New technologies to recycle phosphor

Sven Gjedde SommerUniversity of Southern Denmark

Faculty of EngineeringInst. of Chemical Eng., Biotechnology and Environmental

Technology

Problems and opportunities

Cordell et al. 2009; The story of phosphorus: Global food security and food for thought

Which technology ensure that livestock manure P is not lost or wasted?

• The untreated manure is applied to field – fulfilling the crop need for plant nutrients. Focus may be on P, N and K.

Regional and local high production of cattle and pigs

• Manure must be transported from farms with too much plant nutrients to farms having a need with TANKERS or by pumping.

• Manure is separated, processesed, transported– Biogas treated– Incinerated

• Ash, charcoal, Pelleted with additives• P refining

Struvite formation and sedimentation in a thickener

Mg2++NH4++PO4

3-+6H2O MgNH⇌ 4PO4, 6H2O(s)

AnimalSeparation index

(%)

Origin P,total

Swine 41

Cattle 57

Screen or filterbed separation without additives

AnimalSeparation

index (%)

Origin P,total

Swine 30

Cattle 40

Using additives, koagulants iron and aluminium or/and polymers

Animal Separation index, %

P, total

Swine 79

Cattle 87

Screw press separation

AnimalSeparation index

(%)

Origin P,total

Swine 30

Cattle 40

Decantering centrifuge

Animal Separation index (%)

Origin P,total

Swine 73

Cattle 69

Separation cost

Amount of manure treated annually (1000 tonnes)10 20 30 40 50 60 70 80 90 100

Trea

tmen

t cos

ts (E

UR

O/to

nne)

0

1

2

3

4Screw press Decanter centrifuge The cost of an efficient separation of slurry

using coagulants and flocculants andincluding the cost of screw press separation was estimated to be €1.8 per ton slurryEstevez et al. 2005

Separation efficiency Cost Cost Quality

Ton per year % Kg P in fiber € per ton slurry € per kg P DM, %

Filter + additivesI 79 1,422 1,8 1,3 12

Screw press 2000 30 0,54 0,7 1,3 12

Screw press 50000 30 0,54 0,2 0,4 20-40

Decanter 2000 73 1,314 2,5 1,9 20-40

Decanter 50000 73 1,314 0,5 0,4 20-40

Cost QualityTon per year € per kg P DM, %

Filter + additives 1,3 12Screw press 2000 1,3 20-40Screw press 50000 0,4 20-40Decanter 2000 1,9 20-40Decanter 50000 0,4 20-40

So what then? (Google translation of “Hvad Så”?)

• Farmers can spread the fibre fraction on land and incorporate it (Avoid ammonia emission)

• The manure could be dried to produce a product that can be stored and transported: – Drum drying and pelleting– Torrefaction (Drying using the gas produced for

heating) and pelleting

TorrefactionPyrolysis at low temperatures: 200-320 oC

Agri-Tech Producers

Development needed to retain ammonium.Loss of about 20% of DM.Energy density of 18–20 GJ/m³ compared to 10–11 GJ/m³ Torrefied fibres can be pelleted and stored without risk of more emission of GHG and ammonia. Torrefied biomass results in lower handling costs.

Use of pellets

• The pellets may be considered a mineral fertilizer and applied to fields.

• Alternatively the pellets may be incinerated and the ash can be used:– As a fertilizer– P can be recovered and used for P products

Ash as a fertilizer

• P-availability of ash is reduced – by increasing temperature of the incineration or thermal gasification process.

• A “maize fertilizer” have been developed by Kommunekemi. – Sulphuric and nitric acid added, the sludge dried and

pelletized. – Acid addition increased P availability and N addition

contributed to a fertilizer fulfilling plant nutrient needs of maize (corn) plants.

