| 摘要 |
<p>PURPOSE:To stably and efficiently proceed the reaction in a high-temp. acid producing tank, to minimize the volume of the tank and to enable a stable and high-load operation by specifying a free organic acid concentration in the high-temp. acid producing tank. CONSTITUTION:Raw water is introduced to the high-temp. acid producing tank 1 together with circulating water from a high-temp. methane producing tank 2 which is returned via a piping 13 to produce the acid. The circulating rate is adjusted so that the COD concentration of inflow water to the high-temp. acid producing tank 1 is made at 1000mg/l. In the high-temp. acid producing tank 1, the circulating rate is properly adjusted by considering the relation among the raw water concentration, circulating water quantity, inflow water concentration, residence time and pH so that the free organic acid concentration is <=400mg/l. The pH in the high-temp. acid producing tank 1 is controlled to 6-7 for controlling methane fermentation. Thus, both acid producing efficiency in the high-temp. acid producing tank and methane producing efficiency in the high-temp. methane producing tank can be maintained high.</p> |
