Biosensors for rapid and continuous analysis of oxygen demand

29/12/2021

Clean water is not an inexhaustible resource, while it is an essential part of all production and human activities. Recently, population growth and economic development accompanied by climate change leave clean water sources even more at risk of being depleted. In addition, in the face of the increasing risk of the presence of harmful pollutants in the wastewater streams after treatment, developing analytical techniques at a reasonable cost to quickly assess the quality of wastewater treatment is becoming more and more urgent.

In recent years, scientists have focused on studying analytical techniques using biological agents as a sensor to quickly determine the quality of wastewater. However, in Vietnam at present, research on biosensors applied in wastewater quality assessment in general is still quite limited. The Project "Research on manufacture of biosensors applied in rapid and continuous analysis of biochemical oxygen demand (BOD)" code VAST07.01/19-20 led by Dr. Pham Thi Thuy Phuong, the Institute of Chemical Technology, was implemented with the goal of developing a new low-cost bioreactor-based biosensor to quickly determine the BOD value of wastewater, helping to monitor the environment more favorably. The topic has been accepted and rated as Excellent.

The project has successfully researched and fabricated biosensors for rapid and continuous analysis of biochemical oxygen demand, achieving the following results:

BOD analysis time on biosensor is shortened by about 10 minutes thanks to semi-continuous operation. Accordingly, the measurement time is reduced compared to the continuous method and allows the determination of the BOD value in real time.

It successfully developed a simple method and materials, in particular a bioreactor designed and manufactured in the style of PBBR - Packed-bed Bioreactor. Thereby, PBBR can be implemented at the place of operation, in order to manufacture biosensors at low cost using available components and equipment assemblies in the domestic market.

The biosensor can operate stably and continuously for 20 hours and then needs to be recalibrated for continued use. PBBR can be stored by saturated aeration to stabilize the microbiome for about 2 weeks when not in use.

The project has also built the complete software to receive and process the results of biosensor operation, demonstrating the ability to quickly determine BOD5 in aquatic wastewater and canal water in the inner city of Ho Chi Minh City, with the largest coefficient of variation of < 10% (traditional BOD5 measurement method < 20%), and there is no statistical difference between the two measurements when using model wastewater according to the formula from the Organization for Economic Cooperation and Development (OECD) as standard solution.

Although the project has achieved certain successes in the fabrication and application of BOD biosensor, the research team wishes to continue receiving support to develop this research direction so that the product can be deployed in practice.