title: Alkaline treatment of high-solids sludge and its application to anaerobic digestion.
abstract: High-solids anaerobic digestion is a promising new process for sludge reduction and bioenergy recovery, requiring smaller digestion tanks and less energy for heating, but a longer digestion time, than traditional low-solids anaerobic digestion. To accelerate this process, alkaline sludge disintegration was tested as a pretreatment method for anaerobic digestion of high-solids sludge. The results showed that alkaline treatment effectively disintegrated both low-solids sludge and high-solids sludge, and treatment duration of 30 min was the most efficient. The relation between sludge disintegration degree and NaOH dose can be described by a transmutative power function model. At NaOH dose lower than 0.2 mol/L, sludge disintegration degree remained virtually unchanged when sludge total solids (TS) content increased from 2.0 to 11.0%, and decreased only slightly when sludge TS increased to 14.2%. Although high-solids sludge required a slightly higher molarity of NaOH to reach the same disintegration level of low-solids sludge, the required mass of NaOH actually decreased due to sludge thickening. From the view of NaOH consumption, sludge TS of 8-12% and a NaOH dose of 0.05 mol/L were optimum conditions for alkaline pretreatment, which resulted in a slight increase in accumulative biogas yield, but a decrease by 24-29% in digestion time during the subsequent anaerobic digestion.
authors.affiliation: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: li.huan@sz.tsinghua.edu.cn.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: li.huan@sz.tsinghua.edu.cn.
authors.forename: Huan
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: li.huan@sz.tsinghua.edu.cn; Joint Research Center of Urban Resource Recycling Technology of Graduate School at Shenzhen, Tsinghua University and Shenzhen Green Eco-Manufacturer High-Tech Co. Ltd, Shenzhen 518055, China.
authors.forename: Yuyao
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D012037:Refuse Disposal / Q000379:methods*; D012972:Sodium Hydroxide / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D012972:Sodium Hydroxide