the water body. Therefore, it is currently difficult to prevent the occurrence of water body black and odor in time only based on monitoring the dissolved oxygen in the water body. And the present invention can prevent the water body from becoming black and odorous by monitoring the content of Fe 2+ or AVS in the sediment and controlling it below the threshold.

[0055] In some embodiments, the river water body in the sampling area of Dongguan is relatively static. The DO-t change curve of the culture system with FeSO4 added to the sediment shows a trend of first decreasing and then increasing, and DO min > 2 mg / L. The content of AVS in the sediment is mainly monitored. The control threshold of AVS in the sediment is obtained according to the following method:

[0056] After collecting sediment samples and removing impurities, they are divided into multiple equal groups and filled into plexiglass cylinders with a height of 25 cm so that the sediment thickness is 8-10 cm. Different masses of Na2S are added respectively, and the initial content of AVS in the sediment is measured to make the AVS content range in the mixed sediment cover the AVS content range of the urban river sediment.

[0057] Add tap water to fill the plexiglass cylinder, and measure the initial DO concentration of the tap water; after balancing for a period of time until the suspended particles settle and a clear sediment-water interface appears, start timing, and culture for a period of time t under static conditions. Wait until the oxygen consumption rate caused by S 2- is greater than the atmospheric reoxygenation rate to stop the experiment (such as when the DO of the water body rapidly decreases and then remains at a certain value), simulate the relatively static situation of the black and smelly river water body, measure the DO concentration of the overlying water corresponding to different static culture times. The DO concentration of the overlying water shows a trend of first decreasing and then increasing, and the lowest DO concentration < 2 mg / L. Establish a linear relationship between the AVS content of the surface sediment and the maximum oxygen consumption within t time, and obtain the linear equation y1 = 0.3184 * x1 + 0.0417, R 2 = 0.9647; where x1 is the AVS content of the surface sediment, and y1 is the oxygen consumption obtained according to DO 初 -DO min obtained.

[0058] According to the obtained linear equation, calculate the corresponding limit value of the AVS content of the surface sediment according to the oxygen consumption y1 (DO min -2) corresponding to 2 mg / L. For example, for the relatively static rivers in Dongguan, the corresponding AVS contents of the sediment when the water bodies change from Class I, Class II, and Class III water bodies to black and smelly water bodies are 17.14 g / kg, 12.43 g / kg, and 9.29 g / kg respectively. That is, the AVS content of the sediment that should be controlled to prevent the water body from changing from Class I, Class II, and Class III water bodies to black and smelly water bodies should not exceed the corresponding limit values. The control threshold of the AVS content of the sediment can be set as ≤ the corresponding limit values. For example, the Fe 初 control thresholds of the sediment of Class I, Class II, and Class III water bodies can be set as 17 g / kg, 12 g / kg, and 9 g / kg respectively. 2+

[0059] ​In some implementations, the DO-t curve corresponding to the culture system where the river water in the sampling area of Dongguan City was flowing and the sediment without NaS added showed a decrease (DO min <2mg / L) to maintain balance, mainly monitoring the Fe 2+ Content, Fe in the sediment 2+ The control threshold is obtained as follows:

[0060] Sediment samples were collected in the target river area, and after removing impurities, they were divided into multiple groups of equal weight, and were placed in 25 cm high organic glass cylinders to make the sediment thickness 8-10 cm. Different masses of soluble ferrous salts were added to determine the Fe content in the sediment. 2+ Initial content, so that the Fe content in the mixed sediment 2+ The content range covers the river sediment Fe in the urban area 2+ The soluble ferrous salt is preferably a sulfate with a more stable anion, such as FeSO4, whose anion will not participate in the reaction and will not affect the accuracy of the measurement result.

