Development of an innovative sustainable process for simultaneous sewage sludge fluidized bed combustion and REcovery of PHOsphorus in a Ca bed

Project Information

RECaPHOS

Grant agreement ID: 842138

DOI

10.3030/842138

Project closed

EC signature date 27 March 2019

Start date 15 May 2019

End date 29 September 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 262 209,60

EU contribution

€ 262 209,60

Coordinated by

KARLSRUHER INSTITUT FUER TECHNOLOGIE
Germany

Periodic Reporting for period 1 - RECaPHOS (Development of an innovative sustainable process for simultaneous sewage sludge fluidized bed combustion and REcovery of PHOsphorus in a Ca bed)

Reporting period: 2019-05-15 to 2022-05-14

Summary of the context and overall objectives of the project

Phosphorus (P) is an essential nutrient and major economic factor. The EU covers its demands by importing Phosphate rock listed as critical raw material due to its scarce resource. Sewage sludge from waste water treatment plants is a promising alternative source of P. RECaPhos focus was the development of a novel method for phosphorus recovery based on the thermo-chemical reaction of sewage sludge, in the presence of CaO in a fluidized-bed reactor, assuring in the same time the destroy of dangerous pathogens, antibiotics and contaminations.

Initial goal was the development, optimizatiuon, and evaluation of the novel method and the production of rules and data for process up scaling purposes. This should be achieved by means of development of innovative models to investigate the thermodynamics and the kinetics of the process media. Experimental data from host institution facilities and data from literature should be used for models validation and optimization. The results should be used as a basis for the design of a demo plant as well as for the identification/evaluation of the process economics and commercialization potential. Two reference cases should be studied, one for a new plant and one for a retrofit of an existing fluidized bed combustion plant. Comparison with other competitive processes should be realized.

RECaPHOS is original, highly innovative, and ambitious since the same cheap widely available, natural, non toxic, and environmental friendly Ca-based material is used for P adsorption and subsequent P recycling as it is directly used as feedstock for fertilizer production, closing a natural cycle. RECaPHOS is an excellent and unique opportunity for the researcher who is a mother of two daughters to restart her career after more than 4 years of career break prior to call deadline due to maternity and after resettling back to Europe/Germany after a 3 years continuous stay outside Europe in the last 5 years, in a highly innovative non-profit academic institution that supports women and work life balance.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The Recaphos Project is a career restart action combining both scientific research, development of soft skills as well as the development of a career plan.

In this frame the Researcher has been working on these two directions. One hand side the researcher has been investigated the Phosphorus recovery process, participated on networking, qualification and training activities.
The first year the researcher focused on understanding the Phosphorus thematic, interpretating the experimental results of lab tests and getting familiar with modelling works. She worked together with her own small group of students and actively cooperated with the team of ZSW working on Phosphorus.

The great scientific difficulty of her work was that the phosphorus mineral phases detected form real experimentation were not described by the existing commercial thermodynamic databasis, so she focused on experimental work to understand the formation of the phases and the behaviour of phosphorous in the ash in order to evaluate its agronomic efficiency. In this frame she established cooperations among other with University of Stuttgart and Hohenheim. As result of this work a patent is created and is on the way to be submitted to the related authority.

Moving to KIT the researcher expanded the database of the phosphates from different phosphorus rich wastes as they result from various thermal processes. Goal was to obtain a database of the transformed phosphorus after thermal treatment. The data are not easy to obtain since almost no records on the phosphate phases are included in existing product analysis. Additionally by lack of oxygen and relatively low temperatures for P rich biochar production by thermal treatment of biogenic waste the identification of the exact phases are not possible.

In that frame the researcher having quite a clear picture of the existing data quantity and quality adapted a different approach as per the one originally planned in the work program. The new approach was: 1) identify through mineralogical databases the possible phosphates based on the feedstock composition 2) apply and validate the factsage thermodynamic software for binary and ternary systems using data from the literature and the own data collected.


The researcher participated in mentoring and training activities and qualified her self on her way to establisch academic independency.As a result she obtain as per beginning of October and just after the finalisation of the project, a professorship at the university of Stuttgart.

Many students have been involved in the project writing master/bachelor thesis of performing praktika. Additionally the researcher achieved the main goal of the project which was the successful restarting of her academic career after maternity relief.
Due to the pandemic she didn't have the opportunity to travel however she joined quite a few conferences related to the topic.
Finally the researcher could network with early career researcher from 4 European universities in an interdisciplinary consortium involving science communication art and design, environmental sustainability, material science and process engineering.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The researcher identified the restrictions in analytics mainly related to reducing atmospheres where the amorphous phases cannot be identified via XRD while NMR analysis has restrictions in application due tho the iron content of the waste. Additionally existing simulation tools cannot perform relevant prognosis of the phosphates since there is no thermodynamic description of the phosphates originating from thermal and chemical transformation processes of waste.

It is fact that the projects has a high relevance/ impact to the society. Art the moment in Germany phosphorus is recovered highly concentrated from the sludge after treatment. However the high crystallinity make it unavailable for plants direkt fertilisation while the substitution of part of the mined phosphorus in the related chemical industry is facing the challenge of the high amount of Fe and Al. So it is of high importance to describe thermodynamically the phosphorus contained in mixed waste for which mono incineration is the energetically treatment method. In that way we would be able to identify additives as well as key process parameters that influence the transformation of phosphates as wells the other products.

Phosphorus: feed the soil to feed the planet