2004 Volume 51 Issue 3 Pages 141-147
Although the methane fermentation process requires less energy and the collected gas may be used as a fuel, the reaction speed is slow. It leads to the large size reactor and high cost. Therefore, to investigate the practicability and efficiency of the Methane Fermentation as the waste disposal system from the perspective of energy production, advancement of load and reduction of discharge, the thermophilic methane fermentation tests were carried out at the temperature of 55°C changing the loading rate from 2.28 kg-VS/m3/d to 9.90 kg-VS/m3/d continuously. The fermentation could be stable under the following condition, HRT: over 10 days, loading rate: under 9.29 kg-VS/m3/d, moisture percentage: over 90%, Nitrogen content: under 0.0020 kg-N/kg. In case of that the nitrogen concentration in the treated waste is higher, the dilution water is necessary to control the concentration of nitrogen. In the thermophilic methane fermentation, two times more additional water is necessary compared with the mesophilic methane fermentation. The obtained net energy was two times greater by the thermophilic methane fermentation than by the mesophilic methane fermentation in the condition that the additional water for the waste was unnecessary. On the other side, there was no great difference between thermophilic and mesophilic methane fermentation in the condition that the additional water was necessary.
