Develop Photocatalyst-Based Water Treatment Technology

Develop photocatalyst-based water treatment technology for the removal of antibiotic residue in aquaculture water/wastewater

Since antibiotics were introduced for infection control, it has saved countless lives and nowadays, antibiotics are not only used for human healthcare, but expanded to aquaculture and agriculture. The global antimicrobial consumption in aquaculture was projected to reach 13,600 tons by 2030 [1]. The increasing antibiotic use, particularly misuse and overuse has caused water potentially contaminated with antibiotics [2], resulting the antimicrobial resistant risks in the ecosystem, animal, and human health. According to WHO, antimicrobial resistant diseases cause at least 700 thousand dead each year and the number may reach 10 million by 2050 if no action is performed [3].

To prevent antimicrobial resistance, it requires multisectoral actions with different approaches from prevention to remedy methods. Prevention methods such as biosecurity and antibiotic use control help reduce or avoid antibiotic use thereby lessen the risk of antibiotic contamination [4]. However, once antibiotics enter water resources, it can exist for a long time and slowly accumulates in soil and aquatic animals, an important element in the food chain and consequently enhance the antimicrobial resistance. Therefore, it requires effective remedy technologies to remove antibiotic residue from water. Different technologies including adsorption, membrane filtration, advanced oxidation, and biodegradation processes have been considered to remove antibiotics contaminants. Among which advanced oxidation process based on photocatalyst has proved to be the most suitable technology for aquaculture water. This technology can completely degrade antibiotics by light irradiation without the addition of any chemical.

With the support from SEAOHUN via Small Grant Project, a research group from Phenikaa University in Vietnam has successfully developed an advanced oxidation technology based photocatalyst that is able to degrade antibiotics in water. The technology utilized TiO2 as photocatalyst to break down antibiotics and other organic compounds under UV light irradiation. To avoid the release of TiO2 particles into water, TiO2 particles are grafted onto aluminosilicate slabs as a coating layer (Figure 1 a) which can adsorb (Figure 1 b) and degrade organic compounds. A photocatalyst-based water treatment unit as shown in Figure 2 has been developed using the prepared TiO2 coated aluminosilicate slabs. A major part of water treatment unit is a tubular reactor packed with TiO2 coated aluminosilicate slabs.

Figure 1. TiO2 coated aluminosilicate slab (a) and microscopic image showing the adsorption of methylene blue dye by coating layer (b)

Figure 2. Fabricating the photocatalyst-based water treatment unit for the organic pollutant removal. The unit can degrade >60% antibiotics contaminant with the treatment capacity from 20 to 100 L/h. This system can be easily scaled up by assembling multiple units and retrofitted to existing water treatment system. Compared to conventional technologies that based on adsorption or microbiological degradation, this technology does not generate waste because organic compounds could be degraded completely to mineral compounds like water and CO2. To further explore the potential application of the technology, it is being demonstrated with different types of water and wastewater.

References

[1] Schar, D., Klein, E. Y., Laxminarayan, R., Gilbert, M. &Van Boeckel, T. P. (2020). Global trends in antimicrobial use in aquaculture. Scientific Reports 10(1): 21878.

[2] O'Neill, J. (2016). Tackling drug-resistant infections globally: final report and recommendations, Review on Antimicrobial Resistance.

[3] WHO (2019). New report calls for urgent action to avert antimicrobial resistance crisis, https://www.who.int/news/item/29-04-2019-new-report-calls-for-urgent-action-to-avert-antimicrobial-resistance-crisis cited on 4/3/2022.

[4] WHO (2020). Antibiotic resistance, https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance cited on 4/3/2022.

SEAOHUN 2022 Small Grants

Project team leader: Dang Viet Quang

Team members: Ran Van Tan, Phenikaa University. Than Van Thai, Phenikaa University. Hoang Hiep, Vietnam University of Agriculture

- Personal protective equipment, distancing, and group size standards in this photo were consistent with local public health guidance and COVID-19 status in the specific country and time it was taken. This may not reflect best practices for all locations where COVID-19 is still spreading. -