What better way to grow personal, communal and national wealth than converting waste into valuable products.

And that’s what this article is about.

How can we practically take what’s rejected  and convert it into what’s really needed?

That’s the gyst of circular economy – and more precisely waste valorization.

Can we derive value from agricultural waste?

I mean real V.A.L.U.E and not just value.

So what are the possible high value products we could make?

Let’s explore this space.

1. CELLULOSE

All plants have cellulose.

That’s why it’s the most abundant naturally occurring polymer on earth.

But before walking through it’s extraction, what are some of it’s uses?

Packaging comes to mind.

The material is tough as nails so it’s great for paperbags and other packaging material.

And what makes it a better packaging material than plastic is it’s biodegradable.

Besides, it’s also a good water treatment membrane.

So how is cellulose made from a mound of agrowaste?

Well for starters, some waste will give higher yields than others – but all this could be assessed through experimentation.

Also remember that these processes are sort of mini-manufacturing in nature and will require some chemical inputs.

First, the waste should be cut into small pieces and washed.

Secondly, pretreatment with a strong alkali will help breakdown lignin and hemicellulose – the tough stuff in plants.

After this step, one could bleach the material then put in the mix a strong acid for conversion to nanocellulose.

2. SILICA

Silica comes naturally in the form of beach or construction sand.

But since sand harvesting is frowned upon, what if we make our own silica from one of the most abundant agricultural waste around – rice husks.

But before we go deeper, what are some uses of silica?

Fertilizer, humidity absorber, water filter, insulator etc.

So how do we make it from husks?

After washing the husks, treat them in a hot alkali solution to dissolve the silica.

Filter off the reacted rice husks because you are interested in the liquid.

Add an acid to the liquid part (which contains dissolved silicate) converting it into solid silica.

Lastly, wash the silica to neutralize it then use it for your application of choice.

P.S. Silica could also be converted into silicon which has energy applications in solar panels and possibly batteries.

But this would require highly specialised furnaces that allow heating in absence of oxygen.

Silica from rice husks could also be converted into a form of pozzolan cement although its a subject of research.

3. SUGARS

“Sugars?”, you ask…

Oh yes.

Imagine fruit wastes such as mango, pineapple and banana peels.

They contain considerable levels of sugars which could be extracted and reused in food, beverage and supplements.

One of the recommended ways of extracting these sugars us using water.

Just place your waste material in a water bath and heat it to extract as much sugar as possible.

This is because mangos, bananas and pineapple waste contain simple sugars which need no further conversion.

Once extracted, the sugars could be recrystallized (through lowering of temperatures) before being used.

4. BIOCHAR

Biochar is basically charcoal from sources other than trees.

What are it’s uses?

Well biochar is a great soil amendment used in agriculture.

It’s also a great water filter material and a source of energy.

So which wastes are useful for biochar production?

Well basically any dry agrowaste.

For best production, a top lit updraft (TLUD) stove is useful – but waste like rice husks could be converted into biochar in the open.

Biochar making is not complicated at all.

However ensure that you do it away from residential areas because it could be fumy in nature.

Basically, production is done through burning biomass (agrowaste) under low oxygen – in the same way charcoal is made.

There’s some research pointing to biochar as a useful material in the making of batteries of the future.

5. PARTICLE BOARDS & UTENSILS

Small sized waste materials like rice husks could be stuck together using adhesives like starch to form particle boards.

Alternatively, the rice husks could be pulverised and used to make plates, spoons, lunch boxes etc.

Infact this is a business model a number of start ups have explored successfully.

What makes rice husks good for these applications is it takes time to breakdown and it’s from natural sources.

6. BIOETHANOL

This renewable form of energy is gaining traction day by day.

And talk of renewable energy isn’t complete without bioethanol.

What’s bioethanol?

It’s ethanol derived from natural sources.

And in this regard, sugarcane and pineapple waste rarely disappoint.

The rise of sugarcane juice parlors makes this an opportunity waiting to smile on anyone willing to collect the waste and create a value chain out of it.

How?

First, the sugarcane waste is washed then pretreated with an alkali to breakdown the tough parts into cellulose.

Now the second and third steps require some  financial commitment.

The second step involves introducing an enzyme called cellulase into the mix to facilitate breakdown of cellulose to glucose.

Commercial enzymes are available in the market.

Lastly, the glucose – and other simple sugars – are converted to bioethanol using the action of commercial yeast – or hamira as it’s known on Swahili.

The bioethanol is collected by distillation.

Though the process looks straightforward, it’s commercialization is inhibited by a low percentage yield.

So repeated attempts of extraction are necessary to obtain a good yield.

7. ANTI-OXIDANTS & ESSENTIAL OILS

This might look daunting but it actually isn’t.

Imagine a pineapple fruit peel.

It naturally contains active agents known to fight diseases and improve the general health of individuals.

Now this cuts across many fruit and vegetable wastes.

One good way of extracting such agents is through the use of heat.

But some of these useful agents could be extracted in the form of essential oils.

Essential oils are natural oils which could be found in some fruit wastes such as orange and lime peels.

They help fight disease, improve flavor and improve fragrance of lotions etc.

8. COMPOST

We all desire quality food.

But quality food doesn’t come cheap because it involves several inputs such as quality seeds, water, fertilizer and compost.

Compost is not optional in the world of agriculture…

It’s necessary if we’re to farm in a sustainable manner.

It comes from food waste or livestock manure aged in a deliberate way though the action of water and air to produce a deep brown colored substance that not only improves soil nutrition but microbiology also.

Compost is a value product because one could use it for growing crops even where no soil exists.

In other words, it helps conserve our soils and boosts its fertility at the same time.

9. BIODIESEL

Biodiesel is different from bioethanol.

Bioethanol is manufactured.

But biodiesel is simply extracted from oil rich seeds such as castor oil, jatropha and croton.

Also food crops like sunflower are still useful in its production when though this might compete with food needs.

So it’s better to use non- edible seeds or waste such as avocado seeds (which could contain considerable fat levels) to extract biodiesel.

Biodiesel is a useful additive to diesel in vehicles and industry.

10. PROFITABLE INSECTS

Agrowaste need not rot and attract flies, rodents and diseases.

It could be converted into useful protein and vitamins using natural engineers – insects.

Black soldier fly larvae are known to feast on rotting garbage – the kind found in the kitchen bin.

And as they do this, these larvae fatten in the process.

They accumulate high amounts of proteins, carbohydrates and fats useful for growing chicken.

When they mature, these larvae are harvested, dried then used to make chicken feeds.

The same could be said of crickets which are profitable insects that also convert trash into proteins and nutrients available for chicken to feed on.

But crickets could also form a delicacy for people and are gaining traction as a formidable substitute for other protein sources on dinner tables.

11. ALGAE

What do you do with the excessive manure in your farms?

Well it could be applied to soils to grow crops but is that all?

With space, one could make ponds and use the manure as a nutrient source to grow azola, an algae that could be harvested to feed chicken.

IN CONCLUSION

These aren’t the only value chains that could be drawn from agro waste.

Many others exist.

But these could jog up our minds to think of making money out of agrowaste.