Thursday, February 23, 2017

Preliminary Research Results for first six months use of early beta test model of Home Biogas donated to USFs Patel College

At the The International Ecotourism Society (TIES)  conference at the Patel College of Global Sustainability at USF Tampa in January of 2016, as part of a hands on sustainability workshop, Dr. T.H. Culhane and students from the Patel assembled an early version of the Israeli HomeBiogas system that had been donated to the college  through Dr. Culhane for research and education.
The system was an early version of the biodigester with a very heavy steel frame and experimental woven/sewn mesh bags connecting the rubberized digester tank to the exoskeleton frame. The company was exploring more durable and lightweight materials for subsequent models that would help lower manufacture and shipping costs substantially.

The system was displayed empty on stage in the auditorium for the delegates and guests during Culhane's keynote and then the students placed it outside the Patel Building behind the kitchen  for photography to show a possible location for the small household scale digester.
The HomeBiogas system was then moved into the elevator and taken to the Patel College reception area on the second floor and put on display as a floor model  from January to August of 2016 with literature and brochures explaining its operation.

In mid August of 2016 when Culhane arrived from Germany to begin working at the Patel College he was asked to find a location for the digester where it could be "commissioned", i.e.  filled with water and horse manure and  put into active use for research and education.  Because there were few people familiar with the system and no institutions at that time interested or willing to provide a location, it was determined that the best immediate place for the HomeBiogas system was in the backyard of the home that Culhane was renting, belonging to former Patel student Ryan Whitson, who had been at the TIES conference assembling the system and had accompanied Culhane to West Virginia in March of 2016 to build basement biodigesters in an eco-lodge and had familiarity with the systems and their operation and understood their safety and effectiveness.

Eric Weaver, a Ph.D. student at USF who works at Patel, and his son Chris Weaver , who teaches architecture at USF, transported the system in their pick up truck from the Patel College to the Whitson residence at 3411 West Abdella St. Tampa 33607 and over the next couple of days Culhane began experimentation with the digester.

Innoculant and gas production results with digester:

The first experiment that Culhane ran with the digester was to see if it could begin operation without needing to be innoculated with animal manures.  Because Culhane did not have a car and was dedicated to spending the first semester riding bicycles and public transit buses as part of his commitment to sustainability, he wanted to show that the digester could be started using a powdered innoculant that was lightweight and easy to obtain, instead of needing to gather 100 kg or more of fresh horse or cow manure, as is the usual custom. This would enable people in developing countries and poor regions of advanced economies who cannot access or afford pick up trucks get their digesters going with something that can be carried in a hand-bag, substantially lowering the material and labor costs associated with setting up digesters.

Culhane began by obtaining different commercial septic powder preparations: RidX,  and SeptiPak. The use of two powders was done to increase the odds of success since there was only one digester and it takes many weeks to see results. There was worry that if a single preparation was used and it didn't work we would lose time before the winter cold set in.   In future it would be of interest to try out each different commercial septic powder individually to see which works and which doesn't (they might all work!) and which produces the most immediate and best results for the price.

Culhane then filled the digester tank with water and septic powder and waited.  It took 5 weeks before the first flammable gas was produced and Culhane began feeding the digester food waste and grass clippings.

Unfortunately, as can easily happen with small scale biodigesters that are started without the benefit of the fibrous material found in raw animal manures, the methanogens growth rate couldn't keep up with the rate of acidogenic bacteria growth and the system went acid.  Soon all it was making was carbon dioxide gas and the effluent began to smell acrid.

On September 11th Culhane found the pH to be as low as 5 and had to remediate the biodigester with 11 Kg of sodium bicarbonate (baking soda) purchased at HomeDepot from the pool section.  After balancing the pH to near neutral (7), Culhane reinnoculated the system with more septic solutions:

Once the system had recovered, which took another couple of weeks,   the digester worked reliably. By September 28th, fed on food waste and grass clippings, it began to produce enough gas to cook on.

Culhane then purchased a commercial backyard barbecue and grill from HomeDepot on September 30th , one of the less expensive models for under $125 dollars, and Eric Weaver and Eric's wife Kim, who works with the Tampa city planning office helped Culhane transport it to the house.   He showed the Weaver's the successful gas production that night:

This was important because Kim is helping demonstrate to the city the safety of homebiogas so that appropriate code can be written that will obviate the unreasonable fears that people have about the system and help us move forward in getting it approved for institutions (it is already CE and ISO 9001/9004 listed and approved for households, but some institutions in the US still seem to have concerns that need to be allayed through demonstration.)

