LOW-TECH MAGAZINE

Urban Fish Ponds: Low-tech Sewage Treatment for Towns and Cities

In the mid 20th century, whole cities' sewage systems safely and successfully used fish to treat and purify their water. Waste-fed fish ponds are a low-tech, cheap, and sustainable alternative to deal with our own shit -- and to obtain high protein food in the process.

The solar envelope: how to heat and cool cities without fossil fuels

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Architects all over the world have demonstrated the usefulness of buildings which are heated and cooled by design rather than by fossil fuel energy. What has received much less attention, however, is the possibility of applying this approach to entire urban neighbourhoods and cities.

Designing a single, often free-standing, passive solar house is quite different from planning a densely populated city where each building is heated and cooled using only natural energy sources. And yet, if we want passive solar design to be more than just a curiosity, this is exactly what we need. Modern research, which combines ancient knowledge with fast computing techniques, shows that passive solar cities are a realistic option, allowing for surprisingly high population densities.

Illustration by Diego Marmolejo for Low-tech Magazine.