Method for rapidly increasing river water dissolved oxygen

Abstract

The application discloses a method for rapidly improving river water dissolved oxygen, and belongs to the technical field of environmental protection. The method comprises the following technical steps: (1) water quality fluorescence fingerprint database establishment; (2) pollution source dissolved oxygen concentration gradient division; (3) low-oxygen discharge outlet dissolved oxygen and water flow determination; (4) water quality fluorescence fingerprint similarity comparison; and (5) river required ecological water flow calculation. The method comprises the following steps: establishing a water quality fluorescence fingerprint database, dividing a pollution source dissolved oxygen concentration gradient, determining low-oxygen discharge outlet dissolved oxygen and water flow, comparing water quality fluorescence fingerprint similarity, and calculating the ecological water flow required for river water dissolved oxygen to reach the standard. Then, the ecological water flow is dispatched to equivalently hedge the water body with low dissolved oxygen concentration in the river mainstream, so that the river water dissolved oxygen concentration can be simply, rapidly, efficiently and accurately improved, water resource waste in the water flow dispatching process is avoided, the method has good precision and strong operability, and is easy to popularize on a large scale.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental protection, and particularly relates to a method for rapidly improving the dissolved oxygen of river water. BACKGROUND

[0002] Dissolved oxygen (DO) is an important indicator for characterizing, measuring water environment and water ecological quality, and comprehensively reflecting water quality. Dissolved oxygen is a necessary condition for aquatic organisms to survive. Generally, the dissolved oxygen content suitable for the survival and activity of most fish is 5 mg / L or more. When the dissolved oxygen content is less than 4 mg / L, it is low oxygen, less than 3 mg / L is anoxic, and less than 0.2 mg / L is anaerobic. If the water body is in a low oxygen state for a long time, it will affect the aquatic ecosystem, and may cause fish death, most algae cannot survive, and water body blackening and other phenomena. It is also a key participant in the degradation of pollutants in water, and can characterize the amount of substances that can be oxidized and decomposed in water. The dissolved oxygen content is an index for measuring the self-purification capacity of water body, and can reflect the health degree of water body.

[0003] Dissolved oxygen is in a dynamic balance of continuous consumption and recovery in natural water body. The recovery process (source) includes reoxygenation, photosynthesis and external load, and the consumption process (sink) includes organic matter oxidation, nitrification, respiration, sediment oxygen demand, chemical oxygen demand, etc. The net change of dissolved oxygen is actually the interaction of the above sources and sinks, resulting in fluctuating changes of dissolved oxygen. With the rapid development of economic society, the large discharge of domestic sewage and industrial wastewater causes serious burden on surface water environment. Affected by the discharge of external pollutants and seasonality, low oxygen phenomenon occurs in some key monitoring sections from time to time, and gradually becomes a major factor affecting the compliance of the monitoring section and the health of water ecology. External pollution load, especially the large input of oxygen-consuming substances, breaks the original dissolved oxygen balance mechanism. Once the water body receives excessive external organic matter and some plant and animal humus such as domestic sewage and livestock manure pollutants, the dissolved oxygen in the water will be quickly consumed, forming black and smelly water body, directly leading to the decline of water reoxygenation capacity, and serious oxygen deficiency problem in local water area or water layer. At present, the dissolved oxygen low oxygen problem frequently occurs in water section, but it is limited by many factors affecting the concentration of dissolved oxygen in water body, and the influencing mechanism is complex. Especially in the case of limited space for ecological flow regulation in the prevention and control of sudden dissolved oxygen low oxygen water pollution, the management of dissolved oxygen low oxygen water body is difficult and the task is heavy. Therefore, a simple, rapid and accurate method for improving the dissolved oxygen of river water needs to be researched.

