When dried with the new process, sludge from wastewater treatment can be used as fertilizer, dumped in landfills or incinerated. Unlike thermal drying processes, the new technique, known as "mechanically enhanced biodrying" or MEB, does not require any outside source of heat.
Wastewater treatment gives rise to large quantities of runny sludge that contains a low proportion of solid matter. The water usually has to be drained from this sludge before it can be used, dumped in landfills or incinerated, and this is often accomplished via pressing. A solids content of approximately 20 percent can be achieved this way. In some countries this semisolid sludge is spread on fields as fertilizer or dumped in landfills.
In some countries, however, a solids content of at least 60 percent is mandated for these purposes, and this was recently prescribed by law in China as well. In order to attain this high percentage of solid matter, the sludge must be dried. This can be accomplished very rapidly with thermal processes, which demand a great deal of energy. Alternatively, the sludge can be dried with help from the sun, but this can take up to two months.
The Siemens solution increases the solids content of the sewage sludge from 20 to 65 percent within about 22 days; after that, the resulting product can be used as fertilizer or fuel, or it can be disposed of in landfills. The heat required for the drying is produced by biological processes. Microbes break down nutrients in the sludge and generate heat in the process.
The only other type of energy needed is mechanical energy to aerate and mix the sludge in order to keep the biological processes going. A six-month pilot test at a composting plant in the town of Merrimack in the U.S. state of New Hampshire has shown that this technique works even at ambient temperatures as low as minus ten degrees Celsius.
The sewage sludge is automatically aerated and mixed in a controlled process. The system is enclosed, so that any odors can be trapped with a biofilter. The new process is particularly well suited to developing countries where energy is scarce but an abundance of land is available.
Dr. Norbert Aschenbrenner | Siemens InnovationNews
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy