title: Optimized alkaline pretreatment of sludge before anaerobic digestion.
abstract: NaOH was used to disintegrate a mixture composed mainly of primary sludge with biofilm sludge before anaerobic digestion in batch experiments. NaOH pretreatment dissolved some organic substances, and the optimum dose was 0.1mol/L. After the alkali-treated sludge was fed into the digesters, the higher pH delayed the start of digestion and reduced the biogas production during the initial stage, although the system recovered after a lag phase when the dose was lower than 0.04mol/L. Acid conditioning was necessary, but the increased salinity also impacted on the digestion efficiency. For sludge pretreatment, the optimum NaOH dose was 0.1mol/L, and the initial pH of the batch digesters needs to be controlled at less than eight. Under optimized conditions, the organic degradation rate was 38.3% and the biogas yield was 0.65L/g volatile suspended solid (VSS), whereas these values for the control were 30.3% and 0.64L/g VSS, respectively.
authors.affiliation: Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China. li.huan@sz.tsinghua.edu.cn
authors.forename: Huan
authors.initials: H
authors.lastname: Li
authors.forename: Chenchen
authors.initials: C
authors.lastname: Li
authors.forename: Wenjie
authors.initials: W
authors.lastname: Liu
authors.forename: Shuxin
authors.initials: S
authors.lastname: Zou
mesh_terms: D000693:Anaerobiosis; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis; D057919:Biological Oxygen Demand Analysis; D006863:Hydrogen-Ion Concentration; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D012972:Sodium Hydroxide / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D056804:Biofuels; D012722:Sewage; D012972:Sodium Hydroxide