An oil water separator is a tank, vault or skid that pulls free oil, fuel and settled solids out of wastewater, stormwater or compressor condensate by giving oil droplets the time and surface they need to rise out of the flow, and Paul Industries designs, supplies, installs, cleans, repairs and maintains industrial oil water separators in all 50 states. Plant drawings also label the unit an oil & water separator, an OWS or an oil interceptor. Buyers can take it as supply-only, design-build or complete installation.
What is an oil water separator?
A separator is treatment equipment that uses the density difference between oil and water to remove free oil before the water reaches a sewer, a surface water or a reuse system. On a plant site its job is to keep incidental oil from drains, wash water, yard runoff and air system condensate out of the discharge. That job is narrow on purpose: the unit treats water carrying a small amount of oil, and it is never a place to dump bulk or concentrated oil.
A complete oil water separator system is more than the tank. An oil water separator diagram typically shows an inlet with a flow-spreading baffle, a sludge zone, a separation chamber with or without plates, an oil retention baffle, and an outlet weir or underflow pipe. The site drawing adds what surrounds it: the collection drains, sample port, oil storage tank, sludge access, vents, level alarms and any polishing stage downstream. Those items belong on the first drawing, because they decide whether the unit can be run and maintained.
How does an oil water separator work?
A separator works by slowing the flow until oil droplets, which are lighter than water, float up into a layer that a baffle holds back while cleaner water leaves from below that layer. Solids heavier than water settle to the floor at the same time. How do oil water separators work, in one line? Three layers form in a calm tank: oil, water and sludge.
How rise velocity decides what gets caught
The governing idea is a race between two speeds. A droplet moves up at its rise velocity while the water carries it toward the outlet, and it is captured only if it reaches the oil layer or a plate before it reaches the exit. Stokes’ law is the working principle behind every sizing method: rise velocity grows with the density difference and with the square of droplet diameter, and it falls as water viscosity climbs.
A droplet one third the diameter rises nine times slower, which is why shear from a pump or a sharp valve can undo a good design. Colder water is thicker, and water near 41 degrees Fahrenheit is about 1.5 times as viscous as water at 68 degrees, so a separator loses roughly a third of its rise velocity in winter. A 0.95 specific gravity oil rises half as fast as one at 0.90. Dissolved oil and stable emulsions have no droplets to speak of, and those pass through gravity equipment.
Types of oil water separators and how to choose
The types of oil water separators differ mainly in how far each droplet must travel and what force moves it, and that sets the droplet size each one can catch. Comparing them on a project starts with the effluent number required, then the flow, then the oil itself. Droplet figures below are design bases and manufacturer ratings, and field results depend on the oil, temperature and upkeep.
| Type | How it separates | Published droplet basis | Good fit | Plan for |
|---|---|---|---|---|
| Gravity, API channel | Long open channel, rise by buoyancy | About 150 microns | Refineries, terminals, heavy solids and large flows | Large footprint, skimmer and sludge removal, vapor cover |
| Coalescing plate (CPI) | Closely spaced plates shorten the rise distance and merge droplets | Ratings of about 60 microns down to about 20 microns | Fleet shops, wash water, utilities, tight sites | Plate fouling, access to pull and wash the pack |
| Coalescing media or cartridge | Oleophilic fibers or packed media grow droplets | Rated by each manufacturer | Polishing after a gravity stage, small steady flows | Element changes on differential pressure |
| Hydrocyclone | Pressure-driven spin | One vendor curve shows about 90 percent removal at a 25 micron mean droplet | Produced water, limited deck or skid space | Needs feed pressure; tiny droplets slip through |
| Adsorption (carbon, clay, polymer) | Media holds oil on its surface | Treats traces after a separator | Compressor condensate, polishing to low ppm | Media replacement before it saturates |
A coalescing oil water separator earns its smaller footprint from geometry: a droplet rises a fraction of an inch before it touches a plate, joins other droplets and creeps up to the oil layer. A tilted plate interceptor applies that idea in a large basin, with an inclined stack that sends oil up and solids down. A packaged coalescing unit commonly uses corrugated plates in cross flow; one published specification calls for half-inch spacing at a 45 degree corrugation angle to catch 60 micron oil. Polypropylene or PVC plate media still needs regular washing, and some specifications set a Reynolds number under 500 at design flow to hold laminar conditions.
A centrifugal oil water separator, with a motor-driven bowl or disc stack, and a hydrocyclone trade tank volume for energy. Both multiply the force on each droplet, and both suit services where footprint is scarce or the oil has value. A gravity stage ahead of them takes out slugs and grit first.
