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[44 20 8452 2729]ISIS Report 30/09/09
The Community Cooker Turns
Rags to Riches
An extraordinary recycling
project turns rubbish into energy and potentially
transforms slums into resource rich communities Sam Burcher
A fully illustrated and referenced version of this paper is posted on ISIS
members website. Details here
The disturbing scenes of human
deprivation in the highly acclaimed movies Slum
Dog Millionaire and The Constant Gardener [1]
show the real-life slums in India and Africa
overflowing with people and with refuse.
But what if the piles of stinking rubbish could
be converted into what urban slums need most of
all: hot water for washing, pure water for
drinking and heat for cooking?
Nairobi-born architect Jim
Archer has designed and implemented with the help
of his Kenyan fellow Director Mumo Musuva and
their Planning Systems Services team the 2008
World Architecture Festival (WAF) award-winning
project in Kibera, Africas largest slum,
which does just that. The locals in the
Laini Saba district in Kibera have been
instrumental to the success of the project they
call the Jiko ya Jamii, that
translates from Swahili into the Community
Cooker.
Agnes Aringo is a caterer at
Jims architectural firm in Nairobi.
She works on the community cooker and reports [2]
that the cooker is versatile, and that it
boils water, cooks vegetables, stews beef, bakes
cakes, fries food, and can be used to prepare
breakfast, lunch and dinner, and make cups of tea.
The two ovens cook cakes very quickly and each is
large enough to grill a whole goat. You
cant tell that the fuel used to cook this
food is the waste products from the slum. Agnes
says, Nothing is thrown away or should be
thrown away in our environment.
The community cooker in use
A community-led cooker
The slum dwellers themselves
have solved several of the practical problems
presented by the cooker project. Volunteers from
various local youth groups collect, sort and
store the garbage in metal racks adjacent to the
cooker where it can dry. Materials that
cannot be burnt such as rubber and glass are put
to one side. Biodegradable scraps that fall
through become compost manure [3].
The really useful solid waste
materials like paper and plastic bags,
drinks bottles and packaging - and food
scraps from banana, cassava, maize cob and
sugarcane peel, sawdust and even the discarded
carrier bags of human and animal excrement
colloquially known as flying toilets
are forked up to the top level of the racks ready
for incineration. All these items would normally
be left to rot in the street, thrown into water
courses, or dumped in local rivers.
At first, Jim was baffled as
how to reward the sorters for their time and
effort. Its very simple, they
said. We will do the sorting for the public
from say 6 am until midnight. But from
midnight until 6am we will work the cooker for
ourselves. We will make bread and we will
bake buns and we will heat water. We will sell
these and thats how we will make our money.
From that moment on, Jim knew they had a working
project.
Two simple taps are the only
moving controls on the cooker, which has
deliberately been kept very, very simple to
operate and to maintain. One tap controls a
drip flow of recycled sump oil (dirty and
discarded oil from vehicles) and one tap controls
a drip flow of water. A drop of each falls
in equal amounts onto a heated steel plate at the
face of the firebox, where the water vaporises
into hydrogen and oxygen, which causes a
combustive reaction with the flames and increases
the temperature. As the firebox gets hotter
it heats the network of steel pipes that pass
around the cooker. This resourceful technical
innovation was the idea of a local man and self-taught
furnace builder Francis Gwehonah, who has helped
double the firebox temperature from 300oC
to 600 °C.
How the community cooker cooks
The cooker is made entirely of
welded steel and has eight circular hotplates on
the top. This is similar to a
traditional hob design except that
the big metal cooking pots can be partially
submerged into the hotplates to gain and retain
heat from the firebox below. Hot food is served
directly from the saucepans, or can be taken back
home by the person who has collected rubbish, or
purchased a token to exchange for cooking time.
The cooker has two ovens under the hob, one
either side of the firebox.
A tall and narrow chimney rises
out of the firebox between the hotplates and
reaches high above the slum. White vapour emerges
like papal smoke wafting away the almost
odourless fumes from the spotlessly clean kitchen
area. Sliding down below the hob, a wide metal
chute feeds a constant supply of rubbish from the
storage racks into the fireboxs hungry
flames.
In theory, the community cooker
should be operated 24 hours a day providing there
are people to collect, sort and burn rubbish. A
by-product of the incinerator-like cooking
process is the relatively small amount of ash
that collects beneath the firebox which it is
hoped will undergo a second transformation into
material to reduce fly menace in pit latrines and
the smell from open sewers, once toxic levels of
the ash have been tested and if found acceptable.
Hot water for washing
It costs Sh5 (5 Kenyan
shillings, about US$ 0.06) to use the cooker to
make a family meal. A local woman Elizabeth
Mumbi reckons its a bargain. She says [4],
I come here quite often, I find cooking at
this communal place quite cost cutting. The Sh5 I
pay to use the communal jiko is
nothing. Imagine how little kerosene or
charcoal this money can buy. Nothing costs
this little any more.
