Study On The Develepment And Application Of Concrete Modified Hydrophilic Biological Filler

There are various of defects in existing plastic filler surface modification techniques.Surface materials were easy to wear and exfoliate by surface coarsening or surface graftingwith the impact of waterflow. It usually emerged uneven irradiation between the internal andexternal surfaces of the filler by UV. It needed high investment by plasma treatment. A novelconcrete modified hydrophilic filler was created through making concrete adhering to thesurface of plastic filler with many holes of different size. It overcame the shortcomings ofordinary filler such as dissolving in water and exfoliating easily and had advantages of simplepreparation and lower cost. It would have good development prospect in wastewatertreatment.The results showed that concrete slurry was hard to adhere evenly on the surface ofnomal suspending plastic filler and easy to exfoliate from the surface because of the crackresulting from the drying of it. It could improve the evenness of slurry on the plastic filler andmaking concrete adhering to the surface tightly through making holes of different size on theplastic surface, and enhance the capability of resistance damage from falling. The newconcrete modified hydrophilic filler showed the best performance when using a new kind ofelasticity plastic fillers to mix with the slurry, the optium conditions of which was: mass ratioof cementto water was1.5~1.8:1,mass fraction of PVA and PANa was0.5%~1%(relative tocement) and0.5%~1%(relative to water) respectively.Contrast experiment on pre-treatment of landfill leachate by anaerobic suspending mediabeds with new concrete modified hydrophilic filler and new plastic filler was tested andstudied. It was proved that the new modified filler was hydrophilic and increased the biofilmgrowth speed on the filler surface. It can adapt to the raw water well with the noval filler. Theaverage COD removal efficiency was30%, which was5%~10%higher than that with thenormal plastic filler.Another contrast experiment was conducted by pre-biological denitrification process formunicipal wastewater treatment. The results indicated: when aerobic HRT varyed from18h to 8h, the average removal rate of COD and total nitrogen (TN) decrease accordingly. COD、TN removal efficiency of1#reactor (with noval hydrophilic filler) was both little higher than that of2#reactor (without filler), but1#displayed a great resistance to shock loading. When pH value varied fromed6to9.5,1#system was tolerable in the influent pH, and its optimum pH range in COD and TN removal both of6～9.5was much better than2#. COD、TN removal efficiency were5%and12%higher than that of2#respectively. When the influent ammonia concentration was57.2mg/L～86.3mg/L (C/N ratio was5.5～9.6), COD removal rate changed slightly, otherwise it showed great fluctuation in TN removal efficiency in both two systems. COD、TN removal rate of1#reactor was about3%and10%higher than that of2#reactor respectively. It was demonstrated that1#reactor could achieve a certain anti-shock loading capability as far as the TN removal efficiency was concerned.Through analysis of kinetics of bio-denitrification, according to test results and Monod equation, the kinetic model of denitrification in the anoxic reactor with noval hydrophilic fillers was U=76.92·S/S+570.62. When the substrate concentration was much lower than Ks=570.62mg/L, the relationship between substrate degradation rate and substrate concentration accorded with the first-order reaction U=0.134S.