FOR many communities the invasive exotic lantana camara plant or shrub is a common enemy, given its poisonous effect on the natural ecosystem and a threat to grazing land.
Also known as “black cherry” (ubuhobe in IsiNdebele and rukato in Shona) the plant is found in many parts of Zimbabwe especially along rivers and small streams where it can grow up to above two metres tall, forming a dense and impenetrable thicket that suffocates indigenous vegetation.
According to environmental researchers, once the lantana plant invades an area, it smothers trees with adverse negative impact on local bio-diversity, which results in diminishing pastures for livestock or wildlife.
While many people have been oriented to instantly dig out and destroy this shrub, Fortune Mswathi Donga (26) from Nkayi, says the plant can be harnessed to unlock huge economic value – through powering biogas energy plants.
The initiative to design this prototype machine came about during the Covid-19 lockdown last year. During this period, the Applied Chemistry graduate from the National University of Science and Technology (Nust), said he examined the challenge of lantana camara and vast bio-waste in Nkayi and other areas in the region. He said he observed that the district has a lot of untapped biomass waste with the local timber processing company also disposing huge quantities of it in landfills or through incineration.
“I thought about how this biomass waste can be turned to use and be harnessed for economic value. I then focused myself on designing a prototype biomass machine, which can pump up to 60 000 litres of water per hour, and could be scaled up for use on larger commercial projects in mines and irrigation schemes,” said Donga.
“This is a machine prototype that harnesses energy in dry biomass and puts it into productive use. Biomass is a broad and specific term referring to any naturally existing hydrogen and carbon-based material, solid material like wood, shrubs, animal dung and anything that is animal and plant matter capable of decomposing.”
Out of passion and using his university knowledge and exposure from industrial attachment the youth innovator said he started gathering different materials, including a small water pump, to design the prototype machine at his father’s metalwork shop near Nkayi Business Centre.
“I fabricated some components at our shop and managed to build and finish the prototype plant within a month. Now this is the combined biomass convertor and water pump unit,” he said.
“The biomass consumed by this machine prototype includes bio-waste generated by timber and furniture industries – wood cuttings, offcuts, shavings, animal waste, plant remains and invasive plants like lantana camara.
“The particular prototype can be used on irrigation pumps and mining. This can also be tested to higher capacity of generating electricity, which proves that the innovation is adaptable to mechanical power and generation of higher grid.”
Donga said the prototype could work on a continuous operation basis through a manually initiated process by striking a match or lighting that initiates the combustion processes, which provides necessary conditions in the reactor.
“The combustion engine fuelled by the system can be started after three to five minutes, then biomass is fed at any time occasionally during operation without shutting down the reactor,” he said.
“By products (ash and char) can be withdrawn after shutting down the whole system. The prototype is designed to separate spent biomass automatically during operation and can operate for many hours and, if design tweaked can work for days.
“Refilling of biomass is done occasionally so that the fresh biomass in the reactor is available throughout operation.”
To the young innovator, this system is “infinitely beneficial” to the users and more environmentally friendly. Because biomass is not just cheap but free, Donga says this means that the very first noticeable benefit is that whatever production system this innovation is applied to, operates for free – at zero dollars per kilowatt.
“Secondly, the system reduces/eliminates dependence on production from costly and inconsistent power supply and liquid petroleum fuels from filling stations,” he said.
“Thirdly the system is carbon neutral when it comes to emissions, which means it is efficient and healthy. Further, this system is mobile and portable, which means one can take it for a remote operation whether there is power or not, even in the jungle.
“With this innovation you don’t use a drop of fuel, it’s mobile, zero carbon footprint to the atmosphere and most certainly vast swathes of lantana camara in the bush can be used for this.”
As the country thrives to transform the economy into an upper middle-income economy by 2030, Donga says developing sustainable and cost-effective energy sources is critical, and believes his innovation could add more value.
“Where pollution is a public enemy and many people struggle to pay for things like electricity bills and water bills, everyone wants profit. I saw that there are power supply gaps and high tariffs in Zimbabwe,” said Donga.
“This heightens demand for alternative energy as conventional petroleum fuels are inconsistent and costly. And yet the invasive plants like lantana camara and the biomass we produce as waste are being lost with tremendous amounts of energy.
“This needs to be harnessed somehow and I happened to think that lantana camara being a problem is being cut down just to be destroyed and this is not enough motivation.
“If it can be used as a fuel, I am sure everyone will be glad to cut it down and reap benefits at the same time. This prototype machine is the proof of the credibility of the concept,” said Donga.
He said that the process of establishing the plant also proves that Zimbabweans can develop domestic solutions with little import component, which will save the country from loss of forex resources.
Donga said he was ready to showcase his designs to innovative hubs at universities and assist entities that might be keen to tap into the benefits of the initiative.
The youth innovator grew up in Gwamayaya area under Chief Sikhobokhobo in Nkayi and did his primary education at Gwamayaya Primary School and proceeded to Hlangabeza High School for secondary education up 2014. – Chronicle