Green urban development creates rural employment perspectives - Rural21
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36 FOCUS
Green urban development creates rural employment
perspectives
By creating novel value chains from agro-waste for construction materials, rural areas can significantly benefit from
urban growth. At the same time, opportunities develop for greener and more sustainable construction in Africa’s
expanding cities. Female farmers could especially benefit from these new value chains.
By Wolfram Schmidt, Kolawole A. Olonade, Nonkululeko W. Radebe, Vincent Ssekamatte and Faudhia Zando
T he destiny of sub-Saharan Africa’s (SSA)
urban areas will inevitably be determined
by their surrounding rural areas. They provide
Zimbabwe. A recent
workshop on chil-
dren’s visions of their
the goods that are required and consumed in city of the future at
urban areas, such as food, energy, minerals and the Star Kids Initia-
materials for production. With a growing ur- tive in Mukuru estate
ban population, more rural goods are required. in Nairobi, Kenya,
Therefore, the low capacity for rural livelihood clearly showed that
enhancement along with the dramatic urban the urban children
growth is detrimental to sustainable socio-eco- dreamt of more space,
nomic developments in Africa. plants and animals,
which resembles a
Average annual urban growth in sub-Saharan rural setting rather In Africa, only 20 per cent of the urban structures that will have been installed by
Africa is 4.13 per cent, with a 6.48 per cent than an urban one. 2050 are already built. Construction material is in high demand.
maximum and a 0.14 per cent minimum for In contrast, a simi- Photo: Arne Hoel/ World Bank
Equatorial Guinea and Mauritius, respectively. lar workshop with
In contrast, average rural growth is only 1.95 girls and young mothers at the Forward Step of urban construction will take place over the
per cent, with a 3.77 per cent maximum and Organisation in rural Bagamoyo in Tanzania course of the next 30 years. Although often
a -0.81 per cent minimum for Niger and Ga- clearly showed that the major wishes of the fe- considered as unpopular, concrete is the most
bon, respectively. Although the rural popula- male rural population were closer to an urban feasible material for future cities. Compared
tion is increasing in most countries of SSA, its setting. The most important wishes addressed to all other construction materials, it has the
growth relative to urban growth is dramatical- were infrastructure, water and energy supply, lowest carbon footprint and energy demand.
ly smaller. as well as short distances to services, health and In addition, it is the only resource on Earth
educational facilities. In summary, from the that can meet the tremendous global demand.
On average, the urban population grows 2.12 perspective of their future dwellers, this means
times faster than the rural population, and the that cities should have more rural and villages In Africa, steel has to be imported, and tim-
decreasing livelihood potentials in rural areas more urban components. ber is prohibitive in most countries because of
are likely to increase this ratio in the future. already dramatic deforestation. And although
Service, a typical urban business, grew by Thus, instead of overdeveloping already ur- building heights should generally be limited
12.17 per cent from 2000 to 2018, while the banised areas, the development of rural areas to save materials, building heights are per se
agricultural market dropped by 10.90 per cent becomes vital. The creation of rural employ- limited with timber construction. However,
in the same time. The better urban employ- ment perspectives and better livelihoods is key given the tremendous amount of concrete re-
ment perspectives in SSA are also underpinned to a more balanced development of urban and quired in the world, its binder cement alone
by a service employment growth of 26.91 per rural areas. With the aforementioned limited is responsible for about ten per cent of the
cent compared to a decrease of 14.16 per cent development perspectives in the classical rural global carbon emissions. Future African urban
in agriculture. Furthermore, the income gap business areas, it becomes necessary to identi- concrete construction will significantly add up
and the number of people below national pov- fy new perspectives, which lie in the synergies to this already high climate impact. In return,
erty level are much higher in rural areas. between urban growth and rural development. Africa also has more potential than any other
region in the world to invent green and low
carbon concrete innovation, by applying state-
Making use of synergies between Climate-friendly construction of-the-art knowledge and using local supplies
urban and rural development materials offer new income sources in an innovative way.
