Effects of Thermal-Alkaline Pretreatment on Solubilisation and High-Solid Anaerobic Digestion of Dewatered Activated Sludge

Haigang Guo, Shuting Zhang, Lianzhu Du, Junfeng Liang, Suli Zhi, Jiaying Yu, Xuebin Lu, Keqiang Zhang


The effects of thermal-alkaline pretreatment on dewatered activated sludge (DAS) solubilisation and subsequent high-solid anaerobic digestion were studied by response surface methodology (RSM) from 105 to 135 °C and between 5 and 35 mg alkaline/g total solid (TS) DAS. Soluble chemical oxygen demand (SCOD), soluble carbohydrates, and protein concentrations were significantly enhanced in thermal-alkaline pretreated DAS samples. Daily methane yield increased at the middle of digestion, and cumulative methane yield (CMY) significantly increased after thermal-alkaline pretreatment. A first-order linear model of temperature and alkaline was significant for SCOD by RSM, and the determination coefficient (R2) was 94.62%. The quadratic model of temperature and alkaline was also significant for methane yield. R2 of 99.80% confirmed that the model used in this study fit the experimental variables very well. Using the model, the optimum pretreatment condition of methane yield was obtained at 134.95 °C and 23.77 mg alkali. Therefore, RSM was an effective tool in predicting the DAS pretreatment condition for optimum methane yield.


High-solid anaerobic digestion; Thermal-alkaline pretreatment; Dewatered activated sludge; Methane yield

Full Text: PDF

Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126