Industrial Waste Water Treatment

  • 815.344.2960

Car Wash Water Treatment Systems – Model VEW

The VEW car wash water treatment system is designed for the treatment of wastewater generated from wash racks and pressure washers used in car and vehicle and equipment washing processes. VEWs can be used as a single pass and discharge system or as a recycle system depending on the project needs. The VEWs are designed to remove oils, fuels, suspended solids and other contaminants. Where rigorous removal of dissolved minerals and metals are required additional treatment may be added to the design.

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The VEW Car Wash Water Treatment & Recycle Systems are designed for the treatment of wastewater generated from car wash racks and pressure washers used in vehicle and equipment washing processes. VEWs can be used as a single pass and discharge system or as a recycle system depending on the project needs. The Car Wash Water Treatment & Recycle Systems are designed to remove oils, fuels, suspended solids and other contaminants. Where rigorous removal of dissolved minerals and metals are required additional treatment may be added to the design.

Larger flow rated systems can be provided for any flow rate. Any of the technologies in our product lineup can be combined to create the right solution for your application.

Customization & modifications to fit your project needs are offered. Typical performance is 10 & 5 ppm or less, 30 micron oil droplet (performance depends on model).

Products removed: Motor oils, fuels (vehicle/jet), fuel oils, hydraulic fluids, immiscible machining oils, lube oil, transmission fluid, bunker c, DNAPLs, LNAPLs, crude, air compressor lube & other hydrocarbon based derivatives (BTEX etc..), all filterable solids 25 micron and greater. Model sizing is based on the oil/fuel specific gravity, droplet size removal desired and other parameters of the wastestream.


Specification Summary:
System model
Number of model sizes
Process  types
Volume range offered

Design Specification Summary

Design criteria
Influent chamber
Separation chamber
Solids hopper
Clean water effluent chamber
Water baffle
Weir plate
Oil skimmer
Oil reservoir
Media pack
Lifting lugs

Materials of Construction

Surface preparation(steel)

Coatings (steel)


Standards used

Oil separation,TSS & oils filtration
5 – 250 GPM


10 mg/L or less 30 micron free, dispersed and non-emulsified oil droplet
API-421, 1990 & current coalescing media design theory
Influent diffuser or overflow weir
To contain Flopak media pack(s)
Located under and after separation chamber and TPI packs
Located after separation chamber
Water flows over this baffle to exit tank
Vertically adjustable weir plate to maintain operating water level
Fixed or adjustable weir plate integrated into the oil reservoir, located in the separation chamber
Located in separation chamber for temporary storage of skimmed oils
Single or multiple, Flopak media packs
Single or multiple section vapor retaining, gasketed with polyethylene gasket and attached via zinc plate fasteners
NPT couplings up to 3″, 4″ & larger: 150# ANSI B16.5 FF flange
Steel skid base of channel, beam or tube construction
None on FRP VEWs, (4) Minimum, located at lifting points on sidewalls of tank (steel VEWs)


A-36 carbon steel, 304/316 SS, FRP, polyethylene, polypropylene
A-53 black steel, 304/316 SS, FRP, PVC
Dye penetrant on steel construction
Interior surfaces shall be prepared to an SSPC-SP10 near white metal blast. Exterior surfaces shall be prepared to an SSPC-SP6 commercial blast.
Interior coating shall be coated with Ameron High Build Coal Tar Epoxy Amercoat 78HB (16 mils DFT).
Exterior coating shall be coated with Ameron epoxy primer, Amerlock 2, (5-8 mils DFT).  Final coat to be Ameron Amershield Aliphatic Polyurethane Enamel coat (5 mils DFT)Surface color to be Green RT-2203.
Elements of AWS D1.1/1.1M, API, API-650, API-421, ANSI, IEC,AWS D1.6, UL, UL-508,UL-845,SSPC,ASME, CSA, NEMA, NFPA79, NEC

Oil Water Separator Theory

Coalescing Oil Water Separators: Coalescing Oil Water Separators are passive, physical separation systems designed for removal of oils, fuels, hydraulic fluids, LNAPL and DNAPL products from water. Pan America Environmental designed performance can be described by a combination of Stokes Law and current coalescing plate theory, wherein, the oil droplet rise rate and other parameters dictate the surface area required for gravity & coalescent separation.

Separation Process: The water/oil mixture enters the separator and is spread out horizontally, distributed through an energy and turbulence diffusing device. The mixture enters the Flopak media where laminar and sinusoidal flow is established and the oils impinge on the media surface. As oils accumulate they coalesce into larger droplets, rising upward through the pack corrugations until they reach the top of the pack, where they detach and rise to the water’s surface. At the same time solids encounter the media and slide down the corrugations, falling into the v-hopper under the Flopak media.

