Transcript Sustainable Sanitation for the 21st Century

1.4 Demographic Change
Learning objectives: to gain
insights about the role of
demography in sanitation planning
and implementation
Jan-Olof Drangert, Linköping University, Sweden
The Urban Sanitation Challenge
World population (in billions):
2000
2050 (estimate)
Total
6
9.3
Rural
3
3
Urban
3
6
Thus, new housing on virgin land in new cities provides
excellent opportunities for new sanitation options to fulfil the
Millennium Development Goals for sanitation
Jan-Olof Drangert, Linköping University, Sweden
Population growth rates and the proportion living
in informal settlements: means for the largest cities (%)
%
30
25
20
Informal settlements
Population growth/year
15
10
5
LA & C = Latin America
and the Caribbean
0
Africa
Asia
LA & C Oceania Europe
Source: UNDP & Unicef, 2003
City council capacity to do its part
%
Proportion of wastewater being effectively treated
90
80
70
Treated
wastewater
60
50
40
30
20
10
0
Africa
Asia
LA & C
America
Europe
Source: UNDP & Unicef, 2003
Evolution of the relationship between
residents and utilities in Sweden
subscriber
1970
customer
1990
partner
Time
Supply of water
All want to connect
H2Olaw
All water can be
cleaned
Simple treatment
plants
Jan-Olof Drangert, Linköping University, Sweden
Price
Demand
Envir.
law
Cannot treat all
water at
acceptable cost
Demographic patterns are decisive:
The growth-infrastructure hypotheses
Population
transition
transition
Time
Slow development of the
infrastructure
Lowering portion or even
absolute decrease of
infrastructure
Rapid
improvement
Jan-Olof Drangert, Linköping University, Sweden
How to manage sanitation arrangements?
A key question is about control, not degree of centralisation. Two extremes:
Turn-key management where a utility (private or public)
provides the service and the residents just pay the bill
Own-key management where single households or housing
associations initiate, build and control, while they put to use
available skills, materials, and other local resources
WC &
sewerage
Septic
tank
Turn-key
Dry urinediverting toilet
Own-key
Aqua privy
Dug latrine
Jan-Olof Drangert. Linköping University, Sweden
Example 1:
Evolution of w&s in Kisumu town, Kenya
Population
350,000
300,000
200,000
100,000
Independence
50,000
1900
Ownkey
Turn-key
1950 1963
2000
Source: Drangert et al., 2002
N orrk öp in g (in
Example 2: Evolution
th ou san d s )
of w&s in Norrköping, Sweden
Norrköping
140
(thousands)
Town area
expansion
120
Town area
expansion
100
80
p ip e d w a t e r
Town area
expansion
s e w e ra g e
wc
N o rrk ö p in g
60
First
piped
water
40
20
0
2
0
0
0
1
9
9
0
1
9
8
0
1
9
7
0
1
9
6
0
1
9
5
0
1
9
4
0
1
9
3
0
1
9
2
0
1
9
1
0
1
9
0
0
1
8
9
0
1
8
8
0
1
8
7
0
6
8
1
1
8
5
0
0
Source: Drangert & Hallström, 2002
Hypotheses on best management option
Population
transition
transition
proportions
Time
Turn-key
own-key
Turn-key
own-key
Turn-key
own-key
Jan-Olof Drangert, Linköping University, Sweden
Economicdevelopment
Development and Water
Supply
in ain
' Secondary
city' UK
Economic
and
W&S
Cranfield,
National GDP per person real with 0.88% and 2.15% per year trend lines
National GDP per person real with 0.88% and 2.15% per year trend lines
$40,000
$35,000
$30,000
$25,000
$20,000
Water Closets becoming popular in capital city
Newly installed WCs discharging to ditches, Hagley Road
Ordure is emptied anywhere at nightfall;
The city’s first public wash house opened in Kent Street
Mind where you tread, Sir, for the children have been here'
One third of city using unimproved pit latrines
First sewage farm acquired
City trying to convert to bucket latrines as
improvement
'One in three artisan families still had to share external
toilet with neighbours'
45% households access bucket latrines (1 per 10 HHs)
15% using unimproved pit latrines;
Over half houses get WCs - most still outside
open 'drainage [in one slum court] is so
vile that the air seems positively putrid'
20% lacking a WC
Still shared toilets for slums
High-inc
$15,000
Present upper
$10,000
middle-income
Household toilets generally achieved
Present lower middle-income
$5,000
Present low-income economies average GNI pc at PPP
'Cost reflective tariffs' required for newly
privatised providers (300 year sewer
replacement cycle?)
Source: Cranfield university, UK
20
00
19
75
19
50
19
25
19
00
18
75
18
50
18
25
18
00
$0
Evolution of indoor water taps in rural Sweden
10 Mil
90%
100%
BUT, what about the
impact of urbanisation?
63%
5 Mil
50%
70%
29%
17%
10%
1900
1950
2000
Gradual improvement towards full coverage
Jan-Olof Drangert, Linköping University, Sweden
Why do we often act as if we were only a
few hundred million people on earth?
• Small farmers understand and
practise reuse, but urban residents
do not
• Ever more people live in big villages,
towns and cities
• Most farmers have had access to
chemical fertilisers this far
• Change comes with a cost
• But, there is also a saving;
better food security
Local experience
global understanding
However: We still act as
if we were a few hundred
million people on earth!
Jan-Olof Drangert, Linköping University, Sweden