Model ATAGOWS Specification

Provide and install ______Anchorage Tank  Model ATLLS-B-___ MPak® plate pack gravity displacement Oil Water Separator(s). Separator(s) shall be ______in length, ______ in width, and _____ in height.


The separator shall be designed for gravity separation of free oils (hydrocarbons and other petroleum products) along with some settleable solids from water. The source of the influent to the separator shall be gravity flow from floor drains and spills.

Performance Influent Characteristics

Provide Oil Water Separator designed for intermittent and variable flows of water, oil, or any combination of non-emulsified oil/water mixtures ranging from zero to ______gpm. Operating temperatures of the influent oil in water mixture shall range from 40°F. to 45°F. The specific gravities of the oils at operating temperatures shall range from 0.68 to 0.95 and the petroleum hydrocarbon concentration less than or equal to 500 mg/l . The specific gravity of the fresh water at operating temperatures shall range from 1.00 to 1.03.

Effluent Characteristics

The free oil and grease concentration in the effluent from the oil water separator shall not exceed 10 mg/l (10 ppm). Proof shall be provided by the manufacturer in the form of effluent calculations that this goal will be met under the operating conditions specified.

Design Criteria

The oil water separator shall be designed in accordance with Stokes Law and the American Petroleum Institute Manual on Disposal of Refinery Wastes.


Provide shop drawings for the oil water separator that show principal dimensions, materials, and locations of all fittings.


By computer prediction or design calculations, show that the oil water separator is in compliance with effluent requirements when operating under detailed influent conditions. Calculations should show rise and impingement rate at specified specific gravities, water temperature, and oil droplet rise.

Operating Instructions

Provide ______complete sets of installation, operating, and maintenance instructions for the oil water separator system that contain clear and concise descriptions of installation, operation, and maintenance procedures and a list of parts for equipment and data necessary to ordering replacement parts.


Provide a shop fabricated oil water separator system which is comprised of a tank containing an inlet compartment, oleophilic polypropylene oil coalescing plate compartment, and an outlet compartment.

Inlet Compartment

The inlet compartment shall reduce suspended solids to non-clogging levels for plate packs and provide a uniform oily waste water loading across inlet face of the oil coalescing compartment under laminar flow conditions. Equip the compartment with an inlet nozzle with a non-clogging flow distributor and energy dissipater device.

Coalescing Compartment

Equip the coalescing compartment with Facet MPak® oleophilic polypropylene oil coalescing plates assembled in modular packs.

Outlet Compartment

The outlet compartment shall contain an outlet nozzle equal in size to the inlet nozzle and shall contain a sampling port accessible from the surface.


The separator shall be of single wall construction. Gasketed hinged access panels shall extend the entire width of the separator, allowing complete accessibility to the plate pack compartment. Gasketed bolt-down lids shall cover the inlet and outlet compartments.

Waste Oil Storage

The waste oil storage system shall be an integral part of the proposed oil water separator system. The separated waste oil shall be contained in the upper 30% of the overall tank volume and shall, as it accumulates, displace the normal water level. The waste oil shall reach a predetermined volume, at which time an optional oil level sensor will indicate that the waste oil level has reached pump-out level. Waste oil may be suctioned by removing the floor plate cover at the surface.

Tank Supports

The separator shall be supported by legs bolted to the floor slab, or by an integral steel skid.


Automatic High Level Alarm and Interstitial Leak Sensor

A dual station liquid level sensor for high waste oil level and high high oil level, with weatherproof NEMA 4 enclosure, enabling indoor or outdoor installation, shall be provided. The system shall automatically activate an alarm device after the waste oil reaches predetermined levels. The system shall be an Anchorage Tank Monitor II Alarm consisting of the control unit and a Tank Assembly Unit, (lengths as required) or approved equal.

Miscellaneous Appurtenances

Bolts, stiffeners, washers, nuts, screws, pins, and fittings required shall be corrosion resistant which is defined as materials that are nonferrous or nonmetallic.


Flanges shall be ASTM A105, CI 150, RF or FF (to match valve and fitting faces), with standard bolt circle, weld neck type per ANSI B16.5.

Optional Auger Screw

An optional solids collection area in a v-bottom configuration shall be provided with a motorized auger screw to remove solids from the separator. A flanged gate valve and dry-break connection shall be included to facilitate solids removal in a safe manner.

Lifting Lugs

Fit tank with lifting lugs for handling and installation. Locate at each corner. Each lug shall carry the total dry weight of the tank and attendant appurtenances.


Provide a vent for each separator compartment, inlet and outlet pipes and locate on the separator wall above the oil/water level.


Parts requiring adjustment, cleaning, inspection, or repair shall be accessible and capable of convenient removal when required. Plate Packs shall be fully accessible from the gasketed hinged lids.