[0061] Add tap water to fill the plexiglass cylinder and measure the initial DO concentration of the tap water; keep the stirring conditions for dynamic culture until time t (such as observing the oxygen sag curve, when DO recovers to the vicinity of the initial concentration and no longer decreases, the experiment can be stopped), simulate the flow of black and smelly river water and the resuspension of sediment, and measure the DO concentration of the overlying water corresponding to different dynamic culture times. The DO concentration of the overlying water shows a trend of first decreasing and then increasing, and the lowest DO concentration is less than 2 mg / L, establishing the surface sediment Fe 2+ The linear relationship between the content and the maximum oxygen consumption within t time was obtained, and the linear equation y2=0.0961*x2+2.3948, R 2 =0.9198; where x2 is the surface sediment Fe 2+ Content, y2 is according to DO 初 -DO min Oxygen consumption obtained.

[0062] According to the obtained linear equation, according to DO min The corresponding oxygen consumption y2(DO 初 -2) Calculate the corresponding surface sediment Fe 2+ Content limit, such as the sediment Fe in the flowing rivers of Dongguan City, which changes from Class I, Class II, and Class III water bodies to black and odorous water bodies 2+ The contents were 32.31 g / kg, 16.70 g / kg, and 6.29 g / kg, respectively, which are the sediment Fe that should be controlled to prevent the water from changing from Class I, Class II, and Class III water bodies to black and smelly water bodies. 2+ If the content does not exceed the limit, the sediment Fe 2+The content control threshold is set to ≤ the limit value, such as the Fe content in the sediment of Class I, Class II, and Class III water bodies can be 2+ The control thresholds were set at 32g / kg, 16g / kg, and 6g / kg, respectively.

[0063] The following are examples

[0064] Instruments: sediment column sampler (Tianjin Weihang Environmental Technology Co., Ltd., model: WH-2014A), multi-parameter water quality analyzer (YSI 556), sulfide ion selective electrode (Thermo, USA), electric blast drying oven (Shanghai Yiheng Scientific Instrument Co., Ltd., model: DHG-9240A), programmed temperature furnace (Nabertherm, model: P330), UV-visible spectrophotometer (HACH, model: DR2800), Feige centrifuge (Shanghai Anting Scientific Instrument Factory, model: TDL-5), constant temperature oscillator (MSK, Hefei Aibensen Scientific Instrument Co., Ltd.), scanner (Canon, model: 5600F), microplate spectrophotometer (BioTek, USA), micropipette gun (Eppendorf), digital display constant temperature electric heating plate (Changzhou Aohua Instrument Co., Ltd., model: DB-3B).

[0065] Reagent: Ammonium molybdate ((NH4)6Mo7O 24 ·4H2O, AR, Tianjin Miou Chemical Reagent Co., Ltd.), potassium antimony tartrate (K(SbO)C4H4O6·1 / 2H2O, AR, Guangzhou Chemical Reagent Factory), ascorbic acid (C6H8O6, AR, Tianjin Damao Chemical Reagent Factory), concentrated sulfuric acid (H2SO4, AR, Guangzhou Chemical Reagent Factory), o-phenanthroline (1,10-phenanthroline, AR, Aladdin), hydroxylamine hydrochloride (NH2OH·HCl, AR, Tianjin Damao Chemical Reagent Factory), ferrous ammonium sulfate ((NH4)2Fe(SO4) 26 H2O, AR, General-Reagent), ammonium acetate (C2H7NO2, AR, Aladdin), glacial acetic acid (C2H4O2, AR, Aladdin), EDTA (C 10 H 16 N2O8, AR, Aladdin) etc.

[0066] Preparation of reagents:

[0067] ① Iron standard stock solution: Accurately weigh 0.7020g of ammonium ferrous sulfate (NH4)2Fe(SO4) 26 H2O, dissolved in 50mL of (1+1) sulfuric acid, transferred to a 1000mL volumetric flask, added water to the mark, and shaken. This solution contains 100μg of iron per mL.

[0068] ②Iron standard stock solution: Accurately pipette 25.00 mL of the standard stock solution into a 100 mL volumetric flask, add water to the mark, and mix well. Each milliliter of this solution contains 25.00 μg of iron.

