About Hydrodynamic Separators
General Information Performance Data Water Quality Treatment Process Design


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Design

The design of HDS devices varies, and is completed by the manufacturer in accordance with local watershed conditions and target water quality treatment objectives. Often, these systems are designed to replace or retrofit existing catchbasins.

Typically, HDS devices consist of a chamber that is configured for tangential flow, meaning that stormwater enters the device through an angled inlet that creates a swirl action to enhance particle settling. Many also contain a flow partition to minimize sediment re-suspension during times when flow rates exceed the design target.

Typically, HDS devices are equipped with a baffled outlet to remove floating debris, oil, and grease in stormwater runoff. To prevent the re-suspension of captured solids during times of high flow volume, some manufacturers have adapted HDS designs to include internal, online bypasses. When appropriate, these systems also can be outfitted with external, offline bypasses so that high flows can bypass the system completely.