If slurry is separated without use of aluminium or iron additivesMaize or Corn Fertilizer

Kommunekemi A/S

Content of plant nutrient, pct.0 10 20 30 40

NitrogenPhosphorSulphur

Water soluble P

Water + citric acid soluble P

% of total PFibre ash 1 27Maize manure

60-80 90

Maize ash manure

65-75 90Fibre ash

Meat and bone ashWaste water sludge ash

Anita Rye Ottosen Kommunekemi A/S

If slurry is separated with use of polymers, aluminium or iron additivesand cupper and zink has to be removed

Using polymer or iron or aluminium to improve P separation efficiency will also retain cupper and zink in the fibre fraction. These trace metal has to be removed. By dissolution – crystallisation processes• First acid is added to dissolve P which is removed.• Then pH is increased to dissolve Cu and Zn which is then removed.• There are many steps involved and the P recovery is very costly.

18 | Biomasse til el- og varmeproduktion | Karsten Thomsen, Kemi & Materialer | 19-11-2010

Solid manure Animal house Drying

Conditioning

Hammermill

ø8 mm screen

Water 2 %Steam

Additives 0 %

Water 2 %

PelletisingCoolingSieving

Pellet storage

11.500 tons

Fines 5 %

Water 2 %

Introduction Keyfigures Proces Photo gallery Burning of pellets Summary Questions

Production of pellets

Water 3,5 %

Solid manure management scenariosGreenhouse emission from management of solid manure

Side effects – energy and GHG emission

Animal house, Solid manure

ExcretaVS, N, P

NH3 CH4CO2

BiomassVS, Norg,TAN, P

Solid manure storage

CH4CO2

P-Ash

N2CO2

FieldIncineration

CROPS

EnergyNH3N2O, N2,

Animal house, solid manure

Excreta, strawVS, N, PWater

NH3 CH4CO2

Solid manure1) Composting2) Reduced composting

NH3N2O, N2,

CH4

, CO2

Field CROPS

NH3N2O, N2,

1) Baseline2) Baseline + compaction of stored solid manure

Drying and pelleting

NH3VFA

BiomassVS, Norg,TAN, P

3) Incineration4) Drying, pelleting and incineration

Scenario Houses Stores Field Carbon sequestra-tion

Energy consump-tion

Energy production

Total GHG balance, CO2 eqv

CH4 N2O CH4 N2O CH4 N2O

kg CO2 eqv

1) Baseline 137.8 265.7 13.8 68.3 0.0 1576.3 -337.8 0.0 0.0 1724.1

2) Compaction 137.8 265.7 1.4 0.7 0.0 1986.2 -450.4 0.0 0.0 1941.4

3) Incineration 137.8 265.7 13.8 68.3 0.0 0.0 0.0 0.0 -339.2 146.4

4) Drying, pelleting and incineration 137.8 265.7 0.0 0.0 0.0 0.0 0.0 1123.4 -1674.9 -148.0

Greenhouse gas emission from the four scenarios, 6 ton litter from beef cattle production (one unit)

Marieke ten Hoeve – KU-Life

Housing

Pre-storage

Separation

Storage(solid)

Land application

(liquid)

Stirring & pumping

Storage (liquid)

Land application

(solid)

Stirring & pumping

Stirring & pumping

Transportation

Screw Press

PumpingTransportation

Transportation

Loading

Prevented mineral N fertilizer

Prevented mineral N & P

fertilizer

CO2

CH4

N2O

CH4

CO2

CO2CO2

CO2

CO2

NH3

NH3

NH3

NH3

NH3

NO3-

NO3-

P P

N2O

N2O

CO2

CO2

CO2

CO2

CO2

CO2

CO2

Side effect of the treatment

Conclusions

1. Application of untreated manure to crops near the animal house is very a resilient, sustainable and environmentally friendly technology

2. Simple separation can support efficient recycling (Definition see # 1)

3. Chains of treatment that include energy and “mineral fertilizer” production can be an attractive option for an industrial and specialised livestock production sector

4. Economy, regulations and incentives is the drivers.

http:

//co

nten

t.alte

rra.

wur

.nl/W

ebdo

cs/P

DFFi

les/

Alte

rrar

appo

rten

/Alte

rraR

appo

rt21

58.p

df