The cost of treating wastewater contaminated with nitrogen could be lowered in future. Soil scientists at the Helmholtz Centre for Environmental Research (UFZ) have developed a new mathematical model which can help determine the optimum conditions for microbiological water treatment.
One of the key concerns of the European Water Framework Directive (WFD), which came into force in 2000, is the reduction of nitrogen-containing nutrients in waterbodies. One approach is to avoid or optimise the use of nitrogen fertilizers in agriculture. Another approach is to improve wastewater treatment technologies.
Current biological treatment methods are based on the microbial processes of nitrification and denitrification. Although these methods make it possible to treat wastewater containing high levels of nitrogen safely, they also have a considerable disadvantage: the nitrogen that is removed is primarily released into the atmosphere in the form of the greenhouse gas N2O. This is a dilemma in that water protection and climate protection have until now been mutually exclusive.
During experiments with the treatment of nitrogen-contaminated wastewater at the beginning of the 1990s, a previously unknown microbial process was discovered that can break down the main components of the nitrogen contamination in the wastewater (ammonium and nitrate) in the presence of atmospheric oxygen (anaerobically). The only end product is environmentally neutral molecular nitrogen (N2). Exploiting this process, called ‘anammox’, to clean nitrogenous wastewater could in future lead to an entirely climate-neutral treatment of municipal wastewater. In addition, unlike the microbial processes used until now, the anammox process does not require organic nutrients, so in future it will be possible to manage without the addition of nutrients during the treatment process. This will reduce the cost of wastewater treatment still further.
However, particularly with regard to the development of efficient wastewater treatment systems, research into the anammox process is still posing significant problems more than 15 years after it was discovered. The main reason for this is that the end product of the anammox process under investigation (N2) can also be produced simultaneously in the course of the denitrification process, so it has been almost impossible to quantify the conversion rate accurately. In addition, the molecular nitrogen (N2) resulting from the microbiological processes is in principle ‘invisible’ because of the high background concentration of N2 in the atmosphere (≈79 vol. %), since the quantities of N2 released are extremely small compared with the existing atmospheric nitrogen levels. Now for the first time, the two soil scientists Oliver Spott and Florian Stange of the Helmholtz Centre for Environmental Research (UFZ) have succeeded in developing a new mathematical model that can calculate precisely the quantities of N2 from anammox, from denitrification and from the atmosphere. The model is based on analyses using stable isotopes, and means that in future it will be possible to investigate in greater detail the optimum conditions for microbiological treatment of nitrogenous wastewater using the anammox process. This will in turn make it possible to reduce the costs of wastewater treatment in the long term, increase its effectiveness and avoid N2O emissions. The two scientists have published their discovery in the internationally renowned specialist journal Rapid Communications in Mass Spectrometry.
The idea for developing the new mathematical approach using the stable nitrogen isotope 15N came from their collaboration with UFZ colleagues Peter Kuschk and Diego Paredes, who have been looking at the possibility of microbial treatment of nitrogenous wastewater using anammox for a long time. But the new equations are also of great significance for their own work. In 1992 Japanese scientists described for the first time a metabolic process involving soil fungi (Fusarium oxysporum) which is very similar to the process of anaerobic oxidation of ammonium and which was called codenitrification, after the familiar process of denitrification. Despite this, even 15 years after the discovery of codenitrification, scientists still work on the assumption that when nitrogen from the soil is broken down, it is only denitrification that is responsible for the release of molecular nitrogen (N2). Using the 15N isotope technique and the new mathematical approach, it is now possible to calculate precisely the N2 released from the soil during both processes – denitrification and codenitrification. An initial, very recent study by two British scientists has already come to the surprising conclusion that up to 92 per cent of microbially released N2 is attributable to the process of codenitrification. If these initial results can be confirmed and extended to other soils around the world, this would completely change our current understanding of N2 emissions from the soil. The two scientists Oliver Spott and Florian Stange will be using the new equations to tackle this question in collaboration with international scientists.top
http://dx.doi.org/10.1002/rcm.3098Spott O, Russow R, Apelt B, Stange CF:
Sinking groundwater levels threaten the vitality of riverine ecosystems
04.10.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau
A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.
The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...
Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).
Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...
How do some neutron stars become the strongest magnets in the Universe? A German-British team of astrophysicists has found a possible answer to the question of how these so-called magnetars form. Researchers from Heidelberg, Garching, and Oxford used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars could result.
How Do the Strongest Magnets in the Universe Form?
A hot, molten Earth would be around 5% larger than its solid counterpart. This is the result of a study led by researchers at the University of Bern. The difference between molten and solid rocky planets is important for the search of Earth-like worlds beyond our Solar System and the understanding of Earth itself.
Rocky exoplanets that are around Earth-size are comparatively small, which makes them incredibly difficult to detect and characterise using telescopes. What...
Scientists at the Max Planck Institute for Chemical Physics of Solids in Dresden, Princeton University, the University of Illinois at Urbana-Champaign, and the University of the Chinese Academy of Sciences have spotted a famously elusive particle: The axion – first predicted 42 years ago as an elementary particle in extensions of the standard model of particle physics.
The team found signatures of axion particles composed of Weyl-type electrons (Weyl fermions) in the correlated Weyl semimetal (TaSe₄)₂I. At room temperature,...
02.10.2019 | Event News
02.10.2019 | Event News
19.09.2019 | Event News
14.10.2019 | Physics and Astronomy
14.10.2019 | Earth Sciences
14.10.2019 | Health and Medicine