The Hollow Cylindrical Pvc Packing Applied Research In Urban Sewage Treatment

In the process of treating wastewater using Biological Aerated Filter(BAF), biofilm packing is of importance. The packing will effect the result of treatment. Considering the kinds of packing, sand, coke and activated-carbon etc, are often used. In fact, these packing are not fit for biofilm packing in the Biological Aerated Filter(BAF).The PVC using for biof ilm packing in Biological Aerated Filter was studied in this experiment. The density of this kind of PVC is close to that of water and fit for fluidization in Biological Aerated Filter. The formation of biof ilm on this PVC and on the different condition of HRT, PH value, gas quantity and temperature, these affect the removal of COD, NH₃-N, SS and TP. Most importantly, the hydraulic retention time (HRT) will affect the time of the process of the formation of biofilm. In the Biological Aerated Filter with 550L cubage, the best HRT is 1.5h?— 4.0h, and it spent 23 days, the biofilm began to form. The too long HRT and too short HRT is not good for the process.After the formation of the biofilm finished, the wastewater treatment was studied by changing the operating parameter.It is found that the hydraulic retention was shorter (from 4h to 0. 4h), the removal of COD and SS descended slowly, but dropped trend was not evident, and the removal of NH₃-N was dropped sharply. When the temperature was changed from 11 °C to 26.5 °C , the rmoval of COD was affected unconspicuously, the removal of SS was affected slightly and the removal of NH₃-N was affected greatly. When the PH Value was changed from 5.5 to 7. 8, the removal of COD and NH₃-N was affected diminutively. When the contrasting between gas and water was changed from 3 :1 to 10 : 1, the changing from 3 :1 to 5 : 1 affected greatly the removal of COD and NH₃-N, but the changing from:5 : 1 to 10 : 1 affected slightly of COD and NH₃-N , the contrasting of gas and water was not affected the removal of SS.