Nevertheless, the better urban potentials do The most relevant employment and business In order to identify where urban construction
not always result in better living conditions. perspectives in growing African cities results can create rural development perspectives, it
Approximately 60 per cent of SSA’s urban from the sheer need for construction materi- is important to understand typical rural econ-
population live in low-income, disadvantaged als. Only 20 per cent of the urban structures omies. Agriculture usually accounts for about
settlements, with a maximum of 96 per cent in that will have been installed by 2050 are al- 60 to 80 per cent of the livelihoods. Mining is
South Sudan and a minimum of 18 per cent in ready built. In return, this means 80 per cent another major contributor. Retail, administra-
RURAL 21 02/20 37
tion and social services are significantly less im-
Possible climate friendly and low-emission processes from agro-waste to
portant. Therefore, the large branches should
construction materials
be focused on. With regard to potentials in
mining, novel future perspectives lie in choos-
ing clays that cannot be used for ceramics but
can perform excellently as cement replacement
after calcination.
However, one largely neglected available re-
source is agricultural waste materials, which
can be converted into high-performance
concrete constituents. The African continent
provides about 60 per cent of the global un-
used arable land. Most agricultural waste from
food production has a high content of organ-
ic residues. Although they cannot be used for
food, they can still serve as water-reducing or
robustness-enhancing admixture in concrete,
and thus contribute to higher performance
with less cement consumption. These agro-
based organic admixtures can create new and
local business opportunities by replacing crude
oil-based agents, which today in Africa have to
be imported at high prices.
lel to the burning of clay bricks or the energy right value chains in the urban construction
While construction chemicals are a small and can be used for food processing. An ideal pro- business, formerly unused rural wastes can be
specialised market, cement is a high-volume cess with a maximum yield of by-products and converted into cement replacement materials,
market. Therefore, the most relevant resource minimum carbon emissions can be obtained if construction chemical, energy and precursors
is ashes from agricultural waste, which occurs the agro-waste goes through a pyrolysis pro- without creating additional competition. This
in vast amounts and today is not used for oth- cess before being burnt to a reactive ash. This way, rural farmers can significantly enhance
er technologies. If agro-waste is burnt at tem- process produces pyrolysis gas (energy), pyrol- their livelihoods and in parallel contribute to
peratures between 600 and 800 °C, it often ysis oil (chemicals), as well as a bio-char that reduced emissions of climate gases.
contains significant amounts of reactive silica can be further processed as fertiliser or cement
and alumina oxides, and thus can replace Port- replacement. In order to prove the concept,
land cement clinker in concrete by up to 30 a small-scale 2-stage pyrolysis plus kiln pilot Value chains based on cassava waste
per cent or more. plant was built recently on the campus of the in Nigeria
University of Ghana within the context of the
In order to make maximum use of the process, INFRACOST project, funded by Germany’s Cassava is a staple food for over 500 million
the burning of the ashes can be done in paral- Federal Ministry of Education and Research people in the world, and it represents a source
(BMBF). An ex- of food for about 80 per cent of people in
ample of the larger SSA. It is a cheap provider of carbohydrates
Possible climate friendly and low-emission processes from scale coupled with that grows on marginal soil without complex
agro-waste to construction materials a vertical shaft kiln processing. Besides food, cassava starch has also
technology is given been established in paper, textile and pharma-
Existing employment Urban growth New employment
in the upper Figure. ceutical industries. Africa accounts for nearly
potentials perspectives in innovative
and green urban materials 60 per cent of global production. With its
Wastes such as sug- 56 megatons per year, which is 35 per cent
ar cane bagasse, of the African and 20 per cent of the glob-
rice husks, cassa- al production, Nigeria is the largest producer
va peels or palm world-wide. Since cassava has relatively thick
kernel excellent- peels, the waste represents up to 20 per cent
ly qualify as green by mass of the tuber, which today creates large
Portland cement challenges of effective disposal. The peels do
clinker replace- not qualify for livestock feeding, as they can-
ment. Normally, not be well digested and contain low protein.
these wastes have Typically, they are dumped in landfills, burnt
no or low-value uncontrolled, or just left to rot. This causes
use today. Howev- malodour and environmental pollution, and
er, as shown in the it requires plenty of space which could be
Figure on the left, made better use of. There is no significant val-
Rural development by developing the ue chain for the wastes to date, although they
38 FOCUS
civil and environmental engineering, econom-
ics, agriculture, materials and chemistry.
