Low-tech solutions for sustainable living in the West

How we can reduce our carbon footprint with appropriate technologies

In our earlier article: “Achieving high-tech quality with low-tech solutions” we covered solar cookers, including solar-powered kitchens. We dedicate this space to another low-tech solution: biochar filtration systems and activated carbon filters. They both drive the carbon footprint down in water and sanitation in western households filled with high-tech gadgets. Our star pick is a Biochar water filtration system.

However, by installing either of the two water filtration solutions in our homes and workplaces, we can enjoy guilt-free, refreshing water that is pure. Water that doesn’t literally cost the Earth because we keep all those plastic bottles, that would normally wind up in our city landfills, out of them. We briefly look at the pros and cons of the two solutions discussed here.

Why it matters to you and your family

“2 billion people without sufficient access to water leading to 343 conflicts worldwide.” (Pacific Institute, 2018 Report).

“1 in 3 people globally still do not have access to safe drinking water.” (WHO’s 2019 figures)

“90% of the global economy and 78% of jobs worldwide depend on access to enough water of the right quality.” (Water Europe Water Vision 2030 and UNESCO)

Annually, European water services invest approximately €45 billion in water infrastructure, suggesting that €93.5 is invested per inhabitant, per year according to EurEau’s (European Federation of National Associations of Drinking Water Suppliers and Wastewater Services). These are phenomenal costs given that only just over half of wastewater is treated sufficiently to be used again.

How can we access drinking water that is alive and life-sustaining at the same time?

“On average, Europeans consume 128 litres per person daily.” (EurEau survey, 2017)

A deeper look into the costs of drinking water investment in different countries across Europe reveals that they are not recovered, and many countries fall behind the European regulations whilst the rising prices of water are the norm. The feeling all around is that we need a re-think of about every process of water cycle; how water is used, managed and recycled.

“When the well’s dry, we know the worth of water.”

– Benjamin Franklin

Why is the drinking water, treated at high cost to us and the environment, still used for bathing and showers or doing laundry? Significant savings are possible if households switch to biochar filtrations systems for drinking water. Certainly, we can reclaim rain water or surface water from streams using this method. For example, many homeowners do this in arid areas of southern Spain, as droughts are commonplace. Therefore, saving water is key to survival of man and livestock. These systems work in similar ways and are based on a roof capture where water is stored in an underground tank and then filtered inside a house.

“60% of sludge (wastewater) is reused.” (EurEau survey, 2017)

Star solution 2: Biochar water filtration system

Gravity-fed biochar systems are a good low-tech alternative to the conventional systems, particularly in regions where no, or very little, water is treated. Four tanks-barrels form this simple system. Naturally, four types of filtration media differ in diameter; from large stones to gravel to sand and small size biochar pieces. Further, such tank system is connected by pipes allowing the water to be fed through it. Finally, the water ends up in the fourth, clean water tank ready for use by a household. Pipes, which connect the tank, allow the feeding of water through the system without any pumps. The barrels, which sit on the roof and filter the water, are just food-grade plastic. Most importantly, we can assemble the different parts together into a system without power tools. You will need an angle grinder though if you attempt to make a double-drum kiln from recycled drums.

Biochar filters achieve water purity by natural design

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Biochar-based systems work in similar ways to the activated carbon systems. They achieve comparable, if not better, rates of filtration at zero energy inputs as generally they do not need pumps. Although they will require electricity if the water has to come to the site from a stream or other source.

Two greatest advantages are:

1. Systems can be built in a few hours.
2. Filtration units do not require any mechanical parts that can break.

This repair-free system offers an ideal solution for resource-conscious people and poorer communities. The maintenance, which involves replacing biochar, falls in ranges of 4, 6 or 12 months after constructing a system. However, this tends to depend on the breakdown rates of the pollutants in the treated water. Decentralised bio-filtration systems, (as featured in the picture above), developed by Aqueous Solutions, produce 300L and 2000L of drinking water. Although they are too large for a small household’s drinking water needs, the designs can be adapted at the house level.

How biochar filter works

Activated carbon filters are the most common type of filters that give us clean drinking water in our homes today. They rid water of chlorine, bad odours and tastes by locking pollutants in a carbon substrate.

Filtration is not always perfect though, as they can leave behind salts and some inorganic pollutants. For instance, heavy metals from mining, agriculture and pharmaceuticals can fall through the ‘carbon mesh.’ In biochar systems, the purification process works the same. Highly porous biochar particles store pollutants within their mesh.

Are biochar filters a better solution than activated carbon filters?

The key difference between these systems is water flow speeds, which impacts their effectiveness. To learn more about specifications of each filter we can go to product developer’s website. Unlike its counterpart, the biochar system works independently of the water mains. This means that we can regulate the water flow unlike with on-grid filtrations systems. To clarify, in on-grid setup water comes in at high pressure and flows through the system too fast to allow enough time for the activated carbon to do its job well. The advocates of biochar systems argue that they are superior to the standard carbon filtering due to these better adsorption rates for certain contaminants.

How biochar filter is a zero waste solution

A big drawback of carbon filtering is waste creation. Tons of plastic cartridges that encase the carbon need replacing and recycling every year. Also, unlike charcoal, biochar burns clean so it gives off little, or zero, CO2. Modern biochar ovens capture gases for heating so nothing goes to waste. Thus, environmentally, biochar system scores higher. It truly is a zero waste product. Another plus is that if you own such a system, you can make your own biochar in your yard. Or you could purchase it from the community thus supporting green jobs locally. So, combining these improved systems with the existing ones makes a good economic sense in terms of green jobs’ creation.

Biochar – an ancient carbon sequester

It is possible to sequester (remove from the atmosphere) historic carbon emissions as carbon in biochar remains stable for millennia.

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Scientists have found charcoal particles, as old as 400 million years, in sediment layers from wildfires, at the onset of a life on earth. The indigenous people used biochar to fertilise the rainforest soils of the gardens that they planted in the forest.

How do we make biochar?

Biochar is made simply by charring (the pyrolysis) anything organic, i.e., dry wood, hay, bones, timber by-products such as chips and sawdust. This takes place in a two-drum, vacuum sealed charcoal retort (kiln), using high heat.

NASA developed the process of retorting in order to preserve the natural flavour and nutrition in the freshest ingredients. In addition, high heat, which develops in multi-layer tubs, sterilises already cooked meals. Likewise, heat and gasses cook organic matter such as timber in a low oxygen environment into a BIOCHAR ‘meal’ for plants or bio-filtration.

Benefits of ACTIVE CARBON in biochar:
• increases crop yields
• improves nutrient absorption by promoting soil microbes particularly mycorrhizal fungi
• retains moisture, helping plants during drought and helping you save water
biochar production makes biofuels
• reduces soil & water pollution by lowering fertiliser leaching from the land
the heat captured during the pyrolysis generates electricity

Biochar making is a rewarding activity although it requires some practice. My volunteering team and I made a lot of this brilliant garden fertiliser at our former HQ –The Centre for Natural Design & Innovation in Spain.

There are videos that teach how to make your own biochar. All you need is a couple of old metal drums, cutting tools and organic waste to burn. Have fun with using biochar, and please share your experience of making it with us and the readers in comments below.





Images: Featured image of Home-made biochar for plants, Charring wood to make Biochar in a home-made retort  & Crushing biochar images by Earthvoice.  Biochar water treatment unit image from Aqueous Solutions.