Organic Debris

Production waste and other material that accumulates in sewers or manholes.

OSHA

Occupational Safety and Health Administration

Other Sewer Structures

Other portions of the industrial sewer pipelines and manholes, including trap tanks, sumps, and any other structure not specifically identified.

Outfall

An outlet to a sewer system.

Ovality

There are two options: a) the difference between the maximum and mean diameter divided by the mean diameter, and b) the difference of the mean and minimum divided by the mean, at any one cross section of a pipe, generally expressed as a percentage.