API separator vs CPI separator
An API separator is a long, open gravity channel built to the American Petroleum Institute method, while a CPI separator packs coalescing plates into a much smaller vessel to reach finer droplets. The API oil water separator comes from API Publication 421, whose subject is the design and operation of oil water separators in refineries. API has since withdrawn that 1990 publication, and designers and project specifications still cite it.
Its sizing is the Stokes calculation applied to a channel, assuming a 150 micron droplet. An API separator for refinery wastewater typically serves as the first stage ahead of flotation and biological treatment, and one vendor reports typical effluent of 30 to 100 ppm from a standard unit. It tolerates surges, heavy solids and slugs that would blind a plate pack, while CPI units fit where the water is cleaner and space is short. Paul can retrofit plate packs into an existing channel when a permit tightens.
Oil water separator for air compressor systems
An oil water separator for air compressor service treats the oily condensate drained from receivers, dryers, filters and aftercoolers so the water can go to a sewer with authority approval. Separate devices with similar names sit on the air line itself. Paul designs, installs and services both, along with the compressed air piping around them.
| Device | What it treats | Where it goes | What it delivers |
|---|---|---|---|
| Condensate separator | Liquid drained from the air system | Floor level, indoors, downstream of zero-loss or timed drains | Water clean enough for the sewer limit, oil held in a media or a container |
| In line oil water separator or moisture trap | Bulk liquid carried in the air stream | On the header or at a drop, ahead of filters | Less liquid load on downstream filters; drains by a float or timer |
Oil water separators for air compressors on the condensate side work in stages: a pressure-relief chamber, a gravity settling zone with an oil container, and then adsorption media, often carbon. Supply catalogs rate a compressor oil water separator by compressor capacity, with published ranges from about 20 to 7,000 scfm. The lubricant matters as much as the airflow, because polyglycol and some other synthetics emulsify and carry different ratings. Trade guidance adds that activated carbon adsorbs oil and most synthetic lubricants, and that condensate can look clear while still holding hundreds of ppm.
The volumes justify the equipment. One published estimate puts a typical 25 horsepower compressor at about 20 gallons of condensate a day, or roughly eleven 55-gallon drums a month, with drummed disposal that can top $500 per drum. The drain hookup slopes down from each drain into a manifold, stays indoors or heat traced, and has a sample point at the outlet. Air compressor repair visits should check it too, since rising oil at the separator can flag a failing air/oil element.
On the air side, the air oil water separator at a drop is typically a cyclone or baffle, and the oil water separator trap below it holds liquid for the drain. The air filter oil water separator at a machine adds a coalescing element, and a filter-regulator adds pressure control in one body. Coalescing elements are chosen against ISO 8573-1, where the total oil limits run 5 mg per cubic meter for Class 4, 1 for Class 3, 0.1 for Class 2 and 0.01 for Class 1. The element gets replaced when its differential pressure gauge says so.
Oil water separator tank options: underground and above ground
A separator tank is chosen by site grade, traffic, inspection access and what the leak rules demand, and each construction type brings its own installation work. Oil water separator tank design then adds the internals, oil storage volume and sludge volume to that shell.
| Construction | Where it fits | Installation points | Upkeep points |
|---|---|---|---|
| Above ground steel, packaged | Pumped flows, indoor process areas, high water tables, sites where excavation is impractical | Pad, containment, hydrostatic test, freeze protection | Easy to see and reach; coating and cover gaskets |
| Underground steel or fiberglass | Gravity drains, fuel islands, paved yards | Excavation, bedding, buoyancy anchoring, double wall monitoring where required | Risers and access openings set how well it can be cleaned |
| Precast concrete vault | Traffic areas, stormwater, larger plate packs | Crane set, joint sealing, ASTM C891 installation practice | Lining condition; joints stay above resting water where specified |
An above ground oil water separator tank suits a process stream that already sits at a pumpable elevation. It is often stainless or coated carbon steel with a vapor-tight cover, and Paul’s tank fabrication work builds one to the plant’s dimensions; one published specification calls for a four-hour hydrostatic test with no leakage.
