Phosphate removaland phosphate recovery:

Towards Sustainable Development

Dees Lijmbach,President Technical Committee,

Chris Thornton, co-ordinator,CEEPCentre Européen d’Etudes des Polyphosphates

COPPERAS - November 2000

Phosphorus recycling is as old as agriculture

How did phosphorus recycling break down in

Europe?• The growth of cities

(16th Century onwards)

• The introduction of sewage collection and treatment systems

• Decline in agricultural re-use of sewage biosolids

Modern society conducts phosphorus from the land and out to the rivers and sea

Why re-visit phosphorus recycling now?

• Phosphate rock reserves and costs • Impurities in phosphate rock • Increasingly, phosphate removal from waste water will be required by law• Opportunity to improve waste water treatment economics/ sludge cycle• Sewage and animal wastes are, potentially, a rich source of pure

phosphate (45,000 and 200,000 tonnes of P per annum, respectively in UK)

Why re-visit phosphorus recycling now?

• Agricultural spreading is the BEST way to recycle phosphorus (and nitrogen values, biosolids, …)

• But this option is declining across Europe :- concentration of cities / storage - transport problems- competition from animal manures- legislative and social pressure re contaminants

• Also, the P:N ratio in sewage sludge is higher than agronomic requirements

1996 2000 2010 2020 2030 2040 2050 2060 2070

% Depletion

0

20

40

60

80

100

Depletion of Phosphate Rock Reserves

High growth Medium growth Low growth Conservation scenario

Country Deposit P2O5 As Cd Cr Hg U V

(wt %) (ppm) (ppm) (ppm) (ppb) (ppm) (ppm)

Israel 32 5 25 227 130 150 200

Jordan 32 8 5 92 48 78 70

Morocco Bu CraaKouribga

Youssoufia

35.132.631.2

13.49.2

37.515.129.2

200255

855120

758897

106200

Togo 36.7 10 58.4 101 365 94 60

USA Floridaidaho

N. Carolina

31.931.729.9

11.323.711.2

9.192.338.2

60290158

199107233

14110765

10876926

South Africa 39.5 11 <2 9 17

Tunisia 29.3 4.5 39.5 144 44 27

Senegal 35.9 17.4 86.7 140 270 67 523

Australia 28.9 14 4 35 75 84 63

Syria 31.9 4 3 105 28 75 140

China 31 26 2.5 33 4990 22.8 80

Phosphate Rock - Main Impurities

Phosphoric acid analysestrace impurities

• Acid from Morocco phosphate rockppm

• Al 200

• Cd 40• Cr 357• Fe 1600• Mg 5700• Na 1700• Ni 67• Ti 108• Zn 880• Mn 10• Cu 23• As 5• Organic C 50

• Acid from Geestmerambacht recovered phosphates ppm

• Al 950

• Cd <6• Cr 8• Fe 1260• Mg 4200• Na 360• Ni 8• Ti 8• Zn 310• Mn 560• Cu 17• As 2• Organic C >2000

Possible pathways for P-recovery - 1

• Precipitation of a recyclable phosphate product from liquors in wwtp:- calcium phosphate -> P-industry- struvite (magnesium ammonium phosphate) -> fertiliser use

- synergy with biological P-removal high-P side streams, P release in digesters, avoidance of struvite deposit problems)

- other possible technologies may allow precipitation from wwtp main stream - ion exchangers, membranes ...

Full scale phosphate recovery (as calcium phosphates) from sewage : DHV Crystalactor® at Geestmerambacht sewage works,

near Edam, Holland (230,000 pe.)

Full scale struvite recovery plant, Shimane Prefecture, Japan. Capacity :45.000 m2/day.Unitika Ltd /Japan Sewage Works Agency

Phosphorus Recovery:Remaining technical/economic

concerns• Chemistry of P-recovery by CaP or struvite precipitation looks simple but is

poorly understood.• Inadequate knowledge of reaction kinetics.• Existing reactor designs are far from optimised.• Further LCA , economic & logistic evaluation is needed.

Despite this:

• There are already about a dozen demonstration scale and full scale plants operating world-wide.

• Small amounts of recovered phosphate are already reaching industry.

Possible pathways for P-recovery - 2

• Recovery of phosphates in combination with existing chemical P-stripping

- chemical constraints:- no known recycling pathway to date for iron phosphates- aluminium phosphates can be recycled

in Thermphos’ Vlissingen furnaces, Holland

- physical constraints : - how to recover a low-water, recyclable product

and not a “sludge”, - need to separate phosphate product from sludge biosolids

Possible pathways for P-recovery - 3

• Recovery from sewage sludges or sludge incineration ashes

- problems :- iron (from chemical P-stripping/flocculants

used in sewage treatment)- copper (from diffuse sources : piping, diet ...)

CEEP and P recovery• The European detergent and technical phosphate industry is committed to “making it happen” and is leading research in the

area. • Contacts with water companies and regulators• Promotion - communications : SCOPE Newsletter,

P-recovery conference (Holland, 12th-14th March 2001)

• EU 5th Framework Proposal CYCLOPHOSaddressing precipitation of calcium phosphate and struvite

• Possibilities for co-operation with INCOPA ?

Cyclophos Industrial Partners • Water Industry:

- CIWEM- Berlin Wasser- Lyonnaise des Eaux- Thames, Anglian, Yorkshire, Severn Trent- Canal Isabel II - STOWA- Polish water industry- Posch and Partners- WS Atkins

• National regulators:- UK Environment Agency- Spanish Environment Ministry- Swedish Environmental Protection Agency

Phosphorus Recovery: current CEEP research

• Scenarios for struvite recovery economics Imperial College, London

• Feasibility of P-recovery and recycling in Benelux STOWA/Thermphos/Haskoning

• Economics and sludge management implicationsOffice Internationale de l’Eau

• Sludge production implicationsINSA Toulouse, France

Phosphorus Recovery: current CEEP research

• Precipitation reactor design parametersLAGEP/Uinversité Lyon II, France

• P-recovery potential in different areas of 3 bio-P wwtpsCSIC Madrid/ Canal Isabel II Water Company

• Struvite formation in STW Imperial College (joint project with UK water industry).

• Testing of full-scale struvite precipitation reactor at Treviso bio-P sewage works, Italy (Ancona, Verona, Venice Universities)

Phosphorus Recovery: current CEEP research

• Testing of a pilot scale struvite reactor at Zarbze sewage works, Poland, Lodz Technical University Bielsko Biéla

• Crystallisation of calcium phosphates using calcite seed Karlsruhe Research Centre

• Precipitation of calcium phosphates - Centre for Ecology & Hydrology, UK and Natural history Museum, London

• Recovery of phosphates by reversible adsorption onto fly ash, Bath University, UK

Phosphorus Recovery: current CEEP research

• Biologically induced P precipitation in combination with biological P-removal from sewage Queens University, Belfast.

• Application of REM-NUT ion exchange for P recovery from sewage works main stream Bari Polytechnic, Italy

• Pathways for P recovery from sewage sludges Swedish Royal Institute of Technology

• Phosphorus separation and recovery in animal manures Institute of Grassland & Environmental Research, UK.

Recovery of P from iron compounds ?

Results of an initial experiment using sulfate reducing bacteria to solubilise phosphates from iron phosphate sludge,

Jan Suschka,Lodz Tech. Univ,Bielsko Biéla,Poland9 2000

A sustainable future in recycling phosphates