title: Effects of organic loading rate and effluent recirculation on the performance of two-stage anaerobic digestion of vegetable waste.
abstract: The effects of organic loading rates (OLR) and effluent recirculation on dynamics of acidogenic and methanogenic processes in two-stage anaerobic digestion of vegetable waste were investigated. Two systems were performed at OLRs of 1.3, 1.7, 2.1 and 2.6 g VS/L/d. One system recirculated the effluent from the methanogenic reactor to acidogenic reactor. With increasing OLRs, total volatile fatty acid (VFA) concentration increased to approximately 8500 mg/L in acidogenic digester, where pH decreased from 6.4 to 5.2. Daily biogas production and methane content in methanogenic reactor increased from 1.2 to 4.4 L/d and from 27.4% to 60.5%, respectively. However, inhibition of hydrolysis in acidogenic reactor was demonstrated under the OLR of 2.6 g VS/L/d without recirculation, thus indicating system overloading. Effluent recirculation shown a considerable positive effect on alleviating VFA inhibition and improving biogas production in acidogenic reactor because of the effect of dilution and pH adjustment, particularly at high OLRs.
authors: College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, PR China.
authors: Zhuang
authors: Z
authors: Zuo
authors: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing 100083, PR China. Electronic address: wushubiao@gmail.com.
authors: Shubiao
authors: S
authors: Wu
authors: College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, PR China.
authors: Wanqin
authors: W
authors: Zhang
authors: Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing 100083, PR China.
authors: Renjie
authors: R
authors: Dong
mesh_terms: D000693:Anaerobiosis; D018441:Biofilms; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002241:Carbohydrates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008697:Methane / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods*; D014675:Vegetables
chemical_list: D056804:Biofuels; D002241:Carbohydrates; D005227:Fatty Acids; D002244:Carbon; D008697:Methane
keywords: Anaerobic digestion; Organic loading rate; Recirculation; Two-stage process; Vegetable waste