Condensate Management

Oil Water Separator

Oily condensate in, water fit for the sewer out, with gravity doing all the work.

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An oil water separator tank with a blue lid

Product overview

Make your condensate fit for the sewer

Every lubricated compressor sends oil out with its condensate. Our oil water separator takes that oil out, so the water can go to a foul sewer within the oil limits your local authority sets, while the recovered oil is collected separately for disposal as waste oil.

A plant compressing 1,000 m³/h of free air at 25 °C and 60 % RH makes about 13 litres of condensate an hour after the aftercooler and a refrigerated dryer, or roughly 100 m³ over an 8,000-hour year. At a representative oil carryover of 3 mg/m³, it carries around 230 mg of oil per litre.

The separator runs at atmospheric pressure with no electrical supply. Gravity floats the free oil off, then oleophilic media and activated carbon capture the fine droplets and dissolved hydrocarbons, bringing the water down to the low mg/l range that discharge limits require.

Replacement oleophilic foam, a bag of activated carbon and seals beside a separator module
  • 230 mg/lOil in typical untreated condensate
  • 20 mg/lIndian limit for oil to public sewers
  • Roughly 24 kgOil to dispose of a year, from 100 m³ of condensate
  • ZeroPower, pumps or compressed air needed

Benefits

The problems it solves

Condensate from a lubricated compressor is oily effluent, not clean water. Here is what that costs a plant, and how the separator deals with it.

  • Discharge limits

    The problem

    Oil and grease limits of 10–20 mg/l are common, and untreated condensate at hundreds of mg/l exceeds them by one to two orders of magnitude.

    How it solves it

    Gravity, oleophilic media and activated carbon bring your treated water within the oil and grease limits of sewer and surface water consents.

  • Paying to haul water away

    The problem

    Without treatment, every litre must be stored and removed by a waste contractor: 100 m³ or more a year per 1,000 m³/h of compressor capacity.

    How it solves it

    Only the separated oil and the spent media go to a contractor, a small fraction of the condensate you produce.

  • Audits and inspections

    The problem

    Discharging untreated oily condensate can breach discharge consents, and ISO 14001 auditors look for documented treatment.

    How it solves it

    Records of media changes and water tests give you the evidence for ISO 14001 audits and regulatory inspections.

  • Running costs

    The problem

    Pumped and powered treatment adds energy use and more equipment to maintain.

    How it solves it

    Gravity drives the whole process, with no electrical supply, pumps or compressed air, so the only running cost is media replacement.

  • Oil in your drains

    The problem

    Oil builds up on sewer walls with solids and fats, and coats the sludge in effluent treatment plants.

    How it solves it

    Oil and solids are kept out of your drains, interceptors and on-site effluent treatment plant.

  • Hidden compressor faults

    The problem

    A worn oil separator element in the compressor can raise oil carryover several times over.

    How it solves it

    A sudden rise in the oil collected gives you early warning of increased carryover from the compressor.

Where it’s used

Wherever lubricated compressors run

Every lubricated compressor produces oily condensate that ends up at a drain. The separator belongs at the end of that drain line, whatever your industry.

  • Robots welding a car body on an assembly line

    Automotive plants

    Large central compressor stations that produce thousands of litres of condensate a day.

  • A row of yarn winding machines in a textile mill

    Textiles

    Air-jet looms consume large air volumes, often in humid climates, so condensate volumes are high.

  • Wine bottles moving along a bottling line

    Food and beverage

    Plants with lubricated compressors that must keep oil out of effluent covered by environmental audits.

  • Yellow tablets spilling from a medicine bottle

    Pharmaceuticals and chemicals

    Sites with effluent treatment plants that limit the oil entering biological treatment.

  • Molten metal pouring from a ladle in a foundry

    Steel, foundries and cement

    Compressors in dusty, hot conditions that generate condensate carrying oil and solids.

  • Electricity pylons and power lines at sunset

    Power plants and refineries

    Instrument and service air compressors discharging into drainage that is monitored for oil.

Also general manufacturing and engineering, workshops, garages and vehicle depots, mining and construction, hospitals and commercial buildings, shipyards and ports, and temporary compressor installations.

How it works

Settle, skim, polish

Your condensate flows through the separator by gravity alone. The oil is floated off and skimmed, then the water is polished before it leaves.

How an oil water separator works: oily condensate and air from the drains enter an expansion chamber where the air is vented; in the settling tank oil droplets rise and solids sink, and the oil layer overflows a weir into a collection container; water drawn from the bottom of the tank passes through oleophilic media and activated carbon, then rises to the outlet and leaves by gravity through a sampling point to the foul sewer. From your drainsExpansionchamberAir ventOil ≈ 230 mg/l Settling tankRise per hour100 µm · 2.55 m10 µm · 0.026 m Oil weirOil container OleophilicmediaActivatedcarbon Sampling pointTo foul sewerOil: low mg/l 12345Oily condensateSeparated oilAir ventedTreated waterSettled solids

  1. 1. Release the airCondensate and air from your drains enter the expansion chamber. The air, expanding eightfold from 7 bar g, is vented, and the liquid flows on calmly into the tank.

  2. 2. SettleIn the quiet settling tank, solids sink and oil droplets rise: a 100 µm droplet rises 2.55 m an hour, a 10 µm droplet only 0.026 m an hour.

  3. 3. Skim the oilWhen the oil layer on the surface reaches the weir, it overflows into the collection container, with no moving part or level switch.

  4. 4. PolishWater drawn from the bottom of the tank passes through oleophilic media, which capture the fine droplets, then activated carbon, which adsorbs dissolved hydrocarbons.

  5. 5. DischargeTreated water rises to the outlet and leaves by gravity through the sampling point to the sewer. Each new charge of condensate displaces an equal volume of treated water.

Worked example: a 1,000 m³/h plant at 25 °C and 60 % RH, with 3 mg/m³ oil carryover.

Get the full details

Our brochure covers it in detail, and our questionnaire tells us what we need to recommend the right one for your plant.

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