[0069] ③(1+3) Hydrochloric acid: Concentrated hydrochloric acid and distilled water are prepared according to a volume ratio of 1:3.

[0070] ④10% Hydroxylamine hydrochloride solution: Dissolve 10 g of hydroxylamine hydrochloride in 100 mL of water.

[0071] ⑤Buffer solution: Dissolve 40 g of ammonium acetate and 50 mL of glacial acetic acid, and dilute to 100 mL with water.

[0072] ⑥0.5% Aqueous solution of o-phenanthroline (1,10-phenanthroline), add a few drops of hydrochloric acid to assist dissolution.

[0073] Preparation method of H2S absorption solution SAOB: 2M NaOH + 0.1M ascorbic acid + 0.1M EDTA.

[0074] Excel software is used for the preliminary processing of experimental data, Image J software is used for the gray-scale analysis of available S, Origin 8.5 software is used for the drawing of graphs, and ArcGIS10.1 software is used for the drawing of sampling point distribution maps.

[0075] Example 1 Prevention and control of water body black odor in the case of relatively static water body

[0076] 1.1 Monitoring of sediment Fe 2+ of

[0077] Take the sediment from the black and smelly river in Dongguan (relatively static water body), remove stones, weeds and other substances, mix well, take 7 portions of sediment of the same weight, and put them into plexiglass cylinders (inner diameter 9 cm, height 25 cm) respectively, so that the sediment thickness is about 10 cm. Taking the one without adding FeSO4 as the control, add 10 g, 20 g, 40 g, 60 g, 80 g, and 100 g of FeSO4 to the sediment respectively, and mix well. Take the sediment within the top 5 cm of each plexiglass tube and measure the content of Fe in the sediment. The measurement steps are as follows: 2+ of

[0078] ①Drawing of the standard curve

[0079] Transfer 0, 2.00, 4.00, 6.00, 8.00, and 10.00 mL of the iron standard stock solution successively into 150 mL conical flasks. Add distilled water to make up to 50.0 mL, then add 1 mL of (1+3) hydrochloric acid, 1 mL of 10% hydroxylamine hydrochloride, and 1-2 glass beads. Heat to boiling until the solution is reduced to about 15 mL, cool to room temperature, and quantitatively transfer to a 50 mL stoppered colorimetric tube. Add a small piece of Congo red test paper, and dropwise add saturated sodium acetate solution until the test paper just turns red. Then add 5 mL of buffer solution and 2 mL of 0.5% o-phenanthroline solution, and make up to the mark with water. Shake well. After 15 minutes of color development, use a 10 mm colorimetric cell, with water as the reference, measure the absorbance at 510 nm. Then plot the absorbance corrected for the blank against the micrograms of iron, and the standard curve is as Figure 2 shown.

[0080] ② Determination of Fe content in sediment 2+ Content

[0081] Accurately weigh 2-3 g of wet sediment (surface sediment) into a 50 mL centrifuge tube, add 50 mL of 1 mol / L HCl and seal, and store at 2 °C in the refrigerator. Shake the centrifuge tube containing HCl and sediment at room temperature for 24 h, centrifuge for 10 min (4800 rmp), aspirate the supernatant, filter (mixed cellulose filter membrane, pore size 0.45 μm) into a sample bottle, and store at 4 °C for determination.

[0082] Transfer 15 mL of the filtered solution sample from the sample bottle to a 50 mL stoppered colorimetric tube, add buffer solution and o-phenanthroline solution, make up to the mark with water, and shake well. After 15 minutes of color development, use a 10 mm colorimetric cell, measure the absorbance at 510 nm, and make a blank correction. Calculate the Fe 2+ content in each group of surface sediments according to the plotted standard curve. The results are as Figure 3 shown.

