Methane production from rice straw with acclimated anaerobic sludge: effect of phosphate supplementation.
Rice straw particles were directly used as substrate for anaerobic digestion with acclimated sludge under room temperature and different levels of phosphate. Two obvious biogas production peaks were observed for all reactors, with biogas or methane yields of (0.33-0.35)m(3)/kg-VS loaded or (0.27-0.29)m(3) CH(4)/kg-VS loaded and average methane contents of 75.9-78.2%. A separated two-stage first-order kinetic model was developed in this study and showed a good fit to the experimental data when this complicated process was divided into two stages. The average biogas and methane production rate constants were (0.027-0.031)d(-1) and (0.028-0.033)d(-1), respectively, increased by 2-3 times in the second stages than those in the first. The results indicated that an adequate level of phosphate addition (465 mg-P/L) could accelerate the biogasification process: 7-13 days earlier appearance of the two peaks and shorter time needed for complete biogasification of rice straw.
Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Shanghai 200433, China. zflei@fudan.edu.cn
Zhongfang
Z
Lei
Jiayi
J
Chen
Zhenya
Z
Zhang
Norio
N
Sugiura
D000064:Acclimatization / Q000187:drug effects*; D000693:Anaerobiosis / Q000187:drug effects; D056804:Biofuels / Q000032:analysis; D019149:Bioreactors / Q000382:microbiology; D003198:Computer Simulation; D005232:Fatty Acids, Volatile / Q000032:analysis; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008697:Methane / Q000096:biosynthesis*; D008956:Models, Chemical; D012275:Oryza / Q000737:chemistry*; D010710:Phosphates / Q000494:pharmacology*; D012722:Sewage / Q000382:microbiology*; D014866:Waste Products / Q000032:analysis*
D056804:Biofuels; D005232:Fatty Acids, Volatile; D010710:Phosphates; D012722:Sewage; D014866:Waste Products; D008697:Methane