Culhane then used the weekend to modify the grill for use with biogas as documented in the following video:

Culhane demonstrated the success of this easily modified grill to Maryann Bishop from the non-profit organization "Rosebud Continuum" in Land O Lakes, where the family was working with Solar CITIES, Culhane's 501C3, to build a much larger cement Puxin digester (10m3)   later that week, to give the family confidence and experience in home scale biogas before they invested in a much larger and more expensive and permanent system built out of concrete:

Having successfully demonstrated that one can start a HomeBiogas system in the fall in Florida on a couple of packages of HomeDepot purchased septic powders, fed on yard waste and food scraps, and run an easily modified grill on the biogas, Culhane then set about providing a cooking solution for low income families in Haiti, where he visited after the Hurricane to provide relief.  Haitian families can not afford a 125 dollar barbecue, so Culhane made a stove out of a coffee can for use in his own home, fed by a clear plastic tube from the back yard. The coffee can biogas stove is something Culhane learned in Kenya from Dominic Wanjahia Kahumbu  from Simply Logic biogas and has subsequently built out of paint cans and powdered milk cans.  By using such a simple system at home Culhane demonstrates that this low cost alternative is perfectly appropriate for both impoverished and wealthier communities since there is no smoke or soot or toxins and it is a great way to introduce recycling to people concerned about our environment.

Durability results for early model of digester:

With  continued use of the digester on a daily basis at the residence where Culhane was testing the beta model of HomeBiogas it was noticed that the expansion of the digester bladder over time was causing the hanging bag that attaches it to the frame of the digester to tear:

Each week Culhane noticed the tear progressing further and further until the bag looked like it was going to burst.  To save the situation, Culhane wrapped the digester with $100 worth of ratchet straps as a temporary fix, and reported the situation to the company.

The unit had been a beta testing demo unit, with a heavy steel frame and hanging bags that were still under test and Solar CITIES has been given the honor of field testing units as they evolve.  Since the time that this unit was developed and sent to USF, the company has learned many things and completely changed the materials used to make the digesters.  The most recent units are made from different plastics and the heavy steel frame has been replaced with light weight aluminum among other substantial changes.

From a research perspective we learned a lot from this "early adopter" use of the system here in Florida.

Expansion to other Locations before Christmas

By November of 2016, despite the expected slow down in gas production caused by low winter temperatures, Culhane had demonstrated to many Patel students and community visitors the promise of small biogas and got permission to build hand-made Solar CITIES IBC tank varieties of household scale biodigesters in several locations.  Working with teachers and students from Blake High School, where Maryann Bishop's daughter is a coach, with funding from the Bishop's for materials, Solar CITIES and Patel students built two IBC tank biodigesters, one for the High School and another for the Faith Lutheran Evangelical Church.

In these locations we experimented with a new design using the lid of the digester as the feeding inlet pipe, finding that it creates more rigidity but that the uniseal needs better sealant.

New Year Location Change and New Experimental Locations

When Culhane returned from the Arava Institute and the Clinton Global Initiative Volunteer Solar CITIES projects in Israel, Palestine and Jordan in January he found that he and Ryan had to move out of the house on Abdella immediately as the house needed renovation.

 Culhane was invited to move into the Bishop residence at 22843 Hale Road, Land O Lakes Florida, 34639, on the farm property where the Bishops are building the Rosebud Continuum Educational Center 501C3 that was co-created by former Patel Student Michael Kuras with other graduates of the program (among them Eve Spengler, who runs a composting company, and Ericka McThenia and Mary Bishop) and with Professor Joseph Dorsey.  The center has been proposed as a site where the Food Energy Water Nexus can be put into real-time practice where students from High School through Graduate School can come and do research and implement ideas and experiment.
We had already built a Puxin digester there:

Because it was imperative that all of Culhane's belongings be moved  out of the residence at Abdella and there was still no location at the college to house the digester, which was by now falling apart,

A decision had to be made about whether it was worth it to continue to try and work with the digester with the worn out materials or retire it (i.e. dispose ot it).  Culhane decided it would be within the spirit of the original intent of research and education to see if the system could be repaired.

Eric Weaver came with his truck and we decided to move the digester to the new residence where Culhane would be living in Land O Lakes and try to fix it there and see if we could get more life out of it.  We drained the system of all of its biodigestate and lifted it onto the truck.

