I offloaded the sack in my storeroom.

Now I had fuel that could last me for weeks.

You see, charcoal is our most common fuel in Africa.

And as an ardent African, I would not disappoint.

The charcoal sack weighed probably slightly over sixty kilos.

Each day, I would take a handful of pieces, light up my charcoal stove – which we fondly refer to as a jiko in East Africa – and cook my meal for the day.

Charcoal fuel sustains millions of us in Africa.

But we have just scratched the tip of it’s enormous potential.

AGROWASTE

When we harvest food – or even after eating it – we sometimes remain with waste material that lingers around…

Maize leaves maize cobs and stovers…

Wheat and rice leave behind husks or hulls…

Mangos leave behind mango seeds…

Though my list isn’t conclusive, these waste materials find their use in low value applications like mulching, fillers for livestock feeds etc.

However, what happens when we introduce an element that easily converts these wastes into – literally – black gold?

PYROLYSIS

Pyrolysis is simple using fire to break up matter.

It happens when wood is converted to charcoal…

But it could also work with the farm waste mentioned above, but the only difference is in this case, we’ll not make charcoal but biochar.

Biochar is charcoal made out of natural material other than wood – of course our goal is to cueb cutting down of trees.

So instead, wood could be substituted with the farm waste mentioned above.

Though their raw materials are different, charcoal and biochar have many similarities.

First, they are both black in color – symbolising the presence of carbon.

Second, they are lightweight due to the porosity.

Now this porosity is achieved through the power of heat – it forces volatile materials to escape leaving millions of empty spaces.

Last (but not least) both of them are good sources of fuel.

But let’s set aside convention for a moment.

What innovations are possible with biochar?

WATER

Because of increased porosity, biochar acts as a sieve.

Imagine pouring dirty water through a piece of cloth…

We expect the cloth to trap particles and release cleaner water on the other side.

Now that’s precisely what biochar does when it interacts with water.

Infact a very unique form of biochar called activated carbon has been developed by a number of water companies and sold as filters for domestic use.

Activated carbon is biochar with a very high level of porosity.

It’s been used extensively to remove pollutants from both drinking and waste water.

But its porosity is not only useful in the water front alone.

AIR QUALITY

Urban air pollutants like particulate matter increase the occurrence of respiratory diseases.

Also other forms of pollutants like oxides of sulfur, nitrogen and carbon monoxide make it difficult to enjoy fresh air in a city.

Activated carbon has been tried and tested as a viable absorber for air borne pollutants and has been sold commercially by some companies.

It has also been used as livestock bedding in pig and cattle farming to reduce stinky odors.

But that’s not all.

CARBON CAPTURE

Activated carbon, being highly porous, could be engineered to capture carbon dioxide from air.

I actually learnt that this is an area of active research from a presentation my students were doing.

So the porosity of activated carbon – a derivative of biochar – would prove useful in water/ air quality and climate change mitigation.

But it doesn’t stop at that.

AGRICULTURE

It must be stated that porosity also has a great role to play in application of activated carbon – and biochar – in agriculture.

These pores, could help in:

Storing fertilizer nutrients…

Activated carbon – and by extension, biochar has shown promising applications as fertilizers.

It could be used to trap agricultural nutrients like nitrates and phosphates from wastewater for reuse in the farm.

Creating a home for soil microorganisms…

Porous biochar creates a haven for microorganism colonies in the soil.

Studies have shown the proliferation of good bacteria, fungi and other useful microbes when biochar ir introduced in farming.

Removing pollutants from the soil….

Just like it’s use in water and air quality, activated carbon could be used to ‘suck up’ pollutants from heavily polluted soils.

Water retention…

Again, the pores play a key role in hosting water molecules within them.

This aids in availing water to stressed crops during dry seasons.

But we’re still not yet through with the biochar story…

BATTERIES

Ever opened up a radio battery?

There’s this black matter that looks like charcoal in it.

Believe it or not that substance is charcoal but it could also be known by another name – carbon black.

Carbon black is that black deposit on a plate when you put it at the top of a flame.

But biochar isn’t just useful in radio batteries but also in lithium ion batteries – the batteries that run our phones, laptops and tablets.

Lithium ion batteries are made up of a number of materials like cobalt, lithium, polymers, and…. yes, you guessed it – activated carbon.

Remember that activated carbon is a form of biochar with high porosity. So they are more or less like brothers…

Activated carbon happens to be a good conductor of electricity making it useful in electrical applications like batteries.

And we’ve not even touched the surface of it’s use in cosmetics, pharmaceuticals, and soap industry.

BOTTOM LINE

Agrowaste could be left in the farms to assimilate into the soil structure – a well-known conservation agriculture practice.

It could be assimilated into livestock feeds.

But how can we tap into it’s potential to create higher value products?

That’s the gist of upcycling – a circular economy principle which focusses on conversion of low value waste into high value products.

So next time you see maize cobs, think biochar.

But go beyond thinking biochar…

Think about the products you could derive from biochar…

The water filters…

The air purifiers…

The batteries…

The fertilizers…

And this is not even a conclusive list.

Surely, biochar is truly black gold.