ANAEROBIC TREATMENT OF HIGH-CONCENTRATION ORGANIC WASTE LIQUID

摘要

PURPOSE: To make efficient treatment by lessening the amt. of an alkali for neutralization and shortening the HRT in an acid forming vessel at the time of subjecting a high-concn. org. waste liquid to an anaerobic treatment by an upflow anaerobic sludge blanket (UASB) method. CONSTITUTION: The org. waste liquid having a CODcr concn. of >=8000mg/l from a liquid-to-be-treated introducing path 3 is introduced into an acid forming vessel 1 where the waste liquid is mixed with the return liquid returned from a return path 5 and the alkali supplied from an alkali supplying path 6 and is subjected to an acid forming treatment. At this time, the return liquid flow rate is so adjusted that the volumetric ratio of the liquid to be treated/the return liquid exceeds 3. The introducing amt. of the liquid to be treated is so adjusted that the HRT (the volume of the acid forming vessel/the flow rate of the liquid to be treated) of the liquid to be treated in the acid forming vessel 1 attains <=4 hours. The acid forming liquid is introduced into the lower part of a methane fermentation vessel 2 and is passed through a sludge blanket 12 in upward current flow, by which the liquid is subjected to methane fermentation. The treated liquid is partly returned as the return liquid into the acid forming vessel 1 and the balance thereof is discharged as the treated liquid.