基于质量守恒的二沉池一维通量模型

A one-dimension flux model for the secondary settling tank based on the mass conservation

基于质量守恒定律，导出了二沉池的一维通量模型。模型考虑了二沉池表面积的变化，低浓度污泥沉降和区域沉降采用了Takacs速率公式，压缩沉降采用了压缩沉降速率公式。结果表明，单元层的污泥质量守恒，模型在进水污泥浓度、进水流量、回流比及其组合的脉冲扰动下仍有较强的稳定性；二沉池出水悬浮物浓度与回流污泥浓度的模拟值分别为16．40mg／L与7．01g／L，和实测值范围15-19mg／L与6．46—8．32g／L较为吻合；污泥层高度的预测值为0．55m，与实测值0．45m较为一致。同时，恰当地选取二沉池分层数和模拟迭代时间可以从根本上避免模拟失真，将二沉池分为30层及其以上可得到理想的模拟结果。

Based on the mass conservation law, a one-dimensional flux model for the Secondary Settling Tank （SST） with varying cross-sectional areas was led out. Takacs function was adopted for describing the settling at low concentration and the zone settling, and a compression settling velocity function for the compression settling. The sludge mass conservation in unit layer, and the model was still very stable under the disturbances of influent flow rate, influent solid concentration, return flow ratio and their combination. The simulated SST effluent sludge concentration and return flow sludge concentration were 16.40mg/L and 7.01g/L respectively, coinciding a little with actually measured value range of 15-19mg/L and 6.46-8.32g/L. The forecasted sludge blanket height was 0.55m, being the same relatively with the actually measured value 0.45m. Meanwhile, suitable selection of the number of SST unit layer and the simulated time step could basically avoid the simulating distortion. The model dividing the settler into 30 or more unit layers be able to accurately represent the SST performance.