Study On Capability Of The Initial Rainwater Detention Tanks In Separate System Based On SWMM

In order to protect the environment of Dianchi Lake,the state and Kunming government put a lot of financial and material resources during the Twelfth Five-Year Plan,and carry out a series of treatment project,and the trunk engineering framework from source controlling to the end intercepting was established. Control Initial rainwater is especially important in the condition of separated system.Initial rainwater detention tank makes a very obvious effect on controlling non-point source pollution, and it has a strong practicability. Initial rainwater detention tank can collect initial dirty rainwater. This paper investigate the Sewerage System of Chenggong New Area, select the area between Luolong river and Xinkai river as research subject. According to the actual circumstances underlying surface conditions and pipe network model establish SWMM. Parameters of the model were initially identified, according to the measured rainfall data for the model parameters calibrated to give a final model parameters. the Chicago rain, combined with heavy rain in Kunming formula, synthetic P = 0.5, P = 1 rainfall time series and then add to the model. The simulation results is the luolong river sewage pipe can accommodate before 50% flow when P=0.5 no matter ransition state or plan state. As for the before 50% of the runoff under the current state when P=1, the luolong river sewage pipe will overflow and Many flood points, overflow traffic as well.In order to control overflow pollution when P=1. This paper presents three control schemes. Just add storage tank 、 just adjust pipe and add storage tank+ adjust pipe.making a comparison of three schemes.Just add storage tank separate is unreasonable from economic and practical projects,Just adjust pipe will increase investment and have a great impact to urban areas.add storage tank+ adjust pipe is reasonable.Finalization of the positions of the three storage tanks under ransition state.They are located luolong park、chunrong east road、xianghe road.Its volume, respectively 4000m3、2000m3、2000 m3.Three storage tank position unchanged under plan state.Its volume, respectively 5000m3、2500m3、2500 m3.Study storage Tank efficiency of control pollutants under ransition state when p=1.This paper selected COD, TN, TP three pollutants as research subjects.The three storage Tank can accommodate Overflow when intercept before 50% flow.For COD, TN, TP three pollutants holdout efficiency is 16%, 16%, 11%.By making a brief economic comparison between just adjust pipe and add storage tank+ adjust pipe.The result is the scheme of add storage tank+ adjust pipe is more frugally, and to save about 8.20 million yuan of funds.