Typically waste water flows from a collection point (such as Sump Pit) into an Above Ground Cone Bottom Multiple Tank Oil-Water-Solids Separator, which settles out most of the solids from the waste stream.

Cone Bottom Storage Tanks are an effective means of separating solids from water. The steep slope of the cone tank bottoms enhances separation and allows solids to be decanted through a valve in the bottom. This can be automated upon request. These solids can then be easily flushed out of the cone tanks and allowed to dry prior to disposal.

For system pictured, the waste water flows from a Washpad and Sump Pit into the first tank of the Above Ground Cone Bottom Three Tank Oil-Water-Solids Separator. The waste stream then flows into a Watermaze Bioremediation System, which creates the proper environment to allow continuously introduced microbes to consume emulsified oils and control BOD and COD before final discharge into sewer.

Some companies have installed separation systems underground. There are several reasons to avoid this.  See list of System Comparisons between underground separator and above ground cone tank separator systems.
To view a power point presentation illustrating this and other Site Design Pretreatment Comparisons - click here.