Wastewater cleaning with electricity
A team of researchers from the Sydney School of Chemical and Biomolecular Engineering has made great progress in achieving the decontamination of large flows of highly contaminated industrial wastewater. These researchers have developed a method of electrochemical oxidation with the aim of removing very complex pollutants from water.
The study involved wastewater contaminated with a cocktail of chemical species of both organic and inorganic nature, coming from a biofuel production process. This water contained substances rich in carbon, nitrogen and phosphorus and was generated in a pilot plant for the production of biofuels from microalgae designed by the team of researchers. The process of producing this type of biofuel generates an aqueous phase solution as a by-product from the liquefaction of the algae, which contains a significant fraction of the decomposed components of the raw material and is suspected of having harmful effects on the environment, so it must be treated before final disposal.
Basically the process consists of treating the waste water with electricity, using specially designed electrodes, in which, when the electric discharge is made, oxidation reactions are carried out on its surface. It was used for the first time an electrochemical oxidation process to reduce the content of soluble organic components in the coproduct in aqueous phase of the liquefaction of the microalgae Chlorella sp. using as anode the diamond doped with boron. During these reactions the contaminants were decomposed into harmless gases, ions or minerals. According to the data reported in the study, the process removed up to 99% of the carbon, nitrogen was converted from organic to inorganic forms, remaining predominantly in solution as ammonia and nitrate.
What is exceptional about the process is that they have managed to remove even very poorly biodegradable and fairly persistent compounds, such as pharmaceuticals, pesticides and other organic compounds that are difficult to treat and that are often present in industrial wastewater streams. On the other side, the process is relatively simple and does not require the addition of other chemicals, nor does it generate hazardous waste streams.
There is a strong trend in the world for the development of biofuels, especially using microalgae present in abundance in nature. However, little is being done about the treatment that effluents from this type of process should receive, so this type of research can provide great opportunities for better use of resources.
As we know, wastewater is an important issue in our society, since large volumes of urban wastewater are generated daily, of which industrial flows are loaded with pollutants that conventional treatment plants cannot handle properly, and finding solutions to this is often complicated and costly. Therefore, finding simple procedures that do not generate dangerous sub-products is of utmost importance to ensure the sustainability of the ecosystems around industrial centers.
Wastewater is even a huge opportunity for resource exploitation. Properly managed, wastewater can be a sustainable source of water, biogas, nutrients and other recoverable resources.
Thank you for reading me. Until the next post!