[0083] It can be seen from Figure 3 that as the addition amount of FeSO4 increases, the Fe 2+ content in the surface sediment also increases linearly. In addition, in this example, the Fe 2+ content in the surface sediment of black and smelly water bodies in Dongguan was also synchronously measured in the range of 17.22-44.77 g / kg. After adding different amounts of FeSO4 according to this design, the Fe 2+ content in the surface sediment is between 17.9-59.8 g / kg, covering the Fe 2+ content range in the surface sediment of black and smelly water bodies in the actual environment, indicating that the designed addition amount of FeSO4 in this method is reasonable.

[0084] ③ Establish the relationship between the addition amount of FeSO4 and the Fe 2+ content in the surface sediment

[0085] Add tap water to the plexiglass tube until the entire tube is filled, and measure the initial DO concentration of the tap water (8 mg / L), denoted as DO 初 . After equilibration for a period of time until the suspended particulate matter settles and a clear muddy water interface appears, start timing. Then, measure the overlying water DO concentration at 20 min, 40 min, 60 min, 80 min, 100 min, 150 min, 300 min, 360 min, 420 min, 1470 min, 1530 min, and 1740 min in sequence. The DO-t changes with different amounts of FeSO4 added under static culture conditions are as Figure 4 shown.

[0086] From Figure 4 the DO-t changes, it can be seen that in each addition system, the overlying water DO concentration drops from the initial 8 mg / L to the lowest within 40 min, and then the overlying water DO concentration shows an increase as time extends. At the end of the experiment, the DO concentration stabilizes between 6.0 and 7.0 mg / L. Denote the lowest value of the overlying water DO concentration measured during static culture as DO min , and the range of the lowest DO concentration in each addition system is between 3.45 and 4.98 mg / L. It can be seen that DO min is greater than 2 mg / L for all.

[0087] From this, it seems that Fe in the sediment 2+ mainly consumes oxygen instantaneously, consuming a large amount of dissolved oxygen, resulting in a decrease in the ORP of the surface sediment. The release amount of Fe 2+ increases, and the dissolved oxygen drops rapidly. As Fe 2+ is continuously oxidized, the oxygen consumption rate gradually slows down, and then the oxygen consumption rate starts to be less than the reoxygenation rate, and the dissolved oxygen gradually recovers. Once the water body is reoxygenated, divalent iron also becomes unstable and is oxidized to trivalent iron. The ORP of the surface sediment also gradually increases, the release amount of Fe 2+ gradually decreases, and the oxygen consumption ability of Fe 2+ also weakens. Eventually, it cannot maintain the oxygen consumption rate greater than the reoxygenation rate, and black odor does not occur.

[0088] After adding FeSO4, the highest content of Fe 2+ is 59.8 g / kg, approaching the highest value of Fe 2+ content in domestic black-odorous bottom mud, indicating that the non-occurrence of black odor is not due to insufficient FeSO4 added to the bottom mud, resulting in insufficient Fe 2+ to consume enough oxygen. The oxygen consumption of Fe 2+ does not lead to the situation where the water body DO cannot recover. Continuing to add FeSO4 may cause the DO to drop below 2 mg / L and not recover, but Fe 2+The content exceeds the general content range in the sediment, and the obtained threshold has no control significance. Therefore, under the condition of relatively static water body, controlling the content of Fe in the sediment 2+ below 60 g / kg, the Fe in the sediment 2+ will not cause the occurrence of black and odorous water body.

[0089] 1.2 Monitoring of sediment AVS

[0090] ① Establish the relationship between the addition amount of Na2S and the AVS content in the surface sediment

[0091] Take the sediment from the black and odorous river channels in Dongguan mentioned above. After removing stones, weeds and other substances, mix it evenly. Take 5 portions of sediment with the same weight and put them into plexiglass cylinders (inner diameter 9 cm, height 25 cm) respectively, so that the sediment (bottom mud) thickness is about 10 cm. Add different masses of Na2S to the sediment culture system. The addition amounts of Na2S are 0 g, 10 g, 15 g, 25 g, and 37.5 g respectively. Take 5 g of the surface sediment from each plexiglass cylinder and determine the initial AVS content of the sediment according to the following method:

