1) how much does it cost to install the WVO setup
The last conversion I did was around $2,000, but I paid a mechanic to do all of the wiring for me, and I did the rest myself. The WVO fuel pump was the most expensive piece at about $500, but I don't see them listed on WVODesign.com anymore.
2) where do you get your waste oil?
Over the years I have gotten it at a lot of different places, but mostly restaurants. Currently, I get it from the college cafeteria where I work, from my brother's employer's cafeteria, and from a local restaurant. Before we moved about 4.5 years ago, I got it from other restaurants, the bowling alley, the swimming pool, a Chinese food truck, etc. Some of the places put it back in the original jugs and just set it outside for me to pick up, some I have provided a barrel with a lid for them to dump it in, and some just have me get it from their big waste container. The last option is my least favorite because they are usually provided by a third party.
For the ones who put it in a barrel or a large container, I found it easiest to use a large feed scoop and funnel instead of a pump. The pump is okay during the warmer months, but food chunks can still wreak havoc on the process. I was able to get some five-gallon, heavy-duty jugs from a local car wash. The ones I have also have a capped air vent which makes filling and pouring much easier. They are very durable. I got most of mine probably 10 years ago.
3) how much trouble is it to refine the oil to be usable?
I have made a lot of messes over the years as I used trial and error to do a lot of things, but I'm the ultimate cheapskate so I think it is worth the time and effort. I started doing this in 2004 because I was sick of paying $1.35 for a gallon of gas. I have ruined a lot of good shirts and even some pants over the years and I have used a lot of kitty litter to clean up spills; however, since I have saved more than $100,000 in 18 years of doing it, I think it is worth it, but most people are not willing to do and will just continue to complain that gas prices are so high. If you are going to do it, a good pair of coveralls will protect your clothes from most splatters.
The process I currently use is not very labor-intensive, but it's still a lot easier during the warmer months (I have lived in Wyoming and Utah while running WVO). I pre-filter all of my oil through t-shirts I get from thrift stores or our local clothing bank. I get the ugliest ones I can find because they are the cheapest and least worn. I will put two or three inside each other and sew the necks and sleeves together to make a big bag and then I stretch them over a 55-gallon barrel to dump the unfiltered oil in. I use opaque plastic barrels for two reasons. First, I can see how much oil has gone through the t-shirts, and second, I use several screw-in hooks around the outside perimeter of the barrel to secure the t-shirts. I just poke them through the t-shirts.
I actually use t-shirts on the 55-gallon barrel and a 30-gallon barrel. I will pump the oil from the 55-gallon barrel to the 30-gallon barrel (it sits higher than I can see, so I have a float valve, like in a toilet tank, that closes when the barrel is full) and then it gravity feeds into another 55-gallon barrel. I have ball valves on the outlets so I can control the flow. In the third barrel, instead of t-shirts, I have a couple of holes cut in the top to accommodate filter bags. The filter bags have a metal ring around the top so I make the holes in the barrel large enough for the bags to go in, but small enough that the ring keeps it from falling all the way into the barrel. The filter bags that I use filter the oil down to one-micron. Once the oil goes through those bags, I just pump it into the WVO tank and I'm good to go.
This sounds really complicated, but now that it is set up, it's pretty easy. I pour non-filtered oil into the first barrel and walk away. When I go back, I pump it from the first barrel to the second barrel and make sure the gravity feed is slow enough that the filter bags won't overflow and then I walk away. When I return I have oil that is ready to be pumped into the tank.
and, how do you know the waste oil does not have crap in it that is harmful to the engine?
After I filter the oil and put it in the tank, it still goes through the WVO filter and the regular fuel filter just before it goes into the injectors. I have never had anything get through to clog the injectors. The biggest thing to avoid is water. Some restaurants wash out their fryers with water after draining them, but since oil and water don't mix, it's not too hard to avoid if you are careful.