1.2 Resources:

energy

From waste via reuse to sustainability ?

Where are the unlimited resources?

What might be the problem to

access them?

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 (sun-driven 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

• 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.

• 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 extrac-tion is for crop production

• 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

agri-culture households

excr

eta

organics

foo

d

fert

ilize

r

Losseson farm

choice

rain &

irrigation

water

evapo-transpi-ration

nochoice

man

ure

Jan-Olof Drangert, Linköping University, Sweden

Input to and output from the food chain

loss

The water cycle – dynamics does the trick

” but, H2O is always on the move ...”

Instant snap shot:

Ice caps

2.7%

Rivers

0.0002% Lakes

0.007%Oceans

96.5%

Clouds

0.001%

Groundwater 0.7%

Shortage of freshwater !

A dynamic perspective gives a better description:

4 600 years3 000 years

8 days

16 000 years 280

days

Renewable rain gives in 2000 years as much water as is in the oceans!!!

Jan-Olof Drangert, Linköping University, Sweden

Annual renewal and use of fresh water Country H2O

m3 /person/year

km3/yr total in country

Rivers from/to countries

Portion being used

Total use per year per person

- by house-holds

- by indu-stry

- by agri-culture

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%

Tanzania 2 780 76 0 1 % 36 m3 21% 5% 74%Kenya 590 15 0 7 % 48 m3 27% 11% 62%Egypt 30 2 +56 97 % 1 202 m3 7% 5% 88%USA 9 940 2 478 0 19 % 2 162 m3 12% 46% 42%Chile 35 530 468 0 4 % 1 625 m3 6% 5% 89%China 2 470 2 800 0 16 % 462 m3 6% 7% 87%

Source: P. Gleick, 1993

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. Mines exhausted in some 50 years.

• 60% of mined sulphur goes to fertilizer industry and has no substitute. Mines exhausted in some 20 years.

• Costly to recover these plant nutrients from lake sediments compared to trapping them directly at the source i.e.as 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

food

H2O 1.5 l

1.1 l

transpiration & evaporation

0.9 l

Urine: 1.5 lFaeces: 0.15 l

Jan-Olof Drangert, Linköping University, Sweden

+ nutrients

+ nutrients

Vir

tual

wat

er 4

cu.

m.

NUTRIENTS – and demography

World Total16th - 21st century

Billion people

1500 1600 1700 1800 1900 2000

3

6

2100

Jan-Olof Drangert, Linköping University, Sweden

20th

century

9

rural

21th

century

urban

Actual reuse of nutrientsfor urban agriculture & food security

(in Swedish towns 1850 – 2000)

100%

50%

1870 1910 1950 2000

waste pits + urine diversion +WC only WC +WWTP stop

Jan-Olof Drangert, Linköping University, Sweden

Proportion nutrients being reused

Glass, tins, ceramics

Heavy metals

Human resources: capacity to manage sanitation arrangements

Utility

Household

Work hours Paying fees

Level of management

User contribution

pit latrine

urine-diverting toilet

flush toilet,

WWTP,

wetlandGrease trap, Organic waste

septic tank

sewerage

water supply,

biogas

drainage

Jan-Olof Drangert, Linköping University, Sweden

sewerage Organic waste

biogas

”Manpower blindness”: driver of new responsibility sharing

• We tend to account only for what is done by governments and projects in water and sanitation

• What is done by residents and small entrepreneursis rarely appreciated, if at all recognized (blindness)

• Yet, many urbanites survive thanks to such local initiatives

• Here, we pledge that both kinds of activities are needed to solve current sanitation problems

Our pre-conceived views play a role

Jan-Olof Drangert, Linköping University, Sweden