Desire for Greener Land

Biogas B s
Botswana B - GGase
ya Boloko
(Setswan na)
Production
oof
methane gas from cow-dung c
foor
use in ho ousehold
cooking,
heaating
and liighting
in order o to redduce
firewood
demand.
Biogas
plant: Thhe
biogas plannt
can be cons structed in sevveral
ways as long as it can
pr rovide a mediuum
for the bioloogical
material l be digested. Biogas is the name n given to
th he gas that is pproduced
durinng
the decomp position of somme
organic was ste specifically
to o produce methhane
gas. Thee
gas is then captured in a storage tank
(on site) to
be
used for hoousehold
eneergy
needs. In
many partss
of the world
where this
te echnology is used (includding
Botswan na) the mostt
common fo orm of input
material m is coow
dung maaking
it more e appropriatee
for rural environments.
Advantages: A
thee
technology offfers
two major r advantages; ffirst,
at every le evel of use i.e.
in ndividual or insttitutional,
savinngs
in terms of energy is realized.
The only costs that are
bo orne are at insstallation,
otherrwise
input of cow c dung has a minimal cos st of collection
(if f any at all). Thhe
second advantage
is that there is reduceed
usage of fue el wood which
translates
into less cutting down of trees s leading to reduced defo orestation and
de egradation of land. A disadvvantage
is the e initial investmment
which is significant for
po oor farmers.
Above left: TThe
photo show ws the gas collection
tank resting oon
the concrete e-built digester.
Pipes/tubes aat
the top of the e gas tank supply
the
house with mmethane
gas. (P Photo: R.J. Sebbego)
Above right: : This photo sh hows the pilot bbiogas
plant construccted
by the DE ESIRE team in
Mopipi. It wass
installed at one
household tto
serve as a deemonstration
to o the village
community. ( Photo: R.J. Se ebego)
Construction C
off
the biogas pplant:
construc ction of the pllant
consists of o three main Location: So
ch hambers: nammely,
the Diggester
pit whe ere all the mmicrobiological
reactions or Region: Kan
de ecomposition of the materiaal
takes place e. The digesteer
has to be built b to be air- Technology
tig ght with the rreleased
gas oonly
escaping g into the gas holder. The gas holder is Conservatio
co onnected to thhe
digester byy
way of a pip pe. Its main ppurpose
is to collect c all the Stage of inte
ga as that has beeen
fermentedd.
The mixing pit is the inpuut
chamber wh here the dung reclamation o
is s mixed with wwater
and fedd
into the dige ester. The ammount
and quality
of water Origin: Exter
re equired for thiss
is no constraint,
even in this t water streessed
area. Co onstruction of Land use: Fo
th he biogas plannt
has to be doone
according g to specificatioons.
A technic cal drawing of Climate: sem
th he plant is shoown
on page 33.
The purpose e of the technoology
is to use e it for house- WOCAT data
ho old energy (foor
cooking, lighhting
and running
appliancess).
cdewocat.uni
DESIRE site
In n Botswana, tthe
technology
was introdu uced by the RRural
Industrie es Innovation his.eu/en/bote
Center C which iss
a governmennt
funded rese earch institutioon.
Despite the e existence of Related appr
th his company foor
many yearss,
the uptake has h been veryy
low due to po oor marketing Compiled by
and
extension sservices
and lack
of financia al assistance tto
poor farmer rs.
Botswana
Date: 19
Biogas B is suitaable
either for a farm, cattle e post or ruraal
setting whe ere the inputs
(c cow dung) aree
easily availaable.
But there e are possibillities
of experimenting
with
ot ther bio-degraadable
materials
in major centres wheree
cow dung is i not readily
av vailable.
th outhern District t
nye village
area: point loc cation
on measure: management
m
ervention: rehabilitation
/
of denuded land
rnally - 10-50 years y ago
orest land and mixed
mi-arid, subtrop pics
abase reference:
QT BOT05
ibe.ch/wocatQT T
information: www.desire-
teti-botswana
roach: not doc cumented
y: Sebego Reu uben, University
Feeb
2009, updated
6 th 5 on
y of
Jun 2011
SLM Technology: Biogas, Botswana DESIRE – WOCAT 2012
193