System for the biological treatment of water and corresponding method

Patent metadata

Field	Value
Publication number	US-11878923-B2
Application number	US-201816766309-A
Country	US
Kind code	B2
Filing date	Oct 23, 2018
Priority date	Nov 23, 2017
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

A system for biologically treating wastewater comprising a rotating drum disposed within a tank. Biofilm carriers are contained in the drum. One or more hollow tube aerators are secured inside the drum to a perforated wall that forms a part of the drum. As the drum is rotated within the tank, the mixing of the biofilm carriers with the wastewater therein and the action of the hollow tubes aerates the wastewater in the rotating drum.

First claim

The invention claimed is:

1. A system for biologically treating wastewater comprising:
a tank comprising a point of entry for the wastewater to be treated and an exit point for treated wastewater;
a shaft disposed in the tank;
a rotating drum having a wall with one or more openings formed therein and supported on the shaft and configured to be partially submerged in the wastewater in the tank where less than one-half of the drum's internal volume contains the wastewater;
a drive for rotatively driving the drum;
media configured to support a biofilm disposed in the drum and retained in the drum as the drum is rotatively driven;
the media occupying a volume of from 30% to 80% of the internal volume of the rotating drum;
at least one hollow tube disposed in the rotating drum and secured to the wall of the rotating drum, the at least one hollow tube extending generally parallel to the shaft;
the at least one hollow tube includes one or more orifices formed in a section of the tube; and
wherein the drum and the at least one hollow tube are configured to alternatively fill the at least one hollow tube with air and wastewater in response to the drum being rotatively driven.

2. The system of claim 1 wherein the drum and at least one hollow tube are configured to fill the hollow tube with air during one portion of a revolution of the drum and to fill the at least one hollow tube with wastewater during another portion of the revolution of the drum.

3. The system of claim 1 characterized in that the media has a specific surface area greater than 200 m 2 /m 3 .

4. The system of claim 1 wherein the media has a specific surface area of 200 to 1300 m 2 /m 3 .

5. The system of claim 1 wherein the at least one hollow tube is at least four hollow tubes secured to the wall of the rotating drum.

6. The system of claim 1 wherein the tank encases the rotating drum and is generally airtight relative to ambient air outside of the tank.

7. The system of claim 1 wherein the media are made of plastic.

8. The system of claim 1 characterized in that the media are chosen from the group including pieces of pumice stone, expanded clay beads, sludge granulates, granular activated carbon, polystyrene beads, and pieces of cork.

9. A method of biologically treating wastewater comprising:
directing the wastewater to be treated into a tank and into a rotating drum having a perforated wall and disposed in the tank;
containing biofilm carriers in the rotating drum, the biofilm carriers occupying a volume of from 30% to 80% of the internal volume of the rotating drum;
rotating the drum and contacting the biofilm carriers with the wastewater in the drum to biologically treat the wastewater therein;
aerating the wastewater in the drum by employing a plurality of tubes having orifices therein and secured to the wall inside the drum;
as the drum rotates, filling the tubes passing through an air space above a surface of the wastewater in the drum with air, and thereafter submerging the tubes containing the air in the wastewater in the drum causing the air in the tubes to pass into the wastewater in the drum and in the process filling the tubes with wastewater as the tubes move through the wastewater in the drum; and
directing treated wastewater from the drum and out a treated wastewater outlet in the drum.

10. The method of claim 9 wherein the tubes are circumferentially spaced around the inside of the wall of the drum and at any one time one or more of the tubes passes through the air space while one or more other tubes are submerged in the wastewater in the drum and pass through the wastewater.

11. The method of claim 9 wherein the orifices formed in the tubes are oriented such that the orifices face the general direction of the rotation of the drum.

12. The method of claim 9 including maintaining the wastewater level in the drum such that less than half of the internal volume of the drum contains the wastewater.

13. The method of claim 9 wherein the wastewater within the rotating drum is also aerated due to the mixing of the biofilm carriers as the drum rotates.

Assignees

• Veolia Water Solutions & Tech

Inventors

• Sauvignet Philippe
• Meudal Nicolas
• Hertfleder Nikolai
• Inial Goulven
• Lindegaard Sophie

Classifications

• C02F3/085 Primary

  Fluidized beds · CPC title

• C02F3/082 Primary

  Rotating biological contactors · CPC title

• C02F3/104

  Granular carriers · CPC title

• C02F2003/001

  using granular carriers or supports for the microorganisms · CPC title

• C02F2203/006

  details of construction, e.g. specially adapted seals, modules, connections · CPC title