Kubota Corporation

Tadao Fujimoto

Tadaaki Kawasugi

Hiroyuki Fujiuchi

Kenichi Shimizu

Seiichiro Ueda

Akio Toriyama

Taketoshi Madokoro

A waste water treating apparatus includes a circulation type aeration tank having a downward flow chamber and an upward flow chamber extending in the depth direction and communicating with each other at the upper and lower ends thereof. An oxygen containing gas is supplied to the downward flow chamber and waste water and return sludge are supplied to a given position or elevation of the upward flow chamber to be mixed with a mixed liquor flowing through the upward flow chamber, whereby a reduction zone with a low concentration of dissolved oxygen is formed at the upper portion of the upward flow chamber. Denitrification takes place in the above described reduction zone.

Waste water treating apparatus

A method for melting and treating waste to be treated such as waste water treatment sludge and incinerated ash of garbage involves mixing the waste to be treated with an auxiliary fuel in powder, granular or solid form or in the form of mixture thereof which has its own calorie value. Powder coal, coal, coke, waste plastic material, saw-dust, waste paper, carbonized material and used tires can be used as an auxiliary fuel. In addition to the auxiliary fuel, an additive is admixed for adjusting the composition of the waste to have treated so as to be a specific composition ratio.

Method for melting and treating waste

A sludge treating apparatus comprises a centrifugal condensing machine for forcedly condensing a raw sludge produced by a waste water treating apparatus. The raw sludge condensed to approximately 94 to 90% in terms of the percentage of moisture content by means of the centrifugal condensing machine is introduced into an anaerobic digestion tank of a deep well type, where the raw sludge undergoes an anaerobic digestion, and a digested sludge obtained from the anaerobic digestion tank is then dewatered by means of a dewatering apparatus such as a belt press, whereupon the dewatered sludge is applied to a post-treatment apparatus. In execution of the anaerobic digestion process, the reactions corresponding to an acid fermentation stage and acid regression stage may be carried out in advance in separate tanks and the reaction corresponding to an alkaline fermentation stage may be mainly performed in an anaerobic digestion tank.

Sludge treating apparatus

A waste water treating apparatus comprises an inner chamber and an outer chamber disposed around the inner chamber extending to a considerable depth. The inner and outer chamber communicate with each other at the bottom portion, whereby the inner and outer chambers form a downward and upward flow chamber, respectively, for circulating waste water. The waste water that flows from the downward flow chamber to the upward flow chamber is circulated to the downward flow chamber by means of a pump. An oxygen containing gas is simultaneously supplied into the ciculating waste water. An apparatus for monitoring the concentration of oxygen or carbon dioxide in an exhaust gas is provided at an outlet of the upward flow chamber. The oxygen containing gas being supplied is controlled to a predetermined optimum flow rate in response to the monitored concentration.

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Kobe, Japan

Tadao Fujimoto