Thermophilic aerobic waste treatment system

• US 5,656,155 A
• Filed: 11/20/1995
• Issued: 08/12/1997
• Est. Priority Date: 04/26/1994
• Status: Expired due to Term

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: IP Holdings LLC
• Inventors: Li, Yanlong, Norcross, Kenneth L.
• Primary Examiner(s): Wyse, Thomas G.
• Application Number:
  US08/560,160
• Time in Patent Office: 631 Days
• Field of Search: 210/612, 210/621, 210/622, 210/195.1, 210/149, 210/194, 210/200, 210/201, 210/205, 210/218, 210/220
• US Class Current: 210/149
• CPC Class Codes: C02F 3/006 Regulation methods for biological treatment
• CPC Class Codes: C02F 3/12 Activated sludge processes
• CPC Class Codes: C02F 3/1284 Mixing devices
• CPC Class Codes: C02F 3/20 using diffusers
• CPC Class Codes: C02F 3/26 using pure oxygen or oxygen-rich gas
• CPC Class Codes: Y02W 10/10 Biological treatment of water, waste water, or sewage

Abstract

A system for thermophilic aerobic destruction of pathogenic organisms and organic matter within waste water treatment sludge includes a tank for maintaining the sludge and an air transfer apparatus for injecting air into the sludge near the bottom thereof so as to bubble up through the sludge and react exothermically with the thermophilic microorganisms therein so as to kill or destroy the mesophilic micro- organisms within the sludge. The thermophilic reaction is preferably controlled within a desired temperature range by control of the flow of fresh air versus recycled air being injected into the sludge. The fresh air to recycle air ratio can be controlled by several different mechanisms so as to produce the desired temperature range. The air is also utilized to mix the sludge within the tank. A pumping apparatus is also provided for transferring sludge into and out of the tank and for recirculating the sludge for purposes of auxiliary mixing. The pump can also be utilized in conjunction with an eductor for drawing fresh air into the sludge. A process controller is advantageously useable in conjunction with the various equipment to control the overall system.

Claims

1. A thermophilic and aerobic reactor system comprising:

a) a reactor tank for receiving a sludge material;

b) a gas injection mechanism for injecting oxygen containing gas into a lower portion of said material, such that the gas raises through the material;

c) a blower flow connected to an interior of the tank for withdrawing recycle gas from the tank that has passed through the material;

said blower being flow connected to said gas injection mechanism so as to transfer at least a portion of the recycle gas through the material;

d) a fresh air delivery mechanism operably flow connected to said reactor tank; and

e) a temperature controller for measuring the temperature of the material within the reactor tank and for controlling the temperature in the material within the reactor tank within a preselected thermophilic temperature range including means for varying a mix of fresh air to recycle gas such that increasing the percentage of fresh air decreases the temperature and decreasing the percentage of fresh air in the mix increases the temperature.

2. The system according to claim 1 including:

a) pump for withdrawing a portion of the material from the tank and returning the withdrawn portion to the tank.

3. The system according to claim 2 including:

a) an eductor cooperating with said pump to supply the fresh air to the material returned to the tank.

4. The system according to claim 1 including:

a) a tube with a vertically extended center opening located in said tank;

said tube separating the material in the tank into a first part on one side of the tube and a second part on an opposite side of the tube;

said first and second parts of material being flow connected at both a top and a bottom of the tube;

said gas injection mechanism injecting gas in a lower region of said first part of material and not into said second part such that said first part raises with said air and said second part flows downwardly during injection of air thereby mixing the material.

5. The system according to claim 2 wherein:

a) said blower and said pump is located external to said tank and flow connected therewith by piping.

6. The system according to claim 2 wherein:

a) said pump is also selectively flow connectable to a material discharge apparatus such that said pump pumps material from said tank to the discharge apparatus when treatment of the material in the tank is complete.