Section 520. Pre-aeration

Aeration of pretreated sewage should be provided whenever the low dissolved oxygen, or anaerobic condition, of the sewage can interfere with downstream unit operation reliability. Pre-aeration may be used to prevent solids deposition problems in on-line or off-line equalization or storage basins.

1. Pre-aeration unit operations shall be designed so that removal from service will not interfere with normal downstream operation of the remainder of the treatment process.

2. Inlet and outlet devices shall be designed to ensure proper distribution and help prevent solids deposition, while minimizing any hydraulic short circuiting effects.

3. The aeration equipment shall be capable of obtaining both adequate mixing and self-cleaning velocities within the basin. Any of the types of equipment used for aeration of biological reactors may be utilized.

4. A satisfactory means of grit removal shall be provided for operation of pre-aeration basins.

Historical Notes

Former 12VAC5-581-580 derived from Volume 18, Issue 10, eff. February 27, 2002; amended and adopted as 9VAC25-790-520, Virginia Register Volume 20, Issue 09, eff. February 12, 2004.

Statutory Authority

§ 62.1-44.19 of the Code of Virginia.