Dual wastewater treatment with biotechnology and electrochemistry.
Today, wastewater treatment plants (WWTPs) clean wastewater to be able to return it to the environment, treating it as waste and allocating many resources, both energy, and economics, in its purification.
In addition, it is increasing the engineering and the elimination of the innovative technology that we consent not to recover the wealth of the residual residue, even if the time is necessary for the purification.
These technologies applied in the treatment plants have also been improved to increase their performance and, thus, reduce energy consumption.
Thus, a paradigm shift is taking place that consists in ceasing to consider WWTPs as wastewater treatment plants, to considering them plants to extract resources.
What is biotechnology?
In the Convention on Biological Diversity of the United Nations, biotechnology was defined as a new technological application that uses biological systems and living or derivative organisms, for the creation or modification of products or processes for special purposes.
Within these technologies we find bioelectrochemical systems (BES) which are the synergy and combination of a biological process with an electrochemical one, in the same reactor, allowing to improve the performance of current processes, in this specific case, of water treatment from a point of view of specificity and energy efficiency and also opens the door to the recovery of resources.
In other words, two sciences in the treatment of industrial wastewater are coupled: electrochemistry and biotechnology, integrating electrodes within the biological reactor, to recover resources contained in wastewater.
BES technologies integrate electrodes (anode and cathode) within biological reactors.
By means of microorganisms (organic compounds) adhered to the electrodes, the BES catalyze different oxidation and reduction reactions to recover/valorize the resources contained in the wastewater.
The electrons that result from this oxidation are transferred to the anode and used to produce electrical energy.
The new industrial revolution with biotechnology
The main application of biotechnology and the elimination or cleaning of the contamination and attraction of the clean and costly strategy, confront the traditional method of physicochemical measurement.
This new group of innovative technologies means lower consumption of resources associated with its operation.
The fields of application, as they have been collected in the text, include both the recovery of energy and nutrients, as the elimination of pollutants or the conversion of electrical energy into methane, among others.
Currently, although it has been tested on a pilot scale in WWTP, its technical-economic viability has not been demonstrated. However, if this were to be achieved, it would make it possible to reduce the energy consumed in wastewater treatment processes and thus increase the sustainability of the process.
How is biotechnology transforming the industrial sector?
Biotechnology can be applied to treat water and soil, purify water, gaseous effluents, and municipal sewage, in different industrial areas (agribusiness, food industry, some petrochemicals …)
The BES technology analyzes the viability of the use of the product to recover as fertilizer for the agriculture and the reuse of the treated water, through the recovery of ammonium nitrate present in domestic sewage, resulting in the production of fertilizer.
The organic matter in the black water is treated in the anodic chamber of a BES restore. Also, ammonium ions pass through a selective membrane to the cathode chamber where they become ammonia when they are in basic conditions.
In this chamber, a stream of air draws out the ammonia. This stream of air, rich in ammonia, is bubbled into an acid trap, generating a liquid solution of the fertilizer, ammonium nitrate.
Biotechnology in the wastewater treatment
In wastewater treatment, microorganisms degrade organic matter through oxidation that generates electrons, which are used to generate electrical current.
For the rest, the BES system provides an integrated and traditional analogous digestive system, presenting advantage in terms of stabilizing the biological process, increasing the quality and quantity of biogas produced.
On the other hand, BES systems are also being studied as alternative electricity storage systems.
Finally, BES systems are also being studied as alternative electricity storage systems.
In this sense, Power-to-gas technologies, designed to store electrical energy in a gaseous energy vector (hydrogen or methane), are an option to store large amounts of energy.
Specifically, the use of BES, to carry out the conversion of carbon dioxide to methane, a process known as electromethanogenesis, represents a Power-to-gas technology in addition to the existing chemical and biological methanization.
Benefits of biotechnology in water treatment
Using biotechnology in the treatment of industrial wastewater allows:
• Reduce the high costs derived from wastewater treatment with conventional water purification systems.
• Minimize the environmental footprint of companies as a result of industrial activity if it has a place by returning cleaner resources.
• Minimize the consumption of drinking water by reusing the treated water in the production process.
• Reuse the resources obtained in the process, such as other types of energy sources.
MIDES project a case of success
MIDES (Microbial Desalination for Low Energy Drinking Water) is a project that aims to revolutionize the desalination of water to produce drinking water.
Its objective is to develop a more sustainable system for the desalination of saline water with an energy cost, per volume of water produced, significantly lower than the current one.
The strategy to achieve this is to integrate BES systems, in this case, a Microbial Desalination Cell (MDC), as a pre-treatment to the reverse osmosis process with an energy consumption of 3kWh per cubic meter of desalinated water.
In CDM, electrical energy is obtained from the degradation of organic matter contained in wastewater. This electrical energy is used directly in the MDC to reduce the salt content in seawater, through a process similar to electrodialysis, without having to use external electrical energy.
This allows the energy consumption of the global desalination process to be reduced by around 0.5 kWh / m3.
At Amapex we have created a unique biological system for the treatment of industrial wastewater that allows us to create the optimum conditions for the reproduction of organisms, increasing the efficiency of water treatment.
Efficiency translates into a significant reduction in operating costs and a more sustainable process. If you want to know more about this biotechnology system, please contact us.