[0004] Traditional methods for improving river water dissolved oxygen include mechanical oxygenation, chemical oxygenation, biological oxygenation and reducing oxygen-consuming substances. Mechanical oxygenation mainly uses oxygenation machines and water exchange to increase water flow and increase the contact area between air and water, so that oxygen molecules in the air are more easily absorbed into the water. However, the oxygenation machine has high energy consumption and equipment cost, the water exchange has limited oxygenation effect and is greatly affected by water resources, and the ecological flow regulation amount is limited. Chemical oxygenation often uses chemical oxygenation agents such as sodium percarbonate and calcium peroxide. These oxygenation agents can quickly increase the dissolved oxygen content of the water body in emergency situations such as pool flooding rescue, but attention should be paid to the influence of the oxygenation agent on water quality and the environment, as well as its potential impact on other aquatic organisms. Biological oxygenation mainly uses aquatic plants such as algae to produce oxygen through photosynthesis and release it into the water, which is a natural and sustainable method to improve dissolved oxygen. However, it is complex to manage, has high environmental requirements and has the risk of ecological invasion. Reducing oxygen-consuming substances can reduce the respiration of microorganisms and organisms in the water body by reducing organic load and controlling breeding density, thereby reducing the consumption of dissolved oxygen. However, the impact factors of reducing oxygen-consuming substances are complex and complicated.

[0005] Because the dissolved oxygen concentrations of water bodies from different pollution sources are different, the ecological water quantity required to improve the dissolved oxygen of water bodies from different pollution sources to the standard state is different. Water quality fluorescence fingerprint technology is a technology for accurately tracing the source of pollutants. When applied to improving the dissolved oxygen of river water, it identifies the source of oxygen-consuming substances based on the ecological water quantity required for water bodies from different sources of pollutants, so as to accurately regulate the ecological water flow required for the river water dissolved oxygen to reach the standard, and quickly and accurately improve the river water dissolved oxygen, and fundamentally solve the problem of water resource limitation. SUMMARY

[0006] To solve the above problems, the present application provides a method for quickly improving the dissolved oxygen of river water, which comprises the following steps: establishing a water quality fingerprint fluorescence tracing characteristic spectrum database, then comparing the fingerprint similarity of the low-oxygen discharge outlet water sample and the pollution source water sample, to determine the source of pollutants of the low-oxygen discharge outlet water sample, and then calculating the ecological water flow required for the dissolved oxygen of the river mainstream water body to reach the standard according to the ecological water requirement calculation formula, so as to achieve the purpose of simply, quickly, efficiently and accurately improving the dissolved oxygen of river water.

[0007] The present application is realized by the following technical solutions:

[0008] A method for quickly improving the dissolved oxygen of river water, comprising the following steps:

[0009] (1) Water quality fluorescence fingerprint database establishment: Collect various types of pollution sources in the river basin, including industrial pollution sources, agricultural pollution sources, domestic pollution sources, and livestock breeding pollution sources. Use the water pollution early warning tracing instrument to detect the water samples of various pollution sources, obtain the water quality fluorescence fingerprint spectrum of all water samples, and establish a water quality fluorescence fingerprint tracing characteristic spectrum database;

[0010] (2) Dissolved oxygen concentration gradient division of pollution sources: Divide the water samples of various pollution sources into different dissolved oxygen concentration gradients of pollution sources according to the dissolved oxygen limit value. Take a unit water sample of each type of pollution source, add ecological water source, then measure the dissolved oxygen concentration until it meets the standard, and record the added ecological water volume. The specific process is as follows:

[0011]

[0012] (3) Dissolved oxygen and water flow measurement of low-oxygen discharge outlets: Use aerial photography and manual inspection to measure the dissolved oxygen concentration of the water samples of the discharge outlets in the river basin, screen out the number of low-oxygen discharge outlets, and measure the water flow of the low-oxygen discharge outlets;

[0013] (4) Water quality fluorescence fingerprint similarity comparison: Use the water pollution early warning tracing instrument to detect the water samples of the low-oxygen discharge outlets, obtain the water quality fluorescence fingerprint spectrum of the water samples of the low-oxygen discharge outlets, and compare the similarity with the water quality fluorescence fingerprint tracing characteristic spectrum database in step (1) to confirm the pollution source category of the water samples of the low-oxygen discharge outlets;

[0014] (5) River required ecological water volume calculation: According to the dissolved oxygen concentration of the low-oxygen discharge outlets measured in step (3) and the pollution source category confirmed in step (4), corresponding matching is performed with the dissolved oxygen concentration gradient of different pollution sources divided in step (2) to determine the required ecological water volume of a unit water sample of the low-oxygen discharge outlets. The ecological water flow required for the river mainstream water body to meet the dissolved oxygen standard is calculated according to the ecological water demand calculation formula, and then the water body with low dissolved oxygen concentration in the river mainstream is adjusted through ecological flow regulation to quickly improve the dissolved oxygen concentration of the river water body until it meets the standard.

