30th June, 2018.- The project Life Celsius, developed by Acciona Agua and EFE News Agency in Archena (Murcia) faces its final line with «all processes running online and continuously, from the treatment of organic matter to the process of nitrogen removal».
This has been assured by María del Mar Micó, project director, who has been particularly satisfied with the results of the last stage of elimination based on Anammox bacteria; «they have adapted very well since we sowed them. After a short time, they had a considerable activity and now we have higher rates than those collected in similar processes».
These bacteria are responsible for the elimination of nitrogenous compounds from wastewater, once the organic matter has been removed, and its «high activity» demonstrates that «they’re doing their job well».
Also «the expected parameter will be fulfilled in the phase of organic matter elimination, thanks to the substitution of anaerobic digestion treatment by a high-load aerobic treatment», added María del Mar.
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Improvements in the first phase
At first, Celsius proposed to use the permeate of the AnMBR system that previously would have eliminated the organic matter to continue with the elimination of nitrogen, «however, due to the high concentration of sulfate present in the waters of this area, which of course, is not harmful or does not affect a conventional water treatment, it does have negative interferences in the anaerobic digestion process «.
«The effluent that we obtained was not of sufficient quality to be able to feed the rest of the processes and we decided to replace this anaerobic process with an aerobic process, something different from the conventional ones, since we work with a low concentration of sludge inside the system, which it’s called high-load aerobics».
And in this way, the oxygen we apply is aimed only at eliminating organic matter and the nitrogenous processes remain unchanged to be treated in the following stages.
According to María del Mar Micó, at an energetic level «it is somewhat unfavourable in the face of anaerobic digestion, but the fact that it is of high load and that it does not have to add extra oxygen to treat the nitrogen matter we get that, although the energy saving is not as high as expected, we remain at lower levels than those consumed in a conventional treatment plant «.
The Celsius plant
This chemical engineer directs the Life Celsius project with the support of EFE News Agency. It is an initiative financed by the European Commission to test in a small-scale pilot, the plant installed in the Archena WWTP, owned by the company Sanitation and Wastewater Treatment Plant of the Region of Murcia (ESAMUR), a waste water treatment system with low energy consumption.
The plant developed by Life Celsius corresponds to the second phase of the Opto AnMBR project, led by Acciona Agua and Esamur, which began with the installation, in the Archena WWTP, of an anaerobic digester membrane for the elimination of organic matter without oxygen supply and without the need for an external heat source, because the effluent reaches the sewage treatment plant at around 15-20 degrees.
Heat and bacteria
«All biological processes are closely related to temperature, and in general, they all run at higher speed the higher it is and slow down as it falls, remaining even inhibited or stopped», explained María del Mar Micó, «an equation that determines the success of your daily work».
«When bacteria-whose development requires temperatures ranging from 30 to 37 degrees-show high activity implies that they are doing well their work, which, in the case of a treatment plant, means that they are eliminating organic matter or nitrogen compounds optimally».
Therefore, Micó has recognized that this winter and, above all, this spring, colder than usual, «temperatures have had a great impact on the activity of bacteria in the pilot plant, whose water volume is smaller, and they have worked less».
However, «a little that began to increase the temperature, we saw that the activity rebounded again and now we have them the same as we had in the best time of last summer, at full performance» , she explained.
According to the expert, Anammox bacteria that uses this technology for the elimination of nutrients «can adapt to cold winters and not lower their activity as much as other bacteria accustomed to temperate climates».
«When they arrived here -she explained- they came from a plant where they were working at about 35 degrees, and yet, this temperature, of about 20-25 degrees, barely affected their activity and we could quickly see that the system was colonizing with the expected activity».
Traducción: Carmen Gilson