Vacuum degasification (VD) of ammonia from waste streams and subsequent production of nitrogen fertilizer can be one element of the effort towards closing the nitrogen (N) cycle and thus avoiding emissions harmful to the environment. This master’s thesis comprises a literature research for suitable substrates and laboratory experiments for the optimization of a design and experimental design of a VD pilot plant for ammonia recovery. Eight streams among the top 20 food waste streams in Europe and their associated streams, all digestates from digestion or co-digestion of animal waste streams, agricultural digestates and manures were identified as suitable substrates for N-recovery with VD. During 120 min of VD at pH 9.0, 190 mbar and 60 °C a total ammonia-N (TAN) removal rate of 0.81 ± 0.03 was achieved with an NaOH load of about 80 ml (L substrate)-1 in biogas digestate. The TAN removal rate during VD at 190 mbar and 60°C was dependent on pH with a dose response function. For efficient ammonia removal pH = 9.0 was necessary. Evidence for an ammonia volatilization inhibition at pH = 8.5 not explicable by the ammonia dissociation was found. At 158 % of the boiling pressure, 69 % of the TAN removal rate at boiling pressure was reached. Air stripping the hot substrate for 60 min lowered the NaOH load for maintaining pH 9.0 during VD by 30 %. Electrical conductivity (EC) and pH during the degasification treatment did not correlate. Alkaline hydrolysis could be the reason for pH decrease during VD at pH 9.5. In the pilot plant a pH sensor and a possibility to adjust the pH continuously should be installed. The pH for VD experiments at 60°C should be in the range 8.75–9.5. Pressures below the boiling pressure should not be excluded. Experiments with CO2 stripping should be conducted to exhaust the potential for NaOH saving.
Gülle und Gärreste werden häufig als Wirtschaftsdünger in der Landwirtschaft eingesetzt. Sie liefern sowohl organisches Material für den Boden als auch Stickstoff, der ein wichtiger Nährstoff für Pflanzen ist. Oft stimmt jedoch die gesetzlich vorgeschriebene, saisonale Ausbringung der Gülle nicht mit dem Zeitpunkt des tatsächlichen Stickstoffbedarfs der Pflanzen überein. Dies führt zu einem unerwünschten Verlust des Stickstoffs für die Pflanzen durch Emissionen ins Grundwasser (Nitrat) oder in die Atmosphäre (Ammoniak und/oder Lachgas). Besonders in Regionen mit einem hohen Gülleaufkommen und einer hohen Ausbringungsrate der Gülle kann es zu starken Umweltbelastungen kommen. Um die Zufuhr des organischen Materials für den Boden von der Stickstoffzufuhr aus der Gülle für die Pflanzen zu entkoppeln, wurde in dem EU geförderten Projekt Circular Agronomics (www.circularagronomics.eu) eine Pilotanlage entwickelt und konstruiert. Die Pilotanlage soll eine „stickstoffabgereicherte Gülle“ produzieren, die als Bodenverbesserer eingesetzt werden kann. Cirular Agronomics zielt darauf ab, zwischen 80 % und 90 % des Stickstoffs, der ursprünglich als Ammonium vorlag, aus der Gülle bzw. dem Gärrest zurückzugewinnen. In einem anschließenden Gaswäscher reagiert das Ammoniakgas mit Schwefelsäure zu einer Ammoniumsulfatlösung, welche ein typischer mineralischer Stickstoffdünger ist. Dieser kann dann ausgebracht werden, wenn die Pflanze den Stickstoff benötigt und umsetzen kann. Um den Prozess der Vakuumentgasung besser zu verstehen und die optimalen Prozessbedingungen zu untersuchen, wurden im Vorfeld Laborexperimente durchgeführt. In den Versuchen wurden der pH-Wert, die Druckbedingungen und die Prozesstemperatur variiert. Die Experimente zeigten, dass bei einem pH-Wert von 9.0, einer Temperatur von 60 °C und einem absoluten Druck von 190 mbar bis zu 88 % des Ammoniums aus dem Gärrest in Form von Ammoniak abgereichert wurden. Eine CO2-Strippung vor Anhebung des pH-Wertes auf pH 9.0, verringerte zudem die notwendige Natronlaugenzufuhr zur pH-Wert-Anhebung um 30 %. Basierend auf den Ergebnissen der Experimente wurden Schlussfolgerungen für ein optimales Design der Pilotanlage abgeleitet. Derzeit wird die Pilotanlage in Betrieb genommen und erste Versuche durchgeführt, deren Ergebnisse ebenfalls im Vortrag präsentiert werden.
