| With China’s sewage discharge standard being more and more stringent,advanced wastewater treatment has been paid more and more attention. As afiltration system with unique structure, active medium filter has several meritssuch as low one-time investment, backwash without downtime required, andlow operating and maintenance costs. It is playing a more and more importantrole in the field of advanced treatment and upgrading and reconstruction ofwastewater treatment plants. In the paper, international mainstream activemedium filter products was researched, and the structure and operationparameters of active medium filter were optimization by the hydrologic testand the pilot test.In this paper, based on the systematic study of air-lift system,active medium filter used for upgrading and reconstruction of wastewatertreatment plants from Standard B to Standard A with quality index of SS, TP&TN is proved to be feasible by the pilot test, and operational parameterswere optimized.The results of air-lift system test showed that the diameter of sand-liftingtube mainly determines the maximum amount of lifted sand. With the air flowincreased, the amount of lifted water and sand both have a trend of increasingfirst and then decreasing. Under the same condition, there is a linearrelationship between water head and the amount of sand lifted per unit airflow volume.The results of the pilot test showed that influent concentration and airflow didn’t affect the filtering performance of active medium filter. Theremoval efficiency of SS increased gradually with the reduction of thefiltering rate,. For the active medium filter used for upgrading andreconstruction of SS from Standard B to Standard A, the reasonable filteringrate was5m/h~7m/h and best air flow rang was7.96L·m-2·min-1~26.53L·m-2·min-1. Active medium filter didn’t have phosphorus removal capabilityby filtering effect only. Dosing AlCl3&FeCl3as coagulant both can improved its phosphorus removal performance significantly, and the optimal dosingquantity was4.5~5mg Al/mg P or2~3mg Fe/mg P. Active medium filter wasproved to have a good denitrification performance. For denitrification demandof upgrading and reconstruction, the optimal kernel parameters was HRT40min~1h and the dosage of CH3COONa as carbon source was30mg/L. |
