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Phosphate Recovery

INTERNATIONAL CONFERENCE ON PHOSPHORUS RECOVERY FROM SEWAGE AND ANIMAL WASTES Warwick University, UK. 6th & 7th May 1998

Introduction

The European phosphate industry is looking at the potential for recovering the phosphate values of sewage treatment works effluent and animal wastes as a sustainable raw material resource.

Increasingly, municipal wastewater treatment plants are required to remove phosphorus from their effluent, often at significant additional cost. Recovery, as opposed to removal of phosphorus, offers potential benefits to the water industry, where the recovered phosphate would have a market value, and where the recovery technologies also result in a reduction of sludge production. The phosphate industry also perceives benefits from applying recovery technologies. The availability of a recycled raw material addresses some of the industry's resource depletion issues: although phosphate reserves remain substantial, the highest quality phosphate rock deposits are being depleted rapidly. Natural phosphate rock also carries a significant burden of heavy metals that the phosphate industry has to remove and dispose of safely - an increasingly costly activity. In comparison, pilot tests have shown that phosphate can be recovered from waste water and animal wastes in a comparatively pure form.

CEEP's Research Programme

Through the Centre Europeen d'Etudes de Polyphosphates (CEEP), its joint research fund, the phosphate industry has embarked on a research programme aimed at developing processes for the recovery and recycling of phosphate.

In order to help define its own research priorities CEEP sponsored a number of projects during 1996 and 1997 aimed at establishing what work had already been done in the area of phosphate recovery and what approaches might produce promising results. As a result of these scoping studies CEEP intends to launch new research aimed at understanding the underlying processes which take place during the recovery of phosphate and which might lead to the development of viable recovery processes. In particular, we have identified the crystallisation of calcium and magnesium phosphates (including struvite) as phenomena where a better understanding of mechanisms, kinetics and other factors would greatly advance the development of such processes.

Conference Objectives

This conference aims to facilitate a better understanding of the chemical and biological processes which will contribute to the development of sustainable recovery techniques and also to examine the economic and industrial context necessary for viable P-recovery.

On the technical side, the conference will look at the limiting physicochemical and biological conditions for the nucleation and growth of the various recoverable crystalline forms of calcium phosphates and of struvite, in order to identify areas that could benefit from further research.

The conference will also seek to identify the kinds of sewage or animal waste treatment installations where phosphate recovery might be viable and to assess the steps which need to be taken before phosphate recovery can be more widely introduced.

The long-term objective is to initiate contacts and discussion likely to lead to industrial research and development of phosphate recovery, and to identify opportunities for cooperation in this area between the water and animal waste industries, public authorities and the phosphate industry.

Wednesday 6th May 1998

10h00 - 10h30: Registration, access to hotel rooms, coffee

10h30 - 12h15: Why recover phosphates, where from and how?

10h30 John Driver (CEEP) - Albright & Wilson (UK)
Welcome and introduction : the objectives for this conference
Sustainable development : why does the phosphate industry care?

10h50 Dees Lijmbach (CEEP) - ThermPhos International (Holland)
In what forms can the phosphate industry handle recovered P as a raw material?

11h05 Dr. G. Morse - Imperial College of Science and Technology London (UK)
Overview of key pathways for phosphate recovery

11h30 Questions and discussion

12h00 Lunch

Wednesday 6th May 1998

13h30 - 16h45 - Two parallel sessions : Economic and technical perspectives for P-recovery

Session A: Economic perspectives:

Chairperson: Jean-Carlos Gomez, Rhodia Chemicals (France)

13h00 Ingrid Steen (CEEP) - Kemira Kemi AB (Sweden)
Phosphate rock : a non renouable resource

13h20 Dr. John Upton - Head of Technology and Development - Severn Trent Water (UK)
Nutrient removal in the UK - now and in the future

13h45 David Edge - Regional Biosolids Manager, Anglian Water (UK)
Perspectives for nutrient removal from sewage and implications for sludge strategy

14h10 Discussion

14h30 Coffee break

14h45 Dr. Phil Hobbs - Institute of Grassland & Environmental Research (UK)
Animal wastes as a potential source of recoverable phosphorus

15h10 Dr. Lilliana Moldenado - CH2MHill (USA)
Phosphate recovery - an economic assessment

