| 摘要 |
Reference and desired pH values are chosen for the sludge being subjected to anaerobic degradation. The sludge pH is altered by adding a non-oxidizing, poorly degradable acid in order to obtain the desired pH and the sludge is stirred to generate biogas. The preparation of biogas by anaerobic degradation of a protein-containing sludge comprises bringing the sludge into contact with biogas-generating bacteria for carrying out degradation under anaerobic conditions. A reference value representing the pH of the sludge during degradation without the addition of acid is obtained, this value being in the range of 8-8.5. An desired value which is 0.01-2 pH units less than the reference value and lies within the range of 6.5-8 is chosen. Sludge pH is altered by adding a non-oxidizing, poorly degradable acid in order to obtain the desired value and the sludge is stirred to generate biogas. |
