Below Ground Oil Water Separators

This model features a 1000-gallon tank capacity, with flow rates of 100–200gpm.

Contact product manager,
Paul Desmarais
(508) 399-5771

ProductsOil Water Separators

Below Ground Oil Water Separators

Hydro Quip’s Below Ground Oil Water Separators are designed for industries that need to prevent contaminated runoff and spills from getting into public treatment plants and natural waterways. Our design not only exceeds API 421 guidelines and meets local SPCC and NPDES Permits, but it is also capable of achieving a discharge limit of 5ppm or less in accordance with CEN EN 858-1. (See standards and regulations for more information.)

Because we can achieve higher flow rates, smaller unit sizes are possible. Our equipment can be easily cleaned through the removable vapor-tight cover(s), so all servicing and maintenance can be performed outside. There are no chemicals or absorbent mesh packs to remove, replace, or dispose.

Below Ground Oil Water Separators

Our below ground separator stands out from the competition because we base our design on a Reynolds Number of less than 500. A low Reynolds number is required to achieve the rise times of the oil, creating better separation of the oil from the water.

Below Ground Oil Water Separators with Effluent Pump Out Chamber

For pumping water to downstream treatment, a below ground separator design with effluent pump out chamber is available.

Below Ground Oil Water Separators with Grit Chamber

For treating oily water with heavier concentrations of solids, a below ground separator design with grit chamber is available.

Like all our other equipment, these models can be customized to your needs. We can also provide calculations signed by a registered professional engineer. Our calculations take into account potential surge and flow rate, particle characteristics, and temperature. We offer a variety of options for the below ground oil water separator.

Equipment Options

  • Single Wall
  • Double Wall with interstitial space for leak detection
  • Hold down straps
  • Traffic rated covers
  • Concrete deadmen
  • Leak Detection and Level Indicating System
  • Variety of Coating Options (Internal and External)


  • Diverse wastewaters
  • Events that produce stormwater runoffs
  • Spill containment
  • Vehicle maintenance facilities and washing operations