Life CELSIUS: Optimizing Wastewater Treatment Through Biological Processes

Although the number of wastewater treatment plants is growing steadily year by year because of health and environmental considerations, 70 % of wastewater in the world still does not receive any treatment whatsoever. Ironically, most wastewater treatment plants are power-hungry, which means a higher carbon dioxide footprint and increased environmental costs. One of the solutions to this situation could be found in a biotechnological approach for more sustainable operations. Life CELSIUS is an EU-funded Spanish technology Project headed by ACCIONA that aims to develop a new type of wastewater treatment plant for warm countries. Its secret sauce is the use of biological processes to remove organic matter and nitrogen compounds that will reduce power requirements compared to conventional processes.

The Wastewater Treatment Plant of Archena (in the Southern Spanish region of Murcia) has been the setting for a three year-trial. In order to achieve a more efficient and eco-friendly purification process, this technology project has combined current technologies with less common bacteria in wastewater treatment, while also leveraging warmer waters to boost bioprocesses. The higher temperatures of warm climates allow boosting bioprocesses in a natural way, without the need for external heating, thus reducing the overall energy consumption.

Conventional treatment systems usually remove organic matter and nitrogen simultaneously through a biological process that requires large amounts of oxygen. Life CELSIUS provides an alternative system, by introducing independent stages throughout the treatment. Each one of them requires little to no oxygen. As aeration is one of the most power-consuming processes in a wastewater treatment plant, reducing it also cuts power consumption as compared to conventional systems.

The stages of the Life CELSIUS system

Firstly, with this new technique, organic matter is removed through a process that allows recovering large amounts of it and transforming it into biogas in a later stage. Secondly, by acclimatizing bacteria from conventional treatment plants, part of the nitrogen in the wastewater turns into nitrite. Up till now, most systems transform all the nitrogen into nitrite, which requires far more oxygen than the Life CELSIUS model. Finally, the water treated through said processes feeds the anammox, the most novel bacteria in the system, closing the circle.

These bacteria, discovered in 1990 and found since then in a range of natural systems, can transform dissolved nitrogen into nitrogen gas anaerobically, i.e., without the need for oxygen. The nitrite generated in the second stage is combined with the non-treated nitrogen, usually present as ammonium, to produce nitrogen gas dissipated in the atmosphere.

A technology with great potential in warm climates

According to the researchers, the results of this new technology are quite promising. Implementing this technology at a real scale could translate into a 25% power decrease in wastewater treatment, with the corresponding reduction in greenhouse gases. Also, operational costs of the plants would be reduced by 22.5%, both because of the energy savings and the reduced amount of sludge generated by slower anaerobic metabolic processes.

Eventually, Latin America, Africa, the Mediterranean area and other warm regions will benefit from the efficiency gains introduced by water treatment technology Life CELSIUS.  

Source:  Life Celsius