CaO调质污泥自然失水特性及数学模型研究

以城市污泥为对象，研究CaO添加比、空气流速及污泥堆积厚度对CaO调质污泥自然失水特性的影响。结果表明：污泥失水速率与空气流速、CaO添加比成正比，与堆积厚度成反比。基于Page模型建立的通用模型拟合值与实测值吻合较好，均方根误差为6.34%，能较好地模拟CaO调质污泥自然失水过程。根据Page模型计算出的污泥有效水分扩散系数为9.96×10⁻⁹~1.65×10⁻⁷，自然失水时间与CaO添加比、空气流速呈正相关，与污泥堆积厚度呈负相关。以单位失水量总费用为评价指标，采用MATLAB软件中Fmincon函数计算出单位失水量总费用最低时的最优干燥参数组合：CaO添加比为0.02，空气流速为0.6 m/s，污泥堆积厚度为7 mm。

Study on natural water loss characteristics and mathematical model of CaO conditioned sludge

The effects of CaO addition ratio, airflow rate and bulking thickness on the natural water loss characteristics of municipal sludge treated by CaO were studied. The results showed that sludge water loss rate was proportional to airflow rate and CaO addition ratio, but inversely proportional to bulking thickness. The experimental data were well fitted by the general model based on the Page model with the root mean square error of 6.34%, which could better simulate the natural dewatering process of CaO-treated sludge. The effective water diffusion coefficient of the sludge calculated using the Page model was 9.96×10−9-1.65×10−7. The natural water loss time was positively correlated with the CaO addition ratio and airflow rate, and negatively correlated with the bulking thickness. Using the total cost per unit water loss as the evaluation index, the Fmincon function in MATLAB software was applied to calculate the optimal drying parameters under the condition of the lowest total cost per unit water loss. The optimal combination of drying parameters was: CAO addition ratio 0.02, airflow rate 0.6 m/s, sludge accumulation thickness 7 mm.