An Experimental Study On Effective Anaerobic Digestion Of Corn Stalk

Approximately 0.6 billion tons of crop waste is generated in China annually, of which is 0.1 billion tons of corn stalk. Open-field burning is one of main corn stalk disposal methods, causing great environmental and safe concerns. Therefore, it is necessary to find environmentally friendly alternatives for corn stalk disposal and utilization in a way that pollution is minimized.Using anaerobic digestion technology to convert corn stalk to biogas is one of alternatives for corn stalk utilization. However, little research has been conducted on anaerobic conversion of com stalk to biogas. The main reason is that corn stalk contains high percent of lignocelullose, which is not readily biodegradable to anaerobic bacteria, leading to lower digestion rate and biogas production. Increasing digestion temperature and pretreatment are effective methods to improve the biodegradation efficiency and biogas production.This study investigated effects of temperatures and biological and chemical pretreatments on biogas production of corn stalk at different loading rates (35. 50. 65g/L) .The experimental result shows that the cumulative biogas production(CBP) of raw corn stalk at mesophilic temperature is 105% higher than at ambient temperature, the CBP of corn stalk after 60d biological pretreatment is 23% higher than the raw one at mesophilic temperature, the CBP of corn stalk chemically pretreated by NaOH is 114% and 74% higher than that raw corn stalk and the corn stalk biologically pretreated for 60 days, respectively. It was also found that highest cumulative biogas production is obtained at loading rate of 50g/L for all temperatures (mesophilic and ambient temperature), and both biological and chemical pretreatment.Therefore, it is suggested for effective biogasification of corn stalk under the condition: anaerobic digestion of corn stalk chemically pretreated by NaOH at mesophilic temperature at loading rate of 50g/L. This study could provide useful parameters for the design of large-scale anaerobic digestion for corn stalk conversion for biogas production.