As part of their communication activities, multi-actor approach projects are required to produce short “practice abstracts” (PAs) which outline their plans and main findings. The information should be easy understandable and provided throughout the project’s life-cycle. This information must therefore be shared in a specific format (the “EIP Common format”) which is specially made so that project info and results can be shared with those who can apply the findings. The format includes: a short and understandable title, a succinct summary of the issue tackled and the main outcomes and recommendations produced, and contact details to find further information. The content of the submitted practice abstracts can be updated at any moment according to new findings.
General methodology of Life Cycle Assessment that will be used to assess the environmental evaluation of each case study. This includes the description of the used methods and tools, as well as information that applies for all studied systems. The document also comprises the methodological approach, the interpretation concept and specific assumptions for the innovative production strategies assessed within the CS of Circular Agronomics. All studied systems are described in detail and a brief overview over the further steps of the environmental assessment, including data collection and calculations is given.
Circular Agronomics (CA) provides a comprehensive synthesis of practical solutions to improve the current carbon, nitrogen and phosphorus cycling in European agro-ecosystems and related up and downstream processes within the value-chain of food production. CA is a frontrunner project exploiting affordable solutions to meet, among others, the requirements of agriculture, water and waste legislations as well as the EU policy targets regarding emission reduction (mainly NH3, NOx and GHG: CO2, CH4, N2O). The policy analysis contributes to market innovations, to sustainability and European initiatives and finally also to the development of effective joined up policy - further steps towards integrating agriculture in circular economy.
Circular Agronomics, aims to foster the transition from a linear economy to a circular economy. Therefore, this deliverable focuses on circular solutions for waste and wastewaters originating from the food industry. In 2019, the “Best Available Techniques (BAT) Reference Document for the Food, Drink and Milk Industries” (BREF-document) was published by the European Commission. Based on that, the deliverable summarizes the state of the art of the technologies already in use and concludes their suitability for circular economy solutions. In Circular Agronomics, new technologies for the recovery of carbon, nitrogen, phosphorus and potassium are developed and investigated. So far, those technologies are not included in the BREF-document yet. Therefore, the concepts of the technologies are introduced in the deliverable. For a potential integration of those technologies in the BREF-document, the technologies are described in detail in the annex according to the required structure in the BREF-document. However, since the technologies are still under development, those descriptions are considered as a first draft. The authors suggest to update those descriptions at a later stage of the project prior to their potential integration in the BREF-document. Referring to the goal to recover carbon and nutrients, the deliverable presents a detailed characterization of the waste and wastewaters originating from the food industries. Based on that, the five most promising waste and wastewater streams regarding carbon recovery, nitrogen recovery, phosphorus recovery and potassium recovery were selected. For those streams and the corresponding recovery technologies four new concepts are suggested in the deliverable. In order to show the technology providers an overview of potential clients for their technologies and for those concepts, for each selected industry, the European country with the highest production rate was chosen. For this country, the regional distribution of the certain industry was determined.
Objectives: (i) To ensure that knowledge developed during the project is properly captured and dissemination is effectively targeted and carried out systematically (ii) To promote a continuous knowledge exchange and transfer for project outcomes with interested stakeholders beyond the consortium (iii) To formulate fact based policy recommendations that stimulate the transition towards a circular economy (iv) To create public awareness concerning the need for a circular economy and the actions required to move towards its realisation
Objectives: (i) To ensure that knowledge developed during the project is properly captured and dissemination is effectively targeted and carried out systematically (ii) To promote a continuous knowledge exchange and transfer for project outcomes with interested stakeholders beyond the consortium (iii) To formulate fact based policy recommendations that stimulate the transition towards a circular economy (iv) To create public awareness concerning the need for a circular economy and the actions required to move towards its realisation