The picture below shows the torn hanging bag very clearly:

 To get the system working again, Culhane went to Loewe's Hardware and had a 1/2 inch wood sheets for a custom plywood box cut and designed a way to keep the failing digester bag contained.


The system was re-installed for Culhane to continue researching behind the kitchen at the house where Culhane is now living and connected to his modified grill so he can monitor it on a daily basis.  It had been drained but slurry had been saved and there was additional slurry obtained from the larger Puxin digester.

 Students from Patel college came to help construct the box:

 Once the box was built the system was refilled with innoculant, which Culhane had saved from the draining, and with new innoculant from the Puxin system, to see how quickly it the "dragon" would come back to life.

The weather was cold so it took  a couple of weeks to begin producing gas again, but the repairs Culhane and students made were a success.

After his Keynote speech to the Recycle Florida Conference, visitors from the Recycle Florida group, organized by Key West City Planner Dee Dee Green, who had met with Patel professors and students to discuss Biogas potential at Key West City Hall, when Dr. David Randle and Louis Zunguze and Culhane conducted their Keys Marine Lab field trip,  were invited to come see the digester in operation.

Through its new location at the residence/farm of the Bishops,  the Patel HomeBiogas system is now being actively used to demonstrate the vibrancy of this appropriate technology to visitors on a weekly basis, like Alice, the woman from a development agency working in Cameroon shown below:

Extending the Project based on lessons learned:

In late January, seeing the enthusiastic response of the students in the new Navigating the Food/Energy/Water Nexus class at the Patel for getting involved with hands-on research on small biodigesters, Culhane  funded his own Solar CITIES 3 IBC biodigester system to be placed at the Veteran's Garden at the Sustainability Living Center by the Salvation Army across from the Lowry Park Zoo and invited students to come on the weekend and build with the other community volunteers to gain the "biogas bricolage" experience.

In addition to this, following a presentation and meetings Culhane had made in November and December at the Museum of Science and Industry for/with  STEM/STEAM Science educators, the class was invited in the new year to share their expertise at the Butterfly Garden.  The plan was to build a Solar CITIES hand-made system which the students had experience with, and Culhane donated one of the new and improved and more robust HomeBiogas systems he had purchased  to MOSI so that they and the MOSI community could get hands on experience building/assembling digesters and have an active system within easy walking distance of the Patel College that they can begin doing research on.

 Culhane is equipping the system with Arduino microcontrollers and temperature sensors and the students will begin to gather and log real-time data that correlates feeding rate and feedstock with temperature and pH and gas production.

The students of the Patel College FEW Nexus Class also got the opportunity to come on a weekend and participate in the build of Florida's second Puxin digester:

These local biogas building parties are essential to be a culture of biogas innoventors and practitioners who can make this simple technology the most effective go-to solution for transforming food wastes from a huge problem into a hope inspiring solution.

As of this writing, February 23, 2017, Patel Students and other students and community members from the Tampa region now have 5 locations where there are active small scale biodigesters to learn from and about and conduct research into how they can fit into a diverse array of living situations, from residential homes to churches, community gardens, high schools and science museums. 
Florida visitors thinking about replicating biogas systems now can see three different styles operating:
1) The commercial Home Biogas system, ideal for a small family, attractive, CE and ISO listed and now field proven in over 60 countries.
2) The Solar CITIES modular and low cost DIY IBC system, invented by Dr. T.H. Culhane,  which can be built by anyone anywhere and expanded to accomodate larger amounts of food waste and is great for education 
3) The Puxin 10m3 cement community system, two of which are now operating at the Rosebud Continuum, one above ground, one half buried, using barrels of food waste provided by Beef O'Brady's restaurant, with a third planned soon built underground for toilet waste.

With the generous donation of several IBC tote tanks by the Vigo and Alessi families from Alessi Foods/Vigo Importing in Tampa (such as the two shown here being added as gas holders to the Veteran's garden system)  we are now on our way toward being able to make small scale biodigestion technology an integral part of core STEM/STEAM science instruction curricula. 

It is hoped that these active "domestic dragons" will give the Tampa community the expertise and stimulated interest to become leaders in the small biogas (r)evolution now occuring in the world.

Future projects being planned through the Patel College are to extend this work to the city of St. Petersburg, starting with USF project sites at the St. Petersberg Eco-hostel, the Marina, the Yacht Club and even the Amara Zee caravan boat, which can spread the knowledge around the world.

Come join our movement! Yes, you can do this at home!

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