Optimization And Improvement Based On MIKE11 EcoLab Confluence System Cut-off Multiple Selection

Intercepting rain-sewage combined drainage systems are common in old urban areas at home and abroad.In order to prioritize the interception of high-concentration sewage to the sewage treatment plant,try to maximize the water environmental capacity of the receiving water body;make full use of the urban sewage treatment plant Processing capacity;to minimize the initial rainwater pollution to the receiving water body,etc.These goals cannot be achieved by the traditional interception multiple selection method.This article will carry out an innovative discussion on the selection method of the interception multiple of the combined drainage system of rain and sewage in the old city.Changed the traditional single interception multiple selection method that was only limited to the economic factor,or only considered unilaterally or only based on experience to select the interception multiple,but combined with the MIKE11 model to design a quality interception that can consider multiple angles.Multiples,and from many aspects to make it and the traditional closure multiples fully analyzed.It provides a new method for the selection and design of the interception multiple during the transformation of the drainage system of the combined drainage system with intercepting rain and sewage in the old city.The study mainly takes the border river of Fuyang City as an example.First,according to the different quality of point source and non-point source sewage,the study area is divided into three areas:industrial area,residential area,and urban village,and the chemical oxygen demand and ammonia nitrogen are selected as the main research areas.The index is to protect the degree of pollution of the river to the maximum extent;avoid data collection too cumbersome.The overflow outlet is generalized as:a continuous point source at the maximum discharge into the river after 40 minutes of interception under a single rainfall event when the rainfall intensity P>1.Combined with the daily maximum load of the sewage treatment plant,the quality and quality interception multiples are designed.After that,the MIKE11HD,AD,and NAM models were established for Jielinhe,and then coupled with the EcoLab model on this basis to obtain more accurate water quality simulation results.Simulate changes in river pollutants through MIKE11.From the three aspects of whether the concentration of pollutants in the river can be effectively controlled;whether the treatment capacity of the sewage treatment plant is improved,and whether the dynamic water environment capacity of the pollutant is improved,a comparative analysis of the selection scheme of the quality-based interception multiples and the traditional interception multiples is conducted.Discuss whether qualitative interception is better than traditional interception,and provide a new method for accurately selecting reasonable interception multiples.The results show that when the traditional closure factor n0=2,the concentration of COD in the river decreases by 43%and the concentration of ammonia nitrogen decreases by 29%.However,when the closure ratio of quality separation is n0industry=2.5,n0 agriculture=2 and n0 population=1.5,the concentration of COD and ammonia nitrogen in the river are reduced by 51%and 42%respectively.It can be seen that the efficiency of quality separation closure is significantly higher than that of traditional closure.In contrast,when using the mass separation closure multiple,it can save 2.8%of sewage treatment capacity compared with the traditional closure multiple,and the effect is more stable and more economical,which provides a new idea for the selection of closure multiple.The results show that when the traditional interception multiple n₀=2,the concentration of chemical oxygen demand in the river has dropped by 43%,and the concentration of ammonia nitrogen has dropped by 29%;while the interception multiple by quality is n₀=2.5,n₀=2,n₀=1.5,the concentration of chemical oxygen demand in the river has dropped by 51%,and the concentration of ammonia nitrogen has dropped by 42%.It can be seen that whether the concentration of pollutants can be effectively controlled by the mass interception,the effect is significantly higher than the traditional interception,When adopting the sub-quality interception multiple,it saves 2.8%of the sewage treatment volume compared with the traditional interception,and the effect is more stable and economical.It is also better than the traditional interception multiple in terms of whether the treatment capacity of the sewage treatment plant is improved;finally,it is compatible with COD and In terms of whether the dynamic water environmental capacity of ammonia nitrogen can be improved,the quality-based interception has been increased by 30%and 16%,respectively,compared with the traditional interception.Through the comprehensive comparative analysis of these three aspects,it can be seen that the comprehensive effect of the quality-based interception multiple is better than the traditional interception multiple,which provides a new idea for the selection of the interception multiple.