Preparation Of Mesoporous Magnetism Filter And Application Of Integrated Biofilter For Nitrogen And Phosphorus Removal

Water resources face enormous challenges in China,performance such as emissions of pollutant increasing,water waste serious and low utilization rate.To change the current water enviromental of China,we must develop new treatment approache technologies of effective and economical that can conform to water resource in our country.Besides,stacking of industrial solid wastes not only waste resources but also occupy infield.So the preparation of new filler media by solid wastes has an important significance in environment protection.This paper mainly researches the steel slag property,preparation and capability mensuration of mesoporous magnetism filter,the application characteristic of treating domestic sewage in mesoporous magnetism biological aerated filter,preliminary operation of integrated biofilter for nitrogen and phosphorus removal when pollutant concentration is higher.The main composition of steel slag is determined by XRD and chemical component analysis,the kind is selected by combining with Riley theory.The article investigate the characteristic of phosphorus adsorption using steel slag in aqueous solution,we fit adsorption results by Freundlish and Langmuir models,and describe adsorption kinetics of phosphorus both of the two models,as to provide theoretical basis for the steel slag adsorption solution of phosphorus.Mesoporous magnetism filter was preparted with sintered process using moderate amount of pore-forming additives,magnetic and steel slag,binder as main material.The main conditions affecting performance on filter material such as raw material,addition of pore agents,sintering temperature,soaking time were determined by experiments,The orthogonal test was employed to study the optimal preparation parameters of mesoporous magnetism filter,the optimal combination was ?slag:?binder:?magnetic:?pore=5:4:1:1 with sintering temperature at 150? for 30min.The piled density is 632kg/m3,cylinder pressure is 4.17Mpa and crush pressure is 198N.The surface experiment analysis on filter is performed by SEM,the surface of Mesoporous magnetism filter is rough and porous,the aperture is evenly and big.The article investigates the characteristic of phosphorus adsorption using mesoporous magnetism filter in aqueous solution,adsorption was finished nearly 10h,we fit adsorption results by Freundlish and Langmuir models,and both two models can describe adsorption kinetics of phosphorus,adsorption isotherm is consistent with Freundlish model,and the first order dynamic equation was the optimal.Two BAF reactors filled with ceramsite and mesoporous magnetism filter respectivily,to test the performance of treating domestic sewage,The experiment included started-up phase and stably running phase.The pollutants status of biological aerated filter changes with time flies during the start-up,the style of start-up is closed aeration,the removal effect of CODcr is obvious,2#BAF need ten days when the removal rate get to70%is shorter two days than that of 1#BAF,the mesoporous magnetism filter materals reactor had higher phosphorus removal while the removal of 1#reactor was nearly zero.The 2#reactor removal efficiency of ammonia nitrogen is better than 1#reactor due to the high porosity and surface characteristics of mesoporous magnetism filter which conduct to the growth of nitrifying bacteria.During the start-up,backwash helps with discharging suspended biological flocs among filter media and strengthening of bacteria in media surface.Under each hydraulic retention time of the steady operation stage,The removal of CODcr,ammonia nitrogen and phosphorus in two reactors filled with different media were presented.When HRT is three hour,the CODcr concentration in effluent can meet the national discharged standard of sewage.When HRT reduce to 2.5h,the removal rate of CODcr is decreaseed,it take about three days to adapt to the changing HRT and stable operation.Two filter of nitrification ability are greatly influenced by the hydraulic retention time,when HRT greater then 2.Sh,the removal efficiency of ammonia nitrogen is ideal,the ammonia nitrogen concentration of efflunt is lower then 10mg/L.With the increase of hydraulic and organic load,the removal rate will be decreased and the stability of effluent water quality becomes poor.it take about four days to adapt to the changing HRT for nitrifying bacteria and stable operation.The phosphorus removal is not ideal due to characteristics of biological aerated filter,when the concentration of influent phosphorus is lower,the removal efficiency is ideal.With the increase of concentration,the removal rate will be decreased rapidly.When the concentration of phosphorus change to higher,we study the application of integrated biofilter for nitrogen and phosphorus removal.