[0092] Put 5 g (wet weight) of sediment into a 250 mL reaction flask, and add a magnetic rotor to the reaction flask. Take 10 mL of strong alkaline sulfide antioxidant buffer (SAOB) solution (the preparation method is 2M NaOH + 0.1M ascorbic acid + 0.1M EDTA) and place it in an absorption flask, and suspend the absorption flask above the reaction flask. Pass N2 into the reaction flask for 30 seconds to exhaust the air, and seal the reaction flask with a sealing film. Pierce the sealing film with a syringe needle and add 25 mL of 1M HCl to the reaction flask, and seal the needle hole on the sealing film with vaseline. Place the reaction flask on a magnetic stirrer, stir the reaction for 1 - 2 hours, and then use a sulfide ion selective electrode (Thermo, USA) to measure the sulfide concentration in the absorption solution SAOB. AVS is a class of reducing substances existing under anaerobic conditions such as hydrogen sulfide, methanethiol, ethanethiol, etc. S 2- Oxidation and H2S volatilization will both make the measurement results on the low side. Therefore, oxidation of the sample should be minimized during sampling, sample storage and treatment.

[0093] The measurement results of the initial AVS content of the surface sediment in each plexiglass cylinder are shown in Figure 5 shown. It can be seen that the AVS content increases linearly with the increase of the addition amount of Na2S. In this design, the AVS content range of the sediment is between 6.67 - 24.28 g / kg. Synchronously measure the AVS content range in the sediment of the black and odorous river channels in Dongguan is between 7.53 - 21.26 g / kg, and the average value is 14.88 g / kg. It can be seen that the addition amount of Na2S designed in this experiment can make the AVS content range of the added sediment cover the AVS content in the actual environment, and the design is reasonable.

[0094] ② Plot the change curve of the DO concentration in the overlying water over time

[0095] Add tap water to the plexiglass tube until it fills the entire tube, and measure the initial DO concentration of the tap water, denoted as DO 初 . After equilibration for a period of time until the suspended particulate matter settles and a clear muddy water interface appears, start timing. Then, measure the DO concentration in the overlying water at 0 h, 0.1 h, 0.4 h, 0.7 h, 1.1 h, 1.4 h, 1.6 h, 29 h, 44 h, 45 h, 47 h, 64 h, 65 h, 67 h, 70 h, 89 h, 91 h, 94 h, 96 h, 113 h, 118 h, 120 h, 137 h, 139 h, 142 h respectively. The change curve of the DO concentration in the overlying water of each culture system under static culture conditions over time is as Figure 6 shown.

[0096] It can be seen from Figure 6 that in the system without added Na2S, the DO in the overlying water body gradually decreases over time, reaching the lowest level after 70 hours. At this time, the lowest DO concentration is 5.68 mg / L, and then it gradually increases to 7.8 mg / L. In the system with added Na2S, the DO in the water body drops rapidly and reaches the lowest level after 1 hour. The lowest DO is between 0.15 and 0.29 mg / L, and then it remains below 1 mg / L. The characteristic index of slightly black and odorous water body is that the dissolved oxygen (DO) is between 0.2 and 2.0 mg / L. The experimental results show that a large amount of sulfur in the sediment causes continuous oxygen consumption in the water body through reduction. Finally, the oxygen consumption rate caused by S 2- is greater than the reoxygenation rate, resulting in continuous hypoxia in the water body. And S 2- combines with a large amount of Fe 2+ existing in the sediment to form FeS, making the water body turn black.

[0097] ③ Establish the fitting curve of the AVS content in the sediment and the oxygen consumption

[0098] Taking the measured AVS content in the surface sediment as the abscissa and the oxygen consumption as the ordinate, establish the fitting curve of the AVS content in the sediment and the oxygen consumption. Among them, the AVS content in the surface sediment refers to the initial AVS content in the surface sediment, and the oxygen consumption is the maximum oxygen consumption calculated according to the difference between the initial DO concentration and the lowest DO concentration in the water body of each culture system. The plotted fitting curve is as Figure 7 shown, and the expression of its fitting curve is y = 0.3184x + 0.0417, R 2 = 0.9647.

