ALC - Abanaki

DNAPL is short for dense non-aqueous phase liquid. Common DNAPLs include creosote, coal tar, and heavy oils; common DNAPL applications include degreasing and acting as a solvent. On the other hand, DNAPLs can also be the byproduct of industrial processes; in particular, a form of DNAPL known as multi-compound waste is a common type of waste oil. The defining aspect of DNAPLs, density, causes the mixture to sink in liquids like water or coolant. Because the sludge sinks, surface skimmers like rope skimmers have issues treating DNAPLs. Additionally, the density tends to cause problems with devices requiring a pump for collections because of its density, clogging the pipe or even breaking the pump itself.

Sometimes called pumpless groundwater remediation systems, oil skimming is the lowest cost way to remove hydrocarbon contamination from groundwater. Oil skimming alone may clean water to acceptable levels or be used as a pre-filter treatment. It is the most inexpensive way to remove LNAPLs or DNAPLs.

The relationship between oil and water in a mixture is well-known and governed by two physical properties:

There are several types of industrial oil skimmers. Choosing one best suited for your application will maximize oil removal while minimizing capital outlay and oil skimmer operating costs. First, define the application in terms of the following characteristics:

Although designs vary, all oil skimmers rely on specific gravity, surface tension and a moving medium to remove floating oil from a fluid’s surface.

There are many oil skimmer choices available but, how do you determine the best for the application? Two things should be considered at the start of the search. First, how much volume of contaminated oil requires removing? Every skimmer offers an oil removal yardstick measured in gallons per hour. Second, what are the dimensions of tank where skimmer will be operating? Some skimmers remove oil more efficiently than others based on the size of tank.   Even if there is a low volume of floating oil in an application, a smaller skimmer may not be the ideal solution if the surface area is too large. 

If you’re not reclaiming your used oil than you are awarded no points, may not collect $200, or pass Go. If you are, you get all of the points. However, if you are doing this but NOT taking care of the equipment that is helping you reclaim that used oil, then you are just as much a part of the losing team.

Anyone that works with coolant knows about the potential foul stench that looms around the corner. When a machine is shut down for the weekend, oil has a chance to come to the surface of the coolant tank. Bacteria that are living in the coolant tank use up the dissolved oxygen in the coolant mix, a process that is sped up by having a layer of oil on the surface. This allows odor causing anaerobic bacteria to thrive, giving off that familiar “rotten egg” smell.