Self purification capability refers to the ability of environmental elements to reduce the concentration, toxicity or disappear of pollutants entering the environment through complex and diverse physical, chemical and biochemical processes.
Chinese name
Self purification capacity
Foreign name
self-purification capacity
Calculation formula
Q=(Ck-B)x105
Type
Physical self purification, chemical self purification, etc
Self purification capacity is limited.If used improperly, it will lead to the reduction of self purification capacity.For example, when harmful substances produced in production and life enter the soil, they will lead to the depletion or even loss of soil self purification performance, forming increasingly serioussoil pollution。
The self purification capacity of soil is calculated by soil environmental capacity.The calculation formula is as follows:
Q=(Ck-B)x105
Where: Q=soil environmental capacity (kg/hm2)
Ck=soil environmental standard value (mg/kg)
B=regional soil background value (mg/kg)
105=coefficient converting mg/kg to kg/hm2
It can be seen from the above formula that under the soil characteristics and environmental conditions of a certain area, the value of B is certain, and the size of Q is determined by CK.The soil environmental standard value is large, and the soil environmental capacity is also large;On the contrary, the capacity is small.
Simulation of self purification capacity
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In September 2011, a lake area experiment was carried out on Zhushan Lake of Taihu Lake. According to the principle of mass balance, the laws of nutrient import and export and absorption in Zhushan Lake were clarified by measuring the water volume and water quality in and out of the rivers in and out of Zhushan Lake as well as the bay center and bay outlet of Zhushan Lake, so as to provide a basis for improving the parameters of the water volume water quality model,It also provides basic data for further research on the self purification capacity of Taihu Lake. The EcoTaihu model is used to simulate Taihu LakeNutrientsThe model was verified according to the measured results of Zhushan Lake area. The experiment showed that the annual self purification capacity of total nitrogen in Zhushan Lake area was 1979t, and the annual self purification capacity of total phosphorus was 119t. The total nitrogen year of Zhushan Lake was calculated by EcoTaihu modelSelf purification capacityThe annual self purification capacity of total phosphorus is 116 t, and the measured data is in good agreement with the model. The model calculation results show that the self purification capacity of nitrogen element in Taihu Lake in 2006, 2008, and 2010 are respectively 4.00, 4.27, 41100 t. The self purification capacity of phosphorus element in Taihu Lake in 2006, 2008, and 2010 is respectively 1566, 1798, and 1712 t[1]
Significance of self purification ability
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In order to study the relationship between river meandering degree and river self purification capacity, and preliminarily explore the influence of river bank protection structure on this relationship, seven river sections with different river meandering degrees and two bank protection structures were selected as the research objects.Curvature (S) and fractal dimension (box dimension DB) were used to characterize the meandering degree of rivers;With TPNH3-N、NO2-N、NO3-N、CODcr、TOC、DOC、Along the way reduction rate, inorganic nitrogen content, suspended microbial biomass andbiological activityRepresent the self purification capacity of the river.According to the field monitoring in dry season and rainy season, the impact of river meandering degree on the river self purification ability under the two revetment structures of masonry vertical retaining wall and gabion gabion retaining wall is quantitatively studied, and the suspended microbial biomass (suspended microbial lipid and phosphorus content) and biological activity (suspended microbial FDA hydrolase activity) in the river reach are analyzed and studied,To explore the mechanism of the influence of river meandering degree on river self purification capacity.The research results show that the degree of river meandering has a significant impact on the river self purification capacity of the river reach with masonry vertical retaining walls. The reduction rate of several water quality indicators along the river increases significantly with the increase of the degree of river meandering, with the most obvious reduction rate of DOC, BGA-PC and inorganic nitrogen along the river.During the dry season, the concentration of DOC, BGA-PC and inorganic nitrogen increased along the eastern section and decreased along the western section;During the rainy season, the DOC concentration still increased along the eastern section and decreased along the western section, while the reduction rates of inorganic nitrogen and BGA-PC along the western section were 1.60 times (P<0.05) and 2.39 times (P<0.05) of the eastern section, respectively.The rising trend of DOC along the west section of Yunxi River in dry season is only 1/2.53 of that in the east section (P<0.05)inorganic nitrogenThe change trend of the concentration showed that the concentration increased along the east section and decreased along the west section;During the rainy season, the concentration of DOC, BGA-PC and inorganic nitrogen also increased along the eastern section and decreased along the western section.In the respective study sections of Modishachong and Yunxi River, the river section with higher degree of meandering has higher water self purification capacity.The meandering degree of the river also has a significant impact on the river self purification capacity of the gabion retaining wall reach.In the dry season, the reduction rates of several water quality indicators along the river are significantly different with the increase of the meandering degree of the river, especially the change of DOC.In the straight section of Yufeng Chung, the DOC concentration increased along the way, while in the north and south sections of Nanpaiyong, the DOC concentration decreased along the way, and the DOC reduction rate in the south section of Nanpaiyong was 2.47 times that in the north section of Nanpaiyong (P<0.05).rainy seasonThe reduction rate of six water quality indicators, including NH3-N, NO2-N, CODcr, TOC, DOC and BGA-PC, increased significantly with the increase of the meandering degree of the river.Within the range of the surveyed river's linear meandering degree, the reach with higher linear meandering degree has higher water self purification capacity.The degree of river meandering has no significant effect on the lipid and phosphorus content of suspended microorganisms in the reach of masonry vertical retaining wall, but with the increase of the degree of river meandering, suspended microorganisms FDAhydrolaseThe activity was significantly improved.In the reach of Gabion gabion retaining wall, the lipid and phosphorus content of suspended microorganisms and the activity of FDA hydrolase increased significantly with the increase of the meandering degree of river streamline.The increase of the river meandering degree enhances the biological activity of suspended microorganisms in the high mortar masonry vertical retaining wall reach, thus improving the self purification capacity of the river;In the reach of gabion gabion retaining wall, the self purification capacity of the river is improved by increasing the biomass of suspended microorganisms and improving the biological activity of suspended microorganisms.The reduction rate of several water quality indicators along the river reach of gabion gabion retaining wall, the lipid and phosphorus content of suspended microorganisms, and the activity of FDA hydrolase have a significant positive correlation with the curvature and fractal dimension of the studied river reach, which further indicates that the degree of river meandering is significantly related to the river self purification capacity of gabion retaining wall reach.[2]
Application of self purification capacity
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Based on the investigation data in September 2008 and April 2009, the self purification capacity of pearl culture waters in the North Sea was analyzed and discussed for the first time.The results show that the sea area not only has a strong water self purification capacity, but also shows the uniqueSelf purification of water bodycharacteristic.The physical self purification capacity is mainly influenced by the hydrodynamic force of tidal current, and the superior geographical location of the sea area is alsoContaminantsThe migration and diffusion of C provide extremely favorable conditions;The strong chemical purification ability is mainly reflected in the high content of dissolved oxygen as a water oxidant and the low content of total organic carbon as a symbol of the level of organic pollution in water, as well as the nitrogen and phosphorus cycle characteristics as the oxidation products of organic matter;The biological self purification ability mainly depends on the manifestation of biochemical processes in the sea areafood chainAnd the suitable biomass and primary productivity level of existing phytoplankton.[3]
