Research On Preparation Of Wastewater Treatment Filter Media Using Yellow River SILT

Yellow River silt has characteristics of large quantity and difficulty to treat. In this experiment, the Yellow River silt was used as the main material to prepare a new type wastewater treatment filter media. The optimal preparation condition was studied. Yellow River silt filter media were employed in Biological Aerated Filter (BAF) to treat hospital wastewater, the performance of this filter media were investigated.The optimal preparation condition of Yellow River silt filter media is75g of Yellow River silt,10%of cement,8%of sodium silicate and5d of curing time. Yellow River silt presented high total porosity, large total surface area and low bulk and apparent density. The SEM indicated the surface of filter media is tough, but it also has high porosity, which provided an optimum condition for growth of biofilm.Yellow River silt filter media employed in BAF to treat hospital wastewater in this experiment. Conclusions as follows:To start-up the BAF by a new multiple forming biofilm method, removal efficiency of COD reached over60%at the6th day, removal efficiency of both COD and NH3-N removal reached and maintained over87%at the12th day.To research the recovery after BAF Backwashing, removal efficiency of COD could reach the level before backwashing1d after backwashing.The result of contamination wiped off orderliness of BAF at different HRT showed that COD and NH3-N removal were higher when HRT was longer but gas-water ratios was fixedness.The result of contamination wiped off orderliness of BAF at different gas-water ratios showed that COD and NH3-N removal was higher when gas-water ratio was bigger but HRT was fixedness. Considering the treatment effect and running cost of BAF, HRT of6h and A/L of5:1were determined as the optimal operating conditions.Under optimal operating conditions, the effect of contamination removal of BAF at different media height showed that average removal efficiency of COD and NH3-N increased continuously but changed slowly gradually as media height increased. The average removal efficiency of COD and NH3-N increased to nearly70%within0-48cm media height, which was the main zone to remove the contamination. At80cm height the average removal efficiency of both COD and NH3-N reached over87%.Using Yellow River silt as biofilm carrier of BAF to treat hospital wastewater incarnates the concept of recycling economy, which increased the species of wastewater treatment filter medium and theoretical content of preparing filter media. It provided some technical guidance to treat practical hospital wastewater.