污泥厌氧发酵产酸关键影响因素的函数模型研究

本研究以城市剩余污泥预处理液作为底物,调节底物不同C/N比,测定了厌氧发酵过程中几种关键酶的酶活及发酵产物乙酸、丙酸及丁酸的浓度.同时,利用Matlab软件通过回归分析和函数拟合构建了C/N比-关键酶活-酸产量之间的多项式函数模型,发现所建立的二元三次多项式模型的拟合优度R2均大于0.9,且残差平方和较小,因此,判定二元三次多项式更适合描述C/N比-关键酶活-酸产量的数学关系.最后,建立了关键酶活、C/N比和产酸量三因素间的曲面模型,发现该模型能够很好地描述污泥厌氧发酵中C/N比条件对关键酶和产酸类型的影响,并能进一步预测C/N比所对应的酶活和产酸发酵类型,可为今后的实验研究及工程放大提供理论参考.

Function model of the key factors in anaerobic fermentation for VFAs production from sewage sludge

The pretreated sewage sludge liquor was used as substrate for volatile fatty acids (VFAs) production by adjusting the different C/N ratios via anaerobic fermentation. The activities of the key enzymes and the concentrations of acetic acid, propionate and butyrate were measured. With the regression analysis and the model fitting, the function model among C/N ratio, enzyme activities and the acid production was developed. With the R² (goodness fit) of the model over 0.9, and the less sum of squares, the binary cubic polynomial model was evaluated as the best function model for simulating the relationship of C/N ratio, enzyme activity and VFAs production. The surface modeling of key enzyme, VFAs production on C/N ratio conditions was also established. The model can well describe the influence of C/N ratio on the key enzymes and VFAs production in anaerobic fermentation of sludge. The function model provides an effective way to predict the enzyme activity and VFAs fermentation type at different C/N ratios, and is helpful for the future experimental research and the scale up of practical project of VFAs production from sewage sludge.