Program Outline for Solar CITIES workshops: How to get there from here

Solar CITIES Training Program Outline

By T.H. Culhane and Taha Majeed


The mission of Solar C3ITIES biogas program is to “connect community catalysts integrating technologies for industrial ecology solutions”.  Our training is holistic and is designed to train trainers of trainers and create a viable multiplier effect.   We start by working with community leaders to gather together the community catalysts who have self-identified as interested in sharing a passion for problem solving and who recognize that transforming what is now wasted (organic garbage, sunlight and its derivatives) into renewable sources of energy and fertility lies  at the core of sustainable develop.   Therefore the first step in our program is finding the core people who will be trained to train others.

  1. Our core technology is the low cost and local  transduction of food wastes into fuel and fertilizer, particularly in urbanizing spaces, with a secondary commitment to improving ways of transforming toilet wastes into the same values.  We do this at several scales and so our first task in the program is to have a presentation and Q and A in which we identify all of the ways for extracting value from organic residuals and address concerns and issues.The presentation is open to the public and we ask that the identified community catalysts not only attend, but co-lead the Q and A session and help identify key sites for intervention and conducting workshops.
  2. Once potential sites have been suggested, we go with stakeholders and identify the first site for a workshop/build.
  3. At the site our first step is to work with the trainers of trainers (usually no more than 10)  to  build the signature Solar CITIES IBC digester and a floating IBC gas holder to connect to it. We load this system with the requisite 100 kg of fresh animals manure (cow or horse usually) and fill with water and seal it to commission it. This teaches how to use 3 of these low cost,  internationally available recycled intermediate bulk containers to build a fully functioning biogas system that works without need for electricity or pumps.
  4. Our second step is to build the Solar CITIES variant of the ARTI India cylindrical water tank floating drum digester.  This introduces another very effective and time honored way to get value from food waste using local materials, and we show how the two systems, IBC and ARTI, can be put together for even higher efficiencies, yet each can be used alone if necessary. This system is also loaded with manure and water and commissioned.
  5. Our third step is to roll out, set up and commission (fill with inoculant) our Solar CITIES Salchicha (transportable PVC bag) digester.  This is by far the simplest of all digesters, but it requires a heat welding PVC machine to create and so is not yet a “local” solution in most places; unlike the two other systems it must be carried in from the outside.  Because it is light weight and portable, it can be easily deployed, but for now people in communities would have to order it from Pennsylvania’s  Solar CITIES US partners or order similar systems made in China, India, Africa or Israel. Nonetheless, because Solar CITIES makes OUR salchicha digester plans open source and completely avaiable on the internet, any local manufacturer who wants to make the digester bags themselves as a microenterprise is welcome to do so, and we demonstrate how in our trainings.
  6. Gas holding bags and pumping systems are hooked up to the systems for storage and transport use of excess gas so the benefits can be shared with the larger community.

Because it takes several weeks for the sealed commissioned digesters to finish their initial fermentation of the innoculant manure to produce flammable gas, this ends the first phase of our mission.  The entire set up of the three digester types described above can be accomplished in one week. At the close of the workshop stakeholder community catalysts are trained in the use of our social media platforms (facebook group “Solar CITIES Biogas Innoventors and Practitioners” and community website “” to continue sharing results and advice and to ask questions. This helps with the necessary continuity to ensure things do not fail.


The second phase of our program involves a return anywhere from one to three months from the initial setup to assess successes and failures and to supervise the trainers of trainers leading a similar workshop, extending the reach of the program and creating more trainers and installations.  We bring extra gas holding bags at this time to increase the number of people who can be served by the existing digesters.

  1. As part of Phase two, a more detailed presentation is done with the community to discuss the results of using the existing digesters, exploring the social and psychological dimensions of the technology  and to begin working to  scale up to a larger institutional or community digester. The community gets to know the theoretical and practical considerations and costs and benefits of a 4, 6 or 10m3 digester system.
  2. The enlarged team of trainers, armed with knowledge from the construction and use of  home and family scale builds, selects a site for the first community scale digester and the Puxin digester steel molds (concrete forms) are ordered. Stakholders figure out who will be responsible for receiving the shipment from China at the local port and get them transported to the site.


From 2 to 3 months after phase two, with several sets of successfully running family scale digesters under their belts, the community catalysts invite the workshop leaders back to conduct a Puxin cement digester build of 10m3 (large enough to handle the wastes from approximately 100 people, or an institution like a school). This workshop takes a week from start to finish under the right weather conditions, and because we are pouring cement we give the project two weeks for completion to be assured of a good result.

  1. Building the Puxin biodigester:

a) On day one we pour concrete slab b) On day two we assemble the body moulds, put in rebar  and pour cement

c) On day three we assemble the neck moulds, put in rebar  and pour cement

d) on day four we let the concrete cure.

e) On day five we remove the molds and fix the plumbing pipes for input and output

f) On day six we create internal surface area inside the digester and put in the  fiberglass gas capture dome.

g) On day 7 we fill the digester with manure and water and active innoculant from the existing small scale digesters and finish any additional plumbing that needs to be done.

     2. The community begins to explore feeding regimes and community strategies for using the gas and fertilizer equitably.  It is possible that the inoculant from the existing digesters could make the new larger digester produce gas very soon after loading, and if this is the case, experiments can be done with running electric generators and hot water heaters off of the gas.

    3.  Educational signage for the systems is made in local and international languages and an instruction manual is created.


    1.Approximately 3 to 6 months after the Puxin is built, the team leaders return to evaluate performance and tweek and to encourage the set up of  microenterprises using the molds (which now belong to the community), producing salchicha systems of local manufacture and building more IBC and ARTI systems. By this point it is assumed that local catalysts have  learned “how to fish” and no longer need outside intervention.  They are now empowered and supported by the existing and growing Solar CITIES/Biogas Central social network of fellow innoventors and practitioners.