Study On Phosphorus Removal Efficiency Of Artificial Wetland Substratum By Acid Washing Waste Liquid Modified Slag

Wetland phosphorus removal technology is a new type of wastewater treatment technology that utilizes the interaction of matrix,plant and microorganism,and integrates physical,chemical and biotechnology means to achieve phosphorus removal in water.The adsorption of matrix accounts for a large proportion in the removal of phosphorus.The matrix is prone to clogging after prolonged adsorption.Therefore,in this study,a matrix containing rich Al³⁺,Fe²⁺,and Ca²⁺ions,such as coal-fired slag,is selected for wetland removal.Phosphorus research.The use of slag modified by waste acid can also improve the adsorption performance of slag.In the application of constructed wetland,microbial accumulation and plant absorption can be achieved to achieve regeneration of filter material,which is an attempt to achieve sustainable wastewater treatment.This kind of attempt can not only reduce environmental pressure,but also become an important way to utilize waste resources.By modifying the slag.Experiments on the static and dynamic adsorption characteristics of phosphorus,combined with the application conditions of constructed wetlands,were used to construct L₉（3⁴）orthogonal experiments,also the conclusions we found after the experierments were as following:（1）The particle size distribution of coal burning furnace slag is mainly concentrated in the range of 0.45-6mm,mainly including O,Si,Al,Fe,Ca,C,etc.The main oxides include SiO₂,Al₂O₃,CaO,Fe₂O₃ and carbonaceous oxides（including organic matter,carbonate and some carbonaceous impurities）,and a small amount of K₂O,MgO,TiO₂,etc.（2）The phosphorus adsorption amount of slag reached the adsorption equilibrium after 50 min,and the adsorption amount was 0.3mg/g.The adsorption of phosphorus by the four modified cinders of coal burning furnace was higher than that of the original cinders.TThe adsorption capacity of slag modified with waste acid No.2 is much higher than that of waste acid No.1.The adsorption of phosphorus by the four kinds of modified cinders was higher than that of the original cinders.When the analysis data n>0.5 indicated that the adsorption of phosphorus occurred easily.（3）According to the two kinds of dynamic fitting result,four kinds of modified slag of phosphorus adsorption quasi level correlation coefficient of between 0.867 and0.978 respectively,secondary dynamics fitting model between 0.986 to 0.998,The four kinds of slag has a certain complex adsorption process.The chemical was more significant than physical.（4）When modified slag is used in constructed wetlands,the removal rate of total nitrogen can reach more than 90%.The main and secondary factors influencing TN removal rate are A（Filler）,D（HRT）,C（Reed stalk number）.,B（Microorganism）,The optimal combination of TN removal is A₃B₂C₂D₃,The main and secondary factors influencing COD_cr removal rate are D（HRT）,C（Reed stalk number）.,A（Filler）,B（Microorganism）,The main factors influencing TP removal rate were A（Filler）,D（HRT）,C（Reed stalk number）.,B（Microorganism）,and the optimized combination was A₃B₂C₃D₃,and the significance of all factors is extremely significant（P<0.01）.In order to achieve the comprehensive treatment effect,the slag required for the treatment of8m3/d water volume is not less than 2307 kg.The coal-fired slag modified by waste acid can be used as a matrix filler to treat phosphorus-containing wastewater.It is an effective dual-waste resource utilization route,combined with wetland plants and microorganisms to achieve long-term operation.