Effct Of Aeration On Ammonia Stripping In Heavily Polluted Urban River

Aeration is one of the commonly used methods of urban polluted river to improve the water quality, and has developed a variety of aeration techniques and equipments and taken on a good effect. However, the impact of aeration on ammonia stripping of polluted river water is still a lack of in-depth study. In this paper, through simulation experiments to study two different carrier gas (air and nitrogen), different aeration (overlying water aeration and sediment aeration) deal with the urban heavily polluted river water for ammonia stripping, and to explore the pH, temperature, aeration time, aeration quantity on ammonia stripping in the same period, to study the changes of nitrogen morphological and FA of the urban heavy pollution overlying water effecting ammonia stripping, and proposed two kinds of nitrogen-air combination of aeration to treatment river water, and achieved good control of nitrogen effects. The specific main conclusions are as follows:1) Air aeration treat the urban sewage of heavily polluted river, aeration influence the ammonia stripping from urban polluted river water and ammonia stripping is the main way of the system to remove nitrogen. Air aeration increase the effluent pH. At20℃, the aeration amount2L/min conditions, aeration12h sewage pH increased from initial7.12to8.55, increased pH improve the efficiency of ammonia stripping. In addition, the efficiency of ammonia stripping is positively correlated with temperature, aeration time, aeration quantity.2) nitrogen aeration dealing with the high concentrations of ammonia of the urban heavy pollution of the river, can effectively improve the pH value of river pollution, promote ammonia stripping, which can remove the ammonia from polluted river water in a short time. Polluted river water, ordinary air aeration for24hours at pH value of8.93, nitrogen aeration for24hours, the pH value can reach10.15. In addition, the efficiency of ammonia stripping is positively correlated with temperature, aeration time, aeration quantity.3)the control group with a certain amount of self-purification capacity under simulated conditions, showing a slow decline of the NH4+-N and TN in overlying water, nitrate is slowly rising, and the FA concentration of the control group is smaller, the average of ammonia stripping is stable at about0.31mg/L.At the early aeration FA concentration in the group of air aeration obviously rapid increase in ammonia stripping, with the extension of aeration time, the occurrence of nitrification-denitrification system, pH and the FA concentration was decreased, the efficiency of ammonia stripping in rapid decline, to lOd approaches to0. The pH of nitrogen aeration in a short time (24h) rose to a high level, the rapid increase of the concentration of FA in the system, and compared with air aeration group average FA concentration higher than its8times, so pure nitrogen aeration group ammonia stripping of nitrogen aeration efficiency is much higher than the air, the removal efficiency of ammonia nitrogen, and on the aeration of the overlying water more quickly than sediment aeration on ammonia nitrogen removal rate.4)the two nitrogen-air combined aeration deal with the city heavily polluted river sewage aeration stage in the nitrogen removal of ammonia have a more distinct effect, but the first way in static phase due to the release of sediment the role of the ammonia concentration is still a slow rise; in second way because of the early treatment of sediment, sediment release the potential of greatly reducing the standing60d overlying water ammonia concentration was maintained at a lower level may have been to achieve a balance of sediment ammonia release and nitrification. This shows that the release of the second aeration combinations in a longer time scale can be more effective control ammonia from sediment into overlying water.