Stokes Law: This equation relates the terminal settling or rise velocity of a smooth, rigid sphere in a viscous fluid of known density and viscosity to the diameter of the sphere when subjected to a known force field (gravity). The equation is:

V = (2gr²)(d1-d2)/9µ
V = velocity of rise (cm sec-¹),
g = acceleration of gravity (cm sec-²),
r = “equivalent” radius of particle (cm),
dl = density of particle (g cm -³),
d2 = density of medium (g cm-³), and
µ = viscosity of medium (dyne sec cm-²).

Coalescence: Gravity separation utilizes the difference in specific gravity between the oil and water. Oil separates from a fluid at a rate explained by Stokes Law. The formula predicts how fast an oil droplet will rise or settle through water based on the density and size of the oil droplet size and the distance the object must travel. Our separators are built to exploit both variables of Stokes Law.

With the use of our Flopak media oil only need rise a short distance before encountering the oleophilic, coalescing media plates inside the separation chamber as opposed to rising a great distance in gravity separation. Upon impinging on the plates the oils coalesce (gather) into larger droplets until the droplet buoyancy is sufficient to pull away from the media and rise to the water’s surface. The design will meet particular design criteria as indicated below:

 o The hydraulic distribution of the influent flow must assure full usage of the cross-sectional area of the media to fully utilize the plate pack’s surface area.
o Flow control and direction must be determined to prevent hydraulic short circuiting around, under or over the media pack.
o A laminar flow condition must be maintained (Reynolds “Re” number less than 500) in order to assist droplets to rise. Per the American Petroleum Institute’s (API) Publication 421 of February 1990.
o Horizontal flow through velocities in the separator must not exceed 3 feet per minute or 15 times the rate of rise of the droplets whichever is smaller.
o The media containment chamber design, plate design/angle and spacing sufficient to facilitate removal of accumulating solids. Plates are to be smooth surfaced and angled at 60 deg.

Flopak Coalescing Media Design
Pan America’s Flopak coalescing media provides a laminar flow path that creates a quiescent zone to facilitate the impact with and attachment of oils to the media surface by reducing waste stream turbulence and velocity. This control of the waste stream creates a more ideal environment for oil removal. By virtue of our Flopak media design, solids will also collide with the media and settle to the separator bottom to some degree. Due to oil typically being lighter than water, they (oil) will rise up the coalescing plate. As the oil droplets rise up the plate they will coalesce or come together with other droplets, creating progressively larger droplets. Once the droplet size is sufficient or the droplet reaches the top of the media plate the droplet pulls away from the plate and rises to the water surface. To some degree, the solids replicate this process in reverse (settling).


Gravity Separation vs. Coalescing Plates
Two types of oil water separator exist today in varying types of design, but all are dependent on these two types of design.
The first and oldest type is gravity or conventional separation, simple separation via gravity (density differential between two immiscible liquids leads to one of them rising above the other). This design, when designed properly (or even improperly) provides a certain tank length, width and depth that provides a wide, quiet spot in the pipeline to give oils time to rise. This design (also known as an API separator) generally provides a discharge oil concentration of 100 ppm based on a 150 micron droplet size. The API type design relies on a large water volume. This correlates to a tank size that can be 5 times the size of an equally sized coalescing separator.

The coalescing design is known by many names i.e. parallel plate, corrugated plate, slant rib coalescer so on and so forth. However, the concept, operation and design are generally the same. The coalescing concept is based on having a large surface area in contact with the waste stream (coalescing plates). The more surface area provided, the more enhanced the separation process will typically be. By using the coalescing media, the size of the tank is reduced and a higher performance is attained than by gravity separation. Pan America’s Flopak coalescing design provides a discharge oil concentration of 10 PPM or less with an oil droplet size of 30 or as small as a 20 micron oil droplet.





Collection Sump

An FRP collection sump with steel or FRP cover, hatch, vent and fittings can be provided. Diameters of 24”, 30”, 36”, 48”, 60”, 72”, 96” and 120” can be provided and different depths can be provided to provide the volume and elevations required by the project.

Sludge Pumpout System

Air operated, diaphragm pump with air controls & Nema 4 control panel, auto on/off timer, base mounted, 115V/1ph/60Hz power required. Progressive cavity pump system also available. 1 – 100 GPM.

Oil Pumpout System

Air operated, diaphragm pump with air controls, level switches & Nema 4 control panel, base mounted, 115V/1ph/60Hz power required., external oil drum & transfer piping. Gear pump is available as an alternative. 1 – 100 GPM

Freeze Protection

Immersion heaters mounted through tank wall. Each heater has an independent thermocouple well, 0-100 deg. F thermostat and Nema 1 (or optional Nema 4) housing. 230/460V/3ph/60Hz power required.