[0015] Further, in step (5), the ecological water demand calculation formula is:

[0016] wherein V is the ecological water flow required for the river mainstream water body to meet the dissolved oxygen standard, m 3 / d; n is the number of low-oxygen discharge outlets, pieces; v i is the water flow of the i 3 th low-oxygen discharge outlet, m i / d; vt i is the ecological water volume required for a unit water sample of the i 3 th low-oxygen discharge outlet to meet the dissolved oxygen standard, L; 1L is a unit water volume.

[0017] Further, in step (4), the similarity comparison is to compare the water quality fluorescence fingerprint of the low-oxygen discharge outlet water sample with the fluorescence fingerprint characteristics of the water quality fluorescence fingerprint traceability characteristic database, i.e., to compare the similarity of the fluorescence fingerprint peak intensity at the excitation wavelength and the emission wavelength.

[0018] Further, the fluorescence fingerprint characteristics are the protein-like peak intensity at the excitation wavelength of 235 nm and the emission wavelength of 350 nm and the humus-like peak intensity at the excitation wavelength of 260 nm and the emission wavelength of 435 nm.

[0019] Further, when the similarity is greater than 90%, the pollution source category of the low-oxygen discharge outlet water sample can be confirmed.

[0020] Further, in step (3), the dissolved oxygen concentration of the low-oxygen discharge outlet is less than 5 mg / L.

[0021] Further, in steps (2) and (5), the requirement for the dissolved oxygen concentration until reaching the standard is that the dissolved oxygen concentration is greater than 5 mg / L.

[0022] Further, in steps (2) and (3), the determination method of the dissolved oxygen concentration is to use an electrochemical method to determine the dissolved oxygen concentration of the water body surface of 28-30 cm, and the determination time is 4-5 min.

[0023] Further, in steps (1) and (4), before the water sample is detected by using the water pollution early warning tracing instrument, the water sample is stored at 4-5 DEG C, and then the water sample after cold storage is filtered by using a 0.45 mu m filter membrane, and then the detection is performed.

[0024] Further, in step (1), the industrial pollution source includes water samples of industrial production water and drainage, treatment tail water; the agricultural pollution source includes water samples of various types of economic crops discharged from ditches in various types of dry land and paddy fields; the living pollution source includes water samples discharged directly and discharged after treatment by a sewage treatment plant; and the poultry breeding pollution source includes water samples discharged by poultry and fish and shrimp breeding and surrounding water samples.

[0025] Compared with the prior art, the advantages and beneficial effects of the present application are:

[0026] 1. The present application can simply, quickly, efficiently and accurately improve the dissolved oxygen of the river water body by establishing a water quality fluorescence fingerprint database, dividing a pollution source dissolved oxygen concentration gradient, determining the dissolved oxygen and water flow of a low-oxygen discharge outlet, comparing the water quality fluorescence fingerprint similarity, and calculating the ecological water flow required for the river water body to reach the standard of dissolved oxygen, and then performing equivalent hedging on the water body with low dissolved oxygen concentration in the river mainstream through ecological flow regulation, so that the present application can be applied to emergency treatment of water environmental problems, has good precision, and is easy to popularize on a large scale.

[0027] 2、Because the oxygen-consuming substances in the water body have large differences in content, the required ecological water volume is different, the present application aims at different pollution sources input into the river water body, first establishes a water quality fingerprint fluorescence traceability characteristic spectrum database, then compares the fingerprint similarity of the low-oxygen discharge outlet water sample and the pollution source water sample, so as to determine the pollution source, based on the pollution source being clear, the ecological water flow required for the river dissolved oxygen to reach the standard is calculated, so as to simply, quickly, efficiently and accurately improve the dissolved oxygen of the river water body.

[0028] 3、The present application aims at the low-oxygen problem of water body dissolved oxygen caused by different pollution sources input into the river, determines the flow, dissolved oxygen concentration, pollution source of the river water sample from the source, and the ecological water flow required for adjusting the dissolved oxygen to reach the standard, and converts the required ecological flow according to the formula, avoids the waste of water resources in the water flow scheduling process, has good target orientation and good operability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a water quality fluorescence fingerprint spectrum graph of livestock breeding pollution source.

