The first step is finding your source of oil. This may sound easy, but depending on where you live it may be difficult to find a restaurant that uses good oil, which is any 100% vegetable oil, as opposed to shortening. If at all possible, avoid shortening completely, as it will cause you nothing but headaches and filter replacements. Once you’ve sparked out some good dumpsters it is time to make yourself presentable and do some smooth talking. We find it helpful to explain why we want their oil, and convince them that you will be reliable and not leave them in the lurch with overflowing barrels of what they’re convinced is garbage. Unfortunately some people are more optimistic than consistent, and it can ruin it for the rest of us.
Once you’ve got your source locked down, you’ve got to figure out how to collect your black gold. The easiest way when you’re starting out is to have the oil emptied out of the fryer back into the 5 gallon jugs, or cubies, that it comes in. This is a bonus because they are easy to carry, and if you have the space you can let them settle at home before dealing with them. This method works well for the small fry with small fuel needs.
If the oil you’re after is already in the dumpster, then you have to worry about contaminants such as shortening, water and who-knows-what. Make sure that the container has a nice tight fitting lid and that the employees understand the importance of using it. Whether you plan on filtering at home or onboard, you will need a way of moving the oil, either by pumping it out of your dumpster or lifting the whole container. I’ve seen lifting of barrels by cherry picker or small cranes, but you can also roll them if your trailer is low enough. All of this will stir up the barrel, which is bad if there are any contaminants in the oil. If you want to pre-filter cheaply, then use a gravity system. First let the oil settle for three weeks or longer, then drain off the bottom to remove most of the water and shortening. At this point the oil is relatively clean and can be poured into a sock style filter and strained out. It is messy and time consuming but effective for those who have more time then money.
Pumps are tricky, but gear and diaphragm pumps will move oil. However, you have to consider the power output and back pressure from the filters. An air operated pump uses too much air, so the compressor to run it would be big and cumbersome. Electrical pumps need power which is provided by the engine so get the biggest pump that your vehicle and your pocket book can handle. A PTO driven gear pump would be the best but also very expensive. There are so many pumps out there that claim high flow but the truth is that very few were meant to pump cold vegetable oil. With this in mind, you will want to buy a quality pump to insure long life and many clean gallons.
Ideally, the best option would be pumping right out of the dumpster into your tank and driving away. Pumping and filtering on the fly is the dream of all grease burners. Therefore, we have tried countless pump and filter configurations to make this possible. The latest version of our Refuel Kit is a 12vdc gear pump with self cleaning strainers on the inlet and outlet which allows us to filter over 80 gals at a time at up to 15gpm (depending on the temperature of the oil) down to 137 micron,(check out our Refuel kit for more explanation). After the oil is strained then it can settle until we need it, or go right into the tank for final onboard filtering and then burning.