Ch. 5. Applications – sanitation in practice

Campaign in India to request bridegrooms to provide a toilet

Spreading chemical fertilizers in a field

Pupils prepare a meal with produce from school garden

Segregation of various liquid flows from household

5.1 5.1 Phosphorus - Food security Phosphorus - Food security & food for thought& food for thought

Learning objectives: Phosphorus as a resource, and its links to sanitation and to food security

- Should we worry about Phosphorus?

- Are there substitutes for plant nutrients ?

Our Globe sets the scene

We are in an era of unprecedented global environmental change

Jan-Olof Drangert, Linköping University, Sweden

• Water molecules can be made by using a lot of energy

• Water is renewable (sun-driven cycle)

• Water is available in soil and replenished annually by rain

• 70% of global water use is for crop production

• A balanced diet results in the loan of 1300 m3/yr to each person on the planet based on current practice. This is 70 times greater than the 50 l/d per person for basic water needs.

• Phosphorus (P) cannot be manufactured or destroyed

• P is essentially immobile and is mined in only a few countries

• P is naturally available in soil and depleted by crops

• 90% of global P extraction is for crop production

• A balanced diet results in the depletion of 22.5 kg/yr of phosphate rock (=3.2 kg/yr of P) per person based on current practice. 0.5 kg of this reaches the average person’s food.

Source: Cordell, Drangert & White (2009a)

Water and phosphorus for food security

Both are critical to food production, but need to be managed differently

Humanity became addicted to phosphate rock in the 20th century!

Historical sources of phosphorus (1800-2000)

Phosphorus status in soils in Europe

Source: Efma, 2000b

… the linear flow makes countries dependent economically and politically

World phosphate rock reserve estimates (’000 tonnes)

Source: USGS and ESRI

P scarcity is worse than oil scarcity because P CANNOT be substituted for in food production. So,

Food security phosphate rock dependence?

Courtesy IFA. Phosphate rock loading in

Morocco.

Access to phosphate markets

Future fertilizer price spikes are also possible

World Bank, 2009

Peak phosphorus

The peak P timeline is disputed, but all agree the quality of reserves is decreasing and production costs are increasing

Phosphorus through the global food system

Only 1/5 of the P in mined rock reaches the food on our plates!

Securing a sustainable phosphorus future

The future is not all dark! Source: Cordell et al., 2009b

A waste management hierarchy for P recovery

The extended waste management hierarchy includes both liquid and solid waste in urban sanitation systems and agriculture

1. Reduce (a) waste generation, and (b) harmful contents in products; 2. Reuse the waste more or less

as it is;

3. Recycle the waste as input to new products (including biogas);

4. Incinerate to extract the energy content in the remaining waste;5. Safely landfill residues from

the previous steps.Jan-Olof Drangert, Linköping University, Sweden

Can we eat climate-smart and phosphorus-smart?

• Think twice when shopping Don’t buy more food than you have time to eat

• Eat up the food you cook Serve reasonable portions and use the leftovers

• Use your senses Look, smell, taste and feel the food. Most foodstuffs last longer than their indicated ’use-by’ date if they are stored properly

• If you want to eat meat Choose local produce and try to eat fish, chicken and no beef

• Eat more vegetarian food Especially root crops and legumes

• Choose fruits and vegetables of the season Preferably local products

Source: Sweden’s National Food Adminstration Report 2008:9

Nutrients in human excreta

Important nutrients

Urine 500 Lt/year

Faeces 50 Lt/year

Total Nutrient need for 250 kg cereals

Nitrate (N) 5.6 kg 0.09 kg 5.7 kg* 5.6 kg

Phosphorus (P) 0.4 kg 0.19 kg 0.6 kg 0.7 kg

Potassium (K) 1.0 kg 0.17 kg 1.2 kg 1.2 kg

Total amount 7.0 kg 0.45 kg 7.5 kg 7.5 kg

i.e. N+P+K (94%) (6%) (100%) -

 The Urine Equation:

 An adult eats 250 kg of cereals per year, which has been grown on less than 250 m2 and fertilised to more than fifty per cent by the person’s urine.

