A Clean Sweep

By Tom Hobson When properly selected and applied, oil skimmers are a highly economical solution for separating oil from water to allow its reuse or safe disposal.

How Oil Skimmers Work
Oil skimmers are simple, dependable and effective tools for removing oil, grease and other hydrocarbons from water and can pay for themselves within a few months.

All oil skimmers rely on the fluid properties of specific gravity and surface tension although designs may vary. Most use a moving medium to remove floating oil from a liquid surface. Floating oil and grease cling to skimming media more readily than the water. This allows media (in the shape of a belt, disk, drum, etc.) to pass through the fluid surface to pick up floating oil and grease while leaving most of the water behind. The oily material is subsequently removed from the media with wiper blades or pinch rollers.

Grease skimming involves higher viscosity hydrocarbons. These skimmers must be operated at higher temperatures to keep the grease fluid. This may require heating elements in the reservoir and skimmer unity to keep the grease in a liquid state for easier pick-up and discharge. If floating grease forms solid clumps or mats in the reservoir, a spray bar, aerator or other mechanical apparatus can be used to break up the grease and facilitate skimming.

Often, a skimmer by itself can achieve the required level of water purity. For more demanding situations, skimming is a cost-effective pretreatment before more complicated and costly treatments, such as coalescers, membrane filters and chemical processes are employed.