[0099] By establishing the fitting curve of the AVS content in the sediment and the oxygen consumption, according to the above formula, according to the oxygen consumption of (DO 初-2) The calculated AVS content value is used as the AVS limit value of the sediment. According to the control threshold of sediment AVS content ≤ the AVS limit value of the sediment, water body black odor is prevented by monitoring that the sediment does not exceed the control threshold.

[0100] Taking water bodies of Class I, Class II, and Class III (classified according to the surface water environmental function) as examples, calculate the AVS content limit values of the sediment that should be controlled for water body black odor to occur. The DO concentrations of the overlying water of Class I, Class II, and Class III water bodies are 7.5 mg / L, 6 mg / L, and 5 mg / L respectively, and the oxygen consumption (y) is 5.5 mg / L, 4 mg / L, and 3 mg / L respectively. The corresponding AVS contents of the sediment are calculated to be 17.14 g / kg, 12.43 g / kg, and 9.29 g / kg respectively, which are the AVS content limit values of the sediment that need to be controlled to prevent the water body from changing from Class I, Class II, and Class III water bodies to black odor water bodies. The control threshold of sediment AVS content can be set as ≤ the limit value. For example, the AVS control thresholds of the sediment of Class I, Class II, and Class III water bodies can be set as 17 g / kg, 12 g / kg, and 9 g / kg respectively.

[0101] Example 2 Prevention and control of water body black odor under the condition of water body flow

[0102] 1.1 Monitoring of sediment Fe 2+

[0103] ① Set the appropriate addition amount of FeSO4: the same as in Example 1.

[0104] Take the sediment of the black and smelly river channel in Dongguan (with water body flow), remove stones, weeds and other substances, mix evenly, take 7 portions of sediment with the same weight, and put them into plexiglass cylinders (inner diameter 9 cm, height 25 cm) respectively, so that the thickness of the sediment is about 10 cm. Add FeSO4 with masses of 0 g, 10 g, 20 g, 40 g, 60 g, 80 g, and 100 g to the sediment culture system respectively, and mix well. Take the sediment within the top 5 cm of each plexiglass tube to measure the initial content of Fe 2+ in the sediment. The measurement steps are the same as in Example 1, and the designed addition amount of FeSO4 makes the measured content range of Fe 2+ in the sediment cover the content range of Fe 2+ in the sediment of the rivers in this area.

[0105] ② Draw the change curve of the concentration of DO in the overlying water with time

[0106] Add tap water to the plexiglass tube until the entire tube is filled, and measure the initial DO concentration of the tap water. Cultivate for a period of time under stirring conditions to simulate the water flow and sediment resuspension in the black and odorous river channel, and measure the DO concentration of the overlying water at 0h, 5h, 7h, 9h, 10h, 11h, 24h, 35h, 46h, 52h, 54h, and 70h. The DO-t changes with the addition of different amounts of FeSO4 under the stirring culture state are as Figure 8 shown.

[0107] As Figure 8 can be seen, after the start of the experiment, the DO concentration of the overlying water in each culture system gradually decreased, reaching the lowest at about 6.5 hours, and then first gradually increased rapidly and then slowly increased, and finally recovered to about 8 mg / L. Among them, the lowest value of the DO in the overlying water of the culture system with more than 80 g of FeSO4 added was <2 mg / L. For example, the lowest DO concentration in the overlying water of the culture system with 100 g of FeSO4 added was below 0.5 mg / L.

[0108] Taking the measured Fe 2+ content of the surface sediment as the abscissa and the oxygen consumption as the ordinate, establish the fitting curve of the Fe 2+ content of the sediment and the oxygen consumption. Among them, the Fe 2+ content of the surface sediment refers to the initial Fe 2+ content of the surface sediment, and the oxygen consumption is the maximum oxygen consumption calculated according to the difference between the initial DO concentration and the lowest DO concentration of the water body in each culture system. The fitting curve drawn is as Figure 9 shown, and the expression of its fitting curve is y = 0.0961x + 2.3948, R 2 = 0.9198.

