Study on Enhanced Anaerobic Acidogenesis of Excess Sludge at Alkaline pH

It is feasible to utilize the anaerobic fermentation of sludge to acquire acetate and other VFAs for enhanced biological phosphorus removal in wastewater treatment plants.At the same time,the reuse of sludge is realized.The pH is an important parameter to affect the anaerobic fermentation.The effect of pH ranging from 4.0 to 11.0 on the anaerobic acidogenesis of excess sludge at 20 to 22 ℃ was investigated.The results show that VFAs production at pH of 8.0 to 11.0 is higher than that at pH of 4.0 to 7.0.When the pH is controlled at 10.0,the maximal VFAs are achieved on the 12th day,which is almost 3 times of that at pH of 7.0(256.16 mg/gVSS versus 86.63 mg/gVSS).Besides,further theory investigations were carried out on the high production at alkaline conditions,including the released soluble chemical oxygen demand(SCOD),the enzyme activity and the methane production.