Study On Purifying Mechanism Of Huangshui River By Slow Sand Filtration Technology

As water purification is becoming more and more popular,and the purification mechanism also gradually attracted attention,so by adopting slow sand filtration technology to purify the huangshui river in xining city,in order to have a deeper understanding of the purification mechanism of water,research on the structural characteristics and permeability of the sand used for purification technology,at the same time also based on the data of COD_Mnn and ammonia nitrogen in water before and after purification.By studying the adsorption process,thermodynamics and kinetics,fitting the data,providing technical parameters and laying theoretical foundation for water purification in the future,further elucidate the purification essence of the filtration and purification of drinking water.The main contents of the study are as follows:1.Study on the characterization of slow sand filtration technologyIntroduction to water purification installation and principle,Compared to previous water purification devices,not only does it purify the water,but it can soften the hard water,and the SEM characterization of the adsorbent?net sand?used in the purification process was made.When magnified to 500 times,it can be seen that the sand itself is also a porous structure,and there is little difference between the raw sand and the clean sand,it explains the process of purifying water quality by slow sand filtration technology,these gaps and pores act as filters,and can be used multiple times.2.Study on permeability of slow sand filtration processBy changing the content of medium grain to analyze the porosity?Correlation between coefficient of nonuniformity coefficient and curvature coefficient and permeability coefficient,A multivariate nonlinear model is established for the permeability coefficient of gravel soil and three pore characteristic parameters.The correlation between permeability coefficient and the three pore characteristic parameters is analyzed,The results show that:A single feature with stochastic parameters affecting the permeability coefficient,The influence of single characteristic parameters on osmotic coefficient is random,the correlation is about 0.9,however,when the permeability coefficient and the three pore characteristic parameters are used to establish a multivariate regression model,the correlation is more than 0.99.Compared with the previous monadic regression model,the predicted value is closer to the experimental value.3.The adsorption of COD_Mnn in water solution conforms to the Langmuir isotherm equation,and K₁ is positive,that reaction can occur spontaneously at room temperature,slow sand can automatically adsorb organic matter in river water,In the adsorption process of slow reaction kinetics of the two grade sand dynamic analysis model is better for the organic compounds in water;In the process of thermodynamic analysis?H negative explain and clean sand adsorption for the exothermic process of CODMn in water,?G negative also explain the adsorption can be spontaneous,?S added solid-liquid interface during the adsorption process of chaos.4.Study on the kinetics and thermodynamics of ammonia nitrogen adsorption by Slow sand filtration technologyThe adsorption of ammonia nitrogen in the aqueous solution shows that the Freundlich isotherms are more consistent than isotherm Langmuir.In the kinetic analysis,the two stage kinetic model can better reflect the adsorption process of slow sand to ammonia nitrogen in water;In the process of thermodynamic analysis?H negative said bright and clean sand adsorption for the exothermic process of ammonia nitrogen in water,?G negative also explain the adsorption can be spontaneous,?S is negative shown that the adsorption process reduces the confusion of the solid-liquid interface.5.Comparative Analysis between Linear and nonlinear fitting in ammonia nitrogen adsorption Simulation by Slow sand filtration technologyIn Langmuirn Freundlish adsorption isotherm model and quasi-first-order kinetic model,the correlation coefficient of nonlinear fitting is higher than that of linear fitting,explain for these three models,nonlinear fitting can better describe the adsorption process of ammonia nitrogen in sand adsorption water.In the quasi-second-order kinetic model,the correlation coefficient of linear fitting is larger than that of nonlinear fitting,midpoints of the graph are basically on linear fitting lines,it shows that the linear fitting is better and more reasonable for the quasi-second-order dynamic model,this is contrary to the conclusion of the quasi-first-order kinetic model.In the Van't Hoff model,correlation coefficients of linear fitting and nonlinear fitting are close to each other,which fitting method is reasonable.In model fitting,use of nonlinear or linear fitting depends on the situation,not all nonlinear models fit well.