[0109] By establishing the fitting curve of the Fe 2+ content of the sediment and the oxygen consumption, according to the above formula, the Fe 初 content value calculated according to the oxygen consumption of (DO 2+ - 2) is used as the Fe 2+ limit value of the sediment. According to the sediment Fe 2+ content control threshold ≤ sediment Fe 2+ limit value, prevent water body blackening and odoring by monitoring that the Fe 2+ content of the sediment does not exceed the control threshold.

[0110] Taking water bodies of Class I, Class II, and Class III (classified according to the surface water environmental function) as examples, calculate the Fe 2+Content limits. The DO concentrations of the overlying water in Class I, Class II, and Class III water bodies are 7.5 mg / L, 6 mg / L, and 5 mg / L respectively, and the maximum oxygen consumption (y) corresponding to the lowest DO concentration of 2 mg / L is 5.5 mg / L, 4 mg / L, and 3 mg / L respectively. The corresponding sediment Fe 2+ contents are 32.31 g / kg, 16.70 g / kg, and 6.29 g / kg respectively, which are the sediment Fe content limits required to prevent the water body from changing from Class I, Class II, and Class III water bodies to black and odorous water bodies. 2+ The sediment Fe 2+ content control threshold can be set to ≤ the limit value. For example, the sediment Fe 2+ control thresholds for Class I, Class II, and Class III water bodies can be set to 32 g / kg, 16 g / kg, and 6 g / kg respectively.

[0111] 1.2 Monitoring of sediment AVS

[0112] ① Establish the relationship between the addition amount of Na2S and the AVS content in the surface sediment: same as Example 1.

[0113] Take the sediment from the black and odorous river in Dongguan (with water flow), remove stones, weeds and other substances, mix evenly, take 5 portions of sediment of the same weight, and put them into plexiglass cylinders (inner diameter 9 cm, height 25 cm) respectively, so that the sediment (sediment) thickness is about 10 cm. Add Na2S with masses of 0 g, 10 g, 15 g, 25 g, and 37.5 g to the sediment culture system respectively, and mix well. Take 5 g of sediment from each plexiglass tube to measure the initial AVS content in the sediment. The measurement steps are the same as those in Example 1, where the designed addition amount of Na2S enables the measured AVS content range of the sediment after mixing to cover the AVS content range of the river sediment in this area.

[0114] ② Plot the change curve of the DO concentration in the overlying water with time

[0115] Add tap water to the plexiglass tube until it fills the whole tube, and measure the initial DO concentration of the tap water. Cultivate for a period of time under stirring conditions to simulate the water flow and sediment resuspension in the black and odorous river channel. Measure the DO concentration in the overlying water at 0 h, 0.1 h, 0.4 h, 0.7 h, 1.1 h, 1.4 h, 1.6 h, 29 h, 44 h, 45 h, 47 h, 64 h, 65 h, 67 h, 70 h, 89 h, 91 h, 94 h, 96 h, 113 h, 118 h, 120 h, 137 h, 139 h, 142 h. The DO-t changes of adding different amounts of Na2S under the stirring culture state are as Figure 10 shown.

[0116] Compared with static culture, the DO concentration in the water body of the culture system without adding Na2S under stirring culture also decreased rapidly and could not recover, and the DO concentration in the water body of the culture system without adding Na2S also remained below 2 mg / L. The obtained threshold has no regulatory significance and is difficult to monitor and manage. It shows that compared with the relatively static river water body, in the river with flowing water body, the micro-suspension of sediment will cause more S 2- to come into contact with oxygen, causing oxygen consumption in the water body. Therefore, by monitoring the Fe content of the sediment and controlling it below the threshold, it is beneficial to prevent the occurrence of water body black odor. 2+ As described above, it is only a preferred embodiment of the present invention and does not impose any formal restrictions on the present invention. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

