Study On The Nutrients Removal In Reaction-precipitation Integrated Rectangular Airlift Loop Reactor

Reaction-Precipitation Integrated Rectangular Airlift Loop Reactor (RPIR) has high performance of mass transfer and excellent for organics removal. The main objective of this study is to investigate the performance of the RPIR in nutrient removal with anthysis on influence factors. Two kinds of packings-combined packings and suspended packings as biocarriers were tested and three tests have been done.The results demonstrated that suspended packings were more suitable for the RPIR than combined packings. When suspended packings-polyurethane foam boxes have been tested as biocarriers, the optimum operation conditions in the RPIR system were at the HRT of 5h, the COD/N ratio of 10,the MLSS of 8000mg/L, DO concentration of 1mg/L, the SRT of 15 days and the mol ratio of FeP2+P and P reach 1.5. At these conditions, the RPIR system showed excellent efficiency for nutrient removals. The effluent concentrations of COD, NHB4BP+P-N , TN, TP were all to meet the requirements of the highest concentration of available discharged effluent from second stage waste water plant in town(1A).Stable anoxic-anaerobic ozone which forms in polyurethane foam boxes is benefit for simutious nitrification and denification in RPIR system. The COD/N ratio and DO concentration were significant impact the efficiency of nitrogen removal. Only the COD/N ratio should be keep higher than 10, the denitrification could be run successfully.The test showed that the fluid and the mass transfer efficiency were not impacted when packings-polyurethane foam boxes were send to the system, while the biocarriers were high ability of standing against loading shock, benefit for stabilizing the RPIR system and avoiding bulking.The PRIR showed excellent performance for nutrient removal in this study, advantages of small footpoint, low investment and low operation cost and easy management, which were meaningful for practical projects.