The Filtration Process

Once we have collected the waste vegetable oil, we need to filter the oil so that it is ready for use.  The information below details how we initially store and heat the collected oil, our filtration processes, and how we have chosen to store the filtered oil.

After we have collected the oil, we pour the raw oil into a heated 900-gallon metal drum.  It is necessary to heat the oil prior to filtration for several reasons.  First, the viscosity of the oil is high prior to heating, so by heating the oil the viscosity is lowered, allowing for suspended particles to settle.  Also, heating the oil aids in evaporation of water that is suspended in the oil, thus making the final product purer.  Another benefit from heating the oil prior to filtration is that the filtration process becomes faster, and ultimately the lifetime of the filters used in the filtration unit become extended; saving us more time and money because the filters do not have to be changed as often.

Next, the oil is transferred to a filtration unit where it is subjected to primary and secondary filtration techniques.  The heated, raw oil is poured through a screen atop a heated 55-gallon drum that removes large suspended sediments, like French fries and creamers.  As you can see, this drum is elevated so that the oil can then be transferred via the spout at the base of the barrel into the secondary filtration unit.

The secondary filtration unit is a Fryer to Fuel Deluxe Filtration Unit.  In this stage of the filtration process the primary filtered oil is poured through a 100-micron filter and stored in a 55-gallon heated metal drum.   This drum has a lower sludge drain and upper pump suction, ensuring that settled particles stay in the drum and are not transferred to the pressurized filtration unit.  This positioning allows for cleaner oil to be pumped through the next series of filters.  In series with the drum is a ½ Horse 100 vac pump that transfers the oil to two light industrial filter-housing units at a rate of 18 gallons per minute.  At this stage, it is important not to pump oil below the pump suction or else pump damage can occur. 

The first housing unit contains a 5-micron nominal filter and the second housing unit contains a 1-micron absolute filter, which can be filtered at a rate of 55 gallons per minute.  It is at this stage of the filtration process that the oil is refined to its purest state. 

Finally, the useable oil is pumped into a 900-gallon milk tank that we retrofitted with heating coils where it awaits use