Oil/Water Separation

Management and Recovery of Mineral and Biological Oil Wastes

Mineral oils are extensively used in the automotive and transport sectors, providing lubrication as lubricating oils and energy in internal combustion engines, in the form of diesel. They are also used as cutting and grinding fluids and heat transfer fluids in radiators, heating systems, and electricity transformers. At RED Industries, we provide tailored solutions for the management and recovery of both mineral and biological oil wastes, ensuring they are handled and treated appropriately while maximising their positive value and helping to meet your ESG commitments and obligations.

Mineral oils are used in a wide range of industries and applications, from textile manufacturing to cosmetics, personal care, and the food sector. They provide lubrication, act as a binding agent, and prevent dust from sticking and causing blockages in grain handling and storage. Mineral oils are generally hydrophobic and insoluble in water, as seen in the rainbow effect of car engine oil on the surface of a puddle. Oils can have differing densities, causing them to float, sink or form layers in water.

Water contamination due to oil is a serious concern that can occur through various sources. It can lead to severe pollution and pose a risk to human and animal life, plants, and the environment. When oil and water mix, they form a pollutant that can have an adverse impact on water resources and agricultural production. Therefore, it is essential to address the issue of oil-contaminated water to mitigate environmental risks.

Oil contaminated wastes are produced widely and in large volumes from all sectors of industry and manufacturing and can arise from:

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  Cleaning activities at industrial and manufacturing facilities
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  Food processing and manufacture, production, and supply
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  Garage and other automotive based acitvities
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  Machine shops, metal fabrication and the production and manufacture of derivatives and metal components
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  Extraction, refining and processing of oil and gas
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  Tanneries and leather production activities
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  Leak and spill control and clean-up at oil storage and bunkering facilities
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  Machinery and infrastructure operations, maintenance, and repair activities.
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  Drainage systems, separators and interceptor operations and maintenance
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  Sewage processing and stormwater management
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  Maritime operations and shipping
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  Emergency spill response operations

Management and Recovery of Mineral and Biological Oil Wastes

Oil-water mixtures contain various dissolved and suspended substances, including organic and inorganic materials, that require treatment to be safely discharged to the environment. When water is contaminated with insoluble oil, it is easier to manage since the more polluting waste (the oil) can be removed from the water through oil phase separation.

This process involves the natural separation of water from the oil over time by gravity in a storage vessel. In many cases, the oil separates from the water and can be removed from the tank through tapping off from extraction points. Insoluble oil/water treatment can be improved by incorporating developments such as weirs, traps, membrane, carbon technology, and heating systems that increase the purity of the oil fraction and decrease contamination in the water component.

Chemical additives can improve the effectiveness of treatment of oil-contaminated water by altering the waste's chemical, physical properties and enhancing the separation efficiency during the process. Such additives can be specifically designed to target the removal of insoluble contaminants in the waste stream.

Treatment of Oil-Contaminated Water

Treating effluents or water contaminated with oil can be difficult, especially when the organic material present is in an emulsified form and does not readily separate from the water. Water-soluble oils, commonly used as machine or cutting oils, offer excellent lubrication, cutting and grinding performance, and are safe on all metals. They also have good cooling properties effective at carrying chips and swarf. Moreover, they are less expensive than pure oils and provide good rust protection.

These oils are usually supplied in a concentrated form and are derived from mineral oils through the addition of emulsifiers and other additives, allowing the oil to combine with water as an emulsion. To effectively treat these types of oil-water effluents, the emulsion needs to be separated into its separate fractions to allow density separation of oil from water. Separation can be achieved through the addition of de-emulsifiers, which can split the oil and water that are combined in suspension within the waste.

More sophisticated engineered solutions for separating oils from water exist which improve separation efficiency yet remain reliant on the ability to be successful in chemically separating the two.

These systems include:

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  Centrifuge systems
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  Filtration
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  Chemical dosing systems
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  Cyclone sedimentation
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  Ultrafiltration
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  Coalescing filter separators
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  Hydro cyclone separation
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  Biofiltration
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  Oil skimmers