Terra Preta Production, Part II:

In 2013, ZEGG in Germany found itself in the midst of a struggle to keep the rights to their own sewage treatment and drinking water. In this situation, Achim Ecker was looking for ways to reduce water consumption and reuse waste water. After visiting Dr. Jürgen Reckin of the University Eberswalde and the Terra Preta Project in the Botanical Garden in Berlin, he started to work with the fascinating prospects Terra Preta offers. In the last newsletter he shared about the production of biochar, this time he explains ways to charge the biochar with nutrients – using urinals.

Terra preta (literally “black earth” in Portuguese), is a type of very dark, fertile anthropogenic soil first found in the Amazon Basin and now almost everywhere. Terra preta owes its name to its very high charcoal content, and was indeed made by adding a mixture of charcoal, bone, and manure to the otherwise relatively infertile Amazonian soil over many years. Terra preta is less prone to nutrient leaching as charcoal’s porosity brings a better retention of organic matter, of water and of dissolved organic nutrients, as well as of pollutants such as pesticides and aromatic poly-cyclic hydrocarbons.
However, it is important to note that the fresh charcoal must first be “charged” before it can function as a biotope. Several experiments demonstrate that uncharged charcoal can bring a provisional depletion of available nutrients when first put into the soil – until its pores fill up with nutrients. This is overcome by soaking the charcoal for 2 to 4 weeks in any liquid nutrient like urine or plant tea.

Using Precious Urine
We wanted to lower the nitrogen and phosphate levels in our waste water in order to improve the quality of our outflow water. So far we believed that we needed to change over to dry toilets to achieve this. But the legal situation of using human feces is difficult due to possible pathogens in human feces (which is crazy when you think about it: animal manure can be used in agriculture almost without restriction with all the lethal germs it contains due to antibiotics abuse.)
During our research, we learned that urine has the highest content of Nitrogen and Phosphorus, much more than human feces. 80 to 90% of the Nitrogen we shed and 50% of Phosphorus are in the urine. So why waste carefully cleaned drinking water and a well working plant filter to destroy those urgently needed nutrients? In a sewage plant bacterial activity gases out the Nitrogen back into the atmosphere.
Both Nitrogen and Phosphorus are valuable soil ingredients for plant growth and health. Most of the world’s phosphate fertilizers are produced from phosphate rock resources. And they are slowly but surely running out. Peak Phosphorus is close. Nitrogen is taken out of the atmosphere in a technical process that uses energy. Both are expensive.

So we started setting up places to urinate into barrels with organic matter and biochar outside the houses in summer and during our camps. A lot of men and some women used them. It was a great success in raising consciousness for our seminar guests. The women asked for a better design for them to use it.
In the beginning we only had a little biochar from sweat lodges and some camp fires, so we added a lot of wood-chips. Smell occurred as we could not renew the contents of the pee places fast enough, with so many people using them during our big events with up to 400 participants last year! Smell is also a sign for decomposition and thus the loss of Nitrogen – exactly what we wanted to avoid. At that time, we did not have the whole process line set up from collecting urine and making biochar up to having ready Terra Preta soil.

On the way to waterless urinals
When we still did not have a solution of how to produce biochar we started buying expensive sustainable biochar and had it transported to us. Meanwhile, I learned from an article from Ithaca Institute how to produce biochar from brush in a cone like earth hole as described in the last newsletter from my experiments in Portugal (Link: How to Produce your own Biochar for Terra Preta).
In ZEGG the soil consists mainly of sand so an earth cone will not be stable and usable. Our solution was to build a Kontiki kiln from steel. This has the advantage that we can carry it to where the brush is.
To date, we collect the urine in food safe blue 60 ltr. barrels filled with a mix of biochar and leaf compost to get the lacto-acid soil bacteria etc. They can be carried by 2 people and when full they are sealed with the lid for anaerobic fermentation for four weeks. Neither in the phase of being used nor during the fermentation any smell appears. The barrels are great in size for men to pee in. For women they can be fitted with a movable toilet seat and dug into the ground for the right height.

Indoors, we are in the process of installing 10 waterless urinals and urine collection facilities in basements and outside the houses in manholes. The urine will be pumped out into a container on a truck and used to fertilize the compost, to charge biochar, or as quenching water for the Kontiki kiln.
To charge the biochar it is best to let it soak in the barrels for anaerobic fermentation for 4 weeks (depending on temperature). We also started to make Bokashi from kitchen waste which we ram into the 60 ltr barrels for anaerobic lacto-acid fermentation. In this way we don´t loose as much of the nutrients as in a normal aerobic compost.

Building fertile soil
We use composted leaf earth, clay, Bokashi, and grass clippings, charging Biochar in layers to set up a compost stack and letting it sit for another year, covered with EPDM (Rubber canvas), and ocasionally wetted with urine. The goal is to help soil life to regenerate. To have perfect soil, all ingredients should go through the intestinal system of a earthworm. So Biochar particles should be small enough.
First experiments with charged Biochar in the soil are very promising. And using ready Terra Preta substrata after one year the results will be even better.
Terra Preta is not just a fertilizer, it builds permanent fertile soil.

Summary of the Potential of Terra Preta at a glance
– comprehensive improvement of used soils (agriculture and forestry, horticulture)
– increase in areal productivity whilst protecting the resources
– ecological production of food (strong plants)
– comprehensive erosion control (prevention of material losses in the area)
– flood water prevention through high water storage capacity
– climate protection via the fixing of CO² into soils (globally 9.5 gigatons of carbon per year possible!)
– climate protection via the reduction of methane and nitrous oxide in agriculture
– recycling of organic biomass and waste, which are often not disposed off sensibly
– creation of regional value with integrated local production cycles

(source: partly from Wikipedia, the free encyclopedia)