US 7,320,759 B2
Sludge treatment method
Nozomu Yasunaga, Tokyo (Japan); Toshiyuki Kamiya, Tokyo (Japan); Naoki Nakatsugawa, Tokyo (Japan); and Junji Hirotsuji, Tokyo (Japan)
Assigned to Mitsubishi Denki Kabushiki Kaisha, Tokyo (Japan)
Filed on Nov. 13, 2006, as Appl. No. 11/559,006.
Application 11/559006 is a division of application No. 10/961113, filed on Oct. 12, 2004.
Claims priority of application No. 2004-002136 (JP), filed on Jan. 07, 2004; and application No. 2004-160048 (JP), filed on May 28, 2004.
Prior Publication US 2007/0068876 A1, Mar. 29, 2007
Int. Cl. C02F 11/06 (2006.01); C02F 101/10 (2006.01)
U.S. Cl. 210—712  [210/609; 210/718; 210/721; 210/760; 210/906] 14 Claims
OG exemplary drawing
 
1. A sludge treatment method, comprising the steps of:
foaming a sludge-containing liquid by blowing an ozone-containing gas into the sludge-containing liquid to generate sludge-adsorbed bubbles and discharge the bubbles from a bubble discharge port provided in an upper portion of an ozone treatment vessel, wherein the ozone-containing gas is blown into the sludge-containing liquid during the foaming step using a diffuser pipe provided at the bottom of the ozone treatment vessel, and wherein the foaming step further includes mixing the sludge-containing liquid and the bubbles using a bubble mixing blade provided at an upper portion of the ozone treatment vessel and a liquid mixing blade provided at a lower portion of the ozone treatment vessel;
eluting phosphorus in the sludge-containing liquid by supplying the bubbles to a phosphorous elution vessel from the bubble discharge port thereby bringing sludge adsorbed on the bubbles and a sludge-dissolving agent into contact with each other within the phosphorous elution vessel; and
decomposing waste ozone gas not dissolved in the sludge-containing liquid into oxygen, wherein the waste ozone gas is received from an upper portion of the phosphorous elution vessel.