AG-4SS-HP-1H Above Ground Oil Water Separator

Ecologix model AG-4SS-HP-1H parallel-corrugated plate oil water separator will remove essentially 100% of all free and dispersed non-emulsified oil droplets larger than 20 microns in diameter with a specific gravity of .90 or less. The separator is designed for above grade installation and will be constructed of 11 gauge 304 stainless steel and coated inside and out.
The AG-4SS-HP-1H can remove oils and settleable solids from the oil water mixture at a flow rate of 100 GPM at a temperature of 55 degrees F. The design utilizes the difference in specific gravity between oil and water (buoyancy force) enhanced by the use of 36 cubic feet of HD Q-PAC coalescing plates. The separator is designed to receive oily water by gravity/pumped flow that will not mechanically emulsify the oil and will process it on a once through basis. The tank will be a single wall, rectangular unit installed above grade. It will be constructed of stainless steel. The HD Q-PAC coalescing plates are manufactured of UVResistant Polypropylene material.

System Features

  • Design Flow: 1-100 GPM
  • Size 52″ Wide X 72″ High X 84″ Long each
  • 6″ Inlet/Outlet – 150# Flange fitting
  • 2″ Oil outlet – FNPT Fitting
  • (2) 2″ Vent NPT Fittings and (2) 1” Drain NPT Fittings
  • (2) 2″ Sludge Outlet – FNPT fitting
  • Parallel-corrugated plate coalescer designed to remove oil droplets greater than 20 microns with a Reynolds Number of less than 500
  • 84 gallon sludge hopper to capture and contain settleable solids
  • Gasketed removable vapor tight cover for access to chamber compartments

System Components

The AG-4SS oil water separator is a special purpose prefabricated parallel corrugated plate, rectangular, gravity displacement type oil water separator. The separator is comprised of a tank containing an inlet compartment, separation chamber, sludge chamber, and clean water outlet chamber.


The tank is a single wall construction of 11 gauge stainless steel conforming to ASTM A240, type 304 stainless steel. Welding will be in accordance with AWS D1.1 to provide a watertight tank that will not warp or deform under load.

Pipe Connections

All connections 3″ and smaller are FNPT couplings. All connections 4″ and larger are flat face flanges with ANSI 150 pound standard bolt circle. Use flanged piping connections that conform to ANSI B16.5.

Lifting Lugs

The tank is provided with properly sized lifting lugs for handling and installation.


The tank is provided with vapor tight covers for vapor control. Gas vents and suitable access openings to each compartment will be provided. The covers is constructed of marine grade aluminum and will be fastened in place. A gasket shall be provided for vapor tightness. 3/8-16 bolts and threaded knobs will be provided for cover attachment.

Inlet Compartment

The inlet chamber shall be comprised of a non-clog diffuser to distribute the flow across the width of the separation chamber. The inlet compartment shall be of sufficient volume to effectively reduce influent suspended solids, dissipate energy and begin separation. The media will sit elevated on top of a sludge baffle. The sludge baffle will be provided to retain settleable solids and sediment from entering the separation chamber.

Separation Chamber

The oil separation chamber shall contain HD Q-PAC Coalescing Media containing a minimum of 132 square feet per cubic foot of effective coalescing surface area. The medias needle like elements (plates) shall be at 90 degrees to the horizontal or longitudinal axis of the separator. Spacing between these elements shall be spaced 3/16″ apart for the removal of a minimum of 99.9% of free droplets 20 micron in size or greater. The elements are positioned to create an angle of repose of 90 degrees to facilitate the removal of solids that may tend to build up on the coalescing surfaces, which would increase velocities to the point of discharging an unacceptable effluent.
Laminar flow with a Reynolds Number of less than 500 at a maximum designed flow rate shall be maintained throughout the separator packed bed including entrance and exit so as to prevent re-entrainment of oils with water. Flow through the polypropylene coalescing media shall be crossflow perpendicular to the vertical media elements such that all 132 square feet/cubic foot of coalescing media is available for contact with the coalescing surfaces. None of the coalescing media surfaces shall be pointing upward so as not to be available for contact with the cross flowing oily water. The media shall have a minimum of 87% void volume to facilitate sludge and dirt particles as they fall off the vertical elements and settle in the sludge compartment. The media when installed in cross flow OWS shall meet US EPA Method 413.2 and also European Standard 858-1.


An oil retention & underflow weir, and overflow weir. Position underflow weir to prevent resuspension of settled solids.

Sludge Baffle

The sludge baffle shall be located prior to and under the coalescing compartment for the settling of any solids. It shall also prevent any solids from entering the clean water chamber.

Oil Skimmer

The oil separation chamber will be provided with a rotatable pipe skimmer for gravity decanting of the separated oil to a product storage tank.

Clean Water Chamber

The tank will be provided with a clean water chamber that allows the water to leave the separator by gravity/pumped flow through the clean water outlet port.


2″ vents will be provided for vent piping to atmosphere.