The cooker heats up water for
washing which can be taken to a communal bathroom
known as a bafu. Four large
water filled tanks are connected by pipes to each
corner of the cooker roof. They act as a
reservoir for up to 160 gallons of water at any
one time. On average 50 people a day take hot
water into the bafu closet, while as many as 200
people could wash from the rain water stored in
the tanks.
Since the Laini Saba community
cooker became operational in 2007, Jim Archer has
drawn up plans to continue to improve the social
and environmental conditions in Kibera further [5].
He wants to increase the number of cookers to one
per every 50-70 households, which can contain as
many as 20 members per household. Jim is
planning to recycle waste water from bafu closets
to flush through the open pit latrines that often
block and overflow which are to be redesigned as
aqua privies. The runoff from the
aqua privies can then be bio-digested
and the resulting matter and moisture gravity fed
to support the growth of vegetables, fruit trees
and shrubs to create green spaces within the slum.
In this system, waste from one
activity is simply a precious resource for
another. By recycling the flow of wastes in the
environment, the levels of water consumption,
ground pollution, fly and mosquito breeding
grounds and disease are all reduced.
Kibera as it is and as it could be
with planning
UNEP funds cooker project
The United Nations Environment
Programme (UNEP) is a major supporter of the
Community Cooker initiative and has stumped up $10
000 towards its installation. The project is part
of the Nairobi River Basin Programme (NRBP) [6],
designed to rehabilitate and restore the Nairobi
rivers ecosystems to improve livelihoods and
enhance biodiversity. UNEP and the Kenyan
based Paint Manufacturers BASCO who have also
generously contributed to the construction of the
prototype are keen to fund more cookers around
the slum, which has a population of well over 800
000 [7]. Jims team has made the World
Health Organizations 800°C minimum
temperature requirement for incinerators in the
Developing World their bench mark for operational
acceptability within the cookers fire box.
Until the current temperature
of 600 °C is increased a further 200 °C
the rubbish will continue to pile up and the
majority of people in Kibera at least will go
without basic sanitation. However, Jim Archer is
confident his team can raise the temperature, but
until his patent pending design reaches 800°c,
he reluctantly accepts that there should be no
new community cookers.
Cookers not charcoal
About 91 250 tonnes of charcoal
biomass are used for energy every year in Kenya [7].
Contributing to this are several
temporary displaced persons camps,
which permanently shelter well over 110 000
people each. Women and children in these
camps travel further and further every day to
find wood and fuel for cooking, denuding the
countryside for miles around and creating health
problems for themselves from the smoke of the
firewood.
Recent research findings
show that black carbon (BC), the black soot
resulting from the incomplete combustion of
burning fossil fuels contribute to warming the
planet 55 percent as much as CO2, and
that reducing black carbon emissions may be the
quickest, cheapest way to save the climate (see [8]
Black Carbon Warms the Planet Second
Only to CO2,
SiS 44). Community cookers will contribute
a great deal to reducing BC emissions, and hence
earn carbon credits if BC reduction is included
in the Clean Development Mechanism of the Kyoto
Protocol.
The German aid agency GTZ has
expressed an interest in placing community
cookers into the refugee camps they manage and
Jim reckons that each camp would need a thousand
cookers to sustain their populations. He believes
that the money that could be earned through
carbon credits from these cookers could be
reinvested into a massive reforestation project
of native trees undertaken by the refugees
themselves.
An engineering company in the
UK has offered to loan Jim the sensitive
equipment he needs to establish much more
precisely how much carbon is emitted from the
community cooker and how that compares to the use
of charcoal and kerosene plus the emissions from
the piles of rubbish in Kibera. The
Engineering practice ARUP and an NGO called
JHPIEGO who are an affiliate of John Hopkins
University, the Kenyan Red Cross and the Centre
for Sustainable Engineering in the UK, and the
British based Charity Glads House are also
actively interested in the slum cooker project.
Low tech is the future
There are seemingly infinite
uses to which the basic concept of the community
cooker can be applied for local development.
These include kilns for clay bricks, pottery and
tiles, small hot water systems for homes, hot
food and water for hospitals, schools and
colleges, hotels and lodges. However, Jims
low tech and socially inclusive vision of change
under challenging conditions may not appeal to
everyone in an increasingly complicated and
technologically driven world.
But what this relatively low
cost and labour engaging project does do is to
give people something that they have never had
before, hot food and hot water on a regular basis.
In addition, it demonstrates that local solutions
to specific problems such as the global scourge
of plastic and other waste can be transformed
into the basic comforts necessary for human
wellbeing.
It is another example of the
affordable, distributed, decentralised generation
of renewable energy that gives local communities
energy autonomy, which is a key to truly Green Energies [9] (ISIS publication).
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