What to do when your VGS or coalescing separators have problems

Cleanawater on 30 April 2018

Oil water separators are important pieces of equipment for managing waste water from industrial sites. They help companies remain compliant with regulators and protect the environment from pollution. However, like any piece of equipment, they must be cared for to ensure that they are operating as per design.

The worst case scenario is that you only find out something is wrong with your oil water separator when you have a release of out-of-specification water from your facility. To prevent this, here are some of the things you need to check regularly in order to ensure your oil water separator keeps performing as intended.

Common problems and their solutions for vertical gravity and coalescing separators

Water is not flowing, or there is a low flow into the oil separator

A low water flow could indicate a problem with the pump, sump level or the suction line. Some of these issues are common to any kind of separator. For details on how to check these systems, refer to this article that addresses hydrocyclone separators too.

Take these steps to clear the suction line of a gravity or coalescing separator:

  • Clear obstructions by flushing

  • Repair cracks or loose fittings that allow air into the system

  • Clear foot valve from obstructions.

Water is flowing into the waste oil container, or water is flowing out of the top of the separator

  • The waste oil collar inside the unit may be set too low. The collar should be set to five millimetres above the water level when the pump is running to prevent free water from being skimmed off with the waste oil.

  • Look for a discharge blockage. Check media packs, and clean as necessary. Regular blockages may need further investigation into the unit sizing and removal of solid debris.

  • The pump may be rated too high. Excess flow rate through the unit negatively affects its performance.

There is no oil in the waste oil container

  • The waste collar inside the unit may be set too high. The collar should be set to five millimetres above the water level when the pump is running to ensure that oil is removed from the system and does not build up inside the separator.

  • The waste water stream is clean and therefore no oil is being collected. No action required.

  • Oils have formed an emulsion in the waste water stream and cannot be removed by a coalescing or vertical gravity separator. Make sure no unapproved degreasers and detergents are being used in the system. Contact Cleanawater for technical support to handle emulsions.

common oil water separator problems and their solutions oil water separator components

The pump overload keeps tripping and system switching on/off issues

Problems related to switching the equipment on or off are usually related to electrical or control panel issues. These and pump overload checks are described in more detail in our article for hydrocyclone oil separators. See here for more information.

There is oil present in the water discharge

There are 3 potential causes of oil being carried over to the water outlet stream. Firstly, an oil spill may have overloaded the system. Secondly, the waste oil decant tank may be full. Thirdly, there may be a formation of emulsions which would require investigation by Cleanawater experts. Finally, check media packs and clean as per operations and maintenance schedule.

There is a smell coming from the oil water separator

Check all basic operating conditions as you would for a hydrocyclone separator – see here. If the problem persists, arrange for servicing of the unit by Cleanawater technical experts.

Contact Cleanawater for more information about troubleshooting your oil water separator

Expert advice and technical support is close at hand with Cleanawater. Our qualified technicians are experienced in working on vertical gravity and coalescing separators in a variety of industries. We can assist you to diagnose problems and provide solutions to resolve them.

Find out more at Cleanawater or call our expert team on 1800 353 788 today to request service support for your oil water separator.