Research On Polypropylene Fiber Ball-MBR Coupling Process

In this paper,polypropylene fiber was prepared into pellets and applied to MBR domestic sewage treatment system from the perspective of improving the hydraulic characteristics and properties of MBR activated sludge mixture.The effect of polypropylene fiber pellets on MBR was studied by analyzing water quality change,membrane fouling and thermal stability of hollow fiber membrane.In order to further expand the application of polypropylene fiber pellets in water treatment,functional fibers with hydrophilic and hydrophobic groups were prepared by ultraviolet irradiation grafting and microwave amination ring opening reaction,and then added it into activated sludge for further investigation.When polypropylene fiber pellets were added to MBR,the MBR backwash time could be extended by more than 2-3 times.The addition of polypropylene fiber pellets could effectively reduce the protein pollutants and humic acid pollutants on the surface of the hollow fiber membrane in MBR.The effect of polypropylene fiber pellets on MBR membrane fouling was mainly reversible.After adding the polypropylene fiber pellets into MBR,the removal rates of COD and TOC were increased from 93.13%and 95.85%to 97.09%and 96.6%,respectively,and the treatment efficiency of NH4-N and TN was also improved.Adding polypropylene fiber pellets could reduce the contamination of the membrane by tryptophan protein tyrosine protein and humic acid in activated sludge mixture.When the dosage of propylene fiber pellet was 10%,it had little effect on the mechanical properties of hollow fiber membrane.With the increase of its amount,the influence increases gradually.Thermal stability analysis showed that the addition of polypropylene fiber pellets did not change the chemical properties of hollow fiber membrane.GMA was grafted onto the surface of polypropylene fiber by means of ultraviolet radiation to obtain PP-g-GMA fiber.PP-g-GMA fiber and DA were open-loop reaction in a microwave reactor to obtain PP-g-GMA-DA functional fiber with functional groups,such as hydrophobic alkyl long chain,hydrophilic hydroxyl group and secondary amine group on the surface.Functional fiber pellets had an adsorption effect on BPA,and had the same effect in activated sludge,which played a dominant role.When biofilm and attached sludge were grown on its surface,it still adsorbed BPA in the activated sludge mixture.Moreover,the addition of functional fiber pellets did not affect the effluent quality of the activated sludge process,and increased the COD treatment efficiency from 87.25%to 95.25%.