Seizing the opportunity
By creating novel value chains from agro-
waste to construction materials, rural areas
can significantly benefit from urban growth
and contribute to greener and more sustain-
able construction in Africa. This can also be
a potential to accelerate rural development,
which in return would reduce the driving
force for migration to cities. Since one-fit-all
Kolawole Olonade and students of the University Cassava peels could be used for high-performance solutions for agro-waste value chains do not
of Lagos during a workshop on the development urban construction materials, providing income for exist, best-practice solutions have to be devel-
of high-strength self-compacting concrete with female cassava processors. oped individually, based on the local boundary
cassava peel ash. Photo: Wolfram Schmidt framework. These must be worked out in close
Photo: Wolfram Schmidt
collaboration with local academic units, which
are typically located in cities. Hence, the de-
could be used entirely for high-performance be used either on a small scale by formal or velopment of construction materials based on
urban construction materials. Firstly, the starch informal smallholders, or by the large cement agro-waste offers a unique opportunity for
adhered to the peels can be dissolved and con- industry, where the cassava peel ashes could be business and knowledge transfer between rural
verted to a plasticising chemical admixture blended with cement to be sold in the national and urban areas with mutual benefit, and with
which has proven to have the capacity to re- and international retail market. This would re- a highly positive impact on the global climate.
duce the water content in concrete to increase quire complex waste collection infrastructure
its strength. Secondly, the residual peels can be and homogenisation. Smallholder producers
burnt, and the residual ashes can help replace could directly use the ashes to reduce their ce- Wolfram Schmidt is a researcher at Germany’s
cement in concrete in an environmentally ment in concrete for the local market, but un- Bundesanstalt für Materialforschung und
friendly manner. like in the large-scale industry, more training -prüfung (BAM) in Berlin, Germany, with focus on
and technical support would be required. sustainable construction materials. He has initiated
While the technical potential has been proven several pan-African research and education
scientifically before, the socio-economic and collaborations.
climatic impacts are the topic of research with- Obstacles and skill requirements Kolawole Adisa Olonade is a senior lecturer in civil
in the Local-Care project, which was award- engineering at the University of Lagos, Nigeria. He
ed the German African Innovation Incentive The biggest obstacle for the implementation of has been involved in various pan-African research
Award of the BMBF in 2018. Within the proj- such green construction materials techniques collaboration schemes, and together with Wolfram
ect, for the first time, a real structure made out is the societal misconception that agricultural Schmidt, he was awarded the German-African
of cassava-based concrete (see left Photo) will waste products only qualify for low-end use. Innovation Incentive Award in 2018.
be built in 2020 on the campus of the Univer- Furthermore, and despite the striking added Nonkululeko Winnie Radebe is a 3rd year PhD
sity of Lagos – an important matter, because values that can be created, new technologies student at the Karlsruhe Institute of Technology,
research innovation needs tangible pilots in are always accompanied by yet unknown chal- Germany. She is working in the Institute for
order to find acceptance in society. lenges. Typical challenges arise from residues Technical Chemistry and Polymer Chemistry.
of fertilisers as well as scattering qualities and Faudhia Zando and Vincent Ssekamatte are
In this project, a survey among 200 cassava production volumes. These obstacles can be initiators and chairpersons of the Forward Step
processors in Nigeria indicated that 81 per cent solved technically but require research and in- Organization, an empowering and mentorship
were females, mostly between 20 and 50 years terdisciplinary competences. centre for girls and young mothers in Bagamoyo,
of age. Approximately 75 per cent only had Tanzania.
primary education, and thus little potential to Therefore, the knowledge has to be brought Contact: wolfram.schmidt@bam.de
enhance their livelihoods. The revenues from to the prospective rural decision-makers, who
the peels were marginal. Less than 20 per cent need a clear picture of the economic and socie- Acknowledgements:
were sold. Hence, at least 80 per cent would tal potentials of agro-based construction materi- Parts of the presented works on kiln processes and
be available for the cement and concrete in- als markets. Despite new income sources, these cassava peel processing have been developed within
dustry, which could enhance the potentials for markets also help to empower female farmers the projects INFRACOST and Local-Care, respectively.
better livelihoods of the local producers sig- and create more independence, which is of ut- The authors highly appreciate the funding provided
nificantly. Assuming that all available peels will most importance in the rural environments. At by the German Federal Ministry of Education and
be collected and used as sustainable cement the same time, decision-makers need clear in- Research in the schemes CLIENT II and GAIIA.
replacement, this would translate to 2.5 to 5 formation about technical challenges and infra-
per cent of the Nigerian cement market, or structure that has to be established prior to im-
approximately 0.7 million tons of saved car- plementation. This requires closer collaboration
References: www.rural21.com
bon emissions. Both peel ashes and starch can with academia and relevant disciplines such as
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