[0030] Figure 2 It is a water quality fluorescence fingerprint spectrum graph of agricultural pollution source.

[0031] Figure 3 It is a water quality fluorescence fingerprint spectrum graph of domestic pollution source.

[0032] Figure 4 It is a water quality fluorescence fingerprint spectrum graph of industrial pollution source. DETAILED DESCRIPTION

[0033] The present application will be further described in detail by the following examples, which are only used to illustrate the present application and do not limit the protection scope of the present application.

[0034] Example

[0035] A method for quickly improving the dissolved oxygen of river water body, comprising the following steps:

[0036] (1) Water quality fluorescence fingerprint database establishment: Collect various types of pollution sources in a river basin of Guangxi Beibu Gulf, including industrial pollution sources (including industrial water for production and drainage, treated water), agricultural pollution sources (including various types of economic crops in various types of dry land and paddy fields), domestic pollution sources (including direct discharge and discharge after treatment in sewage treatment plants), and livestock breeding pollution sources (including discharge from livestock and fish and shrimp breeding and surrounding water samples). Use water pollution early warning tracing instrument to detect water samples from various pollution sources. First, store the water samples at 4°C, then filter the refrigerated water samples with 25mm x 0.45μm filter membrane, then detect and obtain the water quality fluorescence fingerprint spectrum of all water samples, establish the water quality fluorescence fingerprint spectrum database, and the water quality fluorescence fingerprint spectrum of livestock breeding pollution sources, agricultural pollution sources, domestic pollution sources and industrial pollution sources are shown in Figures Figures 1-4

[0037] (2) Dissolved oxygen concentration gradient division of pollution sources: The water samples from various pollution sources are divided into different dissolved oxygen concentration gradients of pollution sources according to the dissolved oxygen limit value. The division basis is "Surface Water Environmental Quality Standard" (GB3838-2002) and Urban Black and Odorous Water Pollution Degree Classification Standard. Add ecological water to each unit water sample of various pollution sources, then measure the dissolved oxygen concentration until it meets the standard (5mg / L or more). Use electrochemical method for determination. Specifically, use portable multi-parameter water quality detector (SMARTROLL type) to directly measure the dissolved oxygen at the surface of water body 30cm. The measurement time is 5min, and the added ecological water quantity is recorded. The ecological water quantity required by each unit water sample of various pollution sources is shown in Table 1:

[0038] Table 1 Ecological water quantity required by each unit water sample of various pollution sources

[0039]

[0040] (3) Measurement of dissolved oxygen and water flow of low-oxygen discharge outlets: Use aerial photography and manual inspection to identify the river discharge outlets in the basin. Specifically, use unmanned aerial vehicle aerial photography and image interpretation to confirm the location of the river discharge outlets. Use unmanned aerial vehicle aerial photography to confirm whether the river discharge outlets discharge water. Use manual inspection and confirmation to determine the water discharge of the river discharge outlets. Collect water samples and measure the dissolved oxygen concentration of the water samples from the discharge outlets. Use electrochemical method for determination. Specifically, use portable multi-parameter water quality detector (SMARTROLL type) to directly measure the dissolved oxygen at the surface of water body 30cm. The measurement time is 5min. There are 12 low-oxygen discharge outlets with dissolved oxygen concentration lower than 5mg / L, and the water flow of the low-oxygen discharge outlets is measured. The dissolved oxygen concentration and water flow of the water samples from the 12 low-oxygen discharge outlets are shown in Table 2:

[0041] Table 2 Dissolved oxygen and water flow of water samples from low-oxygen discharge outlets ​

[0042]

[0043] (4) Water quality fluorescence fingerprint similarity comparison: The water samples of the low-oxygen discharge outlets are detected by the water pollution early warning tracing instrument to obtain the water quality fluorescence fingerprint spectrum of the low-oxygen discharge outlets, and the similarity comparison is performed with the water quality fingerprint fluorescence tracing characteristic spectrum database in step (1), the fluorescence fingerprint characteristics of the two are compared, specifically the protein-like peak intensity under the excitation wavelength of 235 nm and the emission wavelength of 350 nm and the humus-like peak intensity under the excitation wavelength of 260 nm and the emission wavelength of 435 nm are compared, and when the fluorescence fingerprint characteristics similarity is 90% or more, the pollution source category of the low-oxygen discharge outlet water sample can be confirmed. The similarity comparison results of the 12 low-oxygen discharge outlet water samples and the pollution source categories are shown in Table 3 as follows:

