Numerical Simulation Of Non-steady Activated Sludge System

In the numerical simulation programs that were used for non-steady wastewatertreatment process by biological method, most of the related numerical models wereestablished on the basis of the Monod equation, which considered microbial specificgrowth rate being directly related to the substrate concentration. In this paper, it wasverified by experiments that the key factor affecting the growth of microorganisms was theadsorption capacity of activated sludge, and was non-directly related to the substrateconcentration. This indicates that the Monod equation is not applicable to the non-steadyactivated sludge system. Therefore, it is rather necessary to establish the simulationprogram that was used for properly describing the non-steady biological wastewatertreatment process.In this paper, on the basis of testing and verifying the mode of adsorption, penetrationand metabolism to remove carbon-containing organic matter in wastewater treatmentprocess by biological method was reasonable, the process of removing thecarbon-containing organic matter from the non-steady activated sludge system wasanalyzed in detail, and the corresponding mathematical expression was established. Thedynamic numerical simulation program of the reaction process was programmed usingMatlab7.0programming language. The model parameters in the program wereascertained through related experiments. After running and adjustment the program, thesimulation program was initially established. The mathematical expressions and the modelparameters for each reaction were calibrated, thus a more complete simulation programwas obtained. Validation experiments were completed, the comparison of the simulationresults and the actual results of the validation experiment revealed that the simulationcurves of the substrate concentration and sludge concentration changing with reaction timewere basically consistent with the change trend of measured data. After improved, theprogram could numerically simulate the non-steady wastewater treatment process bybiological method.Through the sensitivity analysis to each model parameters, the results showed that theparameters changing of each model has little effect on the simulation results, as they were all low sensitivity parameters, thus the demands for these parameters could be not soaccurate. Within a certain range, to adjust the time of absorption phase and the value ofinflow components so as to see if the value of the simulated substrate concentration andsludge concentration changed according to certain law, showed that the changes ofsimulation values were in accordance with the actual situation. The improved simulationprogram was applied to the similar situation in practice, and the simulation results werebasically consistent with that in the practical situation. Thus it demonstrated that thesimulation program we had made was reasonable, could be applied in similar cases.