[Experimental investigation of the straw pre-treatment to enhance its high solid anaerobic digestion].
The straw contains a high content of lignin, which cannot be well utilized by anaerobic bacteria in high solid anaerobic digestion process. This paper presents the experimental investigation of the straw pre-treatment, which aims to destroy the complex structure of the lignin to enhance its high solid anaerobic digestion. The straw is pre-treated in different solutions including NaOH, ammonia, H2SO4, and carbamide. The pre-treating effects are expressed by COD concentration dissolved in the solutions and the 14-day biogas generation in the enhanced aerogenic experiment. Different affecting factors, such as the concentration of the chemical solution, the species of the straw, the pre-treatment reaction time, the reaction temperature and the size of the straw, are investigated. The results show that NaOH solution is the most effective pre-treatment chemical among the four different solutions. The experimental results still indicate that the accumulative biogas production can be 1 500 mL (10 g straw) in 14 days after pre-treatment in 4 mg/L NaOH solution and the dissolved COD in the solution reaches 39 000 mg/L after 24 hours. In addition, the experiment shows that the lignin content in the straw is reduced from 28% to 19% after pre-treatment in 1.5% (in weight) NaOH solution, and it can improve the straw treatment efficiency using high solid anaerobic digestion process.
Jiang
Jian-Guo
JG
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China. jianguoj@tsinghua.edu.cn
Zhao
Zhen-Zhen
ZZ
Du
Xue-Juan
XJ
Sui
Ji-Chao
JC
Wu
Shi-Yao
SY
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D008031:Lignin / Q000737:chemistry / Q000378:metabolism; D018547:Plant Stems / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry*; D014908:Triticum
D012972:Sodium Hydroxide; D008031:Lignin