An underground oil water separator tank lets floor drains and yard inlets reach it by gravity with no pump shearing the droplets. Buoyancy load when empty is part of the design, and specifications often name UL 1316 for fiberglass construction and NFPA 30, NFPA 30A and NFPA 70 for the fuel and electrical details. A buried unit handling gasoline also needs vents and level controls selected for the classified area. A concrete oil water separator tank is usually designed around ASTM C857 loads and C858 construction, and a precast oil water separator arrives in sections with 2 to 20 ton load options from published product lines. Every design needs an access opening big enough for a vacuum hose and plate removal.
Oil water separator for floor drain, wash bay and stormwater service
Floor drain, wash water and site runoff separators are detailed around how the oil arrives, because a steady drip and a storm surge call for different equipment. The International Plumbing Code calls for oil separators at repair garages, car washing facilities and factories that produce oily or flammable liquid wastes, subject to the edition adopted and any state amendments.
| Application | What drives the design | Typical choice | Watch for |
|---|---|---|---|
| Floor and trench drains | Drained area, code capacity, spill volume | Gravity tank, code-sized, with water seal | Degreasers and solvents poured down the drain |
| Vehicle wash bay | Pressure washer flow, detergent, grit | Grit trap ahead of a coalescing separator | Stable emulsions from detergent; mud on plates |
| Yard stormwater | Design storm, first flush, drained area | Off-line vault with a high-flow bypass | Sediment loads and low, cold flows |
A floor drain oil water separator under the model plumbing code must extend at least 2 feet below the discharge drain invert and keep an 18 inch outlet water seal. The same drain rules cover an oil water separator: auto shop, fleet garage and process plant maintenance bay alike, although some states size by vehicle count instead of drained area. Our site work includes the drains, trench, sample box and vent piping.
A wash bay oil water separator lives or dies on detergent choice. Army guidance documents the problem: ordinary detergents form stable emulsions that pass through gravity and coalescing units, while separator-friendly products form unstable emulsions that break within about 10 minutes to an hour. Paul handles the wash pad, recycle loop and pump skid as one job.
A stormwater oil water separator normally treats the first flush and bypasses higher flows, since fast flows would wash out collected oil. A catch basin oil water separator, built as a catch basin with a downturned outlet, can suit small paved areas with low oil loads, while a coalescing vault suits fueling and fleet yards. A transformer oil water separator handles a rare large release, so storage volume matters more than routine droplet removal.
Oil water separator sizing: how to size an oil water separator
Separator sizing starts with peak flow, water temperature, oil specific gravity, target droplet size and the effluent limit, then checks the result against the storage needed for oil and sludge. Sizing also means knowing which method governs: code capacity for drains, API or plate calculations for treatment, and manufacturer ratings for compressor units.
The gravity method works as follows, using the widely cited API 421 equations. Rise velocity in feet per minute equals 0.0241 times the specific gravity difference divided by the water viscosity in poise. Horizontal velocity stays at or under 3 feet per minute or 15 times the rise velocity, whichever is smaller. Channel depth runs 3 to 8 feet, width 6 to 20 feet, depth-to-width 0.3 to 0.5, and length at least five times width. Required surface area equals a factor F, about 1.3 to 1.75 for turbulence and short-circuiting, times the flow divided by rise velocity.
As a worked illustration, take 200 gallons per minute, or 26.7 cubic feet per minute, of 68 degree water with 0.90 specific gravity oil. Rise velocity is 0.241 feet per minute. The smallest allowed channel, 6 feet wide and 3 feet deep, gives a horizontal velocity of about 1.5 feet per minute and a factor F near 1.37, so the surface area is about 150 square feet. The 5:1 length rule then pushes the channel to about 30 feet long.
Plates change those numbers sharply. Rise velocity scales with diameter squared, so a 60 micron droplet rises at about 0.039 feet per minute and a 20 micron droplet at about 0.004. Treating 100 gallons per minute therefore needs roughly 350 square feet of projected plate area at 60 microns and about 3,100 square feet at 20 microns, before any safety factor. A plate stack folds that surface into a small tank.
Drains use a simpler rule. The International Plumbing Code asks for 6 cubic feet for the first 100 square feet drained plus 1 cubic foot for each additional 100 square feet, so a 2,400 square foot garage needs 29 cubic feet, or about 217 gallons.
Oil water separator design details that decide performance
Separator design succeeds or fails on inlet conditions, because the calculation assumes calm flow and intact droplets. Internals deserve as much attention as the volume, and gravity feed comes first wherever grade allows.
- Pumping. An oil water separator pump ahead of the unit can shear oil into droplets too small to catch. Where lift is unavoidable, progressive cavity and diaphragm pumps are the usual low-shear choices, or the pump goes downstream.
