Simulation Study Of Luolong River WWTP Optimal Operation In Rainy Season

This study would explored the water quality impact of Kunming Luolong river WWTP in the rainy season, using activated sludge mathematical models as a means to help complete the study; through simulation experiments to study the effect of various process parameters(mixed liquor reflux ratio and sludge recycle ratio, dissolved oxygen, emission amount of sludge, the sludge recycle ratio of retrun to the anoxic) on water quality during the rainy season,to find out the best plan for the rainy season in the sewage plant. On the Luolong River WWTP how to smoothly through the rainy season put forward the guiding scheme.1) Based on the ASM2 D model, the mathematical model of activated sludge was established by WEST software. Because Luolong River WWTP was not running for a long time, so the model can not be established. In this context, establishing the activated sludge mathematical model of the sixth sewage treatment plant in Kunming City which was the recent WWTP near the Luolong River WWTP to replace the Luolong River WWTP activated sludge mathematical model, through the software the operation status of Luolong River sewage plant can be simulated and analyzed. Through WEST software to analysis water quality sensitivity of model kinetic parameters and chemometric parameters, the result show that the kinetic parameters B_H, Q_PP, N_NO_HYD, K_O_AUT, K_NH_AUT, K_NO, MU_H, N_NO_HET and stoichiometry parameters Y_H, Y_PO, Y_PHA affects the effluentsignificantly. Useing the parameter estimation function in WEST software and the basic principles of ASM model to adjust each parameter value and the correction model, using the corrected model to simulate the data of the sixth sewage treatment plant in Kunming City in April,the results show that the calibration model simulation process can better reflect the actual operation situation of water, we can use the model for subsequent analysis.2) Through the analysis of Luolong River WWTP design data and combined with sewage treatment plant site investigation results, can know theoretically capable of maximum treatment water in the Luolong River WWTP in the rainy season is 129600 m3/d, about twice as many as the dry season water, so that the influent water quantity of simulation in the rainy season is two times of the dry season. Based of West software, the sixth sewage plant activated sludge mathematical model as the core, simulation analysis of the Luolong River WWTP in rainy season; the single factor experimental study was carried out to simulate two times the amount of water quantity and low water quality impact during the rainy season, all process parameters which Luolong River WWTP can adjust were analyzed. Results show that, during the rainy season, wastewater treatment plant should close mixliquor return, the DO value should fell to about 1.5mg/l, sludge return ratio should be reduced and returned to the anoxic tank sludge ratio should be adjusted to about 20%, discharging sludge flow should be increased.3) Design the rainy season of water quantity and water quality impact simulation analysis by factorial experiments.The experimental level of factor A sludge reflux ratio was 35%, 45%, 55%, experimental level of factor B returned to the anoxic tank sludge ratio was selected: 20%, 30%, 40%; the experimental level of factor C sludge discharge amount was 550m3/d, 600m3/d, 650m3/d. The results showed that increase the sludge discharge amount, decrease sludge return ratio and keep the low ratio of returned to the anoxic tank sludge would contribute to phosphorus removal; increase the sludge reflux ratio, reducing the sludge discharge amount can contribute to nitrogen removal, three factors for removal of COD is less affected. The optimal process parameters of the regression model’s prediction are: the sludge reflux ratio 47.34%, the reflux to the anoxic tank sludge ratio 20%, the sludge discharge amount 641.28m3/d. According to the simulation results of single factor experiment and factorial experiments, it is concluded that the control scheme of the optimal operation in the rainy season in Luolong River WWTP is: No. 7 reflux revolving gate should be closed; reduce the blast volume of blast blower in order to keep dissolved oxygen in the aerobic tank maintained at about 1.5mg/l; regulation No. 3 sludge reflux pump inverter to reduce the sludge return flow and tighten No.6 valve, so that sludge reflux ratio can remaine at about 45%; open No.3 electric flashboard, make No.3 electric flashboard’s opening is a quarter of of the No. 2 electric flashboard; Open a mud pump 11.6 hours every day.