WVO Filtration 2.0

We have found one of the most overlooked steps in making biodiesel is the filtering and
drying of the WVO. We continue to look for ways to improve the quality of the WVO,
but minimize the use of grid power.

WVO Filtration I
Spring 2004 Our first set up did a great job of filtering the WVO, but did not address the water that was suspended in the oil. We heated the WVO before filtering in a black solar box that greatly sped up the filtration process in the colder months. We then would filter the WVO through polyester screen mesh from our apparel printing business.

WVO Dry/Settle I

August 6, 2004 We brought the WVO filtration equipment back online after major modifications to the above design. This time we got design help from Tom Sineath, and welding expertise from Adrian Boggs. We have determined we would break the process down into two steps. First, fast filtration of the WVO through a 10 micron filter bag and then let time and gravity address the water and finer particles that might still be in the WVO. The two stainless steel tanks in the foreground are for the first filtration processor and the 110 gallon plastic conical tank is used for the water separation.

The problem we found with this design is that it was located on the north side of our building and once winter came we had a giant tank of frozen WVO bringing this process to a halt

The upper tank shown below is used for a higher level of filtration using filter bags. This process is done if the WVO is to be used as SVO and not biodiesel.

	We used three double bagged filter bags made by Filtration Solutions, the inside bag is 5 micron and the outside is 1 micron. In the bottom of this tank is a valve that flows back to the bottom tank. This allows the WVO to filter through multiple cycles, each cycle takes about 1 minutes and right now we cycling for about 15 minutes.


WVO Dry/Settle II
February 16, 2005 After a few months of not being able to filter frozen WVO we got our new WVO filtration system and settling tanks are online. We utilized the same filtration and pump from our earlier systems to pump into two 110 gallon conical tanks. We went ahead an increased the size of the system to get ready for our new 90 gallon reactor that would becoming online shortly to replace our 45 gallon reactor. The plan is to let the WVO settle for about two weeks and then drain the settled water. After the water is drained the WVO goes back into the pump system where it can be run through our filter bags or just drained back into 55 gallon drums. By painting the box black and facing the window panes south we are expecting a big solar gain and the end of our winter WVO freezing. The problem we discovered with this design was thermal lag. The box would heat up during the day, but much of that heat would be lost at night. This was not a problem in the spring and summer months, but in the winter we knew we could not recover from extended cold days which would slow down our process of the water falling out.


WVO Dry/Settle III Compost Heating
October 29, 2005 Final construction was completed on our compost heated WVO filtration and settling system. Jack Martin was the brain child of this idea with the design help from Tom Sineath and the labor of most of our co-op members. Jack had designed a similar system at Appalachian State University and felt that we could maintain an average temperature of 120-130F. We believe by holding the WVO at 100F or higher for about a week will force the water to settle out. The wall that you see in the picture to the right will be finished to a enclosed, composted heated room where the WVO will be filtered then pumped up to the barrels. The plan will be 1 -1 exchange, as each gallon is pumped up, one gallon will gravity drain out.
5 - 55 gallons plastic tanks connected in series by PVC pipe. The WVO is pumped to the farthest barrel out and then gravity drain to the next lower barrel. The slotted black plastic pipe is used to pump air into the compost pile to help activate the microbes. The longer term plan is to power a small DC fan via solar to handle this air circulation.
The finished compost pile and the barrels from the above imaged are completely buried. The pile consist of tree mulch from local tree service companies, horse manure, a little nitrogen fertilizer and some compost starter from the compost pile at ASU. By the third day we had already reached 126 degrees in the pile! We installed a digital temperature probe that continuously measures the temperature inside of the compost pile. We plan to continue to add material to the pile and hopefully only will only have to rebuild the pile once a year. In early January we had to tear down the compost pile when we discovered a smoldering fire inside the pile. We believe in building the pile some of the fertilizer we used to seed the pile got packed against the plastic vent pipe and under the heat of the pile it ignited.
February 25, 2006: We rebuilt the compost pipe using a similar design except for using a PVC pipe that has a higher temperature rating and putting water in the barrels instead of WVO. We have set up a heat exchanger to take the hot water and circulate into the WVO tanks in the solar box. Since we used compost material for the first pile it quickly heated up to 150+ degrees and so far was have been able to keep the WVO tanks at about 100 degrees.