[0044] Table 3 Similarity comparison results of low-oxygen discharge outlet water samples and pollution source categories

[0045]

[0046] (5) River required ecological water flow calculation: According to the dissolved oxygen concentration of the low-oxygen discharge outlet determined in step (3) and the pollution source category confirmed in step (4), the dissolved oxygen concentration gradient of different pollution sources divided in step (2) is matched correspondingly to determine the required ecological water volume of the unit water sample of the low-oxygen discharge outlet, and the ecological water flow required for the river mainstream water body to reach the standard of dissolved oxygen is calculated according to the ecological water demand calculation formula; the ecological water demand calculation formula is:

[0047] In the formula, V is the ecological water flow required for the river mainstream water body to reach the standard of dissolved oxygen, m 3 / d; n is the number of low-oxygen discharge outlets, pieces; v i is the flow of the i th low-oxygen discharge outlet, m 3 / d; v i is the ecological water volume required for the unit water sample of the i th low-oxygen discharge outlet to reach the standard of dissolved oxygen, L; 1L is the unit water volume. The ecological water volume required for the unit water sample of the 12 low-oxygen discharge outlets and the ecological water flow required for the river mainstream water body are shown in Table 4 as follows:

[0048] Table 4 Ecological water volume required for unit water sample of low-oxygen discharge outlet and ecological water flow required for river mainstream water body

[0049]

[0050]

[0051] The ecological water flow required for the river mainstream water body to reach the standard of dissolved oxygen calculated by the above ecological water demand calculation formula is 116600 m 3 / d, and the low-dissolved oxygen concentration water body in the main stream of the river is hedged by ecological flow regulation, so as to quickly improve the dissolved oxygen concentration of the water body in the river to reach the standard.

[0052] The above merely describes preferred embodiments of the present application but should not be used to limit the present application, and any modification, equivalent replacement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for rapidly increasing the dissolved oxygen of a river water body, characterized by, Comprising the following steps: (1) Water quality fluorescence fingerprint database establishment: Collect various types of pollution sources in the river basin, including industrial pollution sources, agricultural pollution sources, domestic pollution sources and livestock breeding pollution sources, use water pollution early warning tracing instrument to detect water samples of various types of pollution sources, obtain water quality fluorescence fingerprint spectrum of all water samples, and establish water quality fluorescence fingerprint tracing characteristic spectrum database; (2) Dissolved oxygen concentration gradient division of pollution sources: The water samples of various types of pollution sources are divided into different dissolved oxygen concentration gradients of pollution sources according to the dissolved oxygen limit value, and the unit water sample of various types of pollution sources is added with ecological water source, then the dissolved oxygen concentration is measured until it meets the standard, and the added ecological water quantity is recorded, as follows: When the dissolved oxygen concentration is 4mg / L≤DO<5mg / L, the ecological water quantity required for unit water sample of various types of pollution sources is: industrial pollution source is 1.2L, agricultural pollution source is 1.5L, domestic pollution source is 2L, and livestock breeding pollution source is 2.5L; When the dissolved oxygen concentration is 3mg / L≤DO<4mg / L, the ecological water quantity required for unit water sample of various types of pollution sources is: industrial pollution source is 3.8L, agricultural pollution source is 4L, domestic pollution source is 5L, and livestock breeding pollution source is 8L; When the dissolved oxygen concentration is 2mg / L≤DO<3mg / L, the ecological water quantity required for unit water sample of various types of pollution sources is: industrial pollution source is 6.8L, agricultural pollution source is 10L, domestic pollution source is 12L, and livestock breeding pollution source is 15L; When the dissolved oxygen concentration is 0.2mg / L≤DO<2mg / L, the ecological water quantity required for unit water sample of various types of pollution sources is: industrial pollution source is 12.2L, agricultural pollution source is 15L, domestic pollution source is 16L, and livestock breeding pollution source is 18L; When the dissolved oxygen concentration is DO<0.2mg / L, the ecological water quantity required for unit water sample of various types of pollution sources is: industrial pollution source is 22.4L, agricultural pollution source is 18L, domestic pollution source is 25L, and livestock breeding pollution source is 20L; (3) Measurement of dissolved oxygen and water flow of low-oxygen discharge outlet: The number of low-oxygen discharge outlets is screened out by measuring the dissolved oxygen concentration of the water sample of the discharge outlet, and the water flow of the low-oxygen discharge outlet is measured; (4) Similarity comparison of water quality fluorescence fingerprint: The water sample of the low-oxygen discharge outlet is detected by the water pollution early warning tracing instrument to obtain the water quality fluorescence fingerprint spectrum of the low-oxygen discharge outlet, and the similarity comparison is carried out with the water quality fluorescence fingerprint tracing characteristic spectrum database in step (1) to confirm the pollution source category of the water sample of the low-oxygen discharge outlet; (5) ecological water flow required by the river is calculated: according to the dissolved oxygen concentration of the low-oxygen discharge outlet determined in step (3) and the pollution source category confirmed in step (4), the dissolved oxygen concentration gradient of different pollution sources in step (2) is matched correspondingly to determine the ecological water required by the unit water sample of the low-oxygen discharge outlet, and the ecological water flow required by the river mainstream water body to reach the standard of dissolved oxygen is calculated according to the ecological water requirement calculation formula, and finally the ecological flow regulation is used to offset the water body with low dissolved oxygen concentration in the river mainstream, so as to quickly improve the dissolved oxygen concentration of the river water body until it reaches the standard; The ecological water demand calculation formula is: ; In the formula, V is the ecological water flow required for the dissolved oxygen of the river trunk water body to reach the standard, m 3 / d; n is the number of low-oxygen discharge outlets, pieces; v i is the water flow of the i th low-oxygen discharge outlet, m 3 / d; vt i is the ecological water quantity required for the dissolved oxygen of the unit water sample of the i th low-oxygen discharge outlet to reach the standard, L; 1L is a unit water quantity.

