Oil-Water Separator

Gravimetric Pre-Treatment Tank

TrenchFormer is uniquely positioned to collect non-point source (NPS) pollution from urban runoff. Our cast-in-place trench drain Oil-Water Separator is a cost-effective addition that separates these urban pollutants into their discrete components. Using a baffle plate, stand-pipe assembly, and gravity, our system separates oil, water, and solid particles from the site’s wastewater.

Uniquely, the TrenchFormer concrete Oil-Water Separator tank is constructed using a lightweight cast-in-place forming system that installs without the necessity of heavy equipment. The basic system contains no moving parts. Periodic removal of captured oil and solids is the only maintenance required.

U-Leg Anchor Studs Removable Solid Cover Baffle Separator EPS Former Inlet Elbow Stand Pipe Assembly Adjustable Rail Clamp Structural Frame


No-float U-Legs eliminate subgrade barrier penetration and the concrete anchoring slab holds the forming system firmly in place.

Anchor Studs

Welded concrete studs independently anchor the frame into the surrounding concrete delivering structural load transfer and maximum service life.

Removable Solid Cover

Solid covers are seated on independently anchored frames and removable for ease of access and maintenance.

Baffle Separator

Overflow baffle functions as a gravity separation device allowing suspended solids to settle to the bottom of the first chamber as a sediment layer and wastewater oil will coalesce and rise to the top.

EPS Former

Expanded Polystyrene former is used to create the correctly-shaped cast-in-place concrete tank.

Inlet Elbow

90° inlet elbow helps stabilize turbulence and directs solids to the bottom of the first chamber.

Stand Pipe Assembly

Locates the discharge outlet at the bottom of the second chamber away from the oil droplets accumulated at the top.  A pipe tee at the top of the assembly serves as a vacuum break and as a means of examining the discharge stream.

Adjustable Rail Clamp

The adjustable clamp allows the formwork to be micro-adjusted once the anchoring slab is poured over the bottom of the u-legs.

Structural Frame

Structural steel angle is independently anchored to maximize load transference into the encasement concrete.


Some oil-water separation requirements extend beyond the capabilities of the standard Trench Former Oil Water Separator.  We can provide a number of options to accommodate specific needs.  The following modifications and accessories are available:

  • 25 mil reinforced geomembrane containment barrier
  • Special capacities and dimensions
  • Internal oil storage
  • Multiple and diffuser baffles
  • Second liner allowing for additional leak detection


Unlike other separators, the Oil Water Separator, by ABT Inc. is a lightweight, easily installed forming system. Using our patented, non-floating formwork, our concrete Oil Water Separator installs without the necessity of heavy equipment, providing a cost-effective system of unequaled efficiency. Categories: Environmental ProductsStorm Water Filtration

Cast-In-Place Trench Drain Oil Water Separator

Oil-Water Separator Standard Features

  • Three storage capacities – 160, 240, and 320 gallon
  • Cast-In-Place Trench Drain Oil Water SeparatorThree flow capacities – 21, 31, and 41 gallons per minute
  • Full perimeter steel anchor frame
  • Patented no-float installation legs
  • Internal PVC piping and fittings
  • Preformed deforming grooves
  • Full width overflow weir to maintain laminar fluid flow
  • Ability to inspect discharge stream
System Specifications
Part Number
Storage Capacity
API Design Capacity
Dimensions (W*D*L)
I/O Invert
Installation Wt. w/o Cover
Shipping Weight
Detail Sheet
gal (ltr)
gpm (lpm)
in. (mm)
lbs (kg)
lbs (kg)
160 (600)
21 (79)
23 x 48 x 48
12″ (305)
75 (34)
235 (107)
240 (900)
31 (119)
23 x 48 x 72
12″ (305)
115 (52)
310 (141)
320 (1200)
41 (158)
23 x 48 x 96
12″ (305)
150 (68)
390 (177)