Today with the University of South Florida's Patel College of Global Sustainability we visited Rosebud Continuum in Land O' Lakes, Florida.
I am currently taking the course IDS 6247: Climate Change Adaptation and Mitigation with Instructor Thomas H. Culhane. He is living with his wife Enas, almost completely off-the-grid in their self-powered 5th wheel RV.
They currently use power from both solar and biogas energy, with a very limited reliance on propane, which they hope to eliminate in the near future.
The DC current from the solar panels is directed through an inverter to turn it into AC, which is stored in a battery. They house these devices in a tent to protect them from the elements.
Another energy source that they generate is biogas via a biogas digester. The take food waste, grind it and add it to the digester, where it turns into biofuel and fertilizer.
Medina and I filling buckets of fertilizer to transport via golf cart to give nutrients to the mango, avocado, breadfruit, papaya and other fruit trees they are growing. The large red drum in the background is the largest of the 4 biodigesters they have on site. The well-type figure next to the biodigester stores the biogas. Previously it was lifeless water inhabitable due to the anaerobic conditions. TH added water plants and now the water has attracted unwanted mosquito larvae.
So today we decided to add 3 small Tilapia to the well to see if they could survive. TH and Enas farm Tilapia already and feed them larvae. We will have to wait and see!
After our fertilizing tour, Enas showed us their tower gardens. They are feeding each tower with fertilizers from different biodigesters to see which one provides the best nutrients. They are growing a variety of lettuces, herbs, and vegetables, and they only planted them a few weeks ago!
Next to the tower gardens, is one of our fellow classmates, Li Zhu's summer project. He created a tier garden with a wide variety of plants. The lemongrass, citronella, basil, and marigolds serve as natural insect repellents.
The Rosebud property has multiple areas for planting, with some local schools bringing students to get involved at Rosebud. TH and Enas need all the help they can get, and don't forget to bring your food waste!
The upcoming project they have been working on is the biodigester dug into the ground next to their RV. They are hoping to fully power the remaining appliances such as the fridge, which they are currently using a hybrid method of electricity and propane. They are filling the digester with grey water from the sinks and shower and black water from the toilet. They've chosen to fill the digester with a "water start," instead of the simpler "inoculum" method, which takes sludge from another digester. They hope to have it full within a month.
Once the digester is full there will be a pipe connected to the white pipe which will carry waste as a form of fertilizer. They've used the hugelkultur method, which layers branches over the pipe that act as anchors for the roots to attach to, as well as absorb water and supply nutrients as they break down.
To end the day, we decided to conduct an experiment on one of the biodigesters, as per a suggestion from someone in Africa who posted on one of TH's photos on Facebook. The person claimed that the pump that TH was using to get the gas from the digester to the generator was unnecessary. The pump siphons energy, as well as costs money, so eliminating it would be beneficial for both TH and future villagers, where costs are prohibitive. So TH removed the pump (the small grey device near his foot).
Now the gas is going from the digester (blue bag on right), through the sulfur filter, to the generator, The lamp is connected to the generator, so when the light is on we know we have power. The generator is initially started with propane, then after 30-45 seconds, the propane is turned off and it runs on the biofuel.
Alas we have light! However the energy was not stable, and needed constant adjustment on the gauge. We thought maybe the sulfur filter had something to do with it, so we removed that next. Now the gas is going directly from the digester to the generator.
Waiting . . .
Counting . . .
It did seem to be more stable without the sulfur filter, however further experiments will be necessary. There seemed to be a very fine line of stability.
And that was our day at Rosebud Continuum. Thanks to TH, Enas, Medina, Diego and the goats!