Amount of nutrients from an average Swede per year

Jan-Olof Drangert, Linköping University, Sweden

Nutrient fertiliser values and CO2 emissions

0

50

100

150

200

250

300

350

400

450

Nitrogen Phosphorus Potassium Sulphur

Toilet water

ww sludge

CO2 equiv

Economic value of NPKS in toilet water and sludge, and reduced emissions of GHG compared to use of chemical fertilisers

H. Jönsson et al., 2012

Million SEK/yr

Nutrient flows originating from householdsToday

HH Excreta 59 % P, 70 % N

Effluent 48 % P, 20 % N

Septage 10 % P 10 % N

To air: 1 % P, 40 % N

Illegal dumping 4 % P, 5 % N

River/lake

To farm: 19 % P, 5 % N

Bio-waste

Illegal dumping 7 % P,10 % N

To compost 14 % P, 15 % N

Greywater 20 % P, 5 % N

Compost 20 % P, 20 % N

To air: 1 % P,15 % N

Jan-Olof Drangert, Vatema

Nutrient flows originating from households Year2030

River/lake

Jan-Olof Drangert, Vatema

HH Bio-waste

Illegal dumping 2 % P, 5 % N

Compost 19 % P, 20 % N

Greywater 20 % P, 5 % N

WWTP20 % P 5 % NEffluent

2 % P, 3 % N

Sludge18 % P 2 % N

To forest: 18 % P 2 % N

Urine40 % P,63 % N

To farm: 40 % P. 63 % N

Faeces 19 % P, 7 % N

Dewater 15 % P 4 % N

To air: 1 % P, 1 % N

Uncontrolled dumping 1 % P, 2 % N

Compost 33 % P, 22 % N

To air: 1 % P, 8 % N

To farm: 32 % P, 14 % N

Effluent 3 % P, 2 % N

A pig and its potential impacts

Cereals

Import

2.5 pigs/yr

Greenhouse gases (18%)

Eutrophication and dead zones in seas

Meat

Recycling to farmland

Jan-Olof Drangert, Linköping University, Sweden

3.5 m3 faeces

4/1.6/1 kg/yr5 m3 urine

5/0.4/3 kg/yr

Can fertilise 1500 m2 and

produce 800 kg of rice

Loss of food in each step of the food chain

Source: FAO, 2011

Plant requirement and nutrient removalCrop Yield,

kg/ha Dry

matter N, kg/ha

P, kg/ha

K, kg/ha

Cereals Rice, paddy 4000 88% 60/45 13/11 25 Wheat straw 4000 85% 70/16 13/ 2 50 Maize 4000 88% 200/51 35/ 9 133 Sorghum 4000 88% 120/56 22/ 9 116 Tubers etc Cassava root 20000 36% 125/32 13/ 1 125 Sweet potatoes 10000 59% 90/49 9/12 12 Potatoes 25000 23% 115/83 20/13 166 Others Soy bean 1000 91% 125/54 13/ 5 33 Ground nuts Banana fruit

1000 25000

94% 31%

50/37 /67

7/ 4 / 8

12

/

Source: Håkan Jönsson, SLU, Sweden

Why is it so difficult to apply P?

Plant need 10-30 kg/ha, but 0.5 kg/ha/day

0.01-0.1 kg/ha.

0.01-0.1 kg/ha.

10-100 kg/ha.10-100 kg/ha.

1000-2000 kg/ha.

1000-2000 kg/ha.

Fast (t,d,w) transport

Fast (t,d,w) transport

Slow (m,y) transport

Slow (m,y) transport

Exercise: a closer look at phosphorus flows Start fr

om the end!

Stay vegetable-based, and return farm waste, your excreta, household and city organic waste to soil !!!

Source: Cordell, Drangert & White (2009a)

Step 1 Step 2 Step 3 Step 4

Recovery of P by using the waste hierarchy

Was the strong link between the water and sanitation sectors in the 20th century a brief

detour in human history?

All rural Essentially urban

agriculture + sanitation

water+

sanitation

agriculture + sanitation

Most common

Parenthesis? What will

come next ?

Jan-Olof Drangert, Linköping University, Sweden

The green revolution in the 1950s saved the world from hunger - by using irrigation water, new crop varieties and chemical fertilisers

Next revolution must be to recycle the nutrients used in food production !

“Two major opportunities for increasing the life of expectancy of the world’s phosphorus resources lie in recycling by recovery from municipal and other waste products and in the efficient use in agriculture of both phosphatic mineral fertilizer and animal manure” European Fertilizer Manufacturers Association (2006)

Epilogue

Jan-Olof Drangert, Linköping University, Sweden