Everything You Need To Know About Soluble Oil Waste

17 June 2021 by CSG

What is soluble oil?

Soluble oil is one of the most common waste streams CSG deals with on a daily basis. All oil and water mixtures are classified as hazardous waste and must be treated accordingly.

Soluble oil plays a major role in many industrial applications as a coolant and lubricant for metalworking and machinery. It has been given many different names by its users, such as cutting oils, suds, cutting fluid, cutting compound, coolant, or lubricant.

A good soluble oil should keep the workpiece at a stable temperature, lubricate the machinery to prevent friction and in turn reduce wear and tear, as well as prevent rusting on machinery.

Soluble oils are generally made from natural or synthetic base oils (for example petroleum distillates, animal fats, or plant oils). They are given certain additives depending on the machinery and application they are used for.

Automotive, aerospace, manufacturing, and the energy sector are just a few of the many industries where cutting oils are used today, and it is an integral part of their day-to-day productivity.

The many ways of recovering soluble oil?

Another benefit of soluble oil, besides protecting the workpiece against high temperatures and reducing wear and tear, is the fact that it can be recovered.

The process of recovering soluble oil is called reclamation, whereby the used soluble oil is treated to remove other fluids and materials it might have been exposed to while it was being used. After treatment the recovered oil can be used as a fuel.

There are many alternatives available for recovering soluble oil, and at CSG we primarily use chemical treatment, filtration and settling tanks but soluble oil can also be recovered through skimmers, coalescers, centrifuges, and magnetic separators.

The best option for you will depend on factors such as type of waste and concentration and the volume of waste that needs to be recovered. If you are unsure what would be best for you CSG’s experienced technical sales team is here to help you make a decision tailored to your needs.

Skimmers are a type of equipment that can be used to remove contaminated oil from the soluble oil. The contaminated oil floats to the top and is removed from the liquid by adhering to the machine’s skimming media (for example a belt, tube, rope, mop, or a disk).

Coalescers and centrifuges not only remove contaminated oil but can also remove contaminated solids. Coalescers gather contaminated oil into larger droplets, which will then rise to the surface where it is skimmed off. This method is generally faster than using only skimmers. Centrifuges on the other hand separate the contaminated oil by spinning the fluid to generate gravitational forces which help to separate the mixture of solids and fluids from each other.

Another alternative for removing contaminants oils and solids from the soluble oil is to use a filtration system which traps solid contaminants as the liquid passes through the filter. CSG uses an Ultra Filtration process which uses high pressure to force the soluble oil through fine membrane filters which separates the oil and water by particle size.

At CSG we also use a chemical treatment process which involves heating the oil before adding a mixture of chemicals which break the soluble oil emulsion.

We generally use settling tanks as a secondary treatment, whereby solid contaminants and fluids are separated in larger tanks through gravity, where heavier liquids and solids sink to the bottom. However, this method can also be used when there are larger volumes of oil or heavier particles that readily fall to the bottom. Magnetic separators work very much in the same way as settling tanks but are more optimal for extracting ferrous particles. Magnetic separators aren’t used by CSG.

How to dispose of soluble oil?

While soluble oil can be recovered there will eventually come a time when it cannot be recycled any further. Disposing of soluble oil must be done with caution, and in recent years the regulations governing the discharge of soluble oil has been heavily regulated.

Even here there are a number of possible options for disposal, but the most suitable option will be very much dependant on the contents of the cutting fluid. At we CSG conduct tests on the liquid to determine whether it is hazardous or non-hazardous, which in turn will determine the best way to dispose of the liquid. Non-hazardous liquids are often easier and less expensive to dispose of than liquids classified as hazardous.

If you want to recycle or dispose of cutting fluids and soluble oils CSG is happy to guide you through the process and discuss the most suitable option for your needs.