Experimental study on anaerobic fermentation of high concentrated cow dung mixed with wheat straw

High concentration of anaerobic fermentation with wheat straw and cow dung as inoculums were conducted for investigating the variation of interrelated index, such as pH, VFAs, TOC, TN and the variation of internal morphology of wheat straw.The results showed that the high concentration of anaerobic fermentation reactor run steady, pH decreased and then increased over time, eventually stabilized at 6.0-7.0.The content of acetic acid increased over time, while the contents of propionic acid, butyric acid and valeric acid increased and then decreased over time. With the process of the fermentation, acetic acid and butyric acid took advantage in the reactor, propionic acid accumulation did not appear. The content of TOC increased, while TN decreased over time. 120d later, C/N reached 15:1, in favor to the follow-up fermentation process. The photographs screened by Scanning Electron Microscope(SEM) indicated that the wheat straw degradated validly and quickly.