| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method and an apparatus which do not use chemicals such as alkali and does not require much mechanical energy in order to reduce the quantity of sludge, and are little in the necessary quantity of energy and are excellent in the treatment efficiency by using ultrasonic wave. SOLUTION: In the method and apparatus for reducing quantity of excessive sludge, organic contaminated water is cleaned by aerobic biological treatment, therein, a cationic surface active agent is added to a part of activated sludge generated from the aerobic biological treatment, the added part of the activated sludge is aerated, air bubbles are attached to the activated sludge, the activated sludge is floated and separated, the floated activated sludge is irradiated with ultrasonic wave and the irradiated sludge is supplied to the aerobic biological treatment process or another aerobic biological treatment process or an anaerobic digesting treatment process and is biologically decomposed. In the method and apparatus for reducing quantity of excessive sludge, furthermore, a part of activated sludge is irradiated with ultrasonic wave in the state of coexistence of a chemical oxidation agent.</p> |
