Hydrodynamic Separators (HDS) – often referred to as oil-grit separators, swirl devices, or vortex separators – are best management practices often used to remove sediment, hydrocarbons, trash and debris from stormwater runoff. HDS units are regularly used as either standalone treatment devices or pretreatment systems to detention, infiltration, rainwater harvesting and green infrastructure systems. In any application, there are a few red flags that the designer should keep in mind.
Additionally, pipe locations into the units should be examined closely to confirm that the knockouts do not interfere with each other, the joints or the top slab. This could impede manufacturability or jeopardize the structural integrity.
Much of what was discussed in this post highlights key features of HDS units that should be addressed early in the project design phases. Things like unit selection, location, and how it is configured with the rest of the drainage network can impact many of the downstream phases in the project life cycle. These discussion points are also features that can be easily overlooked, and addressing or identifying seemingly simple items can save both time and money in the long-run.