Title:
PRETREATMENT OF ACTIVATED SLUDGE
Document Type and Number:
Japanese Patent JP3164850
Kind Code:
B2
Abstract:
PURPOSE: To prevent the deterioration of activated sludge, keep the activated sludge highly active and stabilize treatment by using a reaction sludge formed from excess sludge as a microorganism adsorbent.
CONSTITUTION: The contaminant in raw water is treated with activated sludge as follows. Namely, 100 parts of raw water and 1-30 parts, preferably 3-15 parts, of return sludge are mixed and agitated, the reaction sludge is floated, concentrated and separated, and a sludge contg. ≥0.5%, preferably ≥2%, solid and treated water are obtained. The treated water and return sludge are aerated in an activated-sludge aeration tank, solid is separated from liq., and a final effluent and return sludge are obtained. The return sludge is anaerobically and aerobically digested in a concd. sludge digestion tank to biologically decompose the contaminant adsorbed by the reaction sludge, and a digested sludge is obtained. The digested sludge is drawn off as the excess sludge.
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Inventors:
Seiji Fujino
Application Number:
JP24660691A
Publication Date:
May 14, 2001
Filing Date:
August 31, 1991
Export Citation:
Assignee:
Nihon Arsie Co., Ltd.
International Classes:
C02F3/12; C02F1/24; C02F11/02; (IPC1-7): C02F3/12; C02F1/24; C02F11/02
Domestic Patent References:
| JP5889992A |
Attorney, Agent or Firm:
Wake Misao