- Oil removal. Slotted pipe skimmers, belt or tube skimmers and level-controlled oil pumps keep the layer from building up and escaping.
- Controls. High-oil and high-level alarms, oil stop valves and a data link fit neatly into PLC programming work on the rest of the plant.
A simple oil water separator design for a small maintenance area can be nothing more than a baffled tank with an oil decant and a sample point. A refinery unit may need covers, nitrogen blanketing and carbon filtering of vent gas. Standards to reference include API Publication 421, UL-SU 2215 for engineered separators, which manufacturers publish at 10 ppm, plus the plumbing code and EPA Method 1664 for effluent testing. On oil and gas leases, gun barrel oil water separator design uses a tall settling tank with an internal flume, and our oil and gas teams build it alongside knockouts and water tanks.
Oil water separator manufacturers publish performance on their own test oils and temperatures, so a fair comparison runs against the real water. A permit drawing set shows invert elevations, plate access and venting. Oily streams can continue into process wastewater and effluent treatment or food plant wastewater pretreatment, which take over where free oil removal ends, and meat plant wastewater pretreatment covers animal fat loads in the same way.
Which EPA rules and discharge limits apply?
Federal rules set no single oil limit for every separator, so the binding number comes from the discharge permit or the sewer authority’s local limit. Published allowable values for plant wastewater run from about 10 to 100 ppm, and permit limits for oil and grease are usually tested by EPA Method 1664. State rules can add to the federal rules below.
| Rule | What it says | What it means on site |
|---|---|---|
| 40 CFR 403.5(b)(6) | Prohibits petroleum oil, nonbiodegradable cutting oil and products of mineral oil origin in amounts that cause interference or pass through | Sewer discharges must meet the local limit, an enforceable pretreatment standard; section (b)(1) also bars wastestreams with a closed cup flashpoint below 140 degrees Fahrenheit |
| 40 CFR 110.3 | Treats discharges to waters of the United States that cause a film, sheen or discoloration as potentially harmful | A visible sheen at an outfall can trigger a federal notice |
| 40 CFR 112.1(d)(6), SPCC | Exempts separators used exclusively for wastewater treatment and not to meet a part 112 requirement | Separators used for containment, oil production or oil recovery stay in the SPCC plan |
| 40 CFR 280.10 | Excludes wastewater tank systems at facilities regulated under Clean Water Act sections 402 or 307(b); partially excludes others | Buried separators need a tank-rule review, and buried used oil tanks fall under UST standards |
| 40 CFR 261.31 and 261.32 | Lists refinery separation sludges F037 and F038 and API separator sludge K051 as hazardous | Refinery sludge is managed as listed waste; other plants profile theirs under 40 CFR 262.11 |
| 40 CFR 435 | Sets 42 mg/L daily maximum and 29 mg/L 30-day average for offshore produced water | Offshore treatment trains are designed to this number |
EPA’s SPCC guidance also separates uses in a way that matters during design. A waste oil water separator at a used oil recycler counts as oil recovery, and separators in oil production, including gun barrels and free water knockouts, count as bulk storage containers. Paul gathers the flow, oil and sampling data for permit applications, and the facility signs them as the permit holder, as the regulations require.
Oil water separator maintenance and inspection schedule
Separator maintenance is a routine of checking for leaks and sheen, measuring the oil and sludge layers and cleaning before either reaches its trigger. The schedule below draws on Indiana’s published pollution prevention checklist, and permits or local codes can be stricter; Auburn, Washington, for example, requires monthly inspection.
| Interval | Task | Action trigger |
|---|---|---|
| Daily | Walk the perimeter, inlet and outlet for leaks | Any leak or odor change |
| Weekly | Check the outlet for oil, drains for unauthorized liquids, joints for leaks | Sheen, bypass or wrong chemicals |
| Monthly or quarterly | Measure oil and sludge layers with a sludge judge at more than one point | Sludge at 20 percent of wetted height, oil at 5 percent, or 75 percent of retention capacity |
| Stormwater vaults, per inspection | Read oil and sediment depth, look at the plates | Over 1 inch of oil or 6 inches of sediment in western Washington manuals, or sediment on plates |
| At least yearly | Clean the tank, wash plates or media, inspect baffles, seals and coating; test alarms | Worn parts, failed alarms, saturated pads |
| Compressor units | Drain oil, change carbon before saturation, test the outlet | Cloudy water or the change interval, whichever comes first |
Oil water separator cleaning follows a set order. Paul isolates the inlet, vacuums off the oil, removes water and sludge, pulls and washes plates or media, inspects the shell and refills the unit with clean water so it restarts with a working seal. Hydro blasting and industrial tank cleaning crews from Paul handle heavy deposits, and vault entry follows OSHA permit-required confined space rules in 29 CFR 1910.146. Paul routes recovered oil to used oil recycling under 40 CFR part 279 where it qualifies. Paul samples and profiles the sludge and arranges its disposal, and the plant signs as generator, as the hazardous waste rules require.