2. The method of rapidly increasing river water dissolved oxygen according to claim 1, wherein, In step (4), the similarity comparison is to compare the water quality fluorescence fingerprint spectrum of the low-oxygen discharge outlet water sample with the fluorescence fingerprint characteristics of the water quality fluorescence fingerprint traceability characteristic spectrum database, that is, the similarity of fluorescence fingerprint peak intensity under excitation wavelength and emission wavelength is compared.

3. The method of rapidly increasing river water dissolved oxygen according to claim 2, wherein, The fluorescence fingerprint characteristics are the protein-like peak intensity under 235nm excitation wavelength and 350nm emission wavelength, and the humus-like peak intensity under 260nm excitation wavelength and 435nm emission wavelength.

4. The method of rapidly increasing river water dissolved oxygen according to claim 2, wherein, When the similarity is more than 90%, the pollution source category of the low-oxygen discharge outlet water sample can be confirmed.

5. The method of rapidly increasing river water dissolved oxygen of claim 1, wherein, In step (3), the dissolved oxygen concentration of the low-oxygen discharge outlet is less than 5mg / L.

6. The method of rapidly elevating river water dissolved oxygen of claim 1, wherein, In steps (2) and (5), the requirement that the dissolved oxygen concentration reaches the standard is that the dissolved oxygen concentration is more than 5mg / L.

7. The method of rapidly elevating river water dissolved oxygen according to claim 1, wherein, In steps (2) and (3), the determination method of the dissolved oxygen concentration is to use electrochemical method to determine the dissolved oxygen concentration of 28-30cm of water surface directly by using a portable multi-parameter water quality tester, and the determination time is 4-5min.

8. The method of rapidly elevating river water dissolved oxygen according to claim 1, wherein, In steps (1) and (4), before detecting the water sample by using the water pollution early warning tracing instrument, the water sample is first stored at 4-5℃, then the water sample after cold storage is filtered by using a 0.45μm filter, and then detection is performed.

9. The method of rapidly elevating river water dissolved oxygen according to claim 1, wherein, In step (1), the industrial pollution source includes water and drainage for industrial production, water sample for tail water treatment; the agricultural pollution source includes water sample of various economic crops discharged from ditches in various dry lands and paddy fields; the domestic pollution source includes water sample discharged directly and water sample discharged after treatment in a sewage treatment plant; and the livestock breeding pollution source includes water sample discharged from livestock and fish and shrimp breeding and surrounding water sample.

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