Oil Sight Glass

Two automatic, brass valves with tempered sight glass and protection rods mounted in oil reservoir. If glass is broken check ball stops outflow from reservoir.

External Sight / Level Glass

An externally mounted clear PVC sight tube is provided with multi-point level switch for indication or pump control of oil or water. Switch is removable for cleaning and inspection.

Elevation Stand & Platforms

Epoxy coated steel stand or legs to elevate system to desired level. Standard deck height is 30″. Full platforms & walkways with ladders or stairways can be designed where required or desired.

High Temperature Design

Flopak coalescing media and any piping is constructed of a combination of CPVC &/or polypropylene (or other materials) for temperature resistance up to 180? F.

Alternate Media Construction

Standard Flopak media is PVC. HPVC, polypropylene, glass-coupled polypropylene and 304/316 stainless media is available. Contact PAE to determine proper media type for your application. Media plate spacing is available in 1/2″, 3/4″ & 1.2″.

External Storage/Feed Tanks

A wide variety of tank volumes can be supplied for your water, product and sludge holding needs. Flat bottom and cone bottom designs constructed in polyethylene, fiberglass, steel & stainless steel can be provided.

AQAM Filter Systems

AQAM (Alkyl Quaternary Ammonium Montmorillonite) filter systems can be provided to remove trace hydrocarbons, sheens, DNAPLs, slightly soluble chlorinated hydrocarbons and high molecular weight organics from the separator effluent. Contact Pan America to determine proper filtration needs for your application.
Can be used to protect and increase GAC lifespan.

Carbon Filtration Systems

(GAC) GAC carbon filters can be provided to remove contaminants after the separator. Contact Pan America to determine proper system needs for your application.

Emulsion Cracking Systems

Emulsion cracking systems can be provided to remove oil-in-water emulsions prior to the separator. Contact Pan America to determine proper system needs for your application.

pH Adjustment Systems

pH adjustment systems can be provided to maintain pH levels prior to or after the separator. Contact Pan America to determine proper system needs for your application.

System Containerization

VEW systems with any options can be installed in a 20 or 40’ shipping container(s) to simplify system provision and field implementation. System would include the complete mounting, piping and wiring of the system in one or more container as required by the project.

Trailer Mounting

System can be mounted on a trailer for system mobilization. Trailer design generally includes corner leveling jacks, bubble levels, toolbox, electric or hydraulic brakes, piping and wiring of options.

Field Skid Mounting

System can be mounted to a mobile skid with leveling for quick field mobilization.

Vent Scrubber

Separator vapors can be extracted and scrubbed prior to discharge to atmosphere to remove VOC content.

PLC Controls

PLC based controls can be provided in place of standard relay logic. Communications such as Ethernet and DeviceNet can be provided.

Level Sensors

Level sensors can be provided to detect water and oil/fuels. One or more sensor points can be provided to perform various functions such as high level, low level, pump on/off based on liquid levels and level detection for DCS controls or other functions based on your needs.

Class 1 Div 1 & 2

Systems can be designed for use in a class 1 div 1 or 2 environment. Controls, components and wiring are changed to meet the needs of these environments. Intrinsically safe relays are also used for level sensors.

Oil Monitor

An oil detection system can be provided to monitor effluent oil content and provide various actions based on the oil alarm setpoint. Actions might include: audible/visual alarm, redirection of influent or effluent via actuated valve, shutdown of influent pump or your custom action.

EnBio Biotreatment

A bacteria injection system is provided to meter bacteria that will provide the following benefit:
– Trace/emulsified oil/fuels, BTEX, kerosene reduction by breakdown of petroleum products
– Extends AQAM filter life by reducing oil load
– Reduce or eliminate odors associated with wash facility collection sumps
– May also reduce your BOD concentration
Dosing: The bacteria/enzyme blend is added at 20 oz or less per 1500 gallons for the first week and then is reduced after the first week.


– Chemical metering injection pump mounted to VEW skid, wired to system control panel and plumbed into VEW plumbing
– Automatic controls in the system control panel.
– 5 gallon container of initial enzyme supply
In automatic mode the pump will operate based on the on/off of an adjustable timer system for multiple injection periods.


– Car wash
– Military wash rack
– Aircraft wash rack
– Heavy equipment wash facility
– Forklift wash facility
– Train wash
– Facility wash water
– Barge wash water
– Groundwater remediation


5 or 10 mg/L or less of oil droplets 30 micron and larger of non-emulsified, free and dispersed oils

Pan America Environmental, Inc
2309 N. Ringwood Rd., Ste G, McHenry, IL 60050 USA
815.344.2960   •