15h40 Prof. Hermann Hahn - Institute of Aquatic Environmental Engineering, Karlsruhe (Germany)
Phosphate recovery pathways -economic aspects

16h10 Discussion and conclusions

16h45 Coffee break

Wednesday 6th May 1998

13h30 - 16h45 - Two parallel sessions : Economic and technical perspectives for P-recovery

Session B: Technical solutions for P-recovery

Chairperson: John Godber, Albright and Wilson (Canada)

13h00 Dr. Ir. Marc van Loosdrecht - Delft UT/Kluyver Institute for Biotechnology (Holland)
Biological approaches to phosphorus concentration as a preliminary step to P-recovery

13h25 Dr. Alan House - Institute of Freshwater Ecology, River Laboratory - NERC (UK)
The physico-chemical conditions for calcium phosphate crystallisation

13h50 Dr. Nic Booker - CSIRO (Australia)
Struvite formation in waste water treatment plants: an accident waiting to happen?

14h15 Discussion

14h30 Coffee break

14h45 Working experiences of P-recovery:

Prof. Olaf Schuiling - Institute for Infrastructural, Hydraulic and Environmental Engineering,
Delft (Holland); Alexandra Andrade - Institute of Earth Sciences, Utrecht (Holland)
A full scale plant for recovery of struvite from calf slurry

Mr. Simon Gaastra - Geestmerambacht Sewage Treatment Works (Holland)
Phosphate recovery at Geestmerambacht Sewage Treatment Works

Mr. E. Antusch - Institute of Aquatic Environmental Engineering, Karlsruhe (Germany);
Mr. W. Steckel - Darmstadt-Sud Sewage Works (Germany)
A pilot crystallisation reactor for recovery of calcium phosphate financed by the CEEP

Mr. Hideo Katsuura - Unitika Ltd (Japan)
P-recovery from sewage by a granular forming process.

16h00 Questions and discussion

16h45 Coffee break

Wednesday 6th May 1998

16h45 - 17h00: Coffee break

17h00 - 18h15: Three parallel workshops covering:

P-recovery from animal waste
calcium phosphate crystallisation
struvite recovery

Each workshop will establish its own priorities in terms of topics of discussion with the aim of drawing up proposals to put to the conference on Thursday morning. Subjects for consideration will include: ways forward for the future, subjects of research, areas for development projects.

P-recovery from animal waste

Chairperson: Dees Lijmbach (CEEP), ThermPhos (Holland)

Introductory ideas from:
Philip Haygarth, Institute of Grassland & Environmental Research (UK)
Perspectives for recovering P from animal wastes: how much is there and how accessible is it?
Mr Leo van Ruiten - an Ruiten Adviesbureau (Holland)
Overview of possible pathways for recovering P from animal wastes
Mr Henri-Jean Caupin - Elf Atochem and Grande Paroisse (France)
On-site separative flocculation and filtration system (Ecoliz) which concentrates 80% of P from pig wastes to a solid cake

Calcium phosphate crystallisation

Chairperson: John Godber, Albright and Wilson (Canada)

Introductory ideas from:
Mr. Robert Angel - Process and Industrial Chemists consultants (Australia)
Magnesium and calcium phosphate recovery from sewage treatment effluent: what seemsto work and what doesn't?
Dr. Dietfried Donnaert - Institute for Technical Chemistry, Karlsruhe (Germany)
Competition between carbonate and phosphate at high pH: implications for recovery processes
Jonathan Strickland - Innovation Technologist, Anglian Water (UK)
Perspectives for P-recovery offered by enhanced biological P-removal

Struvite recovey

Chairperson: Prof. Schuiling, Institute for Environmental Engineering, Delft (Holland)

Introductory ideas from:
Rachel Harding - Imperial College London (UK)
Overview of current technologies for struvite recovery
Steve Williams, Thames Water (UK)
Adapting strategies for avoiding struvite build-up problems in plants and transforming them into strategies for recovery

19h00: Dinner

Thursday 7th May 1998

8h30 - 9h15: Continuation of workshops

9h15 - 10h30: Plenary session:
presentation of conclusions of the two parallel sessions and discussion of
questions raised by the three workshops by their chairpersons

10h30 - 10h45: Coffee break

10h45: Presentation of priorities and research proposals identified by each workshop

Questions and discussion

12h00: Final conclusions: John Driver

12h15 - 13h30: Closing lunch

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