Adaptive Research Of The Process Of The Precoating Dynamic Membrane In Reuse Water Treatment

Along with the accelerating process of urbanization in China，the problem ofshortage of water resources in urban has become more apparent，and the recycling ofeffluent of urban sewage treatment plant is an effective way to alleviate the watershortage. In the existing process of wastewater reclamation，the advantage of filmprocessing is high efficiency，low consumption，strong adaptability，and so on，whichhas become one of the main methods of the reclaimed water treatment. The film holeof micro-filtration is easy to be plugged in the reclaimed water treatment. In order tosolve the problem，the thesis adopts the technology of the precoating dynamicmembrane to deal with the secondary settling tank effluent of municipal sewagetreatment plants to explore efficient and flexible reclaimed water treatment technology.In the study the secondary effluent of municipal wastewater treatment as the rawwater,polypropylene microfiltration membrane as a basement membrane,fly ash andperlite as the pre-coated agent,by which the control parameters of the precoatingprocess is determined in the experiments;the experiment studies the removal efficiencyof turbity,ammonia nitrogen,total nitrogen,total phosphorus,COD and bacteria andother water quality indicators by the precoating dynamic membrane process,analysis ofthe mechanism of the precoating dynamic membrane and retention mode,and analysisof the running costs of the treatment process.The main conclusions of the thesisinclude:(1)The pre-coating time decreases as the concentration of the precoating agentincreases.In the early time of filter,the transmembrane pressure increases as theconcentration of the pre-coating agent increases,and the permeate flux decreases as the concentration of the pre-coating agent increases,after some time, the transmembranepressure and the permeate flux are gradually to stable.(2)In the conditions of the secondary effuent quality of the fourth wastewatertreatment plant of Xi’an, the results of adopting the process of the precoating dynamicmembrane are good for turbidity removal,the turbidity decreases from9.0NTU to thefollowing2.0NTU;the removal efficiency of ammonia-nitrogen, total nitrogen,totalphosphorus,chemical oxygen demand(COD) are20%,40%,46%,27%; the removal rateof the total E.coli and the muck E.coli are over3.80log,and the number of total E.coliand muck E.coli are respective below90MPN/L and80MPN/L.(3) By mathematical modeling,the membrane fouling mechanism of the processof the precoating dynamic membrane is the most close to standard blocking model ofMF blocking model.(4) Using the fly ash and perlite as the precoating agent, after the process of theprecoating dynamic membrane disposing the secondary effluent can achieve thequality standard of waste wate of landscape water,and the running costs of the systemis0.11yuan/m~3,0.60yuan/m~3.