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Passivhouse »Wohnen & Arbeiten«Walter-Gropius-Strasse 22 • D-79100 Freiburg
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Email: post(at)passivhaus-vauban.de • Web: www.passivhaus-vauban.de
Why an Alternative Sanitation Concept?
Today, every reasonably educated citizen of the world knows that we have an energy problem, which every person in the world must collectively try to solve because the available fossil energy resorces -crude oil before others- will soon be depleted. However, only few people are aware of the fact that there is an even bigger challenge in sight, behind the energy problem: Exhaustion of other resources. A severalfold of the needed energy even for our lavish lifestyles can easily be obtained from the Sun. But how is it with other resources such as phosphorus or drinking water?
Let's take phosphorus as an example. In most of the phosphorus reserves on earth, phosphorus is not in its pure stage. Phosphorus usually exists in compounds, and appears in the nature as phosphates. Phosphorus is used by people to make fertilizers (plants need phosphate to grow). We, as humans then eat the plants (or the animals which have eaten the plants), so phosphorus accumulates in small amounts in our skeleton. However, most of the phosphorus we take in is excreted. The excreted phosphate, after being diluted, ends up either in rivers and seas (where it contributes to over-fertilisation) or must, with high expenses, be treated in sewage treatment plants, where it is precipitated using complex chemical methods. In both cases, the phosphorus is not economically available to the people anymore: In the sea, the dilution is too high and the refuse from the sewage treatment plants are contaminated with heavy metals like lead and other materials. As long as this is the case, we need to find more phosphorus to use as fertilizer in agriculture.
Phosphorus is not a rare material like gold or platinum, but 80% of the available phosphorus worldwide is mixed with cadmium. Cadmium is strongly toxic; so only the remaining 20% of the available phosphorus in the world can be used by people. Assuming that the phosphorus consumption in the world stays constant, the phosphorus reservoirs will suffice for another 60 to 160 years, depending on which expert you ask the question to. That means: If we keep on acting like we have been so far, we will not have much to eat in 200 years the latest.
We all know today that there is an energy problem but when are honest, we also know the most important solution: The Sun, which will for sure keep on shining for more than 200 years. It seems to be quite different for the other resources: If we all "consumed" phosporus, it would not indeed disappear, but rather end up in the seas and the hazardous waste sites and not have further economical value to humans. Our "western" canal systems and sewage treatment plants were good advances in the past, however, now they are 100 years old. They devour serious expenses for operation and maintenance. There is 100 years over again for us to replace the system with a circulation system. Our installation is one of the few possible technical solutions to this problem.
Our research installation today is too expensive to reproduce in other houses economically. However, if the installation worked, it would be a
waste-water free house: The black water (from toilets) would go from the biogas plant to the fields and is used for fertilization there, the grey water
(the remaining sewage) is treated on site in a membrane filter and then used for flushing the toilets and for watering the gardens in the summer.
On one side, there is the cost of our expensive installation, and on the other side there is the "eliminated need" for a waste water canal network
(we do not need it anymore!). Many say that our installation can be produced in a more cost effective way, then both alternatives would have
the same price.
Thus, our "KombiVak"- System is a good solution for the waste water problem, at least in the cities.
The sanitation concept, which is implemented through the "Wohnen und Arbeiten" consists of three basic parts:
All three components have different uses:
Next Page: The energy concept of "Wohnen & Arbeiten"
Translation: Selin Devranoglu 2005