PURPOSE: To facilitate the microbic disposal of COD constituents, by raising the temperature of the constitutents in the presence of acid or alkali to change the properties of the constituents.
CONSTITUTION: The lignin contained in waste water resulting from the production of paper pulp is relatively easily removed by cohesive sedimentation or microbic treatment. However, the hemicellulose and starch contained in the waste water do not easily cohere and the percentage of microbic oxidation of the hemicellulose and starch is low. As for the disposal of waste water resulting from the reclamation of used paper, the BOD removal percentage is about 90% or more but the COD removal percentage is only about 40 to 50% in general. The present invention relates to a method of improving the COD removal percentage. The waste water containing the COD constituents is kept acid or alkaline at a temperature of not lower than 50°C for at least 30 minutes to facilitate the microbic decomposition of the COD constituents. Then, the waste water is mixed with untreated waste water from a different process. Thereafter, the mixture is separated into solid and liquid and the microbic disposal of the COD constituents is performed.
ITOU MASAMITSU
MIKI ATSUSHI
| JPS523260A | 1977-01-11 | |||
| JPS51136375A | 1976-11-25 |