This work fits easily into wider preventive maintenance or a service contract, with layer readings kept in the log.
Why does a separator discharge a sheen?
Sheen or high oil and grease results usually trace to one of these causes.
| Symptom | Likely cause | Fix |
|---|---|---|
| Sheen after washing | Detergent emulsion | Change detergent, add detention, bench test the water |
| Sheen after rain | High flow carrying oil past the baffle | Add bypass or surge control, clean out the oil layer |
| Oil on the outlet side | Oil layer too thick or a baffle or seal failed | Clean the unit, replace baffle or seal |
| Level high at the inlet | Plates or media blinded, outlet blocked | Pull and wash the pack, jet the outlet line |
| Results worse in winter | Cold water, slower rise, waxy oil | Check against cold design conditions, add heat or area |
Oil water separator cost: what sets the price
Separator cost is set by flow, required effluent, tank construction and how much site work the installation needs, and no reliable public price range covers that span, so Paul prices from the actual inputs. The main drivers are below.
- Peak flow and droplet target, which fix tank and plate size.
- Above ground or buried, including excavation, dewatering, anchoring, paving and traffic loads.
- Single or double wall, leak monitoring, coatings and materials.
- Oil storage, sludge handling, pumps, alarms and controls.
- Permitting, sampling and connection to existing drains.
- Operating cost: cleaning frequency, media, waste disposal and any compressor condensate that no longer has to be drummed.
Who installs oil water separators?
Paul Industries installs oil water separators nationwide, handling the excavation, setting, anchoring, piping, venting, alarms, testing and startup under one contract. Each oil water separator installation ends with a leak test, a clean water fill, a controls check, an effluent sample and operator training. A commercial oil water separator at a fleet yard and an industrial oil water separator tied into plant utilities follow the same sequence, and an urgent overflow or failed unit gets same-day emergency response.
What Paul Industries does with oil water separators
Paul Industries selects, sizes, designs, fabricates, supplies, installs, wires, tests, starts up, cleans, repairs, upgrades and maintains oil and water separation equipment on any plant, yard or air system, in all 50 states. Take the equipment as supply-only, as a design-build package with drains and controls, or as a complete installation, and tie it into industrial water treatment where the water needs more polishing. Send the flow, oil type, discharge point and any permit limit through the request a quote page to start.
Standards referenced: API Publication 421 · UL-SU 2215 · UL 1316 · NFPA 30 · NFPA 30A · NFPA 70 · International Plumbing Code Section 1003.4 · ASTM C857 · ASTM C858 · ASTM C891 · ASTM D1401 · ISO 8573-1 · EPA Method 1664 · 40 CFR 110.3 · 40 CFR 112.1(d)(6) · 40 CFR 261.31 · 40 CFR 261.32 · 40 CFR 262.11 · 40 CFR 279 · 40 CFR 280.10 · 40 CFR 403.5 · 40 CFR 435 · 29 CFR 1910.146 · MARPOL Annex I · IMO MEPC.107(49)
Frequently asked questions
How much does an oil water separator cost?
The price follows flow, effluent target, tank construction and site work, and a buried double-wall unit with paving repair sits far above a floor-standing compressor unit. Paul quotes against your flow, oil type and discharge point, so the number reflects the real installation and its upkeep.
Who provides oil water separator cleaning services?
Paul Industries provides them nationwide, including vacuum removal, plate and media washing, confined space entry, shell inspection, waste profiling, refilling and a record of layer depths for the permit file.
How often should oil water separators be cleaned?
Clean when measurements reach a trigger and at least once a year under Indiana's published checklist. Heavily loaded wash bays and fuel sites can need several cleanings a year, and logged readings show the right interval for each unit.
How frequently does an oil water separator inspection need to happen?
Published guidance ranges from daily leak walks and weekly outlet checks to monthly or quarterly layer measurements, with permits adding their own terms. Inspect after spills and large storms as well, since those events can move a year's worth of oil at once.
When are oil water separators required?
