Project: Sustainable Symbiotic Phosphorus Fertiliser Production from Two Renewable Raw Materials

Phosphorus (P) is required by every cell of living organisms. It is one of the major elements for plant nutrition and therefore essential for crop production. P supply in plant nutrition depends entirely on external inputs into soils. This is achieved by P-fertilisers deriving from rock phosphate deposits that are going into depletion. Serious prognoses anticipate that rock phosphate will be the first low running resource in the world. In the EU, last year 2.530 kt of phosphorus (P2O5 in fertilisers) was consumed and only 313 kt (P2O5 in rock phosphate) was mined. More than 60% of known world phosphate reserves are concentrated in Morocco. In 2007, rock phosphate prices have doubled because of a tight supply situation._x000D__x000D_For these reasons P recycling is becoming an increasingly important issue. Suitable secondary raw materials with regard to their high P-content and abundance are sewage sludge and meat and bone meal. In the EU 989 kt P2O5 is accumulated annually in theses materials, of which 632 kt P2O5 are permanently lost to landfills and other forms of disposal. The CO reasons for their limited recycling are concerns on heavy metal contents, organic pollutants and health hazards. As an additional shortcoming, the availability of P from these materials to plants is poor and storage and transportation are problematic issues._x000D__x000D_As a response, ASH DEC and BAM with the participation of wpa have successfully developed a P-recovery technology for sewage sludge ashes, that removes heavy metals and organic pollutants and produces ready-to-use fertiliser granules (a substantial part of research was carried out within the framework of the EU-FP6-project SUSAN). The technology has been tested at lab- , medium- and technical scales and is ready for the transfer to pilot-scale. Its core process is a thermo-chemical treatment. Sewage sludge ashes are endowed with earthalkaline chlorides and the mixture is treated for approx. 20 min at 1,000°C in a rotary kiln. In this process, organic pollutants are completely destroyed and heavy metals are removed as volatile heavy metal chlorides via the off-gas that is cleaned in a multi stage gas cleaning system. Additionally, the bioavailability of P is improved due to the formation of new P-bearing mineral phases in the thermo-chemical process. The fertilisers produced from the thermo-chemically treated ashes have been licensed in Austria for unlimited use on crop- and woodland. _x000D__x000D_At this point, the technology needs to be transferred to pilot-scale – this is the first phase of the project. Process controlled machinery and equipment for this purpose is currently being installed and will be ready before the project starts. After the technology transfer, two R&D phases are scheduled to implement the apparent improvement potentials: replacement of fossil fuels by renewable ones and development of a recycling process to recover chlorine donors and metals as reusable materials. Targeted renewable fuels are particularly those that enhance the P-content of the product: meat and bone meal and dried sewage sludge granules. Phase 4 will, finally, integrate the newly developed process steps into the pilot plant._x000D__x000D_The project shall achieve the following goals: (i) reduce the fertiliser production costs; (ii) increase the P-content of the fertilisers (e.g. by application of meat and bone meal); (iii) recycle considerable amounts of meat and bone meal as fuel and P-source; (iiii) reduce CO2 emissions of the process deriving from fossil fuels and (iv) establish a process internal chlorine-recycling system that separates the heavy metals from the recycling flow (with subsequent recycling of the separated heavy metals in the secondary metallurgy). The experiments will be carried out in laboratory- and technical scale and in the pilot plant._x000D__x000D_The project faces the following challenges: (i) the introduction of refuse derived fuels as energy and suplementary P-sources for the thermo-chemical treatment of sewage sludge ash; (ii) possible changes of the process- and off gas conditions, (iii) the influence of the newly introduced materials on the fertiliser quality, regarding potential contaminations and a potential adverse effect on bioavailability of P and (iv) the influence of recycled chlorines to the process in terms of heavy metal removal and P-bioavailability._x000D_ _x000D_The methodological approach involves a variation of the amounts of recycled chlorine donor and solid organic fuels such as meat and bone meal, different ways of their addition and combustion and a variation of other relevant process parameters. The assessment of the process and the output materials will involve (i) chemical, physical and structure analysis of the raw products and the final fertilisers and (ii) greenhouse pot- and field experiments with the ash-based fertilisers in comparison to conventional fertilisers._x000D_

Acronym SUSYPHOS (Reference Number: 4314)
Duration 01/02/2009 - 30/10/2011
Project Topic Phosphorus (P) recovery has become mandatory because of depleting primary resources. Sewage sludge and meat and bone meal are the principal drains in the P cycle. The proposed thermo-chemical fertiliser production process makes symbiotic use of nutrient rich materials for energy and P-recovery.
Network Eurostars
Call Eurostars Cut-Off 1

Project partner

Number Name Role Country
5 ANiMOX GmbH Partner Germany
5 ASH DEC Umwelt AG Observer Austria
5 Bundesanstalt für Materialforschung und -prüfung Partner Germany
5 wpa Beratende Ingenieure gmbh Coordinator Austria
5 E-Flox GmbH Partner Germany