Numerical Simulation Of A/A/O Process Under Low Load Optimal Operation Model

Due to the southern city of much rain, piping system most is the confluence system, urban pipeline construction reform is not yet mature, most of the presence of groundwater seepage.Therefore, cause most of the low load operation of the waterworks actual conditions. Low water load,lead to the restricted of microbial growth, the water effect is often not satisfactory. This article focuses on using numerical simulation, find out the best operation condition that can guarantee water under the condition of low load operation up to standard.To test in the laboratory AAO process as the research object, using the Bio Win water treatment simulation software to run the modeling and simulation of the process. Put the AAO process water quality model as the water inflow in laboratory data, modify the component parameters,preliminary simulation shows,model of the effluent COD accords with the the actual model,but the ammonia nitrogen and total nitrogen in the effluent is less than the measured values, the total phosphorus in effluent is slightly larger than the measured values. Sensitivity analysis was carried out on the model, and find out which of the model parameters had a greater influence on the water. Adjust the kinetic parameters of ammonia oxidizing bacteria AOB biggest unit growth rate anaerobic-aerobic attenuation rate; PAO’s largest phosphorus accumulating units under the restricted condition of growth rate, P unit growth rate, the matrix’s hunger or coefficient and the saturation coefficient under the restricted condition of P; Ordinary heterotrophic bacteria OHO largest unit growth rate; Chemometrics parameter of ammonia oxidizing bacteria AOB yield coefficient; The yield coefficient of ordinary heterotrophic bacteria OHO, then the simulation can get preferable simulation accord with the actual water discharge data.Adjusting process parameters or optimize the process structure, ensure water at low load conditions can also achieve all effluent discharging standard is the research emphasis in this paper. This paper studies the temperature, inside reflux ratio, outside reflux ratio, the sludge age, aerobic pool of dissolved oxygen and so on craft parameters influence of the effuent of AAO process, simulation finally found that when setting process parameters as follows:the temperature is20℃, the inside reflux ratio is200%, the outside reflux ratio is70%, the sludge age SRT is13d, dissolved oxygen DO aerobic pool is2mg/L, and cooperate with the precipitation chemical phosphorus removal, the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and other indicators can be stable under the urban sewage treatment plant pollutant emission level of the prescribed by the state standards.