[0117] As described above, it is only a preferred embodiment of the present invention and does not impose any formal restrictions on the present invention. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A monitoring method for preventing the blackening and odorization of river water bodies, characterized in that, It includes the following steps: (1) Simulate different sediment systems: Collect the sediment from the target river area. After removing impurities, add different masses of FeSO4 or NaS respectively to make the initial Fe content of the sediment in the culture system 2+ or the AVS content range cover the Fe 2+ or AVS content of the urban river sediment; (2) Plot the change curve of DO-t in the simulated system: Simulate the flow state of the sampled river water for cultivation, measure the DO concentration of the overlying water in each cultivation system during the cultivation period, and plot the DO-t change curve of the corresponding cultivation system; (3) Calculate the Fe in the sediment 2+ or the limit value of AVS content Based on the DO-t change curve obtained in step (2), with the initial Fe in the sediment 2+ or the AVS content as the abscissa and the maximum oxygen consumption as the ordinate, plot the relationship curve between the oxygen consumption and the sediment Fe 2+ or the AVS content, and obtain the relational expression as y = kx + b, where the oxygen consumption y is DO 初 -DO min , x is the sediment Fe 2+ or the AVS content; calculate the limit value of the sediment Fe 初 -2) based on the oxygen consumption y being (DO 2+ or the AVS content; Set the control threshold of the river sediment Fe 2+ or AVS to ≤ the corresponding limit value, and monitor according to the content of sediment Fe 2+ or AVS not exceeding the control threshold to prevent the water body from turning black and emitting odors.

2. The monitoring method according to claim 1, characterized in that For relatively static rivers in water bodies, static cultivation is adopted. If the DO in the DO-t change curve corresponding to the cultivation system with added FeSO4 min > 2 mg / L, taking the AVS content of the sediment as the monitoring index, monitor according to the AVS content not exceeding the control threshold.

3. The monitoring method according to claim 2, wherein For the relatively static rivers in Dongguan City, static cultivation is adopted, and the AVS limit value of the river sediment is calculated according to the relationship formula between the oxygen consumption and the AVS content of the sediment: y = 0.3184x + 0.0417.

4. The monitoring method according to claim 3, characterized in that According to the oxygen consumption y being (DO 初 - 2), the limit value of the AVS content in the sediment is calculated, and monitoring is carried out according to the sediment AVS control threshold ≤ sediment AVS limit value.

5. The monitoring method according to claim 4, wherein The corresponding AVS control thresholds for river water of Class I, Class II, and Class III are 17 g / kg, 12 g / kg, and 9 g / kg respectively.

6. The monitoring method according to claim 1, characterized in that For rivers with water flow, stirring culture is used to simulate the water flow velocity. If the DO in the DO-t change curve corresponding to the culture system without added NaS is min < 2 mg / L, taking the content of sediment Fe 2+ as the monitoring index, and monitoring is carried out according to the content of Fe 2+ not exceeding the control threshold.

7. The monitoring method according to claim 6, wherein For rivers with water flow in Dongguan City, stirring culture was used to simulate sediment resuspension, and the limit value of sediment Fe in this river was calculated according to the relational expression between the oxygen consumption and the sediment Fe 2+ content: y = 0.0961x + 2.3948 2+ limit value.

8. The monitoring method according to claim 7, characterized in that, According to the oxygen consumption y being (DO 初 - 2), the content limit value of sediment Fe 2+ is calculated. According to the control threshold of sediment Fe 2+ ≤ the content limit value of sediment Fe 2+ , monitoring is carried out.

9. The monitoring method according to claim 8, wherein, The corresponding sediment Fe for Class I, Class II, and Class III river water bodies 2+ The control thresholds are 32 g / kg, 16 g / kg, and 6 g / kg.

10. The monitoring method according to any one of claims 1 to 9, characterized in that, The sediment Fe 2+ or the AVS content is the sediment Fe 2+ or the AVS content.

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