METHOD FOR TREATING ORGANIC WASTE WATER

摘要

Novel methods for treating organic waste water are provided which can remarkably reduce the amount of excess sludge resulting from the biological treatment of organic waste waters. The methods for treating organic waste water comprise: biologically treating the organic waste water; subjecting the resulting biologically treated mixture to a solid-liquid separation; subjecting sludge resulting from a solid-liquid separation to a solubilization treatment for solubilizing an organic matter contained therein; and returning the sludge to the biological-treatment tank, wherein (a) the solubilization treatment is a specific treatment which is a combination of a treatment with an alkali and one or more other certain treatments or (b) a concentrated sludge phase obtained by the solid-liquid separation from the sludge which has been subjected to the solubilization treatment is repeatedly circulated in the solubilization treatment, or both (a) and (b) are carried out.