EcoSanitation: Trading “Flush and Forget” for “Cycle and Sow”

“Flush and forget” or “drop and store” are some of the most common strategies for human waste “treatment” around the globe. These approaches can be seen in massive sewer systems that exhaust effluence away from communities, septic systems that hide and diffuse material locally, and common pit latrines that simply hide and cover the waste. These methods do not treat the waste so much as bury it or move it to another place in the world where it may become someone else’s problem. In doing so, households and communities are missing an incredible opportunity to turn waste into nutrients that can improve public health and reduce hunger.

EcoSanitation is a closed-loop concept of sewage treatment that employs the planet’s natural hydrological cycle to close the gap between sanitation and agriculture. The hydrological cycle, a term we use to illustrate the paths of water between atmosphere, earth and oceans, includes the essential process of evapotranspiration. Evapotranspiration is the sum of water transfer to the atmosphere due to evaporation (from soil) and transpiration (from the metabolic processes of plants). This naturally occurring phenomenon, which separates water vapor from organic material, can be harnessed to safely process the nutrients of human waste while supporting the growth of edible fruits and vegetables.

Read more: EcoSanitation: Trading “Flush and Forget” for “Cycle and Sow” @ Engineering for Change.

Scientific Authority and Media Visibility of Climate Change Scientists and Contrarians

“We juxtapose 386 prominent contrarians with 386 expert scientists by tracking their digital footprints across ∼200,000 research publications and ∼100,000 English-language digital and print media articles on climate change. Projecting these individuals across the same backdrop facilitates quantifying disparities in media visibility and scientific authority, and identifying organization patterns within their association networks.”

“Here we show via direct comparison that contrarians are featured in 49% more media articles than scientists. Yet when comparing visibility in mainstream media sources only, we observe just a 1% excess visibility, which objectively demonstrates the crowding out of professional mainstream sources by the proliferation of new media sources, many of which contribute to the production and consumption of climate change disinformation at scale.”

Source: Petersen, Alexander Michael, Emmanuel M. Vincent, and Anthony LeRoy Westerling. “Discrepancy in scientific authority and media visibility of climate change scientists and contrarians.” Nature communications 10.1 (2019): 1-14. Thanks to Julie Molinié.

Making a Cooling Chamber for Tomatoes

When you pick your tomatoes, if you want to keep them longer, you have to find a way of reducing the temperature. As availability of electricity at village level can be a problem, ways have to be found to lower the temperature of this fragile crop. Some farmers at Dambatta in Kano State, Nigeria have used local mud bricks to make a very effective cooling chamber. Watch the video at AccessAgriculture. Via Practical Action.

Tech Talks

Last week, I spoke at The Conference in Malmö, Sweden, where I saw quite some interesting tech talks. The super-efficient Swedes have already uploaded them, so I present you some of my favorites:

Next week, I’m doing a talk in Paris. Knowing the French a bit, these videos will never be uploaded, so be there.

Off-Grid, Solar-Powered, Zero-Battery Refrigerator

Joey Hess has designed, built and tested an off-grid, solar powered fridge, with no battery bank. Using an inexpensive chest freezer with a few modifications, the fridge retains cold overnight and through rainy periods. The set-up consists of a standard chest freezer, an added thermal mass, an inverter, and computer control. He writes: [Read more…]

Foaming of Recyclable Clays into Low-Cost Thermal Insulators

“Thermal insulators are crucial to reduce the high energy demands and greenhouse emissions in the construction sector. However, the fabrication of insulating materials that are cost-effective, fire resistant, and environmental-friendly remains a major challenge. In this work, we present a room-temperature processing route to fabricate porous insulators using foams made from recyclable clays that can be locally resourced at very low costs.”

Read more: Minas, Clara, et al. “Foaming of Recyclable Clays into Energy-Efficient Low-Cost Thermal Insulators.” ACS Sustainable Chemistry & Engineering (2019).