Influence of pH values on fermentation and acidogenesis of waste activated sludge
pH值对污泥发酵产酸的影响

The volatile fatty acids (VFAs), which are made from the waste activated sludge, are usually regarded as the useful carbon sources for the process of denitrification and dephosphorization in sewage plants. The pH value is an important parameter to affect the anaerobic fermentation. In the study, the change law of many parameters with different pH values during the anaerobic fermentation and acidogenesis of a waste activated sludge was revealed. The results show that alkaline condition is beneficial to the process of fermentation and acidogenesis and the optimal condition is the initial pH value of 10.0 in the process. Under the condition, the VFAs concentration reached 8.90 mmol/L in the eighth day of the process. Furthermore, the release amounts of NH4+-N and PO43--P of the sludge in acid conditions are larger than that under alkaline conditions.