Growth in cattle population is associated with increased manure generation whose current management in low-income countries is associated with health and environmental problems as well as low utilization rates. This trend can be reversed by promoting better manure management technologies. This study assessed vermicomposting as one of the technologies to manage organic wastes, using the case study in Uganda. A vermicomposting system using cattle manure and earthworms (Eudrilus euginea) was monitored for one year with the harvesting of products (compost, earthworm biomass) after every three months. Vermicompost samples from the beginning of the experiment and after every harvest were analyzed for the following parameters: pH, ash content, volatile and total solids, nutrients N, P, K, and C. Emissions of CO₂, CH₄, NH₃, and N₂O were also measured. Material flow analysis was used to determine the flows and retention of nutrients within the system. Results showed that total solids, ash, N, P, and K content significantly increased, while contents of volatile solids and C, as well as the pH, significantly decreased over time. Of the materials that entered the vermicomposting system, 46% went to vermicompost, 2% into earthworms, and 52% was lost to the atmosphere. Substance flow analysis showed that 30% of C went to vermicompost, 69% was emitted to the atmosphere, and 2% ended up in earthworms while 75% of N was transferred to vermicompost, 7% went to earthworms, and 18% escaped into the atmosphere. The cumulative emissions were 102 g CO₂ kg⁻¹ waste, 7.6 g CH₄ kg⁻¹ waste, and 3.943 × 10⁻⁵ g N₂O kg⁻¹ waste on a dry basis, while NH₃ was not detected throughout the measurement time. Compared to other manure management methods, vermicomposting demonstrated good potential in conserving nutrients as well as reducing greenhouse gas emissions.

Occurrence and concentration of a broad spectrum of micropollutants are investigated in Austrian river catchments, namely polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), organotin compounds, perfluoroalkyl acids (PFAAs) and metals. The parallel analysis across multiple environmental and engineered compartments sheds light on the ratio of dissolved and particulate transport and on differences in concentration levels between point and diffuse emission pathways. It is found that some PAHs and organotins are present in rivers, groundwater and bulk deposition at higher concentrations than in municipal wastewater effluents. Among PFAAs and metals, highest concentrations were recorded either in atmospheric deposition or in discharges from wastewater treatment plants. The relevance of the analysis across compartments is best shown by the case of perfluorooctanesulfonic acid (PFOS). Despite municipal wastewater effluents being the emission pathway with highest concentrations, this study reveals that not only rivers, but also atmospheric deposition and groundwater sometimes exceed the environmental quality standard for surface waters. Moreover, this work reveals partially counterintuitive patterns. In rivers with treated wastewater discharges, increasing levels of dissolved compounds were measured at rising flow conditions, whereas the opposite would be expected owing to the dilution effect. This might derive from the mobilisation from soil or suspended particulate matter or rather find its explanation in high concentrations in atmospheric deposition. These hypotheses require however being tested through targeted studies. Additional future research includes the analysis of how regional or catchment specific characteristics might alter the relative importance of different emission pathways, and the modelling of emission and river loads to assess their relative contribution to river pollution.

Recent years came with a paradigm shift for wastewater treatment plants (WWTPs) to extend the sole purpose of contaminant removal to an additional function as resource recovery facilities. This shift is accompanied by the development of new European legislation towards better inclusion of resource recovery from wastewater. However, long operational lifespans and a multitude of treatment requirements demand thorough investigations into how resource recovery can be implemented sustainably. To aid the formulation of new legislation for phosphorus (P) recovery specifically, in 2017 we conducted a survey on Austrian WWTP-infrastructure, with a focus on P removal and sludge treatment, as well as disposal and sludge quality of all WWTPs above 2000 population equivalents (PE). Data were prepared for analysis, checked for completeness and cross-checked for plausibility. This study presents the major findings from this database and draws essential conclusions for the future recovery of P from wastewater. We see results from this study as useful to other countries, describing the current state of the art in Austria and potentially aiding in developing wastewater treatment and P recovery strategies.

Zusammenfassung Die Nutzung von Phosphor (P) erfolgt derzeit in Österreich im Wesentlichen linear, Kreisläufe sind – mit Ausnahme des internen landwirtschaftlichen Kreislaufes der Nutzung von Wirtschaftsdünger (Gülle, Stallmist) – kaum ausgebildet. Gleichzeitig ist Österreich vollständig auf den Import des endlichen Rohstoffes Rohphosphat aus teils geopolitisch instabilen Regionen angewiesen. Demgegenüber weisen kommunales Abwasser und Tiermehle ein beträchtliches P-Potenzial auf, welches jedoch kaum genutzt wird. In Hinblick auf die Kritikalität von P wurden zahlreiche Technologien zur gezielten Rückgewinnung von P aus dem Abwasser entwickelt, welche vom rein technischen Gesichtspunkt bereits einsatzfähig sind bzw. teilweise bereits großtechnisch umgesetzt wurden (v. a. Rückgewinnung aus der flüssigen Phase). Mit dem Ziel einer größtmöglichen Nutzung des abwasserbürtigen Phosphors wäre zukünftig eine Rückgewinnung aus reinen Klärschlamm- oder kombinierten Tiermehl- und Klärschlammaschen anzustreben. Die dafür notwendigen Strukturen wie Verbrennungsanlagen für Klärschlamm alleine oder in Kombination mit Tiermehl müssten dazu allerdings noch ausgebaut werden. Neben neu entwickelten Verfahren können Recyclate von Rückgewinnungsverfahren (z. B. Struvit) oder reine Klärschlamm-/Tiermehlaschen als Sekundärrohstoffe in bestehenden industriellen Prozessen wie etwa der Düngemittel- oder Phosphorsäureindustrie eingesetzt werden. Die Nachbarländer Deutschland und Schweiz streben die Rückgewinnung von P aus Klärschlämmen bzw. deren Aschen bereits über rechtlich verbindliche Ziele an. Damit dies auch in Österreich umgesetzt werden kann, sind in einem ersten Schritt das (politische) Bekenntnis und in weiterer Folge Änderungen der rechtlichen Rahmenbedingungen (z. B. im Düngemittelrecht) sowie verbindliche Vorgaben erforderlich. Instrumente zur Umsetzung eines P-Recyclings können beispielsweise festgelegte Recyclingquoten für die Düngemittelindustrie (z. B. „Pxx“ in Anlehnung an die E10-Bioethanolquote) oder die Einhebung eines „Phosphorcents“ zusätzlich zu den Gebühren der Abwasserreinigung oder Abfallwirtschaft, welcher für den Aufbau der erforderlichen Strukturen (z. B. Verbrennungsanlagen für Klärschlamm und Tiermehl) herangezogen werden kann.