Transcript Ch. 1.1 Resources - Sustainable Sanitation

1.2
Resources
From waste via reuse to sustainability ?
energy
Learning objective:
To familiarise with a coordinated view
on resources, and to understand the
context and role of sanitation
Jan-Olof Drangert, Linköping University, Sweden
Reflections on water and plant nutrients
• Water molecules cannot be
manufactured or destroyed
• Water is renewable (sundriven cycle) everywhere
• Water available in situ (rural,
peri-urban) or imported (cities)
• Energy supplied by humans
(rural) or electricity (urban)
• 70% of global water use is
for crop production
• Phosphorus (P) cannot be
manufactured or destroyed
• P is immobile and mined in
only a few countries
• Food available in situ (rural)
or mostly imported (cities)
• Energy supplied by humans
and sun (rural) or fossil(urban)
• 90% of global rock P extraction is for crop production
• A balanced diet requires a
loan of 1300m3/yr p person
based on current practice.
This is 70 times greater than
the basic water need of 50 l
per person per day.
• A balanced diet results in
depletion of 22.5 kg/yr of
phosphate rock or 3.2 kg/yr
of P per person based on
current practices, of which
0.5 kg is found in the food.
Jan-Olof Drangert, Linköping University, Sweden
Input to and output from the food chain
choice
no
choice
agriculture
loss
households
evapo
transpi
ration
Losses
on farm
Jan-Olof Drangert, Linköping University, Sweden
The water cycle – dynamics does the trick
Instant snap shot:
Shortage of freshwater !
Clouds
0.001%
8 days
” but, H2O is always on the move ...”
A dynamic perspective
gives a better description:
Renewable rain gives in 2000 years
as much water as is in the oceans!!!
Rivers
0.0002%
Groundwater
0.7%
Lakes 280
0.007% days
4 600 years
Oceans
96.5%
3 000 years
16 000
years
Ice caps
2.7%
Jan-Olof Drangert, Linköping University, Sweden
Annual renewal and use of fresh water
Country
H2O m3 km3/yr Rivers
Portion Total use - by
- by
/person/ total in from/to
being
per year
house- induyear
country countries used
per person holds stry
Sweden
21 110
176
+4
2%
479 m3
36%
55%
9%
Holland
680
10
+80
16 %
1 023 m3
5%
61%
34%
Saudi Ara
160
2
0
164 %
255 m3
45%
8%
47%
Lebanon
1 620
5
-1
16 %
271 m3
11%
4%
85%
India
2 170
1 850
+235
18 %
612 m3
3%
4%
93%
2 780
590
30
9 940
35 530
2 470
76
15
2
2 478
468
2 800
0
0
+56
0
0
0
1%
7%
97 %
19 %
4%
16 %
36 m3
48 m3
1 202 m3
2 162 m3
1 625 m3
462 m3
21%
27%
7%
12%
6%
6%
5%
11%
5%
46%
5%
7%
74%
62%
88%
42%
89%
87%
Tanzania
Kenya
Egypt
USA
Chile
China
- by
agriculture
Source: P. Gleick, 2003
Global scarcity of plant nutrients a new driving factor for sanitation
•
Phosphorus is a limited resource, and large untapped
reserves will eventually only be found on sea shelves
and as anthropogenic depositions in lake sediments.
•
95% of mined potash goes to the fertiliser industry
and has no substitute. Exhausted in some 50 years.
•
60% of mined sulphur goes to fertilizer industry and
has no substitute. Exhausted in some 20 years.
•
Costly to recover these plant nutrients from lake
sediments compared to trapping them directly at the
source i.e. output from households and industries.
•
Nitrogen can be manufactured from the N in the air,
but this requires much energy (1 litre of oil to produce
1 kg of nitrogen).
D. Cordell & J-O Drangert, Linköping University, Sweden
Phosphate Rock – Worldwide Estimates
(thousands of metric tons)
P scarcity is worse than oil scarcity
because P CANNOT be substituted
in food production
Courtesy of Ian Caldwell, Stockholm Envrionment Institute, Sweden
Food, water and nutrient flows
0.9 l
H2O
food
1.5 l
transpiration &
evaporation
1.1 l
Faeces:
0.15 l
Urine: 1.5 l
+ nutrients
+ nutrients
Jan-Olof Drangert, Linköping University, Sweden
NUTRIENTS – and demography
Billion
people
9
World Total
16th - 21st century
21th
century
6
20th
century urban
3
rural
1500
1600
1700
1800
1900
2000
2100
Jan-Olof Drangert, Linköping University, Sweden
Actual reuse of nutrients
for urban agriculture & food security
(in Swedish towns 1850 – 2000)
Proportion nutrients
being reused
100%
Glass, tins,
ceramics
Heavy
metals
50%
waste pits + urine diversion
1870
+WC
only WC
1910
1950
+WWTP
stop
2000
Jan-Olof Drangert, Linköping University, Sweden
Human resources: capacity to manage
sanitation arrangements
Level of
management
WWTP,
Utility
sewerage
flush
toilet,
water
supply,
sewerage
Household
urineGrease diverting
trap,
toilet
pit latrine
Work hours
Paying fees
User
contribution
Jan-Olof Drangert, Linköping University, Sweden
”Manpower blindness”:
driver of new responsibility sharing
Our pre-conceived views play a role
• We tend to account only for what is done by
governments and projects in water and sanitation
• What is done by residents and small entrepreneurs
is rarely appreciated, if at all recognized (blindness)
• Yet, many urbanites survive thanks to such local
initiatives
• Here, we pledge that both kinds of initiatives are
needed to solve current sanitation problems
Jan-Olof Drangert, Linköping University, Sweden