Im Rahmen des Forschungsvorhabens „Phorwärts“ wurde auf Basis aktuell erhobener Daten die konventionelle Phosphatdüngemittelherstellung (vom Abbau des Phosphaterzes in der Mine bis zur Anwendung auf dem Feld) mit ausgewählten Verfahren der P-Rückgewinnung aus dem Abwasserpfad ökobilanziell verglichen. Die verschiedenen Düngemittel wurden hinsichtlich ihrer Kontaminationen wie den Schwermetallen, den organischen Schadstoffen und den Pharmaka-Rückständen zusätzlich in einer vergleichenden Risikobewertung der Düngemittelanwendung für die Wirkungspfade Bodenorganismen, Grundwasser und im Hinblick auf die menschliche Gesundheit untersucht. Eine Kostenschätzung der verschiedenen Produktionswege komplettiert den Vergleich der konventionellen Phosphatdüngemittelproduktion mit der Produktion von Recyclingdüngern aus der Kläranlage. Die Ergebnisse der Studie zeigen, dass eine technische Phosphatrückgewinnung aus dem Abwasserpfad unter bestimmten Bedingungen ökologisch und wirtschaftlich sinnvoll ist. Neben dem eigentlichen Phosphatrückgewinnungsverfahren sind in hohem Maße die lokalen Randbedingungen bezüglich der Ergebnisse der vergleichenden Bewertung entscheidend. Unter Berücksichtigung der kommenden gesetzlichen Randbedingungen der Dünge- und der Klärschlammverordnung wird in Zukunft voraussichtlich die Monoverbrennung als primäre Option für die Klärschlammentsorgung dienen und die Phosphatrückgewinnung vorwiegend aus der Klärschlammasche erfolgen. Da bei der Rückgewinnung aus der Klärschlammasche hohe Rückgewinnungsraten, die den Vorgaben der Klärschlammverordnung genügen, erzielt werden können, ist ab dem Kalenderjahr 2029 mit etwa 30.000 bis 40.000 Tonnen Phosphor pro Jahr in Form von Phosphatrezyklaten zu rechnen. Inwieweit und zu welchen Preisen diese Rezyklate durch den Markt angenommen werden, kann aus heutiger Sicht noch nicht abgeschätzt werden.

Kompletter Bericht

In the aftermath of the adoption of the Sustainable Development Goals (SDGs) and the Paris Agreement (COP21) by virtually all United Nations, producing more with less is imperative. In this context, phosphorus processing, despite its high efficiency compared to other steps in the value chain, needs to be revisited by science and industry. During processing, phosphorus is lost to phosphogypsum, disposed of in stacks globally piling up to 3–4 billion tons and growing by about 200 million tons per year, or directly discharged to the sea. Eutrophication, acidification, and long-term pollution are the environmental impacts of both practices. Economic and regulatory framework conditions determine whether the industry continues wasting phosphorus, pursues efficiency improvements or stops operations altogether. While reviewing current industrial practice and potentials for increasing processing efficiency with lower impact, the article addresses potentially conflicting goals of low energy and material use as well as Life Cycle Assessment (LCA) as a tool for evaluating the relative impacts of improvement strategies. Finally, options by which corporations could pro-actively and credibly demonstrate phosphorus stewardship as well as options by which policy makers could enforce improvement without impairing business locations are discussed.

Being one of the key nutrients, there is no doubt about the importance of phosphorus for all life on Earth. This element is even considered “life’s bottleneck”, as Isaac Asimov, one of the brilliant minds of the last century already stated in 1959 in his essay of the same title. Its importance as plant nutrient is emphasized by the huge amount of about one million metric tons of mineral phosphorus annually imported into Europe to sustain good harvests. Since phosphorus is a limited fossil element and given the strong dependency of Europe on phosphorus imports, its extensive recovery from “secondary deposits” is of paramount importance and follows the principles of the European Roadmap for Resource Efficiency. No matter, if there would be a phosphorus peak in the future or even physical scarcity, pure reason alone should force us to secure this vital resource not only for ourselves but also for future generations. Scarcity itself is not a problem of the future, but an actual thread to many people’s life whose cannot effort fertilizers to grow enough food for themselves. They know the essential or real demand of phosphorus humans need to survive, whereas in Europe we can afford luxury uptake. The availability of phosphorus is dramatically dependent on economical drivers. Looking at the current supply-chain efficiency of phosphorus, only about 20% of mined phosphate rock is finally consumed in form of food (Schröder et al. 2010). Most of the precious element is lost on its way from mine to fork. However, phosphorus does not disappear and can, unlike oil, be recycled once used. In developed countries with proper sanitation and wastewater treatment, the wastewater stream represents a relevant phosphorus reserve. In Germany, more than 50% of the annually imported mineral phosphorus destined to be used as fertilizer (about 120,000 metric tons) could be substituted by recovered phosphorus from the wastewater stream if it were recycled completely. Various technologies have been developed in recent years to tap into this secondary resource. They might also be applicable for other material flows like manure and digestate. The traditional application of sewage sludge in agriculture was the dominating recycling path in the past, but is increasingly refused due to concerns about pollutants being harmful for the environment and public health. Technological alternatives are about to contribute to close the phosphorus cycle again (Kabbe 2013). Although some of these techniques are already feasible, they still need to be implemented onto the market. Three waste material flows, sewage sludge, manure and digestate are all alternatives to industrial fertilizers and compete for the same limited land area. Thus, only solutions that safeguard human health and the environment are viable resulting in a driver for wide-spread application of innovative alternatives when direct valorization on arable land falls short. For successful market implementation, new technologies and their resulting products need to be proven capable and feasible. Within the European project P-REX, novel and available technical solutions for phosphorus recovery and recycling will be demonstrated in full-scale. Their performance and feasibility will be systematically assessed and validated, as well as the quality of obtained recycling products with focus on plant-availability and eco-toxicity. Environmental impacts (LCA) and costs (LCC) will be calculated based on these data. Together with the analysis of the legal framework and existing market barriers and market potentials for novel recycling technologies and their products, strategies and recommendations will be developed for efficient and wide-spread implementation of phosphorus recovery with regards to specific regional conditions. A first overview of legal, societal and market aspects has been elaborated within the first project year and was discussed in the stakeholder workshop “Recycled Phosphorus Fertilizer- Market Chances and Requirements” in Podebrady (CZ) in September 2013. The finalized report (A. Nättorp et al, 2013) is available for download at the project’s website: www.p-rex.eu. Stakeholder workshops in different European regions will be organized in 2014 to ensure the involvement of all relevant stakeholder perspectives and regional conditions and needs. Especially the end-user perspectives (plant operators, fertilizer industry, crop farmers) need to be considered more in the overall discussion in the future. P-REX is aiming to increase the European phosphorus recycling rate from municipal wastewater by closing gaps between science, policy and practice, as it was a key message of the First European Sustainable Phosphorus Conference in March 2013: waste less, recycle more and cooperate smart (www.phosphorusplatform.eu). Besides wastewater and sewage sludge, manure and digestate bear substantial quantities of phosphorus for recovery and possible synergies just wait to be applied.