Application Of Aeration Technology On Pollution Treatment Of Xingang River In Shanghai

With the development of the city and the improvement of the population, many rivers were black and odoriferous because a charge of waste water was discharged into rivers, and the main pollutant was organism. Take Xingang river for example, this paper studied the application of aeration technology on treatment of urban organic polluted little rivers by some ways of test in lab and in Xingang river and computer simulation.First of all, the duration,characteristics,kinetic course and oxygen consumption amount of different oxygen consumption stages could be known by the use of the oxygen consumption curves of Xingang river. Also, by the curve fitting of first-degree dynamics and logistics dynamics, speed constant of oxygen consumption in every stage could be got. The total oxygen consumption amount was 26.92kg/d by calculating roughly, and the percentage of sediment oxygen consumption was 84.1%.Secondly, According to laboratory test and computer simulation, this paper analyzed the factors affecting aeration and some measures to improve aerated effect in project. Laboratory contrastive test included different activated sludge capacities,different oxygen capacities and different aeration modes that were consecutive and intermittent aeration. It was showed that the remove rates of COD_Cr,NH₃-N and TN could be improved by enhancing activated sludge and oxygen capacities. And, intermittent aeration had advantage to take off nitrogen. Computer simulation included build and application of water quality model. Water quality model under the condition of aeration was built considering zero-dimension,one-dimension and single reach water quality model based on the Streeter-Phelps model, and using the principle of combined plug-flow reactor. Calculated by MATLAB software and compared with monitor data, the result was satisfied. The result of computer simulation showed: on the one hand, aeration could enhance the self-purification ability of river, and meliorate the water quality of downriver position. On the other hand, water quality of aeration reach was not improved evidently with the increase of oxygen capacity and the number of aerator, while temperature,flow velocity and sediment suspending had large influence on water quality.Finally, consultation was that aeration could enhance DO and dispel the blackening and smell of river. Moreover, aeration had some advantages such as favorable effect,little investment,small occupation of land. So, it's a available measure to treat urban organic polluted little rivers. But, it's difficulty to improve water quality further only with this method. Microorganism capacity,temperature,oxygen capacity,aeration mode and flow velocity were main factors affecting the effect of aeration. In project, in order to realize environmental and economic benefits, it's necessary to select proper sort and quantity of aerator, aerate in condign seasons and fix aerator appropriately avoiding happening sediment suspending. At the same time, take some measures such as adding microorganism,intermittent aeration,controlling the flow velocity,planting hydrophyte and so on to improve the effect of aeration.