Until recently, the vast amount of human-generated wastewater, from urine and domestic sewage to industrial wastewater, has simply been considered waste in need of treatment. This aforementioned “waste” is now receiving renewed attention for the resources and energy it could potentially provide. Just a few examples of this include the rare metals that could be extracted from industrial wastewater and the electrolytes within urine that can be utilized to generate electricity.

The Lab on Chemical Redox Acceleration Technologies for Water Quality or CREATE WQ Lab led by Professor Kangwoo Cho at the Department of Environmental Science and Engineering, POSTECH, is developing catalysts and processes to convert wastewater into clean water and viable energy. Researchers at the Lab work to purify wastewater from pollutants while harvesting useful energy and materials at more expedient speeds.

Work is underway at the CREATE WQ Lab to use wastewater in lieu of clean water as electrolytes to instantly treat water. Under this wastewater electrolysis process, the use of wastewater as electrolytes results in the generation of useful reactive oxygen species including hydroxyl radical as intermediates instead of oxygen. Meanwhile, chlorine ions, when oxidized, produce reactive oxygen species and they make up one of the main components of the commonly-known household cleanser, bleach. If these ions could be generated in place of oxygen, they could be used to sterilize pollutants in wastewater. When paired with renewable energy, it even becomes possible to produce hydrogen all while treating water.

The Lab is also developing wastewater fuel cell technology to generate electricity from wastewater. Essentially, this technology recognizes substances in wastewater that contain energy as potential fuel. Fabricating electrodes from activated carbon used for water treatment triggers a process in the wastewater where positive ions seamlessly move to the cathode while negative ions move to the anode. This process eventually charges the battery and the electricity generated can be reused to isolate pollutants or to separate and enrich such high-priced metals as lithium and transform them into valuable resources.

Such technologies are finding their way into real-life applications. The CREATE WQ Lab is collaborating with Samsung Electronics to help the company navigate greater alignment with increasingly tightening environmental regulatory frameworks. The semiconductor manufacturing process consumes a tremendous amount of water, and it naturally generates different types of wastewater. While all wastewater is currently being treated in accordance with applicable regulations, the company and the Lab are looking ahead to prepare for any new regulations that will be introduced down the road. Furthermore, water treatment technology is a prerequisite for plant expansion which will inevitably increase water needs. While nearby water resources are limited, technology that would enable water to be reused on a continual basis can address such situations.

In the film Martian, the main character, after being left for dead on Mars, successfully cultivates a potato crop on the red planet using the bio-waste of his fellow crew as fertilizers. In harnessing hydrogen as a catalyst to trigger hydrogen-oxygen reactions, he makes water and grow potatoes. Professor Cho reminds us that the same principle applies when such examples are scaled up on a planetary level, commenting “Our ultimate aim at the Lab is to discover methods of leveraging limited energy and resources in a more efficient manner”.