Experimental Study On Pretreatment Of Pharmaceutical Intermediate Wastewater By Blowing Off And Three-dimensional Electrode Methods

As an intercontinental zone,the intertidal ecosystem has the functions of purifying the environment,providing habitats,stabilizing the coast,and regulating the climate.The intertidal ecosystem is facing increasing pressure in the context of increasing global impact and increasing human activity.Multi-stable phenomena are ubiquitous in many ecosystems and are closely related to the health and sustainable development of ecosystems.Therefore,the study of multi-steady state of intertidal ecosystem has important theoretical and practical significance.In this study,the Liaohekou wetland ecosystem was selected as the research area to identify the multi-stable type in the intertidal ecosystem of the Liaohekou,using remote sensing image sequences and high-resolution tidal grids to determine the elevation of each image water edge.Realize the DEM construction of tidal flat,analyze the formation mechanism of multi-stable in the positive feedback effect of biotopography,and verify the mechanism at the landscape scale.Calculate the NDVI extraction vegetation area and the light beach area by remote sensing image data,combined with GIS spatial analysis function.Based on multi-temporal analysis,it is tested whether the conversion of intertidal zone from light beach to vegetation is accompanied by rapid elevation increase,and whether the conversion from vegetation to light beach is accompanied by rapid elevation reduction.The main conclusions are as follows:(1)Identification of multi-stable type of ecosystem in the intertidal zone of LiaohekouTaking the intertidal ecosystem of Liaohekou wetland as the research object,using remote sensing image data to calculate NDVI to verify the multi-stationary "double peak" feature and multi-temporal analysis to extract four regions(stable light beach area(SB),stable The vegetation area(SV),the conversion from vegetation to the light beach area(VB)and the conversion from the light beach to the vegetation area(BV),confirmed the existence of two relative steady states of “vegetation” and “light beach” in the Liaohekou wetland ecosystem..The GIS spatial analysis function is used to test the transformation of intertidal zone from light beach to vegetation and the transformation from vegetation to light beach based on multi-temporal analysis.The image shows the existence and type of four state verification multi-stationary states of intertidal ecosystem.(2)Waterside line inversion DEMThe mapping of tidal flats is affected by tidal and silt,and it is difficult to carry out manual operations in large areas.Therefore,the construction of DEM by remote sensing means an important technical means.The high-precision shallow sea tidal mesh model based on satellite altimetry data(1.2'×1.2')is used to assign the water edge elevation.Using the Spatial Join algorithm in ArcGIS,the tidal level value on the tidal grid is assigned to the water edge to generate a water edge containing tidal level information.Then,Feature to Point breaks up the newly generated waterside line into water edge points,each water edge point assigns different elevation value attributes,and uses the generated water edge points to construct the intertidal digital elevation model using the TIN model.Insufficient data to supplement.(3)Feedback of elevation on sudden transition between steady statesThrough the analysis of the bimodality,mutation,positive feedback and threshold behavior of the intertidal zone,it indicates that there is an alternative steady state.Based on the data,the bare plains and vegetation marshes can be considered as alternatives to stable landscape states.A rapid steady-state transition occurs between them,and the intertidal elevation surveys and aerial photographs from the Liaohekou,which is dominated by macroscopic trends,are analyzed.The study found that(1)the bimodal distribution of intertidal elevation corresponds to a fully exposed state or a dense vegetation state.(2)The transition from bare to vegetation state is accompanied by a relatively rapid height change.(3)The transition from bare to vegetation state may occur above the threshold height.These results indicate the existence of alternative steady state and ecosystem steady state transition.index.In this paper,the positive feedback mechanism of biogeomorphology and the research results of “waterside line inversion DEM” can not only enrich the mechanism of multi-stable state of coastal wetland ecosystem from theory and method,but also can be used to study the estuarine intertidal zone change and research in China.Provide data support and scientific evidence.