Inversion Model Of Reclaimed Water Quality Index Based On Hyperspectral Remote Sensing

The development and utilization of reclaimed water plays an important role in solving the shortage of urban water resources,improving the utilization rate of water resources and improving the ecological environment.It is the key to improve the utilization level of reclaimed water to carry out the investigation on the utilization status of reclaimed water in China and realize the rapid and effective monitoring of water quality in the whole process of reclaimed water treatment.At present,the research on the status quo of reclaimed water utilization in China is not comprehensive and in-depth,and the water quality monitoring level in the process of reclaimed water treatment needs to be improved.In this study,the change and distribution of the amount of reclaimed water in China were investigated,and the change of factors such as the utilization rate of reclaimed water and the construction scale of reclaimed water pipe network were counted,so as to carry out a comprehensive status analysis of the utilization of reclaimed water in China.Considering the supply and demand of reclaimed water comprehensively,29 indicators of 7 categories of factors,such as economic investment and sewage treatment,were selected to analyze the sensitive factors affecting the consumption of reclaimed water.Hyperspectral feature spectrum imager different process of wastewater regeneration recycle water samples were measured spectral values,using different methods of band selection,is sensitive to water samples of COD concentration in spectral band filtering and build hyperspectral inversion model,comparison segment screening method extraction effects of different process in water samples,to determine the optimal inversion model;The comprehensive water quality of different processes for wastewater recycling and reuse was quantitatively calculated by using the comprehensive water quality index.The sensitive bands of the comprehensive water quality of reclaimed water were screened by using different band screening methods,and the hyperspectral inversion model of the comprehensive water quality of reclaimed water was constructed.According to the data analysis results,the main conclusions are as follows:(1)The utilization of reclaimed water in China is developing rapidly,and the utilization of reclaimed water is improving as a whole.From 2011 to 2019,China’s renewable water consumption has been growing.The sewage treatment rate in the towns and villages is 59.67%and 33.30%,respectively.Sewage treatment needs to be popularized,and there is a huge space for sewage recycling.The length of reclaimed water pipeline,sewage treatment and investment of fixed assets of reclaimed water are increasing gradually,which provide favorable conditions for the utilization of reclaimed water.The indexes that are closely related to the reclaimed water consumption for 5 years or more include four indexes: reclaimed water production capacity,reclaimed water pipeline length,drainage facility investment and per capita water resources.Sewage treatment plays an important role in the categories of influencing factors of renewable water consumption.The higher the quantity and quality of sewage recycling treatment,the easier it is to realize sewage recycling and the higher the amount of reclaimed water.(2)Hyperspectral inversion of COD concentration in reclaimed water treatment has a good effect.The COD concentration inversion results of different reclaimed water treatment processes differ greatly,among which the COD concentration inversion results at the water inlet are the best and can achieve a very ideal model inversion effect.The results of anaerobic and aerobic tanks,sedimentation tanks and water outlet are worse than those at the water inlet.SPA band filter has satisfactory inversion effect,can realize sewage treatment on the main water quality processes in the inversion precision of optimization,the Ⅰ,Ⅱ water quality classification accuracy of 100%,the Ⅲ,Ⅳ water quality classification of water were 50.0%and 60.0% respectively,Ⅴ water quality class accuracy can reach 80.95%.(3)Hyperspectral inversion has a good effect on the comprehensive water quality of reclaimed water treatment.The correlation between the comprehensive water quality and spectral reflectance at different treatment processes changed rapidly from negative to positive in the range of 400～800nm,and the correlation was significant.The correlation curves of water samples with different concentrations have obvious similarity.The method of comprehensive evaluation of water quality can be used to establish the hyperspectral quantitative inversion model of the comprehensive water quality of reclaimed water,which has a good effect.The number and distribution of bands selected by different feature band screening methods are different,but they can all use a small number of bands to accurately invert the comprehensive water quality of reclaimed water.SPA algorithm can accurately extract the characteristic wave band of reclaimed water quality,and has a high accuracy in each treatment process.The comprehensive water quality of reclaimed water can be quickly retrieved by spectral index.