Model plumbing code calls for them at repair garages, car washes and factories with oily or flammable waste, and sewer authorities and permits can require them for other sites. SPCC plans may also use one as part of drainage containment at an oil storage facility.
Is an oil water separator considered a UST?
An in ground oil water separator is a wastewater treatment tank system under 40 CFR 280.10: excluded if part of a facility regulated under Clean Water Act sections 402 or 307(b), and partially excluded otherwise. A buried tank storing recovered used oil is treated separately under UST standards, and state programs can add requirements.
What size oil water separator do I need?
Start from peak flow in gallons per minute, or the drained area for floor drains, then add oil type, water temperature and the effluent limit. Compressor units are picked from compressor scfm and lubricant type. Paul runs the calculation and returns a tank and plate selection.
Grease trap vs oil water separator: which one does a plant need?
A grease trap or grease interceptor handles animal and vegetable fats from food preparation under standards such as ASME A112.14.3 and PDI G101, while a separator handles petroleum oils and fuels. Fats also harden and need different cleaning. Plants with both streams keep the two drain systems apart and treat each one on its own terms.
What is oil water separator media, and how long does it last?
Separator media is corrugated plate, oleophilic fiber or adsorbent fill that gives droplets a surface to collect on, while density difference still does the separating. Plates last for years with washing, fibers and cartridges are changed on pressure drop, and carbon is changed before it saturates.
What is the difference between a coalescer and a separator?
A coalescer grows small droplets into larger ones, while a separator provides the calm space where those droplets rise out. Many packaged units do both in one tank, which is why they carry both names on data sheets and drawings.
Coalescing vs centrifugal air separator: what is the difference?
A centrifugal air separator spins liquid out of the air stream and handles bulk water with little pressure drop, while a coalescing element catches fine aerosols at a higher pressure drop. Compressed air systems commonly use the centrifugal device first and the coalescing filter after it.
Can the filter on a compressor condensate separator be reused?
Treat that filter as a replaceable item: spent carbon or adsorbent cartridges hold the captured oil and go out for disposal under local rules. Change them before saturation, and test the outlet water to confirm the change interval suits your compressor and lubricant.
How often do oil water separator filters need changing?
Change intervals depend on run hours, humidity, lubricant and compressor condition, and manufacturers publish a schedule or an indicator such as cloudy test water. Coalescing air filters are changed on differential pressure, and an oil water separator filter on a wastewater polishing stage follows the same logic.
Will water separate from hydraulic oil?
Free water settles out of a healthy oil, and ASTM D1401 measures how readily an oil does so. A hydraulic oil water separator for that duty works in reverse of a wastewater unit, taking water out of oil by coalescer, centrifuge or vacuum dehydrator. Paul supplies and installs that equipment on plant hydraulic systems.
What does a ship oil water separator do?
The unit treats bilge water so that overboard discharge stays at or under the 15 ppm MARPOL Annex I limit, with an oil content meter stopping discharge above that level. Marine oil water separator equipment follows IMO performance specification MEPC.107(49).
Does a fuel oil water separator work like a wastewater separator?
A fuel oil water separator removes water from fuel, the reverse of the wastewater job, using coalescing and water-barrier elements on a day tank or engine supply line. Paul designs and installs these on generator and fuel transfer systems, with a drain and a level alarm on the water sump.
Do detergents stop a separator from working?
Ordinary detergents hold oil in a stable emulsion that flows straight through gravity and coalescing stages. Choose a quick-break product, keep doses low and allow enough detention, and run a bench settling test with your actual wash water before changing equipment.
Does an oil water separator need an SPCC plan?
A unit used only for wastewater treatment is exempt under 40 CFR 112.1(d)(6). A unit serving as secondary containment, or used in oil production or recovery, belongs in the plan, so the role of the unit must be documented on site.
What does API separator stand for?
API refers to the American Petroleum Institute, whose Publication 421 set the gravity sizing method used for refinery channels. The label is still used for any channel-type gravity unit built around that 150 micron droplet calculation, including new ones and retrofits.
What does an oil water separator project need before construction?
A project needs peak flow data, a water sample, the discharge limit and a site survey of drains and utilities. Drawings then add the civil details, manhole and riser locations, the vent route and the sampling point.
Can coalescing plates be added to an existing separator?
Plate packs can often be added to an existing tank or channel to reach a lower effluent value, provided the plate area, access and hydraulics work. Paul checks the shell, calculates the required area, fabricates the supports, installs the pack and tests the result.
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