Biogas is created when organic material is fermented in anaerobic conditions. Specialized bacteria thrive in anaerobic (without oxygen) environments, consuming organic acids and respirating combustible methane. The bacterial activity inside a biogas digester is very similar to the processes occurring in a compost pile. The bacteria break down carbon and require a certain amount of nitrogen to sustain their bodies. Thus, a biogas digester needs to maintain a specific balance between carbon and nitrogen. This balance is expressed in a carbon to nitrogen ratio (C/N). The ideal C/N for a pile of aerobic compost is 25-35. Similarly, the optimal carbon to nitrogen ratio in which organic mater is decomposed inside a biogas digester is 25-35.

Because this C/N is similar to aerobic compost, many people have assumed that the finished product of biogas digestion is a natural fertilizer. They have suggested that the effluent of a digester can be diluted with water an added directly to the soil or to plants. However, research by Dr. Elaine Ingham, a soil biology expert puts this practice into question. She has studied the microbial life of the soil in her laboratories in Corvallis, Oregon at both the Sustainable Studies Institute and Oregon State University. She states in her Compost Tea Brewing Manual 5^th ed. that teas formed in anaerobic conditions contain high levels of natural alcohols that poison and overwhelm other soil microbes, thereby destroying a portion of the life in the soil and harming plants. At present, only aerobic (oxygenated) compost tea can be guaranteed to actually benefit and stimulate life in the soil.

Given this research we must be careful with the ways in which we choose to use the effluent slurry left over after the biogas digestion process. Although there are some harmful alcohols, the slurry may contain a C/N of 30 and be full of water soluble nutrients. This is indeed useful. We need not throw it away as waste, and instead we might build a separate compost pile and add the effluent to it in order to create a healthier environment for soil organisms. The aerobic composting process may do away with some of the natural alcohols and add a diversity of aerobic microbes to the effluent. This extra step may be a way to make good on the promise of biogas—the creation of combustible energy and a high quality fertilizer.

Today I began the research related to an on-site cafeteria waste management system at Brookside Elementary school in Willits, California. The plan is to incorporate the food scraps generated inside the school cafeteria and kitchen into a composting system located on the Energy Farm site. The specific style of composting that I’m considering is vermicomposting. This compost method uses red worms to both process and digest the food scraps. When the worms are finished with the scraps the end result are worm castings. These castings are rich in nitrogen and phosphorous and are intended for use as a soil amendment or as a ready formula for compost tea. There are a number of considerations to tackle related to the project including:

Amount of waste generated per day vs. the worms ability to process it

Available room on the farm for this style of waste management

Possible California regulations related to composting

The type of food scraps that are generated

The separation and collection of food scraps

Securing this process throughout the winter months

Daily time and labor requirements for farmer or laborer

Today I began construction on the toolbox for the Willits Energy Farm. I was able to meet the owner of a property where a house was being remodeled. I introduced myself and explained that I was attempting to gather scrap wood to transform into a toolbox for the farm at Brookside Elementary. As you might expect, the owner was willing to let me dig through scrap piles of wood in search of suitable material. In no time I had gathered enough wood to begin processing.

Since the wood had been torn from a house there were nails and uneven, broken ends on the boards. I therefore needed to use a T-Square to draw a line and make an even cut. Once one end of the board had been processed and “squared-off” I was able to measure out the exact length that I would need. Again, I used the T-Square to draw a straight line and got to sawing. Viola!-A perfectly usable 6ft piece of wood for the box frame!

I kept working, repeating the same process outlined above. Sometimes I would have to stop to remove nails, or switch to my left hand because using the saw with only the right hand is eventually quite tiring. Before long I had each part needed for the frame. I have to admit I really took pride in using a hand tool to do this job.

In a post petroleum situation the use of power tools may not be an option. Lucky for us, intermediate tools like a hand saw or scythe are quite user friendly and give one the added energy of knowing that we don’t need to rely solely on petrol or electricity to get some work done. Many of us are finding that if we roll up our sleeves and get to it we can achieve all sorts of wonderful things. I believe that working in this manner and sharing our knowledge will no doubt lead to the discovery of a multitude of “empower” tools.

Scrap wood that needs to be processed

Finshed 6ft board ready for use

Making cuts with a hand saw

Processed wood to build toolbox frame

Planners and participants at the Willits Energy Farm understand that the following winter months are intended to be used for infrastructure development. Thus, the goal for this winter is to ready the farm site to maintain spring crops. The fence is a big part of this infrastructure. Once completed, it should offer the site protection from deer and rabbits that frequent the farm space. Two other projects on the table are an irrigation system and a storage space for tools and equipment. Together with the perimeter fence these three projects are the minimum that is needed to initiate and maintain new crops.

This week there had been discussion regarding a shed that would be used to store the tools. However, after more consideration it seemed that the timing of the tool shed was a little premature. It is true that we need to store tools and other farm equipment, but until the irrigation system is solidified it will be hard to find a suitable long-term location for a shed. After a bit more thought, I suggested creating a tool box that could be locked and possibly even chained to the fence.

A tool box offers us a couple of quick benefits that a full shed does not. A box is low cost, highly portable, and can be assembled in relatively short order. I plan to acquire a majority of the wood from scrap piles of lumber that have been ripped from houses in the middle of remodeling projects. There are already two such houses in the neighborhood.

The dimensions of the tool box are as follows: 3ft tall, a length of 6ft, and a width of 4ft. This should be plenty of room for a mix of tools and is even able to store the scythe, probably one of the longest tools we have at the moment.

Remodeling project with piles of scrap wood